WorldWideScience

Sample records for magnetoelectricity

  1. Magnetoelectricity in composites

    CERN Document Server

    Bichurin, Mirza

    2011-01-01

    Magnetoelectric composites, which simultaneously exhibit ferroelectricity and ferromagnetism, have recently stimulated a sharply increasing number of research activities for their scientific interest and significant technological promise in the novel multifunctional devices. Natural single-phase compounds are rare, and their magnetoelectric responses are either relatively weak or occurs at temperatures too low for practical applications. In contrast, composites, which incorporate both ferroelectric and ferri-/ferromagnetic phases, typically yield giant magnetoelectric coupling response above r

  2. Magnetoelectric Energy Harvesting

    Science.gov (United States)

    2014-11-20

    zirconate titanate ( PZT ). The non-linear electromechanically coupled phase transition associated with field and stress driven phase transformations...The magnetoelectric coefficient , ME, as estimated from experimental results is: = > 40 × (1) where E is the electric

  3. Magnetoelectric effect in metal–PZT laminates

    Indian Academy of Sciences (India)

    Magnetoelectric (ME) composites are two-phase composites consisting of piezoelectric and piezomagnetic materials as the participating constituents. These magnetoelectric composites when placed under external magnetic field, show electrical polarization (magnetoelectric output). The ME coupling is mediated by ...

  4. Magnetoelectric Jones dichroism

    International Nuclear Information System (INIS)

    Andrews, D L; Daniels, G J; Stedman, G E

    2003-01-01

    Recent work on liquids has verified a novel magnetoelectrical birefringence predicted by Jones. Co-present static electric and magnetic fields generate a differential response to optical polarizations positively or negatively tilted against a plane orthogonal to the one containing the static field vectors. Reports indicated a dichroic counterpart; establishing its theory is the present aim. Results are trilinearly dependent on the irradiance, and the static electric and magnetic fields. For isotropic fluids a scalar quantifies propensity for Jones dichroism. In field-polarized fluids a second scalar also contributes; temperature dependence enables determination of both parameters. (letter to the editor)

  5. Additional magnetoelectric effect in electrode-arrayed magnetoelectric composite

    Directory of Open Access Journals (Sweden)

    D. A. Pan

    2014-11-01

    Full Text Available An electrode-arrayed magnetoelectric (ME composite was proposed, in which the positive and negative electrodes of the PZT-5H plate (Pb(Zr0.52Ti0.48O3 were equally divided into a 2 × 5 array, while the PZT plate remained intact. The ME voltage coefficients of these 10 sections were measured individually and in parallel/series modes. The magnetoelectric coefficient is doubled compared with un-arrayed condition, when the 10 sections are connected in parallel/series using an optimized connecting sequence derived from the charge matching rule. This scheme can also be applied to other types of layered magnetoelectric composites to obtain additional magnetoelectric effect from the original composite structure.

  6. Magnetoelectric effects in manganites

    Science.gov (United States)

    Jeen, Hyoung Jeen

    Research on manganites has been conducted for more than half century. Recent discoveries of colossal responses to external fields such as colossal magnetoresistance effects and correlation among spin, orbital, and lattice in phase separated manganites and multiferroic manganites have motivated me to understand these materials. The main purpose of this dissertation is to understand magnetoelectric effects in phase separated (La1-yPr y)1-xCaxMnO3 (LPCMO) thin films and multiferroic BiMnO3 (BMO) thin films. First, high quality phase separated manganite thin films have been successfully grown. To grow the high quality manganite thin films, extensive effort was devoted to fine tuning of oxygen pressure, temperature, and laser fluence during film growth. As-grown films were characterized with various ex-situ techniques: magnetization measurements, transport measurements, x-ray diffraction, atomic force microscopy, and/or transmission electron microscopy to remove the effects of impurities and unwanted strains except substrate induced strain. Second, three major results were obtained in high quality phase separated LPCMO thin films. These results are based on the dynamic nature of phases in LPCMO. 1) LPCMO thin films showed single domain to multi-domain transition during cooling. This transition can be tuned by substrate stress induced in-plane magnetic anisotropy. 2) Evidence for the origin of colossal electroresistance (CER) effect has been observed. The CER is triggered by dielectrophoresis, or movements of ferromagnetic metallic (FMM) phase, which is manifested in anisotropic transport properties in microfabricated LPCMO cross structures. This fluidic nature of the FMM phase in LPCMO under high electric fields lead to exotic magnetoelectric effects. 3) Electric field effects on magnetotransport properties have been observed. This phenomena can also be tuned by the combined effect of substrate strain and current flow. This combined effect of electric and magnetic

  7. Magnetoelectric control of spin currents

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, J. E.; Vargas, J. M.; Avilés-Félix, L.; Butera, A. [Centro Atómico Bariloche, Instituto de Nanociencia y Nanotecnología (CNEA) and Conicet, 8400 Bariloche, Río Negro (Argentina)

    2016-06-13

    The ability to control the spin current injection has been explored on a hybrid magnetoelectric system consisting of a (011)-cut ferroelectric lead magnesium niobate-lead titanate (PMNT) single crystal, a ferromagnetic FePt alloy, and a metallic Pt. With this PMNT/FePt/Pt structure we have been able to control the magnetic field position or the microwave excitation frequency at which the spin pumping phenomenon between FePt and Pt occurs. We demonstrate that the magnetoelectric heterostructure operating in the L-T (longitudinal magnetized-transverse polarized) mode couples the PMNT crystal to the magnetostrictive FePt/Pt bilayer, displaying a strong magnetoelectric coefficient of ∼140 Oe cm kV{sup −1}. Our results show that this mechanism can be effectively exploited as a tunable spin current intensity emitter and open the possibility to create an oscillating or a bistable switch to effectively manipulate spin currents.

  8. Acoustic wave coupled magnetoelectric effect

    International Nuclear Information System (INIS)

    Gao, J.S.; Zhang, N.

    2016-01-01

    Magnetoelectric (ME) coupling by acoustic waveguide was developed. Longitudinal and transversal ME effects of larger than 44 and 6 (V cm −1 Oe −1 ) were obtained with the waveguide-coupled ME device, respectively. Several resonant points were observed in the range of frequency lower than 47 kHz. Analysis showed that the standing waves in the waveguide were responsible for those resonances. The frequency and size dependence of the ME effects were investigated. A resonant condition about the geometrical size of the waveguide was obtained. Theory and experiments showed the resonant frequencies were closely influenced by the diameter and length of the waveguide. A series of double-peak curves of longitudinal magnetoelectric response were obtained, and their significance was discussed initially. - Highlights: • Magnetoelectric (ME) coupling by acoustic waveguide was developed. • The frequency and size dependence of the ME effects were investigated. • A resonant condition about the geometrical size of the waveguide was obtained. • A series of double-peak curves of longitudinal magnetoelectric response were obtained, and their significance was discussed initially.

  9. Conductivity, dielectric behaviour and magnetoelectric effect in ...

    Indian Academy of Sciences (India)

    intensity of the magnetic field. The maximum value of ME coefficient was observed for 75% ferroelectric phase composite. Keywords. Conductivity; dielectric behaviour; magnetoelectric effect; CuFe2O4; BaTiO3. 1. Introduction. Magnetoelectric composites consist of two phases viz. piezoelectric and piezomagnetic. The ME ...

  10. Magnetoelectric Nanocomposites for Flexible Electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-09-01

    Flexibility, low cost, versatility, miniaturization and multi-functionality are key aspects driving research and innovation in many branches of the electronics industry. With many anticipated emerging applications, like wearable, transparent and biocompatible devices, interest among the research community in pursuit for novel multifunctional miniaturized materials have been amplified. In this context, multiferroic polymer-based nanocomposites, possessing both ferroelectricity and ferromagnetism, are highly appealing. Most importantly, these nanocomposites possess tunable ferroelectric and ferromagnetic properties based on the parameters of their constituent materials as well as the magnetoelectric effect, which is the coupling between electric and magnetic properties. This tunability and interaction is a fascinating fundamental research field promising tremendous potential applications in sensors, actuators, data storage and energy harvesting. This dissertation work is devoted to the investigation of a new class of multiferroic polymer-based flexible nanocomposites, which exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature, with the goal of understanding and optimizing the origin of their magnetoelectric coupling. The nanocomposites consist of high aspect ratio ferromagnetic nanowires (NWs) embedded inside a ferroelectric co-polymer, poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE) matrix. First, electrochemical deposition of ferromagnetic NWs inside anodic aluminum oxide membranes is discussed. Characterization of electrodeposited iron, nickel and highly magnetostrictive iron-gallium alloy NWs was done using XRD, electron and magnetic force microscopy. Second, different nanocomposite films have been fabricated by means of spin coating and drop casting techniques. The effect of incorporation of NWs inside the ferroelectric polymer on its electroactive phase is discussed. The remanent and saturation polarization as well

  11. Tunable features of magnetoelectric transformers.

    Science.gov (United States)

    Dong, Shuxiang; Zhai, Junyi; Priya, Shashank; Li, Jie-Fang; Viehland, Dwight

    2009-06-01

    We have found that magnetostrictive FeBSiC alloy ribbons laminated with piezoelectric Pb(Zr,Ti)O(3) fiber can act as a tunable transformer when driven under resonant conditions. These composites were also found to exhibit the strongest resonant magnetoelectric voltage coefficient of 750 V/cm-Oe. The tunable features were achieved by applying small dc magnetic biases of -5 transformer features can be attributed to large changes in the piezomagnetic coefficient and permeability of the magnetostrictive phase under H(dc).

  12. Magnetoelectric polymer nanocomposite for flexible electronics

    International Nuclear Information System (INIS)

    Alnassar, M.; Alfadhel, A.; Ivanov, Yu. P.; Kosel, J.

    2015-01-01

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites

  13. Magnetoelectric polymer nanocomposite for flexible electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-03-06

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites.

  14. Magnetoelectric polymer nanocomposite for flexible electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.; Alfadhel, Ahmed; Ivanov, Yurii P.; Kosel, Jü rgen

    2015-01-01

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites.

  15. Theory of orbital magnetoelectric response

    International Nuclear Information System (INIS)

    Malashevich, Andrei; Souza, Ivo; Coh, Sinisa; Vanderbilt, David

    2010-01-01

    We extend the recently developed theory of bulk orbital magnetization to finite electric fields, and use it to calculate the orbital magnetoelectric (ME) response of periodic insulators. Working in the independent-particle framework, we find that the finite-field orbital magnetization can be written as a sum of three gauge-invariant contributions, one of which has no counterpart at zero field. The extra contribution is collinear with and explicitly dependent on the electric field. The expression for the orbital magnetization is suitable for first-principles implementations, allowing one to calculate the ME response coefficients by numerical differentiation. Alternatively, perturbation-theory techniques may be used, and for that purpose we derive an expression directly for the linear ME tensor by taking the first field-derivative analytically. Two types of terms are obtained. One, the 'Chern-Simons' term, depends only on the unperturbed occupied orbitals and is purely isotropic. The other, 'Kubo' terms, involve the first-order change in the orbitals and give isotropic as well as anisotropic contributions to the response. In ordinary ME insulators all terms are generally present, while in strong Z 2 topological insulators only the Chern-Simons term is allowed, and is quantized. In order to validate the theory, we have calculated under periodic boundary conditions the linear ME susceptibility for a 3D tight-binding model of an ordinary ME insulator, using both the finite-field and perturbation-theory expressions. The results are in excellent agreement with calculations on bounded samples.

  16. Colossal magnetodielectric effect caused by magnetoelectric effect ...

    Indian Academy of Sciences (India)

    -D laminate composite under low magnetic field. When the composite is placed in an external a.c. magnetic field, magnetoelectric effect is produced, as a result, the dielectric properties of the Pb(Zr,Ti)O3 is changed, i.e. magnetodielectric effect ...

  17. Colossal magnetodielectric effect caused by magnetoelectric effect ...

    Indian Academy of Sciences (India)

    The colossal magnetodielectric effect is reported in Pb(Zr,Ti)O3/Terfenol-D laminate composite under low magnetic field. When the composite is placed in an external a.c. magnetic field, magnetoelectric effect is produced, as a result, the dielectric properties of the Pb(Zr,Ti)O3 is changed, i.e. magnetodielectric effect. Both the ...

  18. Linear Magnetoelectric Effect by Orbital Magnetism

    NARCIS (Netherlands)

    Scaramucci, A.; Bousquet, E.; Fechner, M.; Mostovoy, M.; Spaldin, N. A.

    2012-01-01

    We use symmetry analysis and first-principles calculations to show that the linear magnetoelectric effect can originate from the response of orbital magnetic moments to the polar distortions induced by an applied electric field. Using LiFePO4 as a model compound we show that spin-orbit coupling

  19. Bias magnetic field and test period dependences of direct and converse magnetoelectric hysteresis of tri-layered magnetoelectric composite

    Science.gov (United States)

    Zhou, Yun; Li, Xiao-Hong; Wang, Jian-Feng; Zhou, Hao-Miao; Cao, Dan; Jiao, Zhi-Wei; Xu, Long; Li, Qi-Hao

    2018-04-01

    The direct and converse magnetoelectric hysteresis behavior for a tri-layered composite has been comparatively investigated and significant similarities have been observed. The results show that both the direct and converse magnetoelectric hysteresis is deeply affected by the bias magnetic field and test period. The test time hysteresis caused by a fast varying bias magnetic field can be reduced by prolonging the test period. The observed coercive field, remanence, and ratio of remanence of the direct and converse magnetoelectric effects with the test period obey an exponential decay law. A hysteretic nonlinear magnetoelectric theoretical model for the symmetrical tri-layered structure has been proposed based on a nonlinear constitutive model and pinning effect. The numerical calculation shows that the theoretical results are in good agreement with the experimental results. These findings not only provide insight into the examination and practical applications of magnetoelectric materials, but also propose a theoretical frame for studying the hysteretic characteristics of the magnetoelectric effect.

  20. Equivalent circuit method research of resonant magnetoelectric characteristic in magnetoelectric laminate composites using nonlinear magnetostrictive constitutive model

    International Nuclear Information System (INIS)

    Zhou, Hao-Miao; Li, Chao; Xuan, Li-Ming; Zhao, Ji-Xiang; Wei, Jing

    2011-01-01

    This paper analyzes the magnetoelectric (ME) response around the resonance frequency in the magnetostrictive/piezoelectric/magnetostrictive (MPM) magnetoelectric laminate composites. Following the equivalent circuit method and considering the mechanical loss, we select the nonlinear magnetostrictive constitutive model to present a novel explicit nonlinear expression for the resonant magnetoelectric (ME) coefficient of the magnetoelectric laminate composites. Compared with the experimental results, the predicted resonant ME coefficient of the explicit expression shows a good agreement both qualitatively and quantitatively. Also, when the electromechanical coupling factor of the piezoelectric material, k 31 p , is small, this explicit expression can be reduced to the existing model. On this basis, this paper considers and predicts the magnetoelectric conversion characteristics of the magnetoelectric laminate composites, calculates and analyzes the influences of the thickness ratio of magnetostrictive layer and piezoelectric material, bias magnetic field, and saturation magnetostrictive coefficient on the resonant ME coefficient. This research can provide a theoretical basis for the preparation of magnetoelectric devices with good magnetoelectric conversion characteristics, such as magnetoelectric sensors, energy harvesting transducers, microwave devices etc

  1. Development of magnetoelectric nanocomposite for soft technology

    Science.gov (United States)

    Bitla, Yugandhar; Chu, Ying-Hao

    2018-06-01

    The proliferation of flexible and stretchable electronics has led to substantial advancements in principles, material combinations and technologies. The integration of magnetoelectric systems in soft electronics is inevitable by virtue of their extensive applications. Recently, 2D layered materials have emerged as potential candidates due to their excellent flexibility and atomic-scale thickness scalability in addition to their interesting physics. This paper presents a new perspective on the development of magnetoelectric nanocomposites through materials engineering on a pliant mica with excellent mechanical, thermal and chemical stabilities. The unique features of 2D muscovite mica and the power of van der Waals epitaxy are expected to contribute significantly to the emerging transparent soft-technology research applications.

  2. Magneto-Electric Dipole Antenna Arrays

    OpenAIRE

    Gupta, Shulabh; Jiang, Li Jun; Caloz, Christophe

    2014-01-01

    A planar magneto-electric (ME) dipole antenna array is proposed and demonstrated by both full-wave analysis and experiments. The proposed structure leverages the infinite wavelength propagation characteristic of composite right/left-handed (CRLH) transmission lines to form high-gain magnetic radiators combined with radial conventional electric radiators, where the overall structure is excited by a single differential feed. The traveling-wave type nature of the proposed ME-dipole antenna enabl...

  3. Temperature Dependence of the Resonant Magnetoelectric Effect in Layered Heterostructures

    Directory of Open Access Journals (Sweden)

    Dmitrii A. Burdin

    2017-10-01

    Full Text Available The dependence of the resonant direct magnetoelectric effect on temperature is studied experimentally in planar composite structures. Samples of rectangular shapes with dimensions of 5 mm × 20 mm employed ferromagnetic layers of either an amorphous (metallic glass alloy or nickel with a thickness of 20–200 μm and piezoelectric layers of single crystalline langatate material or lead zirconate titanate piezoelectric ceramics with a thickness of 500 μm. The temperature of the samples was varied in a range between 120 and 390 K by blowing a gaseous nitrogen stream around them. It is shown that the effective characteristics of the magnetoelectric effect—such as the mechanical resonance frequency fr, the quality factor Q and the magnitude of the magnetoelectric coefficient αE at the resonance frequency—are contingent on temperature. The interrelations between the temperature changes of the characteristics of the magnetoelectric effect and the temperature variations of the following material parameters—Young’s modulus Y, the acoustic quality factor of individual layers, the dielectric constant ε, the piezoelectric modulus d of the piezoelectric layer as well as the piezomagnetic coefficients λ(n of the ferromagnetic layer—are established. The effect of temperature on the characteristics of the nonlinear magnetoelectric effect is observed for the first time. The results can be useful for designing magnetoelectric heterostructures with specified temperature characteristics, in particular, for the development of thermally stabilized magnetoelectric devices.

  4. Multifunctional magnetoelectric materials for device applications

    International Nuclear Information System (INIS)

    Ortega, N; Katiyar, Ram S; Kumar, Ashok; Scott, J F

    2015-01-01

    Over the past decade magnetoelectric (ME) mutiferroic (MF) materials and their devices are one of the highest priority research topics that has been investigated by the scientific ferroics community to develop the next generation of novel multifunctional materials. These systems show the simultaneous existence of two or more ferroic orders, and cross-coupling between them, such as magnetic spin, polarisation, ferroelastic ordering, and ferrotoroidicity. Based on the type of ordering and coupling, they have drawn increasing interest for a variety of device applications, such as magnetic field sensors, nonvolatile memory elements, ferroelectric photovoltaics, nano-electronics etc. Since single-phase materials exist rarely in nature with strong cross-coupling properties, intensive research activity is being pursued towards the discovery of new single-phase multiferroic materials and the design of new engineered materials with strong magneto-electric (ME) coupling. This review article summarises the development of different kinds of multiferroic material: single-phase and composite ceramic, laminated composite and nanostructured thin films. Thin-film nanostructures have higher magnitude direct ME coupling values and clear evidence of indirect ME coupling compared with bulk materials. Promising ME coupling coefficients have been reported in laminated composite materials in which the signal to noise ratio is good for device fabrication. We describe the possible applications of these materials. (topical review)

  5. Terahertz Magnetoelectric Resonance Enhanced by Mutual Coupling of Electromagnons

    Science.gov (United States)

    Takahashi, Y.; Yamasaki, Y.; Tokura, Y.

    2013-07-01

    Both electric- and magnetic-dipole active spin excitations, i.e., electromagnons, which mediate the dynamical magnetoelectric effect, have been investigated for a multiferroic perovskite of manganite by optical spectroscopy at terahertz frequencies. Upon the magnetoelectric resonance at 1 meV in the multiferroic phase with the bc-plane spin cycloidal order, a gigantic dynamical magnetoelectric effect has been observed as a nonreciprocal directional dichroism or birefringence. The light k-vector-dependent difference (Δκ=κ+-κ-) of the extinction coefficient (κ±) is as large as Δκ˜1 or 2Δκ/(κ++κ-)˜0.7 at the lowest-lying electromagnon energy. We clarified the mutual coupling of the Eω∥a-polarized electromagnons of the different origins, leading to the enhancement of the magnetoelectric resonance.

  6. Deposition of magnetoelectric hexaferrite thin films on substrates of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zare, Saba; Izadkhah, Hessam; Vittoria, Carmine

    2016-12-15

    Magnetoelectric M-type hexaferrite thin films (SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19}) were deposited using Pulsed Laser Deposition (PLD) technique on Silicon substrate. A conductive oxide layer of Indium-Tin Oxide (ITO) was deposited as a buffer layer with the dual purposes of 1) to reduce lattice mismatch between the film and silicon and 2) to lower applied voltages to observe magnetoelectric effects at room temperature on Silicon based devices. The film exhibited magnetoelectric effects as confirmed by vibrating sample magnetometer (VSM) techniques in voltages as low as 0.5 V. Without the oxide conductive layer the required voltages to observe magnetoelectric effects was typically about 1000 times larger. The magnetoelectric thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance techniques. We measured saturation magnetization of 650 G, and coercive field of about 150 Oe for these thin films. The change in remanence magnetization was measured in the presence of DC voltages and the changes in remanence were in the order of 15% with the application of only 0.5 V (DC voltage). We deduced a magnetoelectric coupling, α, of 1.36×10{sup −9} s m{sup −1} in SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} thin films.

  7. Size effects on magnetoelectric response of multiferroic composite with inhomogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Y.M. [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Department of Mechanics, Shanghai University, Shanghai 200072 (China); Xu, K.Y., E-mail: kyxu@shu.edu.cn [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Department of Mechanics, Shanghai University, Shanghai 200072 (China); Chen, T. [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Department of Mechanics, Shanghai University, Shanghai 200072 (China); Aifantis, E.C. [Laboratory of Mechanics and Materials (LMM), Aristotle University of Thessaloniki, Thessaloniki GR-54124 (Greece); Michigan Technological University, Houghton, MI 49931 (United States); King Abdulaziz University, Jeddah 21589 (Saudi Arabia); School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, 610031 (China); International Laboratory for Modern Functional Materials, ITMO University, St. Petersburg 191002 (Russian Federation)

    2015-12-01

    This paper investigates the influence of size effects on the magnetoelectric performance of multiferroic composite with inhomogeneities. Based on a simple model of gradient elasticity for multiferroic materials, the governing equations and boundary conditions are obtained from an energy variational principle. The general formulation is applied to consider an anti-plane problem of multiferroic composites with inhomogeneities. This problem is solved analytically and the effective magnetoelectric coefficient is obtained. The influence of the internal length (grain size or particle size) on the effective magnetoelectric coefficients of piezoelectric/piezomagnetic nanoscale fibrous composite is numerically evaluated and analyzed. The results suggest that with the increase of the internal length of piezoelectric matrix (PZT and BaTiO{sub 3}), the magnetoelectric coefficient increases, but the rate of increase is ratcheting downwards. If the internal length of piezoelectric matrix remains unchanged, the magnetoelectric coefficient will decrease with the increase of internal length scale of piezomagnetic nonfiber (CoFe{sub 2}O{sub 3}). In a composite consisiting of a piezomagnetic matrix (CoFe{sub 2}O{sub 3}) reinforced with piezoelectric nanofibers (BaTiO{sub 3}), an increase of the internal length in the piezomagnetic matrix, results to a decrease of the magnetoelectric coefficient, with the rate of decrease diminishing.

  8. Size effects on magnetoelectric response of multiferroic composite with inhomogeneities

    Science.gov (United States)

    Yue, Y. M.; Xu, K. Y.; Chen, T.; Aifantis, E. C.

    2015-12-01

    This paper investigates the influence of size effects on the magnetoelectric performance of multiferroic composite with inhomogeneities. Based on a simple model of gradient elasticity for multiferroic materials, the governing equations and boundary conditions are obtained from an energy variational principle. The general formulation is applied to consider an anti-plane problem of multiferroic composites with inhomogeneities. This problem is solved analytically and the effective magnetoelectric coefficient is obtained. The influence of the internal length (grain size or particle size) on the effective magnetoelectric coefficients of piezoelectric/piezomagnetic nanoscale fibrous composite is numerically evaluated and analyzed. The results suggest that with the increase of the internal length of piezoelectric matrix (PZT and BaTiO3), the magnetoelectric coefficient increases, but the rate of increase is ratcheting downwards. If the internal length of piezoelectric matrix remains unchanged, the magnetoelectric coefficient will decrease with the increase of internal length scale of piezomagnetic nonfiber (CoFe2O3). In a composite consisiting of a piezomagnetic matrix (CoFe2O3) reinforced with piezoelectric nanofibers (BaTiO3), an increase of the internal length in the piezomagnetic matrix, results to a decrease of the magnetoelectric coefficient, with the rate of decrease diminishing.

  9. Moving towards the magnetoelectric graphene transistor

    International Nuclear Information System (INIS)

    Cao, Shi; Xiao, Zhiyong; Kwan, Chun-Pui; Zhang, Kai; Bird, Jonathan P.

    2017-01-01

    Here, the interfacial charge transfer between mechanically exfoliated few-layer graphene and Cr 2 O 3 (0001) surfaces has been investigated. Electrostatic force microscopy and Kelvin probe force microscopy studies point to hole doping of few-layer graphene, with up to a 150 meV shift in the Fermi level, an aspect that is confirmed by Raman spectroscopy. Density functional theory calculations furthermore confirm the p-type nature of the graphene/chromia interface and suggest that the chromia is able to induce a significant carrier spin polarization in the graphene layer. A large magnetoelectrically controlled magneto-resistance can therefore be anticipated in transistor structures based on this system, a finding important for developing graphene-based spintronic applications.

  10. Mesoscale Interfacial Dynamics in Magnetoelectric Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Shashank, Priya [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2009-12-14

    Biphasic composites are the key towards achieving enhanced magnetoelectric response. In order understand the control behavior of the composites and resultant symmetry of the multifunctional product tensors, we need to synthesized model material systems with the following features (i) interface formation through either deposition control or natural decomposition; (ii) a very high interphase-interfacial area, to maximize the ME coupling; and (iii) an equilibrium phase distribution and morphology, resulting in preferred crystallographic orientation relations between phases across the interphase-interfacial boundaries. This thought process guided the experimental evolution in this program. We initiated the research with the co-fired composites approach and then moved on to the thin film laminates deposited through the rf-magnetron sputtering and pulsed laser deposition process

  11. Multiferroics and magnetoelectrics: thin films and nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Martin, L W; Crane, S P; Chu, Y-H; Holcomb, M B; Gajek, M; Huijben, M; Yang, C-H; Balke, N; Ramesh, R [Department of Materials Science and Engineering, University of California, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: lwmartin@lbl.gov

    2008-10-29

    Multiferroic materials, or materials that simultaneously possess two or more ferroic order parameters, have returned to the forefront of materials research. Driven by the desire to achieve new functionalities-such as electrical control of ferromagnetism at room temperature-researchers have undertaken a concerted effort to identify and understand the complexities of multiferroic materials. The ability to create high quality thin film multiferroics stands as one of the single most important landmarks in this flurry of research activity. In this review we discuss the basics of multiferroics including the important order parameters and magnetoelectric coupling in materials. We then discuss in detail the growth of single phase, horizontal multilayer, and vertical heterostructure multiferroics. The review ends with a look to the future and how multiferroics can be used to create new functionalities in materials.

  12. Multiferroics and magnetoelectrics: thin films and nanostructures

    Science.gov (United States)

    Martin, L. W.; Crane, S. P.; Chu, Y.-H.; Holcomb, M. B.; Gajek, M.; Huijben, M.; Yang, C.-H.; Balke, N.; Ramesh, R.

    2008-10-01

    Multiferroic materials, or materials that simultaneously possess two or more ferroic order parameters, have returned to the forefront of materials research. Driven by the desire to achieve new functionalities—such as electrical control of ferromagnetism at room temperature—researchers have undertaken a concerted effort to identify and understand the complexities of multiferroic materials. The ability to create high quality thin film multiferroics stands as one of the single most important landmarks in this flurry of research activity. In this review we discuss the basics of multiferroics including the important order parameters and magnetoelectric coupling in materials. We then discuss in detail the growth of single phase, horizontal multilayer, and vertical heterostructure multiferroics. The review ends with a look to the future and how multiferroics can be used to create new functionalities in materials.

  13. Multiferroics and magnetoelectrics: thin films and nanostructures

    International Nuclear Information System (INIS)

    Martin, L W; Crane, S P; Chu, Y-H; Holcomb, M B; Gajek, M; Huijben, M; Yang, C-H; Balke, N; Ramesh, R

    2008-01-01

    Multiferroic materials, or materials that simultaneously possess two or more ferroic order parameters, have returned to the forefront of materials research. Driven by the desire to achieve new functionalities-such as electrical control of ferromagnetism at room temperature-researchers have undertaken a concerted effort to identify and understand the complexities of multiferroic materials. The ability to create high quality thin film multiferroics stands as one of the single most important landmarks in this flurry of research activity. In this review we discuss the basics of multiferroics including the important order parameters and magnetoelectric coupling in materials. We then discuss in detail the growth of single phase, horizontal multilayer, and vertical heterostructure multiferroics. The review ends with a look to the future and how multiferroics can be used to create new functionalities in materials.

  14. Surfaces and Interfaces of Magnetoelectric Oxide Systems

    Science.gov (United States)

    Cao, Shi

    Magnetoelectric materials Cr2O3, hexagonal LuFeO 3 and YbFeO3 are studied in this thesis. The surface of chromia (Cr2O3) has a surface electronic structure distinct from the bulk. Our work shows that placing a Cr2O3 single crystal into a single domain state will result in net Cr2O 3 spin polarization at the boundary, even in the presence of a gold overlayer. From the Cr 2p3/2 X-ray magnetic circular dichroism signal, there is clear evidence of interface polarization with overlayers of both Pd and Pt on chromia. Cobalt thin films on Cr2O3(0001) show larger magnetic contrast in magnetic force microscopy indicating enhancement of perpendicular anisotropy induced by Cr2O3. The interfacial charge transfer between mechanically exfoliated few-layer graphene and Cr2O3(0001) surfaces has been investigated showing hole doping of few-layer graphene. Density functional theory calculations furthermore confirm the p-type nature of the graphene on top of chromia, and suggest that the chromia is able to induce a significant carrier spin polarization in the graphene layer. The surface termination and the nominal valence states for hexagonal LuFeO3 thin films were characterized. The stable surface terminates in a Fe-O layer. This is consistent wit the results of density functional calculations. The structural transition at about 1000 °C, from the hexagonal to the orthorhombic phase of LuFeO3, has been investigated in thin films of LuFeO3. The electronic structure for the conduction bands of both hexagonal and orthorhombic LuFeO3 thin films have been measured. Dramatic differences in both the spectral features and the linear dichroism are observed. We have also studied the ferrimagnetism in h-YbFeO3 by measuring the magnetization of Fe and Yb separately. The results directly show antialignment of magnetization of Yb and Fe ions in h-YbFeO3 at low temperature, with an exchange field on Yb of about 17 kOe. All ferrimagnets, by default, are magnetoelectrics. These findings directly

  15. Self-Biased 215MHz Magnetoelectric NEMS Resonator for Ultra-Sensitive DC Magnetic Field Detection

    Science.gov (United States)

    Nan, Tianxiang; Hui, Yu; Rinaldi, Matteo; Sun, Nian X.

    2013-06-01

    High sensitivity magnetoelectric sensors with their electromechanical resonance frequencies electromechanical systems (NEMS) resonator with an electromechanical resonance frequency of 215 MHz based on an AlN/(FeGaB/Al2O3) × 10 magnetoelectric heterostructure for detecting DC magnetic fields. This magnetoelectric NEMS resonator showed a high quality factor of 735, and strong magnetoelectric coupling with a large voltage tunable sensitivity. The admittance of the magnetoelectric NEMS resonator was very sensitive to DC magnetic fields at its electromechanical resonance, which led to a new detection mechanism for ultra-sensitive self-biased RF NEMS magnetoelectric sensor with a low limit of detection of DC magnetic fields of ~300 picoTelsa. The magnetic/piezoelectric heterostructure based RF NEMS magnetoelectric sensor is compact, power efficient and readily integrated with CMOS technology, which represents a new class of ultra-sensitive magnetometers for DC and low frequency AC magnetic fields.

  16. An intrinsic approach to forces in magnetoelectric media

    International Nuclear Information System (INIS)

    Tucker, R.W.; Walton, T.J.

    2009-01-01

    This paper offers a conceptually straightforward method for the calculation of stresses in polarisable media based on the notion of a drive form and its property of being closed in spacetimes with symmetry. After an outline of the notation required to exploit the powerful exterior calculus of differential forms, a discussion of the relation between Killing isometries and conservation laws for smooth and distributional drive forms is given. Instantaneous forces on isolated spacetime domains and regions with interfaces are defined, based on manifestly covariant equations of motion. The remaining sections apply these notions to media that sustain electromagnetic stresses, with emphasis on homogeneous magnetoelectric material. An explicit calculation of the average pressure exerted by a monochromatic wave normally incident on a homogeneous, magnetoelectric slab in vacuo is presented and the concluding section summarizes how this pressure depends on the parameters in the magnetoelectric tensors for the medium.

  17. Inverse bilayer magnetoelectric thin film sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yarar, E.; Piorra, A.; Quandt, E., E-mail: eq@tf.uni-kiel.de [Chair for Inorganic Functional Materials, Institute for Materials Science, Faculty of Engineering, Kiel University, Kaiserstraße 2, D-24143 Kiel (Germany); Salzer, S.; Höft, M.; Knöchel, R. [Microwave Laboratory, Institute of Electrical and Information Engineering, Faculty of Engineering, Kiel University, Kaiserstraße 2, D-24143 Kiel (Germany); Hrkac, V.; Kienle, L. [Chair for Synthesis and Real Structure, Institute for Materials Science, Faculty of Engineering, Kiel University, Kaiserstraße 2, D-24143 Kiel (Germany)

    2016-07-11

    Prior investigations on magnetoelectric (ME) thin film sensors using amorphous FeCoSiB as a magnetostrictive layer and AlN as a piezoelectric layer revealed a limit of detection (LOD) in the range of a few pT/Hz{sup 1/2} in the mechanical resonance. These sensors are comprised of a Si/SiO{sub 2}/Pt/AlN/FeCoSiB layer stack, as dictated by the temperatures required for the deposition of the layers. A low temperature deposition route of very high quality AlN allows the reversal of the deposition sequence, thus allowing the amorphous FeCoSiB to be deposited on the very smooth Si substrate. As a consequence, the LOD could be enhanced by almost an order of magnitude reaching 400 fT/Hz{sup 1/2} at the mechanical resonance of the sensor. Giant ME coefficients (α{sub ME}) as high as 5 kV/cm Oe were measured. Transmission electron microscopy investigations revealed highly c-axis oriented growth of the AlN starting from the Pt-AlN interface with local epitaxy.

  18. Unidirectional magnetoelectric-field multiresonant tunneling

    International Nuclear Information System (INIS)

    Kamenetskii, E O; Hollander, E; Joffe, R; Shavit, R

    2015-01-01

    Unidirectional multi-resonant tunneling of the magnetoelectric (ME) field excitations through a subwavelength (regarding the scales of regular electromagnetic radiation) vacuum or isotropic-dielectric regions has been observed in two-port microwave structures having a quasi-2D ferrite disk with magnetic dipolar mode (MDM) oscillations. The excitations manifest themselves as Fano-resonance peaks in the scattering-matrix parameters at the stationary states of the MDM spectrum. The ME near-field excitations are quasimagnetostatic fields ∇-vector × H-vector =0 with non-zero helicity parameter: F=(1/(16π))Im{ E-vector ⋅( ∇-vector × E-vector ) ∗ }. Topological phase properties of ME fields are determined by edge chiral currents of MDM oscillations. We show that while for a given direction of a bias magnetic field (in other words, for a given direction of time), the ME field excitations are considered as ‘forward’ tunneling processes, in the opposite direction of a bias magnetic field (the opposite direction of time), there are ‘backward’ tunneling processes. Unidirectional ME field resonant tunneling is observed due to the distinguishable topology of the ‘forward’ and ‘backward’ ME field excitations. We establish a close connection between the Fano-resonance unidirectional tunneling and the topology of the ME fields in different microwave structures. (paper)

  19. Magnetoelectric polymer-based composites fundamentals and applications

    CERN Document Server

    Martins, Pedro

    2017-01-01

    The first book on this topic provides a comprehensive and well-structured overview of the fundamentals, synthesis and emerging applications of magnetoelectric polymer materials. Following an introduction to the basic aspects of polymer based magnetoelectric materials and recent developments, subsequent chapters discuss the various types as well as their synthesis and characterization. There then follows a review of the latest applications, such as memories, sensors and actuators. The book concludes with a look at future technological advances. An essential reference for entrants to the field as well as for experienced researchers.

  20. Artificial immune system for effective properties optimization of magnetoelectric composites

    Science.gov (United States)

    Poteralski, Arkadiusz; Dziatkiewicz, Grzegorz

    2018-01-01

    The optimization problem of the effective properties for magnetoelectric composites is considered. The effective properties are determined by the semi-analytical Mori-Tanaka approach. The generalized Eshelby tensor components are calculated numerically by using the Gauss quadrature method for the integral representation of the inclusion problem. The linear magnetoelectric constitutive equation is used. The effect of orientation of the electromagnetic materials components is taken into account. The optimization problem of the design is formulated and the artificial immune system is applied to solve it.

  1. Magnetoelectric coupling of a magnetoelectric flux gate sensor in vibration noise circumstance

    Directory of Open Access Journals (Sweden)

    Zhaoqiang Chu

    2018-01-01

    Full Text Available A magnetoelectric (ME flux gate sensor (MEFGS consisting of piezoelectric PMN-PT single crystals and ferromagnetic amorphous alloy ribbon in a self-differential configuration is featured with the ability of weak magnetic anomaly detection. Here, we further investigated its ME coupling and magnetic field detection performance in vibration noise circumstance, including constant frequency, impact, and random vibration noise. Experimental results show that the ME coupling coefficient of MEFGS is as high as 5700 V/cm*Oe at resonant frequency, which is several orders magnitude higher than previously reported differential ME sensors. It was also found that under constant and impact vibration noise circumstance, the noise reduction and attenuation factor of MEFGS are over 17 and 85.7%, respectively. This work is important for practical application of MEFGS in real environment.

  2. Magnetoelectric force microscopy based on magnetic force microscopy with modulated electric field.

    Science.gov (United States)

    Geng, Yanan; Wu, Weida

    2014-05-01

    We present the realization of a mesoscopic imaging technique, namely, the Magnetoelectric Force Microscopy (MeFM), for visualization of local magnetoelectric effect. The basic principle of MeFM is the lock-in detection of local magnetoelectric response, i.e., the electric field-induced magnetization, using magnetic force microscopy. We demonstrate MeFM capability by visualizing magnetoelectric domains on single crystals of multiferroic hexagonal manganites. Results of several control experiments exclude artifacts or extrinsic origins of the MeFM signal. The parameters are tuned to optimize the signal to noise ratio.

  3. An analytical nonlinear magnetoelectric coupling model of laminated composites under combined pre-stress and magnetic bias loadings

    International Nuclear Information System (INIS)

    Zhou, Hao-Miao; Qu, Shao-Xing; Ou, Xiao-Wei; Xiao, Ying; Wu, Hua-Ping

    2013-01-01

    Based on the equivalent circuit method, this paper adopts the nonlinear magnetostrictive constitutive relations to establish an analytical nonlinear magnetoelectric coefficient model for magnetostrictive/piezoelectric/magnetostrictive laminated magnetoelectric composites. When the pre-stress is set to zero in the model, the predicted results of the magnetoelectric coefficient coincide well with the available experimental results both qualitatively and quantitatively. Using the model, we can qualitatively predict the influence of the pre-stress, magnetic bias fields and the volume fraction of the magnetostrictive material on the magnetoelectric coefficient. The predicted results show that the influences of the pre-stress on the magnetoelectric coefficient, which varies with the magnetic bias field, before and after reaching the magnetoelectric coefficient maximum, are opposite. That is, the influence of the pre-stress on curves of the magnetoelectric coefficient reverses when the magnetoelectric coefficient reaches its maximum. Therefore, the correct setting of the pre-stress can lower the applied magnetic bias field and improve the magnetoelectric coefficient. The established nonlinear magnetoelectric effect model can provide a theoretical basis for regulating the magnetoelectric coefficient by the pre-stress and magnetic bias field and make it possible to design high-precision miniature magnetoelectric devices. (paper)

  4. A low frequency vibration energy harvester using magnetoelectric laminate composite

    International Nuclear Information System (INIS)

    Ju, Suna; Chae, Song Hee; Choi, Yunhee; Lee, Seungjun; Ji, Chang-Hyeon; Lee, Hyang Woon

    2013-01-01

    In this paper, we present a vibration energy harvester using magnetoelectric laminate composite and a springless spherical permanent magnet as a proof mass. The harvester utilizes a freely movable spherical permanent magnet to transform external vibration into a time varying magnetic field applied to the magnetoelectric transducer. The laminate composite consists of a Ni–Mn–Ga-based MSMA (magnetic shape memory alloy) element and a PZT (lead zirconate titanate) plate. A proof-of-concept harvester has been fabricated and characterized at various input accelerations and frequencies. A maximum open circuit voltage of 1.18 V has been obtained in response to a 3g vibration at 17 Hz with the fabricated device. Moreover, a maximum output voltage of 10.24 V and output power of 4.1 μW have been achieved on a 950 Ω load, when the fabricated energy harvester was mounted on a smartphone and shaken by hand. (paper)

  5. Giant magnetoelectric effect in pure manganite-manganite heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Sanjukta; Pankaj, Ravindra; Yarlagadda, Sudhakar; Majumdar, Pinaki; Littlewood, Peter B.

    2017-11-01

    Obtaining strong magnetoelectric couplings in bulk materials and heterostructures is an ongoing challenge. We demonstrate that manganite heterostructures of the form (Insulator) /(LaMnO3)(n)/Interface/(CaMnO3)(n)/(Insulator) show strong multiferroicity in magnetic manganites where ferroelectric polarization is realized by charges leaking from LaMnO3 to CaMnO3 due to repulsion. Here, an effective nearest-neighbor electron-electron (electron-hole) repulsion (attraction) is generated by cooperative electron-phonon interaction. Double exchange, when a particle virtually hops to its unoccupied neighboring site and back, produces magnetic polarons that polarize antiferromagnetic regions. Thus a striking giant magnetoelectric effect ensues when an external electrical field enhances the electron leakage across the interface.

  6. The theoretical ultimate magnetoelectric coefficients of magnetoelectric composites by optimization design

    International Nuclear Information System (INIS)

    Wang, H.-L.; Liu, B.

    2014-01-01

    This paper investigates what is the largest magnetoelectric (ME) coefficient of ME composites, and how to realize it. From the standpoint of energy conservation, a theoretical analysis is carried out on an imaginary lever structure consisting of a magnetostrictive phase, a piezoelectric phase, and a rigid lever. This structure is a generalization of various composite layouts for optimization on ME effect. The predicted theoretical ultimate ME coefficient plays a similar role as the efficiency of ideal heat engine in thermodynamics, and is used to evaluate the existing typical ME layouts, such as the parallel sandwiched layout and the serial layout. These two typical layouts exhibit ME coefficient much lower than the theoretical largest values, because in the general analysis the stress amplification ratio and the volume ratio can be optimized independently and freely, but in typical layouts they are dependent or fixed. To overcome this shortcoming and achieve the theoretical largest ME coefficient, a new design is presented. In addition, it is found that the most commonly used electric field ME coefficient can be designed to be infinitely large. We doubt the validity of this coefficient as a reasonable ME effect index and consider three more ME coefficients, namely the electric charge ME coefficient, the voltage ME coefficient, and the static electric energy ME coefficient. We note that the theoretical ultimate value of the static electric energy ME coefficient is finite and might be a more proper measure of ME effect

  7. A nonlinear magnetoelectric model for magnetoelectric layered composite with coupling stress

    International Nuclear Information System (INIS)

    Shi, Yang; Gao, Yuanwen

    2014-01-01

    Based on a linear piezoelectric relation and a nonlinear magnetostrictive constitutive relation, A nonlinear magnetoelectric (ME) effect model for flexural layered ME composites is established in in-plane magnetic field. In the proposed model, the true coupling stress and the equivalent piezomagnetic coefficient are taken into account and obtained through an iterative approach. Some calculations on nonlinear ME coefficient are conducted and discussed. Our results show that for both the flexural bilayer and trilayer composites, the true coupling stress in the composites first increase and then approach to a constant value with the increase of applied magnetic fields, affecting the nonlinear ME effect significantly. With consideration of the true coupling stress, the ME effect is smaller than that without consideration of the true coupling stress. Moreover, the proposed theoretical model predicts that the ME coefficient of the trilayer composite (does not generate the bending deflection) is much larger than that of bilayer composite (generates the bending deflection), which is in well agreement with the previous works. The influences of the applied magnetic field on the true coupling stress and fraction ratio corresponding to the extreme ME coefficients of layered structures are also investigated. - Highlights: • This paper develops a nonlinear model for layered ME composite. • The true coupling stress is obtained through an iterative approach. • The influences of coupling stress and flexural deformation are discussed. • The dependence of ME coefficient on magnetic field is studied

  8. Modeling of Magnetoelectric Interaction in Magnetostrictive-Piezoelectric Composites

    Directory of Open Access Journals (Sweden)

    M. I. Bichurin

    2012-01-01

    Full Text Available The paper dwells on the theoretical modeling of magnetoelectric (ME effect in layered and bulk composites based on magnetostrictive and piezoelectric materials. Our analysis rests on the simultaneous solution of elastodynamic or elastostatic and electro/magnetostatic equations. The expressions for ME coefficients as the functions of material parameters and volume fractions of components are obtained. Longitudinal, transverse, and in-plane cases are considered. The use of the offered model has allowed to present the ME effect in ferrite cobalt-barium titanate, ferrite cobalt-PZT, ferrite nickel-PZT, and lanthanum strontium manganite-PZT composites adequately.

  9. Phenomenological treatment of the gigantic magnetoelectric effect in some ferroelectromagnets

    International Nuclear Information System (INIS)

    Chupis, I.E.

    2005-01-01

    It is shown that observed in DyMn 2 O 5 and TbMnO 3 colossal changes of dielectric constant and electric polarization with magnetic field are possible in the ferroelectromagnets with close magnetic and ferroelectric transition temperatures and a small value of electric polarization. The appearance of electric polarization in commensurate magnetic state of TbMnO 3 and the reorientation of electric polarization by magnetic field was interpreted as a result of a renormalization of the ferroelectric energy by the magnetoelectric interaction. The existence of a weak ferromagnetic moment along c-axis in TbMnO 3 commensurate phase was predicted

  10. Magnetoelectric effect in Cr2O3 thin films

    Science.gov (United States)

    He, Xi; Wang, Yi; Sahoo, Sarbeswar; Binek, Christian

    2008-03-01

    Magnetoelectric materials experienced a recent revival as promising components of novel spintronic devices [1, 2, 3]. Since the magnetoelectric (ME) effect is relativistically small in traditional antiferromagnetic compounds like Cr2O3 (max. αzz 4ps/m ) and also cross- coupling between ferroic order parameters is typically small in the modern multiferroics, it is a challenge to electrically induce sufficient magnetization required for the envisioned device applications. A straightforward approach is to increase the electric field at constant voltage by reducing the thickness of the ME material to thin films of a few nm. Since magnetism is known to be affected by geometrical confinement thickness dependence of the ME effect in thin film Cr2O3 is expected. We grow (111) textured Cr2O3 films with various thicknesses below 500 nm and study the ME effect for various ME annealing conditions as a function of temperature with the help of Kerr-magnetometry. [1] P. Borisov et al. Phys. Rev. Lett. 94, 117203 (2005). [2] Ch. Binek, B.Doudin, J. Phys. Condens. Matter 17, L39 (2005). [3] R. Ramesh and Nicola A. Spaldin 2007 Nature Materials 6 21.

  11. Topological magnetoelectric effects in microwave far-field radiation

    Energy Technology Data Exchange (ETDEWEB)

    Berezin, M.; Kamenetskii, E. O.; Shavit, R. [Microwave Magnetic Laboratory, Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer Sheva (Israel)

    2016-07-21

    Similar to electromagnetism, described by the Maxwell equations, the physics of magnetoelectric (ME) phenomena deals with the fundamental problem of the relationship between electric and magnetic fields. Despite a formal resemblance between the two notions, they concern effects of different natures. In general, ME-coupling effects manifest in numerous macroscopic phenomena in solids with space and time symmetry breakings. Recently, it was shown that the near fields in the proximity of a small ferrite particle with magnetic-dipolar-mode (MDM) oscillations have the space and time symmetry breakings and the topological properties of these fields are different from the topological properties of the free-space electromagnetic fields. Such MDM-originated fields—called magnetoelectric (ME) fields—carry both spin and orbital angular momenta. They are characterized by power-flow vortices and non-zero helicity. In this paper, we report on observation of the topological ME effects in far-field microwave radiation based on a small microwave antenna with a MDM ferrite resonator. We show that the microwave far-field radiation can be manifested with a torsion structure where an angle between the electric and magnetic field vectors varies. We discuss the question on observation of the regions of localized ME energy in far-field microwave radiation.

  12. Multiferroic and magnetoelectric materials – Developments and perspectives

    Directory of Open Access Journals (Sweden)

    Shvartsman V. V.

    2012-06-01

    Full Text Available Multiferroic (MF materials with simultaneous magnetic and electric long range order and occasionally, mutual magnetoelectric (ME coupling, have recently attracted considerable interest. The small linear ME effect has been shown to control spintronic devices very efficiently, e.g. via the classic ME antiferromagnet Cr2O3 using exchange bias. Similar nano-engineering concepts exist also for type-I MF single phase materials, whose magnetic and polar orders have distinct origins like BiFeO3. Strong ME coupling occurs in type-II multiferroics, where ferroelectricity is due to spiral spin order as in TbMnO3. Record high ME response coming close to applicability arises in stress-strain coupled multiphase magnetoelectrics such as PZT/FeBSiC composites. Higher order ME response in disordered systems (“type-III multiferroics” extends the conventional MF scenario toward ME quantum paraelectric and multiglass materials with polarization-induced control of magnetic exchange, as e.g. in EuTiO3, Sr0.98Mn0.02TiO3, and PbFe0.5Nb0.5O3.

  13. Magnetoelectric properties of magnetic/ferroelectric multilayer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Sung-Ok; Eum, You-Jeong; Koo, Chang-Young; Lee, Hee-Young [Yeungnam University, Gyeongsan (Korea, Republic of); Park, Jung-Min [Osaka University, Osaka (Japan); Ryu, Jung-Ho [Korea Institute of Materials Science, Changwon (Korea, Republic of)

    2014-07-15

    Magnetic/ferroelectric multilayer thin films using PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PZT) and two different magnetic materials, i.e., Terfenol-D and CuFe{sub 2}O{sub 4} (CuFO) layers, were fabricated, and their magnetoelectric (ME) coupling behavior was investigated. The PZT layer was first coated onto Pt/Ti/SiO{sub 2}/Si substrate by sol-gel spin coating method. Pt layer, which served as an electrode and a diffusion barrier, was grown on the PZT layer by using the ion-beam sputtering method. The ME voltage coefficients were calculated from the ME voltage data measured utilizing a magnetoelectric test system. The Terfenol-D/Pt/PZT films were found to show a higher in-plane ME voltage coefficient than that the CuFO/Pt/PZT films due primarily to the higher magnetostriction coefficient of Terfenol-D.

  14. Physics considerations in targeted anticancer drug delivery by magnetoelectric nanoparticles

    Science.gov (United States)

    Stimphil, Emmanuel; Nagesetti, Abhignyan; Guduru, Rakesh; Stewart, Tiffanie; Rodzinski, Alexandra; Liang, Ping; Khizroev, Sakhrat

    2017-06-01

    In regard to cancer therapy, magnetoelectric nanoparticles (MENs) have proven to be in a class of its own when compared to any other nanoparticle type. Like conventional magnetic nanoparticles, they can be used for externally controlled drug delivery via application of a magnetic field gradient and image-guided delivery. However, unlike conventional nanoparticles, due to the presence of a non-zero magnetoelectric effect, MENs provide a unique mix of important properties to address key challenges in modern cancer therapy: (i) a targeting mechanism driven by a physical force rather than antibody matching, (ii) a high-specificity delivery to enhance the cellular uptake of therapeutic drugs across the cancer cell membranes only, while sparing normal cells, (iii) an externally controlled mechanism to release drugs on demand, and (iv) a capability for image guided precision medicine. These properties separate MEN-based targeted delivery from traditional biotechnology approaches and lay a foundation for the complementary approach of technobiology. The biotechnology approach stems from the underlying biology and exploits bioinformatics to find the right therapy. In contrast, the technobiology approach is geared towards using the physics of molecular-level interactions between cells and nanoparticles to treat cancer at the most fundamental level and thus can be extended to all the cancers. This paper gives an overview of the current state of the art and presents an ab initio model to describe the underlying mechanisms of cancer treatment with MENs from the perspective of basic physics.

  15. Magnetoelectric effect in structures which consist from ferrimagnetic and piezoelectric components

    International Nuclear Information System (INIS)

    Koronovs'kij, V.Je.

    2007-01-01

    Magnetoelectric (ME) properties of the structure which consists from mechanically connected magnetostriction and piezoelectric plates were investigated on example of the yttrium-ferrite-garnet (YIG) - piezoelectric. The laser polarimeter is using

  16. Improving the magnetoelectric performance of Metglas/PZT laminates by annealing in a magnetic field.

    Science.gov (United States)

    Freeman, E; Harper, J; Goel, N; Gilbert, I; Unguris, J; Schiff, S J; Tadigadapa, S

    2017-01-01

    A comprehensive investigation of magnetostriction optimization in Metglas 2605SA1 ribbons is performed to enhance magnetoelectric performance. We explore a range of annealing conditions to relieve remnant stress and align the magnetic domains in the Metglas, while minimizing unwanted crystallization. The magnetostriction coefficient, magnetoelectric coefficient, and magnetic domain alignment are correlated to optimize magnetoelectric performance. We report on direct magnetostriction observed by in-plane Doppler vibrometer and domain imagining using scanning electron microscopy with polarization analysis for a range of annealing conditions. We find that annealing in an oxygen-free environment at 400 °C for 30 min yields an optimal magnetoelectric coefficient, magnetostriction and magnetostriction coefficient. The optimized ribbons had a magnetostriction of 50.6 ± 0.2 μ m m -1 and magnetoelectric coefficient of 79.3 ± 1.5 μ m m -1 mT -1 . The optimized Metglas 2605SA1 ribbons and PZT-5A (d 31 mode) sensor achieves a magnetic noise floor of approximately 600 pT Hz -1/2 at 100 Hz and a magnetoelectric coefficient of 6.1 ± 0.03 MV m -1 T -1 .

  17. Improving the magnetoelectric performance of Metglas/PZT laminates by annealing in a magnetic field

    Science.gov (United States)

    Freeman, E.; Harper, J.; Goel, N.; Gilbert, I.; Unguris, J.; Schiff, S. J.; Tadigadapa, S.

    2017-08-01

    A comprehensive investigation of magnetostriction optimization in Metglas 2605SA1 ribbons is performed to enhance magnetoelectric performance. We explore a range of annealing conditions to relieve remnant stress and align the magnetic domains in the Metglas, while minimizing unwanted crystallization. The magnetostriction coefficient, magnetoelectric coefficient, and magnetic domain alignment are correlated to optimize magnetoelectric performance. We report on direct magnetostriction observed by in-plane Doppler vibrometer and domain imagining using scanning electron microscopy with polarization analysis for a range of annealing conditions. We find that annealing in an oxygen-free environment at 400 {}\\circ {{C}} for 30 min yields an optimal magnetoelectric coefficient, magnetostriction and magnetostriction coefficient. The optimized ribbons had a magnetostriction of 50.6 ± 0.2 μ {{m}} {{{m}}}-1 and magnetoelectric coefficient of 79.3 ± 1.5 µm m-1 mT-1. The optimized Metglas 2605SA1 ribbons and PZT-5A (d31 mode) sensor achieves a magnetic noise floor of approximately 600 pT {{{H}}{{z}}}-1/2 at 100 Hz and a magnetoelectric coefficient of 6.1 ± 0.03 MV m-1 T-1.

  18. Influence of the linear magneto-electric effect on the lateral shift of light reflected from a magneto-electric film

    International Nuclear Information System (INIS)

    Dadoenkova, Yu S; Petrov, R V; Bichurin, M I; Bentivegna, F F L; Dadoenkova, N N; Lyubchanskii, I L

    2016-01-01

    We present a theoretical investigation of the lateral shift of an infrared light beam reflected from a magnetic film deposited on a non-magnetic dielectric substrate, taking into account the linear magneto-electric interaction in the magnetic film. We use the stationary phase method to evaluate the lateral shift. It is shown that the magneto-electric coupling leads to a six-fold enhancement of the lateral shift amplitude of a p-(s-) polarized incident beam reflected into a s-(p-) polarized beam. A reversal of the magnetization in the film leads to a nonreciprocal sign change of the lateral shift. (paper)

  19. Magnetoelectric Coupling in CuO Nanoparticles for Spintronics Applications

    Science.gov (United States)

    Kaur, Mandeep; Tovstolytkin, Alexandr; Lotey, Gurmeet Singh

    2018-05-01

    Multiferroic copper oxide (CuO) nanoparticles have been synthesized by colloidal synthesis method. The morphological, structural, magnetic, dielectric and magnetodielectric property has been investigated. The structural study reveals the monoclinic structure of CuO nanoparticles. Transmission electron microscopy images disclose that the size of the CuO nanoparticles is 18 nm and the synthesized nanoparticles are uniform in size and dispersion. Magnetic study tells the weak ferromagnetic character of CuO nanoparticles with coercivity and retentivity value 206 Oe and 0.060 emu/g respectively. Dielectric study confirms that the dielectric constant of CuO nanoparticles is around 1091 at low frequency. The magnetoelectric coupling in the synthesized CuO nanoparticles has been calculated by measuring magnetodielectric coupling coefficient.

  20. Magnetic force driven magnetoelectric effect in bi-cantilever composites

    Science.gov (United States)

    Zhang, Ru; Wu, Gaojian; Zhang, Ning

    2017-12-01

    The magnetic force driven magnetoelectric (ME) effect in bi-cantilever Mn-Zn-Ferrite /PZT composites is presented. Compared with single cantilever, the ME voltage coefficient in bi-cantilever composite is a little lower and the resonance frequency is higher, but the bi-cantilever structure is advantageous for integration. When the magnetic gap is 3 mm, the ME voltage coefficient can achieve 6.2 Vcm-1Oe-1 at resonance under optimum bias field Hm=1030 Oe; when the magnetic gap is 1.5 mm, the ME voltage coefficient can get the value as high as 4.4 Vcm-1Oe-1 under much lower bias field H=340 Oe. The stable ME effect in bi-cantilever composites has important potential application in the design of new type ME device.

  1. Equivalent Circuit for Magnetoelectric Read and Write Operations

    Science.gov (United States)

    Camsari, Kerem Y.; Faria, Rafatul; Hassan, Orchi; Sutton, Brian M.; Datta, Supriyo

    2018-04-01

    We describe an equivalent circuit model applicable to a wide variety of magnetoelectric phenomena and use spice simulations to benchmark this model against experimental data. We use this model to suggest a different mode of operation where the 1 and 0 states are represented not by states with net magnetization (like mx , my, or mz) but by different easy axes, quantitatively described by (mx2-my2), which switches from 0 to 1 through the write voltage. This change is directly detected as a read signal through the inverse effect. The use of (mx2-my2) to represent a bit is a radical departure from the standard convention of using the magnetization (m ) to represent information. We then show how the equivalent circuit can be used to build a device exhibiting tunable randomness and suggest possibilities for extending it to nonvolatile memory with read and write capabilities, without the use of external magnetic fields or magnetic tunnel junctions.

  2. Theory of Magnetoelectric Properties of 2D Systems

    Science.gov (United States)

    Chen, S. C.; Wu, J. Y.; Lin, C. Y.; Lin, M. F.

    2017-12-01

    This book addresses important advances in diverse quantization phenomena. 'Theory of Magnetoelectric Properties of 2D Systems' develops the generalized tight-binding model in order to comprehend the rich quantization phenomena in 2D materials. The unusual effects, taken into consideration simultaneously, mainly come from the multi-orbital hybridization, the spin-orbital coupling, the intralayer and interlayer atomic interactions, the layer number, the stacking configuration, the site-energy difference, the magnetic field, and the electric field. The origins of the phenomena are discussed in depth, particularly focusing on graphene, tinene, phosphorene and MoS2, with a broader model also drawn. This model could be further used to investigate electronic properties of 1D and 3D condensed-matter systems, and this book will prove to be a valuable resource to researchers and graduate students working in 2D materials science.

  3. Resonance of magnetization excited by voltage in magnetoelectric heterostructures

    Science.gov (United States)

    Yu, Guoliang; Zhang, Huaiwu; Li, Yuanxun; Li, Jie; Zhang, Dainan; Sun, Nian

    2018-04-01

    Manipulation of magnetization dynamics is critical for spin-based devices. Voltage driven magnetization resonance is promising for realizing low-power information processing systems. Here, we show through Finite Element Method (FEM) simulations that magnetization resonance in nanoscale magnetic elements can be generated by a radio frequency (rf) voltage via the converse magnetoelectric (ME) effect. The magnetization dynamics induced by voltage in a ME heterostructures is simulated by taking into account the magnetoelastic and piezoelectric coupling mechanisms among magnetization, strain and voltage. The frequency of the excited magnetization resonance is equal to the driving rf voltage frequency. The proposed voltage driven magnetization resonance excitation mechanism opens a way toward energy-efficient spin based device applications.

  4. Microwave magnetoelectric fields: An analytical study of topological characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Joffe, R., E-mail: ioffr1@gmail.com [Microwave Magnetic Laboratory, Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer Sheva (Israel); Department of Electrical and Electronics Engineering, Shamoon College of Engineering, Beer Sheva (Israel); Shavit, R.; Kamenetskii, E.O. [Microwave Magnetic Laboratory, Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer Sheva (Israel)

    2015-10-15

    The near fields originated from a small quasi-two-dimensional ferrite disk with magnetic-dipolar-mode (MDM) oscillations are the fields with broken dual (electric-magnetic) symmetry. Numerical studies show that such fields – called the magnetoelectric (ME) fields – are distinguished by the power-flow vortices and helicity parameters (E.O. Kamenetskii, R. Joffe, R. Shavit, Phys. Rev. E 87 (2013) 023201). These numerical studies can well explain recent experimental results with MDM ferrite disks. In the present paper, we obtain analytically topological characteristics of the ME-field modes. For this purpose, we used a method of successive approximations. In the second approximation we take into account the influence of the edge regions of an open ferrite disk, which are excluded in the first-approximation solving of the magnetostatic (MS) spectral problem. Based on the analytical method, we obtain a “pure” structure of the electric and magnetic fields outside the MDM ferrite disk. The analytical studies can display some fundamental features that are non-observable in the numerical results. While in numerical investigations, one cannot separate the ME fields from the external electromagnetic (EM) radiation, the present theoretical analysis allows clearly distinguish the eigen topological structure of the ME fields. Importantly, this ME-field structure gives evidence for certain phenomena that can be related to the Tellegen and bianisotropic coupling effects. We discuss the question whether the MDM ferrite disk can exhibit properties of the cross magnetoelectric polarizabilities. - Highlights: • We obtain analytically topological characteristics of the ME-field modes. • We take into account the influence of the edge regions of an open ferrite disk. • We obtain a “pure” structure of the electromagnetic fields outside the ferrite disk. • Analytical studies show features that are non-observable in the numerical results. • ME-field gives evidence for

  5. Microwave magnetoelectric fields: An analytical study of topological characteristics

    International Nuclear Information System (INIS)

    Joffe, R.; Shavit, R.; Kamenetskii, E.O.

    2015-01-01

    The near fields originated from a small quasi-two-dimensional ferrite disk with magnetic-dipolar-mode (MDM) oscillations are the fields with broken dual (electric-magnetic) symmetry. Numerical studies show that such fields – called the magnetoelectric (ME) fields – are distinguished by the power-flow vortices and helicity parameters (E.O. Kamenetskii, R. Joffe, R. Shavit, Phys. Rev. E 87 (2013) 023201). These numerical studies can well explain recent experimental results with MDM ferrite disks. In the present paper, we obtain analytically topological characteristics of the ME-field modes. For this purpose, we used a method of successive approximations. In the second approximation we take into account the influence of the edge regions of an open ferrite disk, which are excluded in the first-approximation solving of the magnetostatic (MS) spectral problem. Based on the analytical method, we obtain a “pure” structure of the electric and magnetic fields outside the MDM ferrite disk. The analytical studies can display some fundamental features that are non-observable in the numerical results. While in numerical investigations, one cannot separate the ME fields from the external electromagnetic (EM) radiation, the present theoretical analysis allows clearly distinguish the eigen topological structure of the ME fields. Importantly, this ME-field structure gives evidence for certain phenomena that can be related to the Tellegen and bianisotropic coupling effects. We discuss the question whether the MDM ferrite disk can exhibit properties of the cross magnetoelectric polarizabilities. - Highlights: • We obtain analytically topological characteristics of the ME-field modes. • We take into account the influence of the edge regions of an open ferrite disk. • We obtain a “pure” structure of the electromagnetic fields outside the ferrite disk. • Analytical studies show features that are non-observable in the numerical results. • ME-field gives evidence for

  6. The magnetoelectric coupling effect in multiferroic composites based on PZT–ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Bartkowska, J.A., E-mail: joanna.bartkowska@us.edu.pl

    2015-01-15

    In the multiferroic materials, the dielectric and magnetic properties are closely correlated through the coupling interaction between the ferroelectric and magnetic order. We attempted to determine the values of magnetoelectric coupling coefficient, from the temperature dependences of the dielectric permittivity for the ferroelectric–ferromagnetic composite PZT–ferrite type, namely PSZTC–NiZn and PBZTN–NiZn. The main component of the ferroelectric–ferromagnetic composite was PZT type powder (with ferroelectric properties), which was synthesized using sintering of a mixture of simple oxides in solid phase. The second element of the ferroelectric–ferromagnetic composite was the ferrite powder (with ferromagnetic properties). Ferrite powder was synthesized using calcination. Next, the mixed components were synthesized using sintering of the mixture of simple oxides in a solid phase (compaction by a free sintering method). The temperature dependences of the dielectric permittivity (ε) for the different frequencies and for both multiferroic composites were investigated. Based on dielectric measurements and theoretical considerations, the values of the magnetoelectric coupling coefficient were specified. - Highlights: • The magnetoelectric effect at two different ferroelectric–ferromagnetic composites based on a PZT and nickel–zinc ferrite. • Multiferroics composite incorporate both ferroelectric and magnetic phases. • The mechanism of the magnetoelectric coupling between ferroelectric and magnetic properties, in multiferroic composites, is caused by the strain. • The determination of the magnetoelectric coupling coefficient based on a theoretical model and the measurements of dielectric permittivity.

  7. The magnetoelectric coupling effect in multiferroic composites based on PZT–ferrite

    International Nuclear Information System (INIS)

    Bartkowska, J.A.

    2015-01-01

    In the multiferroic materials, the dielectric and magnetic properties are closely correlated through the coupling interaction between the ferroelectric and magnetic order. We attempted to determine the values of magnetoelectric coupling coefficient, from the temperature dependences of the dielectric permittivity for the ferroelectric–ferromagnetic composite PZT–ferrite type, namely PSZTC–NiZn and PBZTN–NiZn. The main component of the ferroelectric–ferromagnetic composite was PZT type powder (with ferroelectric properties), which was synthesized using sintering of a mixture of simple oxides in solid phase. The second element of the ferroelectric–ferromagnetic composite was the ferrite powder (with ferromagnetic properties). Ferrite powder was synthesized using calcination. Next, the mixed components were synthesized using sintering of the mixture of simple oxides in a solid phase (compaction by a free sintering method). The temperature dependences of the dielectric permittivity (ε) for the different frequencies and for both multiferroic composites were investigated. Based on dielectric measurements and theoretical considerations, the values of the magnetoelectric coupling coefficient were specified. - Highlights: • The magnetoelectric effect at two different ferroelectric–ferromagnetic composites based on a PZT and nickel–zinc ferrite. • Multiferroics composite incorporate both ferroelectric and magnetic phases. • The mechanism of the magnetoelectric coupling between ferroelectric and magnetic properties, in multiferroic composites, is caused by the strain. • The determination of the magnetoelectric coupling coefficient based on a theoretical model and the measurements of dielectric permittivity

  8. Resonant magnetoelectric response of cantilevers with magnetostrictive and piezoelectric layers on opposite sides of the substrate

    Directory of Open Access Journals (Sweden)

    Matthias C. Krantz

    2013-06-01

    Full Text Available A theory is derived for the bending-mode magnetoelectric coefficients at resonance for magnetostrictive and piezoelectric layers on opposite sides of a substrate. Results are given for the transverse ME coefficient in the Metglas-Si-AlN system with magnetic field excitation parallel and electric polarization perpendicular to the cantilever. The center-substrate layer sequence is found to produce about 50 % enhancement of the magnetoelectric effect compared to magnetoelectric bilayers on one side of a substrate. Up to about 10 % additional enhancement of the ME effect is predicted if the magnetostrictive and piezoelectric layers are separated from the substrate by spacer layers with lower Youngs modulus. Lowest order bending mode resonance frequencies are given.

  9. Electromagnetic wave propagation in time-dependent media with antisymmetric magnetoelectric coupling

    International Nuclear Information System (INIS)

    Lin, Shi-Rong; Zhang, Ruo-Yang; Ma, Yi-Rong; Jia, Wei; Zhao, Qing

    2016-01-01

    Highlights: • Time-dependent permittivity combined with antisymmetric magnetoelectric coupling will yield a novel linear birefringence. • Distinct dynamical behaviors of these two birefringent modes are analyzed. • As a new nonlinear optical effect, a scheme utilizing optical Kerr effect in moving media is proposed. - Abstract: This paper deals with electromagnetic wave propagation in time-dependent media with an antisymmetric magnetoelectric coupling and an isotropic time-dependent permittivity. We identify a new mechanism of linear birefringence, originated from the combined action of the time-dependent permittivity and the antisymmetric magnetoelectric coupling. Permittivity with linear and exponential temporal variations exemplifies the creation and control of these two distinct types of linear birefringent modes. As a novel nonlinear optical effect, a scheme utilizing optical Kerr effect in moving media is proposed for the realization of the predicted birefringence.

  10. Electromagnetic wave propagation in time-dependent media with antisymmetric magnetoelectric coupling

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Shi-Rong [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Zhang, Ruo-Yang [Theoretical Physics Division, Chern Institute of Mathematics, Nankai University, Tianjin 300071 (China); Ma, Yi-Rong; Jia, Wei [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Zhao, Qing, E-mail: qzhaoyuping@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

    2016-07-29

    Highlights: • Time-dependent permittivity combined with antisymmetric magnetoelectric coupling will yield a novel linear birefringence. • Distinct dynamical behaviors of these two birefringent modes are analyzed. • As a new nonlinear optical effect, a scheme utilizing optical Kerr effect in moving media is proposed. - Abstract: This paper deals with electromagnetic wave propagation in time-dependent media with an antisymmetric magnetoelectric coupling and an isotropic time-dependent permittivity. We identify a new mechanism of linear birefringence, originated from the combined action of the time-dependent permittivity and the antisymmetric magnetoelectric coupling. Permittivity with linear and exponential temporal variations exemplifies the creation and control of these two distinct types of linear birefringent modes. As a novel nonlinear optical effect, a scheme utilizing optical Kerr effect in moving media is proposed for the realization of the predicted birefringence.

  11. Magnetoelectric Interactions in Lead-Based and Lead-Free Composites.

    Science.gov (United States)

    Bichurin, Mirza; Petrov, Vladimir; Zakharov, Anatoly; Kovalenko, Denis; Yang, Su Chul; Maurya, Deepam; Bedekar, Vishwas; Priya, Shashank

    2011-04-06

    Magnetoelectric (ME) composites that simultaneously exhibit ferroelectricity and ferromagnetism have recently gained significant attention as evident by the increasing number of publications. These research activities are direct results of the fact that multiferroic magnetoelectrics offer significant technological promise for multiple devices. Appropriate choice of phases with co-firing capability, magnetostriction and piezoelectric coefficient, such as Ni-PZT and NZFO-PZT, has resulted in fabrication of prototype components that promise transition. In this manuscript, we report the properties of Ni-PZT and NZFO-PZT composites in terms of ME voltage coefficients as a function of frequency and magnetic DC bias. In order to overcome the problem of toxicity of lead, we have conducted experiments with Pb-free piezoelectric compositions. Results are presented on the magnetoelectric performance of Ni-NKN, Ni-NBTBT and NZFO-NKN, NZFO-NBTBT systems illustrating their importance as an environmentally friendly alternative.

  12. The multimodal magnetoelectric effect in the ring-shaped magnetostrictive-piezoelectric bulk composites

    Science.gov (United States)

    Radchenko, G. S.; Filippov, D. A.; Laletin, V. M.

    2015-11-01

    The theoretical and experimental investigation of the direct magnetoelectric effect in the ring-type structures made of the bulk magnetostrictive-piezoelectric composites has been presented. The analytical expression for the magnetoelectric voltage coefficient has been obtained using the effective parameters method. The frequency dependence of this parameter is also analyzed. The dependence of the resonant frequency and the amplitude of this effect of the geometrical parameters of the ring for the first and second oscillation modes are presented. The experimental investigation of the direct magnetoelectric effect for the ring-type composite specimens consisting of the nickel ferrite spinel-PZT bulk composite is done. The obtained experimental data are in good agreement with the theoretical predictions.

  13. Magnetoelectric Interactions in Lead-Based and Lead-Free Composites

    Directory of Open Access Journals (Sweden)

    Shashank Priya

    2011-04-01

    Full Text Available Magnetoelectric (ME composites that simultaneously exhibit ferroelectricity and ferromagnetism have recently gained significant attention as evident by the increasing number of publications. These research activities are direct results of the fact that multiferroic magnetoelectrics offer significant technological promise for multiple devices. Appropriate choice of phases with co-firing capability, magnetostriction and piezoelectric coefficient, such as Ni-PZT and NZFO-PZT, has resulted in fabrication of prototype components that promise transition. In this manuscript, we report the properties of Ni-PZT and NZFO-PZT composites in terms of ME voltage coefficients as a function of frequency and magnetic DC bias. In order to overcome the problem of toxicity of lead, we have conducted experiments with Pb-free piezoelectric compositions. Results are presented on the magnetoelectric performance of Ni-NKN, Ni-NBTBT and NZFO-NKN, NZFO-NBTBT systems illustrating their importance as an environmentally friendly alternative.

  14. A theory of the inverse magnetoelectric effect in layered magnetostrictive-piezoelectric structures

    Science.gov (United States)

    Filippov, D. A.; Radchenko, G. S.; Firsova, T. O.; Galkina, T. A.

    2017-05-01

    A theory of the inverse magnetoelectric effect in layered structures has been presented. The theory is based on solving the equations of elastodynamics and electrostatics separately for the magnetostrictive and piezoelectric phases, taking into account the conditions at the interface between the phases. Expressions for the coefficient of inverse magnetoelectric conversion through the parameters characterizing the magnetostrictive and piezoelectric phases have been obtained. Theoretical dependences of the inverse magnetoelectric conversion coefficient on the frequency of the alternating-current electric field for the three-layer PZT-Ni-PZT structure and the two-layer terfenol- D-PZT structure have been calculated. The results of the calculations are in good agreement with the experimental data.

  15. Predicting Magnetoelectric Coupling in Layered and Graded Composites

    Directory of Open Access Journals (Sweden)

    Mirza Bichurin

    2017-07-01

    Full Text Available Magnetoelectric (ME interaction in magnetostrictive-piezoelectric multiferroic structures consists in inducing the electric field across the structure in an applied magnetic field and is a product property of magnetostriction and piezoelectricity in components. ME voltage coefficient that is the ratio of induced electric field to applied magnetic field is the key parameter of ME coupling strength. It has been known that the ME coupling strength is dictated by the product of the piezoelectric and piezomagnetic coefficients of initial phases. As a result, using the laminates with graded piezoelectric and piezomagnetic parameters are a new pathway to the increase in the ME coupling strength. Recently developed models predict stronger ME interactions in composites based on graded components compared to homogeneous ones. We discuss predicting the ME coupling strength for layered structures of homogeneous and compositionally graded magnetostrictive and piezoelectric components based on the graphs of ME voltage coefficients against composite parameters. For obtaining the graphs, we developed equations for ME output in applied magnetic field for possible modes of operation and layered structure configurations. In particular, our studies have been performed on low-frequency ME coupling, enhanced ME effect in electromechanical resonance (EMR region for longitudinal and bending modes. Additionally, ME coupling at magnetic resonance in magnetostrictive component and at overlapping the EMR and magnetic resonance is investigated. We considered symmetric trilayers and asymmetric bilayers of magnetostrictive and piezoelectric components and multilayered structures based on compositionally stepped initial components.

  16. Magnetoelectric antiferromagnets as platforms for the manipulation of solitons

    Science.gov (United States)

    Zarzuela, Ricardo; Kim, Se Kwon; Tserkovnyak, Yaroslav

    2018-01-01

    We study the magnetic dynamics of magnetoelectric antiferromagnetic thin films, where an unconventional boundary ferromagnetism coexists with the bulk Néel phase below the Néel temperature. The spin exchange between the two order parameters yields an effective low-energy theory that is formally equivalent to that of a ferrimagnet. Dynamics of domain walls and skyrmions are analyzed within the collective-variable approach, from which we conclude that they behave as massive particles moving in a viscous medium subjected to a gyrotropic force. We find that the film thickness can be used as a control parameter for the motion of these solitons. In this regard, it is shown that an external magnetic field can drive the dynamics of domain walls, whose terminal velocity is tunable with the sample thickness. Furthermore, the classification of the skyrmion dynamics is sensitive to the spatial modulation of the sample thickness, which can be easily engineered with the present (thin-film) deposition techniques. Current-driven spin transfer can trigger drifting orbits of skyrmions, which can be utilized as racetracks for these magnetic textures.

  17. Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

    Directory of Open Access Journals (Sweden)

    N. I. Polzikova

    2016-05-01

    Full Text Available We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW resonator (HBAR formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

  18. All-Silicon Switchable Magnetoelectric Effect through Interlayer Exchange Coupling.

    Science.gov (United States)

    Liu, Hang; Sun, Jia-Tao; Fu, Hui-Xia; Sun, Pei-Jie; Feng, Y P; Meng, Sheng

    2017-07-19

    The magnetoelectric (ME) effect originating from the effective coupling between electric field and magnetism is an exciting frontier in nanoscale science such as magnetic tunneling junction (MTJ), ferroelectric/piezoelectric heterojunctions etc. The realization of switchable ME effect under external electric field in d0 semiconducting materials of single composition is needed especially for all-silicon spintronics applications because of its natural compatibility with current industry. We employ density functional theory (DFT) to reveal that the pristine Si(111)-3×3 R30° (Si3 hereafter) reconstructed surfaces of thin films with a thickness smaller than eleven bilayers support a sizeable linear ME effect with switchable direction of magnetic moment under external electric field. This is achieved through the interlayer exchange coupling effect in the antiferromagnetic regime, where the spin-up and spin-down magnetized density is located on opposite surfaces of Si3 thin films. The obtained coefficient for the linear ME effect can be four times larger than that of ferromagnetic Fe films, which fail to have the reversal switching capabilities. The larger ME effect originates from the spin-dependent screening of the spin-polarized Dirac fermion. The prediction will promote the realization of well-controlled and switchable data storage in all-silicon electronics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

    Energy Technology Data Exchange (ETDEWEB)

    Polzikova, N. I., E-mail: polz@cplire.ru; Alekseev, S. G.; Pyataikin, I. I.; Kotelyanskii, I. M.; Luzanov, V. A.; Orlov, A. P. [Kotel’nikov Institute of Radio Engineering and Electronics of Russian Academy of Sciences, Mokhovaya 11, building 7, Moscow, 125009 (Russian Federation)

    2016-05-15

    We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW) resonator (HBAR) formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE) this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

  20. Tunable characteristics of bending resonance frequency in magnetoelectric laminated composites

    Institute of Scientific and Technical Information of China (English)

    Chen Lei; Li Ping; Wen Yu-Mei; Zhu Yong

    2013-01-01

    As the magnetoelectric (ME) effect in piezoelectric/magnetostrictive laminated composites is mediated by mechanical deformation,the ME effect is significantly enhanced in the vicinity of resonance frequency.The bending resonance frequency (fr) of bilayered Terfenol-D/PZT (MP) laminated composites is studied,and our analysis predicts that (i) the bending resonance frequency of an MP laminated composite can be tuned by an applied dc magnetic bias (Hdc) due to the △E effect; (ii) the bending resonance frequency of the MP laminated composite can be controlled by incorporating FeCuNbSiB layers with different thicknesses.The experimental results show that with Hdc increasing from 0Oe (1 Oe=79.5775 A/m)to 700 Oe,the bending resonance frequency can be shifted in a range of 32.68 kHz ≤ fr ≤ 33.96 kHz.In addition,with the thickness of the FeCuNbSiB layer increasing from 0 μm to 90 μm,the bending resonance frequency of the MP laminated composite gradually increases from 33.66 kHz to 39.18 kHz.This study offers a method of adjusting the strength of dc magnetic bias or the thicknesses of the FeCuNbSiB layer to tune the bending resonance frequency for ME composite,which plays a guiding role in the ME composite design for real applications.

  1. Enhanced magnetoelectric coupling in a composite multiferroic system via interposing a thin film polymer

    Science.gov (United States)

    Xiao, Zhuyun; Mohanchandra, Kotekar P.; Lo Conte, Roberto; Ty Karaba, C.; Schneider, J. D.; Chavez, Andres; Tiwari, Sidhant; Sohn, Hyunmin; Nowakowski, Mark E.; Scholl, Andreas; Tolbert, Sarah H.; Bokor, Jeffrey; Carman, Gregory P.; Candler, Rob N.

    2018-05-01

    Enhancing the magnetoelectric coupling in a strain-mediated multiferroic composite structure plays a vital role in controlling magnetism by electric fields. An enhancement of magnetoelastic coupling between ferroelectric single crystal (011)-cut [Pb(Mg1/3Nb2/3)O3](1-x)-[PbTiO3]x (PMN-PT, x≈ 0.30) and ferromagnetic polycrystalline Ni thin film through an interposed benzocyclobutene polymer thin film is reported. A nearly twofold increase in sensitivity of remanent magnetization in the Ni thin film to an applied electric field is observed. This observation suggests a viable method of improving the magnetoelectric response in these composite multiferroic systems.

  2. A non-commutative formula for the isotropic magneto-electric response

    International Nuclear Information System (INIS)

    Leung, Bryan; Prodan, Emil

    2013-01-01

    A non-commutative formula for the isotropic magneto-electric response of disordered insulators under magnetic fields is derived using the methods of non-commutative geometry. Our result follows from an explicit evaluation of the Ito derivative with respect to the magnetic field of the non-commutative formula for the electric polarization reported in Schulz-Baldes and Teufel (2012 arXiv:1201.4812v1). The quantization, topological invariance and connection to a second Chern number of the magneto-electric response are discussed in the context of three-dimensional, disordered, time-reversal or inversion symmetric topological insulators. (paper)

  3. Spin-driven ferroelectricity and magneto-electric effects in frustrated magnetic systems

    International Nuclear Information System (INIS)

    Arima, Taka-hisa

    2011-01-01

    The interplay between magnetism and electricity in matter has become a central issue of condensed-matter physics. This review focuses on the ferroelectricity induced by magnetic order mostly in frustrated magnets, which is nowadays referred to as magneto-electric (ME) multiferroic, or often only as multiferroic. Some distinct types of microscopic origins relevant to the spin-driven ferroelectricity are discussed in detail. Then one sees that the frustration-based spin-driven ferroelectrics can exhibit nonlinear and giant ME responses of phase-transition type and of domain-control type, in contrast to the conventional magnetoelectrics hosting linear ME effects. (author)

  4. Stress induced magnetic-domain evolution in magnetoelectric composites

    Science.gov (United States)

    Trivedi, Harsh; Shvartsman, Vladimir V.; Lupascu, Doru C.; Medeiros, Marco S. A.; Pullar, Robert C.

    2018-06-01

    Local observation of the stress mediated magnetoelectric (ME) effect in composites has gained a great deal of interest over the last decades. However, there is an apparent lack of rigorous methods for a quantitative characterization of the ME effect at the local scale, especially in polycrystalline microstructures. In the present work, we address this issue by locally probing the surface magnetic state of barium titante–hexagonal barium ferrite (BaTiO3–BaFe12O19) ceramic composites using magnetic force microscopy (MFM). The effect of the piezoelectrically induced local stress on the magnetostrictive component (BaFe12O19, BaM) was observed in the form of the evolution of the magnetic domains. The local piezoelectric stress was induced by applying a voltage to the neighboring BaTiO3 grains, using a conductive atomic force microscopy tip. The resulting stochastic evolution of magnetic domains was studied in the context of the induced magnetoelastic anisotropy. In order to overcome the ambiguity in the domain changes observed by MFM, certain generalizations about the observed MFM contrast are put forward, followed by application of an algorithm for extracting the average micromagnetic changes. An average change in domain wall thickness of 50 nm was extracted, giving a lower limit on the corresponding induced magnetoelastic anisotropy energy. Furthermore, we demonstrate that this induced magnetomechanical energy is approximately equal to the K1 magnetocrystalline anisotropy constant of BaM, and compare it with a modeled value of applied elastic energy density. The comparison allowed us to judge the quality of the interfaces in the composite system, by roughly gauging the energy conversion ratio.

  5. Field-induced reentrant magnetoelectric phase in LiNiPO4

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Fogh, Ellen; Kihara, Takumi

    2017-01-01

    Using pulsed magnetic fields up to 30 T we have measured the bulk magnetization and electrical polarization of LiNiPO4 and have studied its magnetic structure by time-of-flight neutron Laue diffraction. Our data establish the existence of a reentrant magnetoelectric phase between 19 T and 21 T. W...

  6. A novel perovskite oxide chemically designed to show multiferroic phase boundary with room-temperature magnetoelectricity

    Science.gov (United States)

    Fernández-Posada, Carmen M.; Castro, Alicia; Kiat, Jean-Michel; Porcher, Florence; Peña, Octavio; Algueró, Miguel; Amorín, Harvey

    2016-09-01

    There is a growing activity in the search of novel single-phase multiferroics that could finally provide distinctive magnetoelectric responses at room temperature, for they would enable a range of potentially disruptive technologies, making use of the ability of controlling polarization with a magnetic field or magnetism with an electric one (for example, voltage-tunable spintronic devices, uncooled magnetic sensors and the long-searched magnetoelectric memory). A very promising novel material concept could be to make use of phase-change phenomena at structural instabilities of a multiferroic state. Indeed, large phase-change magnetoelectric response has been anticipated by a first-principles investigation of the perovskite BiFeO3-BiCoO3 solid solution, specifically at its morphotropic phase boundary between multiferroic polymorphs of rhombohedral and tetragonal symmetries. Here, we report a novel perovskite oxide that belongs to the BiFeO3-BiMnO3-PbTiO3 ternary system, chemically designed to present such multiferroic phase boundary with enhanced ferroelectricity and canted ferromagnetism, which shows distinctive room-temperature magnetoelectric responses.

  7. Nonlinear magnetoelectric effect in paraelectric state of Co4Nb2O9 single crystal

    Czech Academy of Sciences Publication Activity Database

    Cao, Ym.; Deng, Gc.; Beran, Přemysl; Feng, Zj.; Kang, Bj.; Zhang, Jc.; Guiblin, N.; Dkhil, B.; Ren, W.; Cao, Sx.

    2017-01-01

    Roč. 7, č. 10 (2017), č. článku 14079. ISSN 2045-2322 Institutional support: RVO:61389005 Keywords : magnetoelectric * single crystal * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 4.259, year: 2016

  8. Dynamic Magnetostriction of CoFe2 O4 and Its Role in Magnetoelectric Composites

    Science.gov (United States)

    Aubert, A.; Loyau, V.; Pascal, Y.; Mazaleyrat, F.; LoBue, M.

    2018-04-01

    Applications of magnetostrictive materials commonly involve the use of the dynamic deformation, i.e., the piezomagnetic effect. Usually, this effect is described by the strain derivative ∂λ /∂H , which is deduced from the quasistatic magnetostrictive curve. However, the strain derivative might not be accurate to describe dynamic deformation in semihard materials as cobalt ferrite (CFO). To highlight this issue, dynamic magnetostriction measurements of cobalt ferrite are performed and compared with the strain derivative. The experiment shows that measured piezomagnetic coefficients are much lower than the strain derivative. To point out the direct application of this effect, low-frequency magnetoelectric (ME) measurements are also conducted on bilayers CFO /Pb (Zr ,Ti )O3 . The experimental data are compared with calculated magnetoelectric coefficients which include a measured dynamic coefficient and result in very low relative error (measured for several amplitudes of the alternating field Hac, and a nonlinear response is revealed. Based on these results, a trilayer CFO/Pb (Zr ,Ti )O3 /CFO is made exhibiting a high magnetoelectric coefficient of 578 mV /A (approximately 460 mV /cm Oe ) in an ac field of 38.2 kA /m (about 48 mT) at low frequency, which is 3 times higher than the measured value at 0.8 kA /m (approximately 1 mT). We discuss the viability of using semihard materials like cobalt ferrite for dynamic magnetostrictive applications such as the magnetoelectric effect.

  9. Continuous Magnetoelectric Control in Multiferroic DyMnO3 Films with Twin-like Domains

    Science.gov (United States)

    Lu, Chengliang; Deniz, Hakan; Li, Xiang; Liu, Jun-Ming; Cheong, Sang-Wook

    2016-02-01

    The magnetic control of ferroelectric polarization is currently a central topic in the multiferroic researches, owing to the related gigantic magnetoelectric coupling and fascinating physics. Although a bunch of novel magnetoelectric effect have been discovered in multiferroics of magnetic origin, the manipulation of polarization was found to be fundamentally determined by the microscopic origin in a certain multiferroic phase, hindering the development of unusual magnetoelectric control. Here, we report emergent magnetoelectric control in DyMnO3/Nb:SrTiO3 (001) films showing twin-like domain structure. Our results demonstrate interesting magnetically induced partial switch of polarization due to the coexistence of polarizations along both the a-axis and c-axis enabled by the twin-like domain structure in DyMnO3 films, despite the polarization-switch was conventionally believed to be a one-step event in the bulk counterpart. Moreover, a continuous and periodic control of macroscopic polarization by an in-plane rotating magnetic field is evidenced in the thin films. This distinctive magnetic manipulation of polarization is the consequence of the cooperative action of the twin-like domains and the dual magnetic origin of polarization, which promises additional applications using the magnetic control of ferroelectricity.

  10. An easy way to measure accurately the direct magnetoelectric voltage coefficient of thin film devices

    Energy Technology Data Exchange (ETDEWEB)

    Poullain, Gilles, E-mail: gilles.poullain@ensicaen.fr; More-Chevalier, Joris; Cibert, Christophe; Bouregba, Rachid

    2017-01-15

    Tb{sub x}Dy{sub 1−x}Fe{sub 2}/Pt/Pb(Zr{sub x}, Ti{sub 1−x})O{sub 3} thin films were grown on Pt/TiO{sub 2}/SiO{sub 2}/Si substrate by multi-target sputtering. The magnetoelectric voltage coefficient α{sup Η}{sub ΜΕ} was determined at room temperature using a lock-in amplifier. By adding, in series in the circuit, a capacitor of the same value as that of the device under test, we were able to demonstrate that the magnetoelectric device behaves as a voltage source. Furthermore, a simple way to subtract the stray voltage arising from the flow of eddy currents in the measurement set-up, is proposed. This allows the easy and accurate determination of the true magnetoelectric voltage coefficient. A large α{sup Η}{sub ΜΕ} of 8.3 V/cm. Oe was thus obtained for a Terfenol-D/Pt/PZT thin film device, without DC magnetic field nor mechanical resonance. - Highlights: • Magnetoelectric device behaves as a voltage source. • A simple way to subtract eddy currents during the measurement, is proposed.

  11. Electric field mediated non-volatile tuning magnetism in CoPt/PMN-PT heterostructure for magnetoelectric memory devices

    Science.gov (United States)

    Yang, Y. T.; Li, J.; Peng, X. L.; Wang, X. Q.; Wang, D. H.; Cao, Q. Q.; Du, Y. W.

    2016-02-01

    We report a power efficient non-volatile magnetoelectric memory in the CoPt/(011)PMN-PT heterostructure. Two reversible and stable electric field induced coercivity states (i.e., high-HC or low-HC) are obtained due to the strain mediated converse magnetoelectric effect. The reading process of the different coercive field information written by electric fields is demonstrated by using a magnetoresistance read head. This result shows good prospects in the application of novel multiferroic devices.

  12. Progress in Dual (Piezoelectric-Magnetostrictive Phase Magnetoelectric Sintered Composites

    Directory of Open Access Journals (Sweden)

    Rashed Adnan Islam

    2012-01-01

    presented which will lead to development of high-performance magnetoelectric materials.

  13. Current—voltage characteristics of lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composites

    International Nuclear Information System (INIS)

    De-An, Pan; Shen-Gen, Zhang; Jian-Jun, Tian; Li-Jie, Qiao; Jun-Sai, Sun; Volinsky, Alex A.

    2010-01-01

    Current–voltage measurements obtained from lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composite showed that a sinusoidal current applied to the copper coil wrapped around the hollow cylinder circumference induces voltage across the lead zirconate titanate layer thickness. The current–voltage coefficient and the maximum induced voltage in lead zirconate titanate at 1 kHz and resonance (60.1 kHz) frequencies increased linearly with the number of the coil turns and the applied current. The resonance frequency corresponds to the electromechanical resonance frequency. The current–voltage coefficient can be significantly improved by optimizing the magnetoelectric structure geometry and/or increasing the number of coil turns. Hollow cylindrical lead zirconate titanate/nickel structures can be potentially used as current sensors. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  14. Piezoelectric and Magnetoelectric Thick Films for Fabricating Power Sources in Wireless Sensor Nodes

    Directory of Open Access Journals (Sweden)

    Jong-Jin Choi

    2009-08-01

    Full Text Available In this manuscript, we review the progress made in the synthesis of thick film-based piezoelectric and magnetoelectric structures for harvesting energy from mechanical vibrations and magnetic field. Piezoelectric compositions in the system Pb(Zr,TiO3–Pb(Zn1/3Nb2/3O3 (PZNT have shown promise for providing enhanced efficiency due to higher energy density and thus form the base of transducers designed for capturing the mechanical energy. Laminate structures of PZNT with magnetostrictive ferrite materials provide large magnitudes of magnetoelectric coupling and are being targeted to capture the stray magnetic field energy. We analyze the models used to predict the performance of the energy harvesters and present a full system description.

  15. NiCo-lead zirconium titanate-NiCo trilayered magnetoelectric composites prepared by electroless deposition

    International Nuclear Information System (INIS)

    Zhou, M. H.; Wang, Y. G.; Bi, K.; Fan, H. P.; Zhao, Z. S.

    2015-01-01

    The NiCo layers with various Ni/Co atomic ratio have been successfully electroless deposited on PZT layers by varying the bath composition. As the cobalt atomic ratio in the deposited layer increases from 17.2 to 54.8 wt%, the magnetostrictive coefficient decreases. The magnetoelectric effect depends strongly on the magnetostrictive properties of magnetostrictive phase. The magnetoelectric coefficient of NiCo/PZT/NiCo trilayers increases with Ni/Co atomic ratio of the deposited NiCo layers increasing from 45:55 to 83:17. A maximum ME voltage coefficient of α E,31 = 2.8 V ⋅ cm −1 ⋅ Oe −1 is obtained at a frequency of about 88 kHz, which makes these trilayers suitable for applications in actuators, transducers and sensors

  16. A shear-mode magnetoelectric heterostructure for harvesting external magnetic field energy

    Science.gov (United States)

    He, Wei; Zhang, Jitao; Lu, Yueran; Yang, Aichao; Qu, Chiwen; Yuan, Shuai

    2017-03-01

    In this paper, a magnetoelectric (ME) energy harvester is presented for scavenging external magnetic field energy. The proposed heterostructure consists of a Terfenol-D plate, a piezoelectric PZT5H plate, a NdFeB magnet, and two concentrators. The external magnetic field is concentrated to the Terfenol-D plate and the PZT5H plate working in shear-mode, which can potentially increase the magnetoelectric response. Experiments have been performed to verify the feasibility of the harvester. Under the magnetic field of 0.6 Oe, the device produces a RMS voltage of 0.53 V at the resonant frequency of 32.6 kHz. The corresponding output power reaches 44.96 μW across a 3.1 kΩ matching resistor.

  17. NiCo-lead zirconium titanate-NiCo trilayered magnetoelectric composites prepared by electroless deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, M. H.; Wang, Y. G.; Bi, K., E-mail: bike@bupt.edu.cn [State Key Laboratory of Information Photonics and Optical Communications and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Fan, H. P. [School of Mechanical and Electrical Engineering, Qingdao Technological University Qindao College, Qingdao 266106 (China); Zhao, Z. S. [Shandong Engineering Consulting Institute, Jinan 250013 (China)

    2015-04-15

    The NiCo layers with various Ni/Co atomic ratio have been successfully electroless deposited on PZT layers by varying the bath composition. As the cobalt atomic ratio in the deposited layer increases from 17.2 to 54.8 wt%, the magnetostrictive coefficient decreases. The magnetoelectric effect depends strongly on the magnetostrictive properties of magnetostrictive phase. The magnetoelectric coefficient of NiCo/PZT/NiCo trilayers increases with Ni/Co atomic ratio of the deposited NiCo layers increasing from 45:55 to 83:17. A maximum ME voltage coefficient of α{sub E,31} = 2.8 V ⋅ cm{sup −1} ⋅ Oe{sup −1} is obtained at a frequency of about 88 kHz, which makes these trilayers suitable for applications in actuators, transducers and sensors.

  18. Soft x-ray resonant diffraction study of magnetic structure in magnetoelectric Y-type hexaferrite

    Science.gov (United States)

    Ueda, H.; Tanaka, Y.; Wakabayashi, Y.; Kimura, T.

    2018-05-01

    The effect of magnetic field on the magnetic structure associated with magnetoelectric properties in a Y-type hexaferrite, Ba1.3Sr0.7CoZnFe11AlO22, was investigated by utilizing the soft x-ray resonant diffraction technique. In this hexaferrite, the so-called alternating longitudinal conical phase is stabilized at room temperature and zero magnetic field. Below room temperature, however, this phase is transformed into the so-called transverse conical phase by applying an in-plane magnetic field (≈ 0.3 T). The transverse conical phase persists even after removing the magnetic field. The magnetoelectricity, which is magnetically-induced electric polarization, observed in the hexaferrite is discussed in terms of the temperature-dependent magnetic structure at zero field.

  19. Gigantic optical magnetoelectric effect in CuB2O4

    International Nuclear Information System (INIS)

    Saito, Mitsuru; Taniguchi, Kouji; Arima, Taka-hisa

    2008-01-01

    Although it has been well known that materials in which both space inversion and time reversal symmetries are broken can host optical magneto-electric effect, i.e., change in optical constants with the reversal of propagating direction of light, the largest change in absorption ever reported on this effect was 0.2%. Here we show that optical absorption in noncentrosymmetric weak ferromagnetic material CuB 2 O 4 changes by more than 100% with reversal of a low magnetic field of 300 Oe. The gigantic optical magneto-electric effect is ascribed to the canted antiferromagnetic spin ordering of square-coordinated Cu 2+ sites, where the local inversion is slightly broken. (author)

  20. Magnetic structure driven ferroelectricity and large magnetoelectric coupling in antiferromagnet Co4Nb2O9

    Science.gov (United States)

    Srivastava, P.; Chaudhary, S.; Maurya, V.; Saha, J.; Kaushik, S. D.; Siruguri, V.; Patnaik, S.

    2018-05-01

    Synthesis and extensive structural, pyroelectric, magnetic, dielectric and magneto-electric characterizations are reported for polycrystalline Co4Nb2O9 towards unraveling the multiferroic ground state. Magnetic measurements confirm that Co4Nb2O9 becomes an anti-ferromagnet at around 28 K. Associated with the magnetic phase transition, a sharp peak in pyroelectric current indicates the appearance of strong magneto-electric coupling below Neel temperature (TN) along with large coupling constant upto 17.8 μC/m2T. Using temperature oscillation technique, we establish Co4Nb2O9 to be a genuine multiferroic with spontaneous electric polarization in the anti-ferromagnetic state in the absence of magnetic field poling. This is in agreement with our low temperature neutron diffraction studies that show the magnetic structure of Co4Nb2O9 to be that of a non-collinear anti-ferromagnet with ferroelectric ground state.

  1. Electric-field-adjustable time-dependent magnetoelectric response in martensitic FeRh alloy

    Czech Academy of Sciences Publication Activity Database

    Fina, I.; Quintana, A.; Padilla-Pantoja, J.; Martí, Xavier; Macià, F.; Sánchez, F.; Foerster, M.; Aballe, L.; Fontcuberta, J.; Sort, J.

    2017-01-01

    Roč. 9, č. 18 (2017), s. 15577-15582 ISSN 1944-8244 R&D Projects: GA MŠk(CZ) LM2011026; GA ČR GB14-37427G EU Projects: European Commission(XE) 268066 - 0MSPIN Institutional support: RVO:68378271 Keywords : magnetoelectric * martensitic alloy * multiferroic * piezoelectric * thin film Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 7.504, year: 2016

  2. DC magnetic field sensing based on the nonlinear magnetoelectric effect in magnetic heterostructures

    International Nuclear Information System (INIS)

    Burdin, Dmitrii; Chashin, Dmitrii; Ekonomov, Nikolai; Fetisov, Leonid; Fetisov, Yuri; Shamonin, Mikhail

    2016-01-01

    Recently, highly sensitive magnetic field sensors using the magnetoelectric effect in composite ferromagnetic-piezoelectric layered structures have been demonstrated. However, most of the proposed concepts are not useful for measuring dc magnetic fields, because the conductivity of piezoelectric layers results in a strong decline of the sensor’s sensitivity at low frequencies. In this paper, a novel functional principle of magnetoelectric sensors for dc magnetic field measurements is described. The sensor employs the nonlinear effect of voltage harmonic generation in a composite magnetoelectric structure under the simultaneous influence of a strong imposed ac magnetic field and a weak dc magnetic field to be measured. This physical effect arises due to the nonlinear dependence of the magnetostriction in the ferromagnetic layer on the magnetic field. A sensor prototype comprising of a piezoelectric fibre transducer sandwiched between two layers of the amorphous ferromagnetic Metglas ® alloy was fabricated. The specifications regarding the magnetic field range, frequency characteristics, and noise level were studied experimentally. The prototype showed the responsivity of 2.5 V mT −1 and permitted the measurement of dc magnetic fields in the range of ∼10 nT to about 0.4 mT. Although sensor operation is based on the nonlinear effect, the sensor response can be made linear with respect to the measured magnetic field in a broad dynamic range extending over 5 orders of magnitude. The underlying physics is explained through a simplified theory for the proposed sensor. The functionality, differences and advantages of the magnetoelectric sensor compare well with fluxgate magnetometers. The ways to enhance the sensor performance are considered. (paper)

  3. Magnetoelectric Transverse Gradient Sensor with High Detection Sensitivity and Low Gradient Noise

    OpenAIRE

    Zhang, Mingji; Or, Siu Wing

    2017-01-01

    We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME) transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG) technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites having a transverse orientation and an axial separation. The output voltage of the gradient sensor is directly obtained from the transverse MFG-induced difference in ME vo...

  4. Magnetoelectric coupling in the Haldane spin-chain system Dy2BaNiO5

    Science.gov (United States)

    Singh, Kiran; Basu, Tathamay; Chowki, S.; Mahapotra, N.; Iyer, Kartik K.; Paulose, P. L.; Sampathkumaran, E. V.

    2013-09-01

    We report the results of various measurements, namely magnetization, complex dielectric permittivity, and electric polarization (P), on Dy2BaNiO5 as a function of temperature (T) and magnetic field (H), apart from heat capacity (C), with the primary motivation of exploring the existence of magnetoelectric (ME) coupling among Haldane spin-chain systems. The M(T) and C(T) data establish long-range magnetic ordering at 58 K. The most noteworthy observations are: (i) Distinct anomalies are observed in the dielectric constant (ɛ') vs T and loss (tanδ) vs T at different temperatures (i.e., 12.5, 30, 50, and 58 K); at low temperatures, three magnetic-field-induced transitions are observed in ɛ' vs H at 6, 40, and 60 kOe. These transition temperatures and critical magnetic fields track those obtained from magnetization data, establishing the existence of strong magnetoelectric coupling in this compound. (ii) Correspondingly, electric polarization could be observed as a function of T and H in the magnetically ordered state, thereby indicating magnetism-induced ferroelectricity in this compound; this result suggests that this compound is a possible multiferroic material among spin =1 (nickel-containing) compounds, with successive magnetic transitions and strong magnetoelectric coupling.

  5. Artificial dispersion via high-order homogenization: magnetoelectric coupling and magnetism from dielectric layers

    Science.gov (United States)

    Liu, Yan; Guenneau, Sébastien; Gralak, Boris

    2013-01-01

    We investigate a high-order homogenization (HOH) algorithm for periodic multi-layered stacks. The mathematical tool of choice is a transfer matrix method. Expressions for effective permeability, permittivity and magnetoelectric coupling are explored by frequency power expansions. On the physical side, this HOH uncovers a magnetoelectric coupling effect (odd-order approximation) and artificial magnetism (even-order approximation) in moderate contrast photonic crystals. Comparing the effective parameters' expressions of a stack with three layers against that of a stack with two layers, we note that the magnetoelectric coupling effect vanishes while the artificial magnetism can still be achieved in a centre-symmetric periodic structure. Furthermore, we numerically check the effective parameters through the dispersion law and transmission property of a stack with two dielectric layers against that of an effective bianisotropic medium: they are in good agreement throughout the low-frequency (acoustic) band until the first stop band, where the analyticity of the logarithm function of the transfer matrix () breaks down. PMID:24101891

  6. Interface Magnetoelectric Coupling in Co/Pb(Zr,Ti)O3.

    Science.gov (United States)

    Vlašín, Ondřej; Jarrier, Romain; Arras, Rémi; Calmels, Lionel; Warot-Fonrose, Bénédicte; Marcelot, Cécile; Jamet, Matthieu; Ohresser, Philippe; Scheurer, Fabrice; Hertel, Riccardo; Herranz, Gervasi; Cherifi-Hertel, Salia

    2016-03-23

    Magnetoelectric coupling at multiferroic interfaces is a promising route toward the nonvolatile electric-field control of magnetization. Here, we use optical measurements to study the static and dynamic variations of the interface magnetization induced by an electric field in Co/PbZr0.2Ti0.8O3 (Co/PZT) bilayers at room temperature. The measurements allow us to identify different coupling mechanisms. We further investigate the local electronic and magnetic structure of the interface by means of transmission electron microscopy, soft X-ray magnetic circular dichroism, and density functional theory to corroborate the coupling mechanism. The measurements demonstrate a mixed linear and quadratic optical response to the electric field, which results from a magneto-electro-optical effect. We propose a decomposition method of the optical signal to discriminate between different components involved in the electric field-induced polarization rotation of the reflected light. This allows us to extract a signal that we can ascribe to interface magnetoelectric coupling. The associated surface magnetization exhibits a clear hysteretic variation of odd symmetry with respect to the electric field and nonzero remanence. The interface coupling is remarkably stable over a wide frequency range (1-50 kHz), and the application of a bias magnetic field is not necessary for the coupling to occur. These results show the potential of exploiting interface coupling with the prospect of optimizing the performance of magnetoelectric memory devices in terms of stability, as well as fast and dissipationless operation.

  7. First-Principles Study of Enhanced Magnetoelectric Effects at the Fe/MgO(001) Interface

    Science.gov (United States)

    Niranjan, M. K.; Jaswal, S. S.; Tsymbal, E. Y.; Duan, C.-G.

    2010-03-01

    The magnetoelectric effect allows affecting magnetic properties of materials by electric fields with potential for technological applications such as electrically controlled magnetic data storage. In this study we explore, using first-principles methods, the magnetoelectric effect at the Fe/MgO(001) interface^,1. By explicitly introducing an electric field in our density-functional calculations we demonstrate that the magnetic moment of Fe atoms at the interface changes linearly as a function of the applied electric field with the surface magnetoelectric coefficient being strongly enhanced as compared to that for the clean Fe(001) surface.^1 The effect originates from the increased screening charge associated with a large dielectric constant of MgO. The influence of electric field on relative occupancy of the Fe-3d orbitals leads to significant change in the surface magnetocrystalline anisotropy. These results are compared with the available experimental work.^2 Our results indicate that using high-k dielectrics at the interface with ferromagnetic metals may be very effective in controlling the magnetic properties by electric fields thereby leading to interesting device applications. ^1 C.-G. Duan et al., Phys. Rev. Lett. 101, 137201 (2008). ^2 T. Maruyama et al., Nat. Nanotech., 4, 158 (2009).

  8. Room temperature magnetoelectric coupling and electrical properties of Ni doped Co - ferrite - PZT nanocomposites

    Science.gov (United States)

    Chakraborty, Sarit; Mandal, S. K.; Dey, P.; Saha, B.

    2018-04-01

    Multiferroic magnetoelectric materials are very interesting for the researcher for the potential application in device preparation. We have prepared 0.3Ni0.5Co0.5Fe2O4 - 0.7PbZr0.58Ti0.42O3 magnetoelectric nanocomposites through chemical pyrophoric reaction process followed by solid state reaction and represented magnetoelectric coupling coefficient, thermally and magnetically tunable AC electrical properties. For the structural characterization XRD pattern and SEM micrograph have been analyzed. AC electrical properties reveal that the grain boundaries resistances are played dominating role in the conduction process in the system. Dielectric studies are represents that the dielectric polarization is decreased with frequency as well as magnetic field where it increases with increasing temperature. The dielectric profiles also represents the electromechanical resonance at a frequency of ˜183 kHz. High dielectric constant and low dielectric loss at room temperature makes the material very promising for the application of magnetic field sensor devices.

  9. Giant and universal magnetoelectric coupling in soft materials and concomitant ramifications for materials science and biology

    Science.gov (United States)

    Liu, Liping; Sharma, Pradeep

    2013-10-01

    Magnetoelectric coupling—the ability of a material to magnetize upon application of an electric field and, conversely, to polarize under the action of a magnetic field—is rare and restricted to a rather small set of exotic hard crystalline materials. Intense research activity has recently ensued on materials development, fundamental scientific issues, and applications related to this phenomenon. This tantalizing property, if present in adequate strength at room temperature, can be used to pave the way for next-generation memory devices such as miniature magnetic random access memories and multiple state memory bits, sensors, energy harvesting, spintronics, among others. In this Rapid Communication, we prove the existence of an overlooked strain mediated nonlinear mechanism that can be used to universally induce the giant magnetoelectric effect in all (sufficiently) soft dielectric materials. For soft polymer foams—which, for instance, may be used in stretchable electronics—we predict room-temperature magnetoelectric coefficients that are comparable to the best known (hard) composite materials created. We also argue, based on a simple quantitative model, that magnetoreception in some biological contexts (e.g., birds) most likely utilizes this very mechanism.

  10. Large magnetoelectric coupling in magnetically short-range ordered Bi₅Ti₃FeO₁₅ film.

    Science.gov (United States)

    Zhao, Hongyang; Kimura, Hideo; Cheng, Zhenxiang; Osada, Minoru; Wang, Jianli; Wang, Xiaolin; Dou, Shixue; Liu, Yan; Yu, Jianding; Matsumoto, Takao; Tohei, Tetsuya; Shibata, Naoya; Ikuhara, Yuichi

    2014-06-11

    Multiferroic materials, which offer the possibility of manipulating the magnetic state by an electric field or vice versa, are of great current interest. However, single-phase materials with such cross-coupling properties at room temperature exist rarely in nature; new design of nano-engineered thin films with a strong magneto-electric coupling is a fundamental challenge. Here we demonstrate a robust room-temperature magneto-electric coupling in a bismuth-layer-structured ferroelectric Bi₅Ti₃FeO₁₅ with high ferroelectric Curie temperature of ~1000 K. Bi₅Ti₃FeO₁₅ thin films grown by pulsed laser deposition are single-phase layered perovskit with nearly (00l)-orientation. Room-temperature multiferroic behavior is demonstrated by a large modulation in magneto-polarization and magneto-dielectric responses. Local structural characterizations by transmission electron microscopy and Mössbauer spectroscopy reveal the existence of Fe-rich nanodomains, which cause a short-range magnetic ordering at ~620 K. In Bi₅Ti₃FeO₁₅ with a stable ferroelectric order, the spin canting of magnetic-ion-based nanodomains via the Dzyaloshinskii-Moriya interaction might yield a robust magneto-electric coupling of ~400 mV/Oe·cm even at room temperature.

  11. Magnetoelectric coupling in layered LSMO/PZT nanostructures

    International Nuclear Information System (INIS)

    Leufke, Philipp M.

    2014-01-01

    Multiferroic thin film composites with electric field-effect driven magnetoelectric (ME) coupling offer the possibility to reversibly tune magnetic properties in materials intended for device applications. The structural and functional versatility of such artificial heterostructures makes them attractive not only for various data processing, storage and sensor applications but also for studying the fundamental ME coupling mechanisms. La 1-x Sr x MnO 3 (LSMO)/PbZr y Ti 1-y O 3 (PZT) is an ideal choice for such a composite, combining the unrivaled ferroelectric (FE) properties of PZT with the multiple electronic and magnetic phenomena exhibited by the mixed valency manganite LSMO. The main physical feature used in realization of the LSMO/PZT ME composites is a striking sensitivity of LSMO magnetism to the charge carrier density. Here, the low-doping region is of particular interest, where the competition between the fundamental magnetic coupling mechanisms, Double-Exchange (DE) versus Superexchange (SE), is most distinctive. In the present work an unconventional sputtering technique - the Large-Distance Magnetron Sputtering (LDMS) method - has been established, which allowed for epitaxial deposition of these heterostructures with highest crystallinity and markedly smooth interfaces, necessary for effective field-effect control of magnetism. The large target-substrate distance effectively suppressed the destructive oxygen ion bombardment, inherently connected with oxide sputtering, and yielded an outstanding lateral uniformity of the film stack. The latter was vital for the fabrication of large capacitor structures of several square millimeter area that were required for detecting the ME coupling in a Superconductive Quantum Interference Device (SQUID) magnetometer. The growth of LSMO on various single crystalline substrates was mastered by exploring a vast deposition parameter space, encompassing Radio Frequency (RF) and Direct Current (DC) sputtering. Commensurately

  12. Magnetoelectric coupling in layered LSMO/PZT nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Leufke, Philipp M.

    2014-01-29

    Multiferroic thin film composites with electric field-effect driven magnetoelectric (ME) coupling offer the possibility to reversibly tune magnetic properties in materials intended for device applications. The structural and functional versatility of such artificial heterostructures makes them attractive not only for various data processing, storage and sensor applications but also for studying the fundamental ME coupling mechanisms. La{sub 1-x}Sr{sub x}MnO{sub 3} (LSMO)/PbZr{sub y}Ti{sub 1-y}O{sub 3} (PZT) is an ideal choice for such a composite, combining the unrivaled ferroelectric (FE) properties of PZT with the multiple electronic and magnetic phenomena exhibited by the mixed valency manganite LSMO. The main physical feature used in realization of the LSMO/PZT ME composites is a striking sensitivity of LSMO magnetism to the charge carrier density. Here, the low-doping region is of particular interest, where the competition between the fundamental magnetic coupling mechanisms, Double-Exchange (DE) versus Superexchange (SE), is most distinctive. In the present work an unconventional sputtering technique - the Large-Distance Magnetron Sputtering (LDMS) method - has been established, which allowed for epitaxial deposition of these heterostructures with highest crystallinity and markedly smooth interfaces, necessary for effective field-effect control of magnetism. The large target-substrate distance effectively suppressed the destructive oxygen ion bombardment, inherently connected with oxide sputtering, and yielded an outstanding lateral uniformity of the film stack. The latter was vital for the fabrication of large capacitor structures of several square millimeter area that were required for detecting the ME coupling in a Superconductive Quantum Interference Device (SQUID) magnetometer. The growth of LSMO on various single crystalline substrates was mastered by exploring a vast deposition parameter space, encompassing Radio Frequency (RF) and Direct Current (DC

  13. Crystal growth of hexaferrite architecture for magnetoelectrically tunable microwave semiconductor integrated devices

    Science.gov (United States)

    Hu, Bolin

    Hexaferrites (i.e., hexagonal ferrites), discovered in 1950s, exist as any one of six crystallographic structural variants (i.e., M-, X-, Y-, W-, U-, and Z-type). Over the past six decades, the hexaferrites have received much attention owing to their important properties that lend use as permanent magnets, magnetic data storage materials, as well as components in electrical devices, particularly those operating at RF frequencies. Moreover, there has been increasing interest in hexaferrites for new fundamental and emerging applications. Among those, electronic components for mobile and wireless communications especially incorporated with semiconductor integrated circuits at microwave frequencies, electromagnetic wave absorbers for electromagnetic compatibility, random-access memory (RAM) and low observable technology, and as composite materials having low dimensions. However, of particular interest is the magnetoelectric (ME) effect discovered recently in the hexaferrites such as SrScxFe12-xO19 (SrScM), Ba2--xSrxZn 2Fe12O22 (Zn2Y), Sr4Co2Fe 36O60 (Co2U) and Sr3Co2Fe 24O41 (Co2Z), demonstrating ferroelectricity induced by the complex internal alignment of magnetic moments. Further, both Co 2Z and Co2U have revealed observable magnetoelectric effects at room temperature, representing a step toward practical applications using the ME effect. These materials hold great potential for applications, since strong magnetoelectric coupling allows switching of the FE polarization with a magnetic field (H) and vice versa. These features could lead to a new type of storage devices, such as an electric field-controlled magnetic memory. A nanoscale-driven crystal growth of magnetic hexaferrites was successfully demonstrated at low growth temperatures (25--40% lower than the temperatures required often for crystal growth). This outcome exhibits thermodynamic processes of crystal growth, allowing ease in fabrication of advanced multifunctional materials. Most importantly, the

  14. Magnetoelectric Effect in Gallium Arsenide-Nickel-Tin-Nickel Multilayer Structures

    Science.gov (United States)

    Filippov, D. A.; Tikhonov, A. A.; Laletin, V. M.; Firsova, T. O.; Manicheva, I. N.

    2018-02-01

    Experimental data have been presented for the magnetoelectric effect in nickel-tin-nickel multilayer structures grown on a GaAs substrate by cathodic electrodeposition. The method of fabricating these structures has been described, and the frequency dependence of the effect has been demonstrated. It has been shown that tin used as an intermediate layer reduces mechanical stresses due to the phase mismatch at the Ni-GaAs interface and, thus, makes it possible to grow good structures with a 70-μm-thick Ni layer. The grown structures offer good adhesion between layers and a high Q factor.

  15. Diffraction studies on the origin of giant magneto-electric effects in multiferroics

    International Nuclear Information System (INIS)

    Arima, Taka-hisa

    2009-01-01

    Magnetic ferroelectrics termed multiferroics often exhibit a giant magneto-electric response such as an appearance, disappearance, and rotation of ferroelectric polarization by the application of a magnetic field. In most multiferroics, long-wavelength spiral magnetic order arises from the competition among some magnetic exchange interactions. Spin-polarized neutron diffraction studies reveal that the ferroelectric polarization direction corresponds to the helicity of spiral magnetism. A change in magnetic order with the application of a magnetic field has been investigated for various multiferroics by means of synchrotron x-ray diffraction, because it can provide us some information about the periodicity and type of magnetic order. (author)

  16. Optical activity of oriented molecular systems in terms of the magnetoelectric tensor of gyrotropy

    International Nuclear Information System (INIS)

    Arteaga, Oriol

    2014-01-01

    The optical activity of oriented molecular systems is investigated using bianisotropic material constitutives for Maxwell's equations. It is shown that the circular birefringence and circular dichroism for an oriented system can be conveniently expressed in terms of the two components of the symmetric magnetoelectric tensor of gyrotropy that are perpendicular to this direction of light propagation. This description establishes a direct link between the optical activity measured at a certain direction and the tensors that describe the oscillating electric and magnetic dipole and electric quadrupole moments induced by the optical wave. (paper)

  17. Shape and size effects on layered Ni/PZT/Ni composites magnetoelectric performance

    Energy Technology Data Exchange (ETDEWEB)

    Pan, D A; Zhang, S G; Qiao, L J [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A [Department of Mechanical Engineering, University of South Florida, Tampa FL 33620 (United States)], E-mail: lqiao@ustb.edu.cn

    2008-09-07

    This paper presents the magnetoelectric (ME) effect in trilayered Ni/PZT/Ni composites which is related to their size and shape. The ME composites with the same interfacial areas but different geometrical shapes have different ME voltage coefficients. Longitudinal resonant modes in the rectangular and triangular trilayered ME composites were studied. One should choose optimized size, shape and working frequency of the ME composites in order to gain the maximum ME effect. This study plays a guiding role for trilayered ME composites design for real applications. (fast track communication)

  18. Magnetoelectric effect in a sandwich structure of gallium arsenide–nickel–tin–nickel

    Science.gov (United States)

    Galichyan, T. A.; Filippov, D. A.; Tihonov, A. A.; Laletin, V. M.; Firsova, T. O.; Manicheva, I. N.

    2018-04-01

    The results of investigation of the magnetoelectric effect in a nickel-tin-nickel sandwich structure obtained by galvanic deposition of gallium arsenide on a substrate are presented. The technology of constructing such structures is described and the experimental results of the frequency dependence of the effect are presented. It is shown that the use of tin as an intermediate layer reduces the mechanical stresses resulting from the incommensurability of the phases, which permits obtaining qualitative structures with the nickel thickness of about 70 μm. The resulting structures exhibit good adhesion between the layers and have a high quality factor.

  19. Eddy-current effect on resonant magnetoelectric coupling in magnetostrictive-piezoelectric laminated composites

    Science.gov (United States)

    Liu, Guoxi; Zhang, Chunli; Chen, Weiqiu; Dong, Shuxiang

    2013-07-01

    An analytical model of resonant magnetoelectric (ME) coupling in magnetostrictive (MS)-piezoelectric (PE) laminated composites in consideration of eddy-current effect in MS layer using equivalent circuit method is presented. Numerical calculations show that: (1) the eddy-current has a strong effect on ME coupling in MS-PE laminated composites at resonant frequency; and (2) the resonant ME coupling is then significantly dependent on the sizes of ME laminated composites, which were neglected in most previous theoretical analyses. The achieved results provide a theoretical guidance for the practice engineering design, manufacture, and application of ME laminated composites and devices.

  20. Jumping magneto-electric states of electrons in semiconductor multiple quantum wells

    International Nuclear Information System (INIS)

    Pfeffer, Pawel; Zawadzki, Wlodek

    2011-01-01

    Orbital and spin electron states in semiconductor multiple quantum wells in the presence of an external magnetic field transverse to the growth direction are considered. Rectangular wells of GaAs/GaAlAs and InAs/AlSb are taken as examples. It is shown that, in addition to magneto-electric states known from one-well systems, there appear magneto-electric states having a much stronger dependence of energies on a magnetic field and exhibiting an interesting anti-crossing behavior. The origin of these states is investigated and it is shown that the strong field dependence of the energies is related to an unusual 'jumping' behavior of their wavefunctions between quantum wells as the field increases. The ways of investigating the jumping states by means of interband magneto-luminescence transitions or intraband cyclotron-like transitions are considered and it is demonstrated that the jumping states can be observed. The spin g factors of electrons in the jumping states are calculated using the real values of the spin–orbit interaction and bands' nonparabolicity for the semiconductors in question. It is demonstrated that the jumping states offer a wide variety of the spin g factors

  1. Theory of magnetoelectric effect in multilayer nanocomposites on a substrate: Resonant bending-mode response

    Directory of Open Access Journals (Sweden)

    Matthias C. Krantz

    2013-05-01

    Full Text Available Resonant bending-mode magnetoelectric (ME coefficients of magnetostrictive-piezoelectric multilayer cantilevers are calculated analytically using a model developed for arbitrary multilayers on a substrate. Without quality factor effects the ME coefficient maxima in the four-dimensional parameter space of layer numbers, layer sequences, piezoelectric volume fractions, and substrate thicknesses are found to be essentially constant for nonzero substrate thickness. Global maxima occur for bilayers without substrates. Vanishing magnetoelectric response regions result from voltage cancellation in piezoelectric layers or absence of bending-mode excitation. They are determined by the neutral plane position in the multilayer stack. With Q-factor effects dominated by viscous air damping ME coefficients strongly increase with cantilever thickness primarily due to increasing resonance frequencies. The results yield a layer specific prediction of ME coefficients, resonance frequencies, and Q-factors in arbitrary multilayers and thus distinction of linear-coupling and Q-factor effects from exchange interaction, interface, or nonlinear ME effects.

  2. Bilinear magnetoelectric resistance as a probe of three-dimensional spin texture in topological surface states

    Science.gov (United States)

    He, Pan; Zhang, Steven S.-L.; Zhu, Dapeng; Liu, Yang; Wang, Yi; Yu, Jiawei; Vignale, Giovanni; Yang, Hyunsoo

    2018-05-01

    Surface states of three-dimensional topological insulators exhibit the phenomenon of spin-momentum locking, whereby the orientation of an electron spin is determined by its momentum. Probing the spin texture of these states is of critical importance for the realization of topological insulator devices, but the main technique currently available is spin- and angle-resolved photoemission spectroscopy. Here we reveal a close link between the spin texture and a new kind of magnetoresistance, which depends on the relative orientation of the current with respect to the magnetic field as well as the crystallographic axes, and scales linearly with both the applied electric and magnetic fields. This bilinear magnetoelectric resistance can be used to map the spin texture of topological surface states by simple transport measurements. For a prototypical Bi2Se3 single layer, we can map both the in-plane and out-of-plane components of the spin texture (the latter arising from hexagonal warping). Theoretical calculations suggest that the bilinear magnetoelectric resistance originates from conversion of a non-equilibrium spin current into a charge current under application of the external magnetic field.

  3. On the possibility of using X-ray Compton scattering to study magnetoelectrical properties of crystals

    Energy Technology Data Exchange (ETDEWEB)

    Collins, S. P., E-mail: steve.collins@diamond.ac.uk; Laundy, D.; Connolley, T.; Laan, G. van der; Fabrizi, F. [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom); Janssen, O. [Department of Physics, New York University, New York, NY 10003 (United States); Cooper, M. J. [Department of Physics, University of Warwick, CV4 7AL (United Kingdom); Ebert, H.; Mankovsky, S. [Universität München, Department Chemie, Haus E2.033, Butenandtstrasse 5-13, D-81377 München (Germany)

    2016-02-16

    The possibility of using X-ray Compton scattering to reveal antisymmetric components of the electron momentum density, as a fingerprint of magnetoelectric sample properties, is investigated experimentally and theoretically by studying the polar ferromagnet GaFeO{sub 3}. This paper discusses the possibility of using Compton scattering – an inelastic X-ray scattering process that yields a projection of the electron momentum density – to probe magnetoelectrical properties. It is shown that an antisymmetric component of the momentum density is a unique fingerprint of such time- and parity-odd physics. It is argued that polar ferromagnets are ideal candidates to demonstrate this phenomenon and the first experimental results are shown, on a single-domain crystal of GaFeO{sub 3}. The measured antisymmetric Compton profile is very small (≃ 10{sup −5} of the symmetric part) and of the same order of magnitude as the statistical errors. Relativistic first-principles simulations of the antisymmetric Compton profile are presented and it is shown that, while the effect is indeed predicted by theory, and scales with the size of the valence spin–orbit interaction, its magnitude is significantly overestimated. The paper outlines some important constraints on the properties of the antisymmetric Compton profile arising from the underlying crystallographic symmetry of the sample.

  4. High-sensitivity dc field magnetometer using nonlinear resonance magnetoelectric effect

    International Nuclear Information System (INIS)

    Burdin, D.A.; Chashin, D.V.; Ekonomov, N.A.; Fetisov, Y.K.; Stashkevich, A.A.

    2016-01-01

    The design and operation principle of dc field magnetometer using nonlinear resonance magnetoelectric effect in a ferromagnetic–piezoelectric structure are described. It is shown that under action of ac pumping magnetic field the structure generates the output voltage containing higher harmonics whose amplitudes depend on the dc magnetic field. Best performance of the device is obtained if the signal of the third harmonics is used for the dc field measurement. The sensitivity can be considerably (by approximately three orders of magnitude) increased if advantage is taken of the acoustic resonance of the structure at this frequency. There exists the optimal pumping field ensuring the highest sensitivity. Further increasing of this field expands the range of measurable dc fields at the expense of deteriorated sensitivity. The magnetometer fabricated on the basis of a planar langatate-Metglas structure had sensitivity up to ~1 V/Oe and allowed detection of the fields as low as ~10"−"5 Oe. - Highlights: • Operational principle and design of new type dc field magnetometer is described. • Magnetometer uses nonlinear magnetoelectric effect in a langatate-Metglas structure. • Magnetometer has sensitivity of ~1 V/Oe and detects fields as low as 10"−"5 Oe. • The proposed magnetometer can compete with well known fluxgate sensors.

  5. High-sensitivity dc field magnetometer using nonlinear resonance magnetoelectric effect

    Energy Technology Data Exchange (ETDEWEB)

    Burdin, D.A.; Chashin, D.V.; Ekonomov, N.A. [Moscow State University of Information Technologies, Radio Engineering and Electronics, Moscow (Russian Federation); Fetisov, Y.K., E-mail: fetisov@mirea.ru [Moscow State University of Information Technologies, Radio Engineering and Electronics, Moscow (Russian Federation); Stashkevich, A.A. [LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 93430 Villetaneuse (France)

    2016-05-01

    The design and operation principle of dc field magnetometer using nonlinear resonance magnetoelectric effect in a ferromagnetic–piezoelectric structure are described. It is shown that under action of ac pumping magnetic field the structure generates the output voltage containing higher harmonics whose amplitudes depend on the dc magnetic field. Best performance of the device is obtained if the signal of the third harmonics is used for the dc field measurement. The sensitivity can be considerably (by approximately three orders of magnitude) increased if advantage is taken of the acoustic resonance of the structure at this frequency. There exists the optimal pumping field ensuring the highest sensitivity. Further increasing of this field expands the range of measurable dc fields at the expense of deteriorated sensitivity. The magnetometer fabricated on the basis of a planar langatate-Metglas structure had sensitivity up to ~1 V/Oe and allowed detection of the fields as low as ~10{sup −5} Oe. - Highlights: • Operational principle and design of new type dc field magnetometer is described. • Magnetometer uses nonlinear magnetoelectric effect in a langatate-Metglas structure. • Magnetometer has sensitivity of ~1 V/Oe and detects fields as low as 10{sup −5} Oe. • The proposed magnetometer can compete with well known fluxgate sensors.

  6. Magnetic order, hysteresis, and phase coexistence in magnetoelectric LiCoPO4

    DEFF Research Database (Denmark)

    Fogh, Ellen; Toft-Petersen, Rasmus; Ressouche, Eric

    2017-01-01

    The magnetic phase diagram of magnetoelectric LiCoPO4 is established using neutron diffraction and magnetometry in fields up to 25.9 T applied along the crystallographic b axis. For fields greater than 11.9 T, the magnetic unit cell triples in size with propagation vector Q = (0, 1...... ≈ to (0, 1/2,0) appear for increasing fields in the hysteresis region below the transition field. Traces of this behavior are also observed in the magnetization. A simple model based on a mean-field approach is proposed to explain these additional ordering vectors. In the field interval 20.5-21.0 T....../3,0). A magnetized elliptic cycloid is formed with spins in the (b, c) plane and the major axis oriented along b. Such a structure allows for the magnetoelectric effect with an electric polarization along c induced by magnetic fields applied along b. Intriguingly, additional ordering vectors Q ≈ to (0, 1/4,0) and Q...

  7. Non-Resonant Magnetoelectric Energy Harvesting Utilizing Phase Transformation in Relaxor Ferroelectric Single Crystals

    Directory of Open Access Journals (Sweden)

    Peter Finkel

    2015-12-01

    Full Text Available Recent advances in phase transition transduction enabled the design of a non-resonant broadband mechanical energy harvester that is capable of delivering an energy density per cycle up to two orders of magnitude larger than resonant cantilever piezoelectric type generators. This was achieved in a [011] oriented and poled domain engineered relaxor ferroelectric single crystal, mechanically biased to a state just below the ferroelectric rhombohedral (FR-ferroelectric orthorhombic (FO phase transformation. Therefore, a small variation in an input parameter, e.g., electrical, mechanical, or thermal will generate a large output due to the significant polarization change associated with the transition. This idea was extended in the present work to design a non-resonant, multi-domain magnetoelectric composite hybrid harvester comprised of highly magnetostrictive alloy, [Fe81.4Ga18.6 (Galfenol or TbxDy1-xFe2 (Terfenol-D], and lead indium niobate–lead magnesium niobate–lead titanate (PIN-PMN-PT domain engineered relaxor ferroelectric single crystal. A small magnetic field applied to the coupled device causes the magnetostrictive element to expand, and the resulting stress forces the phase change in the relaxor ferroelectric single crystal. We have demonstrated high energy conversion in this magnetoelectric device by triggering the FR-FO transition in the single crystal by a small ac magnetic field in a broad frequency range that is important for multi-domain hybrid energy harvesting devices.

  8. A Room Temperature Ultrasensitive Magnetoelectric Susceptometer for Quantitative Tissue Iron Detection

    Science.gov (United States)

    Xi, Hao; Qian, Xiaoshi; Lu, Meng-Chien; Mei, Lei; Rupprecht, Sebastian; Yang, Qing X.; Zhang, Q. M.

    2016-07-01

    Iron is a trace mineral that plays a vital role in the human body. However, absorbing and accumulating excessive iron in body organs (iron overload) can damage or even destroy an organ. Even after many decades of research, progress on the development of noninvasive and low-cost tissue iron detection methods is very limited. Here we report a recent advance in a room-temperature ultrasensitive biomagnetic susceptometer for quantitative tissue iron detection. The biomagnetic susceptometer exploits recent advances in the magnetoelectric (ME) composite sensors that exhibit an ultrahigh AC magnetic sensitivity under the presence of a strong DC magnetic field. The first order gradiometer based on piezoelectric and magnetostrictive laminate (ME composite) structure shows an equivalent magnetic noise of 0.99 nT/rt Hz at 1 Hz in the presence of a DC magnetic field of 0.1 Tesla and a great common mode noise rejection ability. A prototype magnetoelectric liver susceptometry has been demonstrated with liver phantoms. The results indicate its output signals to be linearly responsive to iron concentrations from normal iron dose (0.05 mg Fe/g liver phantom) to 5 mg Fe/g liver phantom iron overload (100X overdose). The results here open up many innovative possibilities for compact-size, portable, cost-affordable, and room-temperature operated medical systems for quantitative determinations of tissue iron.

  9. Unidirectional Magneto-Electric Dipole Antenna for Base Station: A Review

    Science.gov (United States)

    Idayachandran, Govindanarayanan; Nakkeeran, Rangaswamy

    2018-04-01

    Unidirectional base station antenna design using Magneto-Electric Dipole (MED) has created enormous interest among the researchers due to its excellent radiation characteristics like low back radiation, symmetrical radiation at E-plane and H-plane compared to conventional patch antenna. Generally, dual polarized antennas are used to increase channel capacity and reliability of the communication systems. In order to serve the evolving mobile communication standards like long term evolution LTE and beyond, unidirectional dual polarized MED antenna are required to have broad impedance bandwidth, broad half power beamwidth, high port isolation, low cross polarization level, high front to back ratio and high gain. In this paper, the critical electrical requirements of the base station antenna and frequently used frequency bands for modern mobile communication have been presented. It is followed by brief review on broadband patch antenna and discussion on complementary antenna concepts. Finally, the performance of linearly polarized and dual polarized magneto-electric dipole antennas along with their feeding techniques are discussed and summarized. Also, design and modeling of developed MED antenna is presented.

  10. Review of multi-layered magnetoelectric composite materials and devices applications

    Science.gov (United States)

    Chu, Zhaoqiang; PourhosseiniAsl, MohammadJavad; Dong, Shuxiang

    2018-06-01

    Multiferroic materials with the coexistence of at least two ferroic orders, such as ferroelectricity, ferromagnetism, or ferroelasticity, have recently attracted ever-increasing attention due to their potential for multifunctional device applications, including magnetic and current sensors, energy harvesters, magnetoelectric (ME) random access memory and logic devices, tunable microwave devices, and ME antenna. In this article, we provide a review of the recent and ongoing research efforts in the field of multi-layered ME composites. After a brief introduction to ME composites and ME coupling mechanisms, we review recent advances in multi-layered ME composites as well as their device applications based on the direct ME effect, magnetic sensors in particular. Finally, some remaining challenges and future perspective of ME composites and their engineering applications will be discussed.

  11. Magnetoelectric investigations on poly (vinylidene fluoride)/CoFe2O4 flexible electrospun membranes

    Science.gov (United States)

    Durgaprasad, P.; Hemalatha, J.

    2018-02-01

    Flexible and free standing magnetoelectric polymer nanocomposite electrospun membranes, which exhibit both ferroelectric and magnetic orderings simultaneously, are fabricated. CoFe2O4 nanoparticles of different weight percentages are embedded as fillers in poly (vinylidene fluoride) (PVDF) matrix. The percentage of electroactive β phase is analysed using XRD and FTIR studies. Investigations on the effect of filler on the structural, functional, morphological properties are discussed. CoFe2O4 content in PVDF plays a main role in controlling the α and β phase conformations and makes significant effect on the ferroelectric and ferromagnetic properties of PVDF/CoFe2O4 membranes. The domain switching behaviour of these ferroelectric membranes is confirmed through DC-EFM studies. In addition to the coexistence of ferroelectric and ferromagnetic orderings, the cross coupling between them have been proved.

  12. Micromechanics approach to the magnetoelectric properties of laminate and fibrous piezoelectric/magnetostrictive composites

    International Nuclear Information System (INIS)

    Huang Haitao; Zhou, L.M.

    2004-01-01

    We use a micromechanics approach to study the magnetoelectric (ME) properties of the piezoelectric/magnetostrictive composite with a 2-2 laminate structure and a 3-1 fibrous structure. It is found that the 3-1 composite has a higher ME coefficient than the 2-2 one, if the volume ratio of piezoelectric material is the same. The reason is that the 3-1 fibrous composite makes use of the longitudinal piezoelectric response and the piezoelectric voltage constant g 33 is 2-3 times that of g 31 . Generally, a smaller volume ratio of the piezoelectric material will generate a higher ME response. The tensile stress at the piezoelectric/magnetostrictive interface of the 3-1 fibrous composite, however, could be high enough to induce plastic deformation or microcracks, which leads to a ME coefficient lower than the theoretically predicted one

  13. Magnetoelectric properties of Co-doped BiFeO3 nanoparticles

    Science.gov (United States)

    Shrimali, V. G.; Rathod, K. N.; Dhruv, Davit; Zankat, Alpa; Sagapariya, Khushal; Solanki, Sapana; Solanki, P. S.; Shah, N. A.; Kataria, B. R.

    2018-05-01

    The magnetoelectric (ME) properties of sol-gel grown BiFe0.95Co0.05O3 (BFCO) nanoceramics, with different sizes, were investigated at room-temperature. X-ray diffraction (XRD) measurement was performed to investigate structural properties of the samples understudy. Magnetic field-dependent dielectric permittivity has been systematically investigated in the frequency range of 20 Hz to 1 MHz. To ensure the origin of magnetodielectric response, the magnetoimpedance (MI) spectroscopy was adopted using equivalent circuit model. The a.c. conductivity was found to obey the Jonscher’s universal power law. The modifications in spiral spin structure in the BFCO nanoparticles with size less than ˜62 nm significantly affect the ME coupling parameters.

  14. Magnetoelectric Jones birefringence and dichroism in a medium of free atoms

    International Nuclear Information System (INIS)

    Mironova, P V; Ovsiannikov, V D; Chernushkin, V V

    2006-01-01

    Theoretical treatment of the magnetoelectric Jones birefringence and dichroism is developed through the bilinearity in static electric and magnetic field dipole-forbidden corrections to the amplitude of Rayleigh scattering. In particular cases of orientation of the static fields relative to the polarization and wave vectors of monochromatic radiation, the amplitude determines corrections to the refractive index of atomic gas responsible for (i) the Jones birefringence and dichroism (ii) linear birefringence and dichroism and (iii) directional anisotropy for the monochromatic wave. The analytical equations and numerical data for the indicated corrections, calculated for alkaline-earth-like atoms, determine optimal conditions for observing the effects in vapours. For resonance on 1 D 2 state essential enhancement is discovered in the frequency dependence for the ratio of refractive index anisotropy of the Jones effect to the square-root product of corresponding anisotropies determining the Kerr and Cotton-Mouton effects

  15. Theory of magnetoelectric coupling in 2-2-type magnetostrictive/piezoelectric composite film with texture

    International Nuclear Information System (INIS)

    Liu Chaoqian; Fei Weidong; Li Weili

    2008-01-01

    It is well accepted that textures in polycrystalline films have significant effects on film properties. The magnetoelectric (ME) coupling in a 2-2-type multiferroic composite film was theoretically discussed using Landau-Ginsburg-Devonshire theory, where the influences of dispersive texture and residual stress were considered. As an example, the 2-2-type CoFe 2 O 4 /BaTiO 3 composite film was theoretically analysed, wherein the case of both the magnetostrictive phase and the piezoelectric phase with (0 0 1)-oriented texture was considered. Our results show that the ME coupling is enhanced with the texture degree of the piezoelectric phase and/or the magnitude of the residual tensile stress, but weakened with the magnitude of residual compressive stress. With increasing texture degree of the magnetostrictive phase, the ME coupling is enhanced when the texture degree is smaller than a critical value, but weakened when the texture degree is larger than the critical value

  16. Magnetic structures, phase diagram and spin waves of magneto-electric LiNiPO4

    DEFF Research Database (Denmark)

    Jensen, Thomas Bagger Stibius

    2007-01-01

    LiNiPO4 is a magneto-electric material, having co-existing antiferromagnetic and ferroelectric phases when suitable magnetic fields are applied at low temperatures. Such systems have received growing interest in recent years, but the nature of the magneticelectric couplings is yet to be fully...... through the last three years, it is not the primary subject of this thesis. The objective of the phD project has been to provide groundwork that may be beneficiary to future studies of LiNiPO4. More specifically, we have mapped out the magnetic HT phase diagram with magnetic fields below 14.7 T applied...... along the crystallographic c-axis, determined the magnetic structures for the phases in the phase diagram, and have set up a spin model Hamiltonian describing the spin wave dynamics and estimating the relevant magnetic interactions....

  17. Ferroelectric ferrimagnetic LiFe2F6 : Charge-ordering-mediated magnetoelectricity

    Science.gov (United States)

    Lin, Ling-Fang; Xu, Qiao-Ru; Zhang, Yang; Zhang, Jun-Jie; Liang, Yan-Ping; Dong, Shuai

    2017-12-01

    Trirutile-type LiFe2F6 is a charge-ordered material with an Fe2 +/Fe3 + configuration. Here, its physical properties, including magnetism, electronic structure, phase transition, and charge ordering, are studied theoretically. On one hand, the charge ordering leads to improper ferroelectricity with a large polarization. On the other hand, its magnetic ground state can be tuned from the antiferromagnetic to ferrimagnetic by moderate compressive strain. Thus, LiFe2F6 can be a rare multiferroic with both large magnetization and polarization. Most importantly, since the charge ordering is the common ingredient for both ferroelectricity and magnetization, the net magnetization may be fully switched by flipping the polarization, rendering intrinsically strong magnetoelectric effects and desirable functions.

  18. Designing switchable near room-temperature multiferroics via the discovery of a novel magnetoelectric coupling

    Science.gov (United States)

    Feng, J. S.; Xu, Ke; Bellaiche, Laurent; Xiang, H. J.

    2018-05-01

    Magnetoelectric (ME) coupling is the key ingredient for realizing the cross-control of magnetism and ferroelectricity in multiferroics. However, multiferroics are not only rare, especially at room-temperature, in nature but also the overwhelming majority of known multiferroics do not exhibit highly-desired switching of the direction of magnetization when the polarization is reversed by an electric field. Here, we report group theory analysis and ab initio calculations demonstrating, and revealing the origin of, the existence of a novel form of ME coupling term in a specific class of materials that does allow such switching. This term naturally explains the previously observed electric field control of magnetism in the first known multiferroics, i.e., the Ni–X boracite family. It is also presently used to design a switchable near room-temperature multiferroic (namely, LaSrMnOsO6 perovskite) having rather large ferroelectric polarization and spontaneous magnetization, as well as strong ME coupling.

  19. Anisotropic magnetoelectric characteristics in five-layer magnetization-graded multiferroic composites

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2017-05-01

    Full Text Available We investigate the anisotropic magnetoelectric(ME characteristics for the five-layer magnetization-graded multiferroic composites(MGMC. The magnetic anisotropy and corresponding anisotropic magnetomechanical effect, demagnetization effect and magneto-mechanical damping’s dependence on magnetic field direction result in an obvious anisotropic ME coupling effect. The experimental results show that ME voltage coefficient in H33 mode is remarkably larger than the other ones (H11, H31 and H13 over the whole Hdc range. Correspondingly, ∂VME/∂Hdc arrives about 420mV/Oe at an optimum bias magnetic field of 46Oe, which is approximately 40 times larger than that of the previous reported composite. Furthermore, it also demonstrates an obvious angular dependence on dc magnetic field. Taking advantage of these specifications, the MGMC can be used to detect weak dc magnetic field and its spatial orientation.

  20. FEM Modeling of a Magnetoelectric Transducer for Autonomous Micro Sensors in Medical Application

    Science.gov (United States)

    Yang, Gang; Talleb, Hakeim; Gensbittel, Aurélie; Ren, Zhuoxiang

    2015-11-01

    In the context of wireless and autonomous sensors, this paper presents the multiphysics modeling of an energy transducer based on magnetoelectric (ME) composite for biomedical applications. The study considers the power requirement of an implanted sensor, the communication distance, the size limit of the device for minimal invasive insertion as well as the electromagnetic exposure restriction of the human body. To minimize the electromagnetic absorption by the human body, the energy source is provided by an external reader emitting low frequency magnetic field. The modeling is carried out with the finite element method by solving simultaneously the multiple physics problems including the electric load of the conditioning circuit. The simulation results show that with the T-L mode of a trilayer laminated ME composite, the transducer can deliver the required energy in respecting different constraints.

  1. The converse magnetoelectric coupling in asymmetric granule/matrix composite film with Ni/PZT component

    Science.gov (United States)

    Chen, Bo; Su, Ning-Ning; Cui, Wen-Li; Yan, Shi-Nong

    2018-04-01

    In this work, a type of asymmetric granule/matrix composite film is designed, where the Ni granule is dispersed in PZT matrix, meanwhile the top and bottom electrode is constituted by Au and SRO respectively. Predicted through the electrostatic screening model and mean field approximation, considerable electrostatic charge is induced on Ni granule surface by ferroelectric PZT polarization. Predicted through the spin splitting model and spherical shell approximation, both the magnetization and magnetic anisotropy of Ni granule are modulated by ferroelectric PZT polarization. As the volume fraction of Ni granule is increased, the electric modulation of magnetization and magnetic anisotropy is reduced and enhanced respectively. As the dimension of granule/matrix composite is varied, such modulation is retained. Due to the large area-volume ratio of nano-granule, this work benefits to realize the converse magnetoelectric coupling in nanoscale.

  2. Generation of localized strain in a thin film piezoelectric to control individual magnetoelectric heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jizhai; Liang, Cheng-Yen; Sepulveda, Abdon; Carman, Gregory P.; Lynch, Christopher S., E-mail: cslynch@seas.ucla.edu [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095 (United States); Paisley, Elizabeth A.; Ihlefeld, Jon F. [Electronic, Optical, and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    2015-08-31

    Experimental results demonstrate the ability of a surface electrode pattern to produce sufficient in-plane strain in a PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PZT) thin film clamped by a Si substrate to control magnetism in a 1000 nm diameter Ni ring. The electrode pattern and the Ni ring/PZT thin film heterostructure were designed using a finite element based micromagnetics code. The magnetoelectric heterostructures were fabricated on the PZT film using e-beam lithography and characterized using magnetic force microscopy. Application of voltage to the electrodes moved one of the “onion” state domain walls. This method enables the development of complex architectures incorporating strain-mediated multiferroic devices.

  3. Edge geometry effects on resonance response of electroplated cylindrical Ni/PZT/Ni magnetoelectric composites

    Science.gov (United States)

    Yakubov, Vladislav; Xu, Lirong; Volinsky, Alex A.; Qiao, Lijie; Pan, De'an

    2017-08-01

    Trilayer Ni/PZT/Ni cylindrical magnetoelectric (ME) composites were prepared by electrodeposition, a process, which creates sub-millimeter raised edges due to current concentration near sharp points. The ME response in both axial and vertical modes was measured with the edges, with only outer edges removed, and with both outer and inner edges removed. The ME voltage coefficient improved at resonance by 40% and 147% without the edges in the vertical and axial modes, respectively. The observed improvements in three different samples were only present at the ME resonance and no changes were detected outside of the ME resonance. Mechanical quality factor at resonance also improved with no effect on the resonant frequency. Experimentally demonstrated minor geometry changes resulted in substantial ME improvement at resonant frequency. This study demonstrates device performance optimization. The observed effects have been attributed to improved vibrations in terms of decreased damping coefficient and enhanced vibration amplitude at resonance.

  4. Performance of magnetoelectric PZT/Ni multiferroic system for energy harvesting application

    Science.gov (United States)

    Gupta, Reema; Tomar, Monika; Kumar, Ashok; Gupta, Vinay

    2017-03-01

    Magnetoelectric (ME) coefficient of Lead Zirconium Titanate (PZT) thin films has been probed for possible energy harvesting applications. Single phase PZT thin films have been deposited on nickel substrate (PZT/Ni) using pulsed laser deposition (PLD) technique. The effect of PLD process parameters on the ME coupling coefficient in the prepared systems has been investigated. The as grown PZT films on Ni substrate were found to be polycrystalline with improved ferroelectric and ferromagnetic properties. The electrical switching behavior of the PZT thin films were verified using capacitance voltage measurements, where well defined butterfly loops were obtained. The ME coupling coefficient was estimated to be in the range of 94.5 V cm-1 Oe-1-130.5 V cm-1 Oe-1 for PZT/Ni system, which is large enough for harnessing electromagnetic energy for subsequent applications.

  5. Giant magnetoelectric effect in negative magnetostrictive/piezoelectric/positive magnetostrictive semiring structure

    Science.gov (United States)

    Zeng, Lingyu; Zhou, Minhong; Bi, Ke; Lei, Ming

    2016-01-01

    Magnetoelectric (ME) Ni/PZT/TbFe2 and TbFe2/PZT composites with two semiring structures are prepared. The dependence between ME coupling and magnetostrictive property of the composite is discussed. Because Ni possesses negative magnetostrictive property and TbFe2 shows positive magnetostrictive property, the ME voltage coefficient of Ni/PZT/TbFe2 semiring structure is much larger than that of TbFe2/PZT. In these composites, the ME voltage coefficient increases and the resonance frequency gradually decreases with the increase of the semiring radius, showing that structural parameters are key factors to the composite properties. Due to the strong ME coupling effect, a giant ME voltage coefficient αE = 44.8 V cm-1 Oe-1 is obtained. This approach opens a way for the design of ME composites with giant ME voltage coefficient.

  6. Longitudinal elliptically polarized electromagnetic waves in off-diagonal magnetoelectric split-ring composites.

    Science.gov (United States)

    Chui, S T; Wang, Weihua; Zhou, L; Lin, Z F

    2009-07-22

    We study the propagation of plane electromagnetic waves through different systems consisting of arrays of split rings of different orientations. Many extraordinary EM phenomena were discovered in such systems, contributed by the off-diagonal magnetoelectric susceptibilities. We find a mode such that the electric field becomes elliptically polarized with a component in the longitudinal direction (i.e. parallel to the wavevector). Even though the group velocity [Formula: see text] and the wavevector k are parallel, in the presence of damping, the Poynting vector does not just get 'broadened', but can possess a component perpendicular to the wavevector. The speed of light can be real even when the product ϵμ is negative. Other novel properties are explored.

  7. Controlled self-assembly of multiferroic core-shell nanoparticles exhibiting strong magneto-electric effects

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasulu, Gollapudi; Hamilton, Sean L.; Lehto, Piper R.; Srinivasan, Gopalan, E-mail: srinivas@oakland.edu [Physics Department, Oakland University, Rochester, Michigan 48309-4401 (United States); Popov, Maksym [Physics Department, Oakland University, Rochester, Michigan 48309-4401 (United States); Radiophysics Department, Taras Shevchenko National University of Kyiv, Kyiv 01601 (Ukraine); Chavez, Ferman A. [Chemistry Department, Oakland University, Rochester, Michigan 48309-4401 (United States)

    2014-02-03

    Ferromagnetic-ferroelectric composites show strain mediated coupling between the magnetic and electric sub-systems due to magnetostriction and piezoelectric effects associated with the ferroic phases. We have synthesized core-shell multiferroic nano-composites by functionalizing 10–100 nm barium titanate and nickel ferrite nanoparticles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst. The core-shell structure was confirmed by electron microscopy and magnetic force microscopy. Evidence for strong strain mediated magneto-electric coupling was obtained by static magnetic field induced variations in the permittivity over 16–18 GHz and polarization and by electric field induced by low-frequency ac magnetic fields.

  8. Edge geometry effects on resonance response of electroplated cylindrical Ni/PZT/Ni magnetoelectric composites

    Directory of Open Access Journals (Sweden)

    Vladislav Yakubov

    2017-08-01

    Full Text Available Trilayer Ni/PZT/Ni cylindrical magnetoelectric (ME composites were prepared by electrodeposition, a process, which creates sub-millimeter raised edges due to current concentration near sharp points. The ME response in both axial and vertical modes was measured with the edges, with only outer edges removed, and with both outer and inner edges removed. The ME voltage coefficient improved at resonance by 40% and 147% without the edges in the vertical and axial modes, respectively. The observed improvements in three different samples were only present at the ME resonance and no changes were detected outside of the ME resonance. Mechanical quality factor at resonance also improved with no effect on the resonant frequency. Experimentally demonstrated minor geometry changes resulted in substantial ME improvement at resonant frequency. This study demonstrates device performance optimization. The observed effects have been attributed to improved vibrations in terms of decreased damping coefficient and enhanced vibration amplitude at resonance.

  9. Magnetoelectric behavior of carbonyl iron mixed Mn oxide-coated ferrite nanoparticles

    Science.gov (United States)

    Ahad, Faris B. Abdul; Lee, Shang-Fan; Hung, Dung-Shing; Yao, Yeong-Der; Yang, Ruey-Bin; Lin, Chung-Kwei; Tsay, Chien-Yie

    2010-05-01

    The dielectric and magnetic properties of manganese oxide-coated Fe3O4 nanoparticles (NPs) were measured by the cavity perturbation method at x-band microwave frequencies ranging from 7-12.5 GHz with controlled external magnetic field up to 2.2 kOe at room temperature. Different ratios (5%, 10%, and 20% by weight) of coated NPs were prepared by sol-gel method then mixed with carbonyl iron powder in epoxy matrix. The saturation magnetization is inversely proportional to the NPs ratio in the mixture between 150 and 180 emu/g. The real part of the permittivity decreased with increasing NPs concentration, but the permittivity change by magnetic field increased. The tunability behavior is explained by insulator-ferromagnetic interface magnetoelectricity and the large surface volume ratio for the NPs.

  10. Colossal magnetodielectric effect and spin flop in magnetoelectric Co4Nb2O9 crystal

    International Nuclear Information System (INIS)

    Yin, L. H.; Yang, J.; Dai, J. M.; Song, W. H.; Zhu, X. B.; Zou, Y. M.; Sun, Y. P.

    2016-01-01

    We have investigated the detailed magnetic, magnetoelectric (ME), magnetodielectric (MD) and thermal expansion properties in Co 4 Nb 2 O 9 crystal. A magnetic-field-induced spin flop was observed below antiferromagnetic (AFM) transition temperature T N . Dielectric constant at applied magnetic field nearly diverges around the AFM transition, giving rise to a colossal MD effect as high as ∼138% around T N . Theoretical analysis of the ME and MD data revealed a major contribution of critical spin fluctuation to the colossal MD effect in Co 4 Nb 2 O 9 . These results suggest that linear ME materials with large ME coupling might be potentially used to realize large MD effect for future application.

  11. Polarization and angle independent magneto-electric Fano resonance in multilayer hetero-nanoshells

    Science.gov (United States)

    Wang, Wudeng; Xiong, Li; Zheng, Li; Li, Wei; Shi, Ying; Qi, Jianguang

    2018-05-01

    In this work, we have demonstrated that the Si-SiO2 -Au multilayer hetero-nanoshells can support the polarization and angle independent magneto-electric Fano resonance. Such Fano resonance arises from the direct destructive interference between the orthogonal electric dipole mode of Au core and magnetic dipole mode of the Si shell and is independent of the angle due to the high structural symmetry. In contrast to metal particle arrays, here is a possibility to generate controllable interaction between the electric and magnetic dipole resonances of individual nanoshell with the structural features. The discrete magnetic responses provided directly by the Si shell pave the groundwork for designing the magnetic responses at optical frequencies and enable many fascinating applications in nanophotonics.

  12. A Novel Wideband Magneto-Electric Dipole Antenna with Improved Feeding Structure

    Directory of Open Access Journals (Sweden)

    N. Marwah

    2016-08-01

    Full Text Available A novel feeding structure in magneto-electric dipole antenna is proposed and analyzed, which is simpler and better in performance than previous designs, involving differential feeding.  Due to this improved feeding structure, the antenna has achieved an impedance bandwidth of 133.3% ( 0.5 GHz – 2.5 GHz, resulting into an ultra-wide band antenna. The maximum broadside gain 7.5dBi with unidirectional radiation pattern has also been reported for the entire the range of operation. Symmetry in E-plane and H-plane radiation patterns has been observed due to the symmetry in structure and excitation of antenna. The antenna has also been able to achieve cross polarization levels.

  13. Reconfigurable Magneto-Electric Dipole Antennas for Base Stations in Modern Wireless Communication Systems

    Directory of Open Access Journals (Sweden)

    Lei Ge

    2018-01-01

    Full Text Available Magneto-electric (ME dipole antennas, with the function of changing the antenna characteristics, such as frequency, polarization, or radiation patterns, are reviewed in this paper. The reconfigurability is achieved by electrically altering the states of diodes or varactors to change the surface currents distributions or reflector size of the antenna. The purpose of the designs is to obtain agile antenna characteristics together with good directive radiation performances, such as low cross-polarization level, high front-to-back ratio, and stable gain. By reconfiguring the antenna capability to support more than one wireless frequency standard, switchable polarizations, or cover tunable areas, the reconfigurable ME dipole antennas are able to switch functionality as the mission changes. Therefore, it can help increase the communication efficiency and reduce the construction cost. This shows very attractive features in base station antennas of modern wireless communication applications.

  14. Observation of the universal magnetoelectric effect in a 3D topological insulator

    Science.gov (United States)

    Dziom, V.; Shuvaev, A.; Pimenov, A.; Astakhov, G. V.; Ames, C.; Bendias, K.; Böttcher, J.; Tkachov, G.; Hankiewicz, E. M.; Brüne, C.; Buhmann, H.; Molenkamp, L. W.

    2017-01-01

    The electrodynamics of topological insulators (TIs) is described by modified Maxwell's equations, which contain additional terms that couple an electric field to a magnetization and a magnetic field to a polarization of the medium, such that the coupling coefficient is quantized in odd multiples of α/4π per surface. Here we report on the observation of this so-called topological magnetoelectric effect. We use monochromatic terahertz (THz) spectroscopy of TI structures equipped with a semitransparent gate to selectively address surface states. In high external magnetic fields, we observe a universal Faraday rotation angle equal to the fine structure constant α=e2/2hc (in SI units) when a linearly polarized THz radiation of a certain frequency passes through the two surfaces of a strained HgTe 3D TI. These experiments give insight into axion electrodynamics of TIs and may potentially be used for a metrological definition of the three basic physical constants. PMID:28504268

  15. Enhanced Broadband Vibration Energy Harvesting Using a Multimodal Nonlinear Magnetoelectric Converter

    Science.gov (United States)

    Lin, Zhiming; Yang, Jin; Zhao, Jiangxin; Zhao, Nian; Liu, Jun; Wen, Yumei; Li, Ping

    2016-07-01

    In this work, we present a multimodal wideband vibration energy harvester designed to scavenge energy from ambient vibrations over a wide frequency range. The harvester consists of a folded cantilever, three magnetoelectric (ME) transducers, and two magnetic circuits. The folded cantilever enables multi-resonant response formed by bending of each stage, and the nonlinear magnetic forces acting on the folded cantilever beam allow further broadening of the frequency response. We also investigate the effects of the position of the ME transducer on the electrical output in order to achieve optimal performance. The experimental results show that the vibration energy harvester exhibited three resonance peaks in a range of 5 Hz to 30 Hz, a wider working bandwidth of 10.1 Hz, and a maximum average power value of 31.58 μW at an acceleration of 0.6 g (with g = 9.8 m/s2).

  16. Atomically engineered ferroic layers yield a room-temperature magnetoelectric multiferroic

    Science.gov (United States)

    Mundy, Julia A.; Brooks, Charles M.; Holtz, Megan E.; Moyer, Jarrett A.; Das, Hena; Rébola, Alejandro F.; Heron, John T.; Clarkson, James D.; Disseler, Steven M.; Liu, Zhiqi; Farhan, Alan; Held, Rainer; Hovden, Robert; Padgett, Elliot; Mao, Qingyun; Paik, Hanjong; Misra, Rajiv; Kourkoutis, Lena F.; Arenholz, Elke; Scholl, Andreas; Borchers, Julie A.; Ratcliff, William D.; Ramesh, Ramamoorthy; Fennie, Craig J.; Schiffer, Peter; Muller, David A.; Schlom, Darrell G.

    2016-09-01

    Materials that exhibit simultaneous order in their electric and magnetic ground states hold promise for use in next-generation memory devices in which electric fields control magnetism. Such materials are exceedingly rare, however, owing to competing requirements for displacive ferroelectricity and magnetism. Despite the recent identification of several new multiferroic materials and magnetoelectric coupling mechanisms, known single-phase multiferroics remain limited by antiferromagnetic or weak ferromagnetic alignments, by a lack of coupling between the order parameters, or by having properties that emerge only well below room temperature, precluding device applications. Here we present a methodology for constructing single-phase multiferroic materials in which ferroelectricity and strong magnetic ordering are coupled near room temperature. Starting with hexagonal LuFeO3—the geometric ferroelectric with the greatest known planar rumpling—we introduce individual monolayers of FeO during growth to construct formula-unit-thick syntactic layers of ferrimagnetic LuFe2O4 (refs 17, 18) within the LuFeO3 matrix, that is, (LuFeO3)m/(LuFe2O4)1 superlattices. The severe rumpling imposed by the neighbouring LuFeO3 drives the ferrimagnetic LuFe2O4 into a simultaneously ferroelectric state, while also reducing the LuFe2O4 spin frustration. This increases the magnetic transition temperature substantially—from 240 kelvin for LuFe2O4 (ref. 18) to 281 kelvin for (LuFeO3)9/(LuFe2O4)1. Moreover, the ferroelectric order couples to the ferrimagnetism, enabling direct electric-field control of magnetism at 200 kelvin. Our results demonstrate a design methodology for creating higher-temperature magnetoelectric multiferroics by exploiting a combination of geometric frustration, lattice distortions and epitaxial engineering.

  17. Theory of magnetoelectric effect in multilayer nanocomposites on a substrate: Static bending-mode response

    Directory of Open Access Journals (Sweden)

    Matthias C. Krantz

    2013-02-01

    Full Text Available Magnetoelectric (ME coefficients for bending excitation in static magnetic fields and the bending response of multilayer composites with alternating magnetostrictive (MS and piezoelectric (PE layers on a substrate are investigated systematically. Theory and closed-form analytic solutions for the static magnetoelectric and the bending response coefficients are presented. Results of systematic variation of layer numbers, layer sequences, PE volume fractions, substrate thicknesses, and four different material systems (employing FeCoBSi, Terfenol-D, AlN, PZT, and Si are given for a fixed total composite thickness of 5μm. Among more than 105 structures investigated the greatest static ME coefficient of 62.3 V/cmOe is predicted for all odd layer number FeCoBSi-AlN multilayer composites on a Si substrate at vanishing substrate thickness and a PE material fraction of 38%. Varying the substrate thickness from 0μm to 20μm and the PE fraction from 0% to 100%, broad parameter regions of high ME coefficients are found for odd and large layer number nanocomposites. These regions are further enhanced to narrow maxima at vanishing substrate thickness, which correspond to structures of vanishing static bending response. For bilayers and even layer number cases broad maxima of the ME coefficient are observed at nonzero substrates and bending response. The optimal layer sequence and PE fraction depend on the material system. Bending response maxima occur at zero Si substrate thickness and nonzero PE fractions for bilayers. For multilayers nonzero Si substrates and zero PE fractions are found to be optimal. Structures of even ME layer numbers of PE-MS...Sub layer sequence display regions of vanishing bending response with large ME coefficients, i.e., produced by longitudinal excitation.

  18. From non-linear magnetoacoustics and spin reorientation transition to magnetoelectric micro/nano-systems

    Science.gov (United States)

    Tiercelin, Nicolas; Preobrazhensky, Vladimir; BouMatar, Olivier; Talbi, Abdelkrim; Giordano, Stefano; Dusch, Yannick; Klimov, Alexey; Mathurin, Théo.; Elmazria, Omar; Hehn, Michel; Pernod, Philippe

    2017-09-01

    The interaction of a strongly nonlinear spin system with a crystalline lattice through magnetoelastic coupling results in significant modifications of the acoustic properties of magnetic materials, especially in the vicinity of magnetic instabilities associated with the spin-reorientation transition (SRT). The magnetoelastic coupling transfers the critical properties of the magnetic subsystem to the elastic one, which leads to a strong decrease of the sound velocity in the vicinity of the SRT, and allows a large control over acoustic nonlinearities. The general principles of the non-linear magneto-acoustics (NMA) will be introduced and illustrated in `bulk' applications such as acoustic wave phase conjugation, multi-phonon coupling, explosive instability of magneto-elastic vibrations, etc. The concept of the SRT coupled to magnetoelastic interaction has been transferred into nanostructured magnetoelastic multilayers with uni-axial anisotropy. The high sensitivity and the non-linear properties have been demonstrated in cantilever type actuators, and phenomena such as magneto-mechanical RF demodulation have been observed. The combination of the magnetic layers with piezoelectric materials also led to stress-mediated magnetoelectric (ME) composites with high ME coefficients, thanks to the SRT. The magnetoacoustic effects of the SRT have also been studied for surface acoustic waves propagating in the magnetoelastic layers and found to be promising for highly sensitive magnetic field sensors working at room temperature. On the other hand, mechanical stress is a very efficient way to control the magnetic subsystem. The principle of a very energy efficient stress-mediated magnetoelectric writing and reading in a magnetic memory is described.

  19. Composition-microstructure-property relationships in dual phase bulk magnetoelectric composite

    Science.gov (United States)

    Islam, Rashed Adnan

    The coexistence of coupled electrical and magnetic properties in the "magnetoelectric" material has led to the possibility of developing smarter and smaller electronic components. In order to make this possibility a reality, significant efforts are required to understand the science of magnetoelectric (ME) behavior and apply this understanding to develop higher sensitivity material. The primary aims of this thesis are to identify the role of composition, microstructural variables, composite geometry, texturing, post sintering heat treatment, and nanoscale assembly on ME coefficient. The overall objective is to synthesize, characterize and utilize a high ME coefficient composite. The desired range of ME coefficient in the sintered composite is more than 1.5 V/cm.Oe. At first, a piezoelectric composition in the system of Pb(Zr,Ti)O 3 - Pb[(Zn,Ni)1/3Nb2/3]O3 was designed and synthesized which has high energy density (d.g) parameter of 18456.2 x 10-15m2/N and high g constant of 83.1 V-m/N in order to use it as the matrix in piezoelectric---magnetostrictive composite. Secondly it was found that soft piezoelectric phase shows much better magnetoelectric response. The magnetoelectric coefficient for Pb(Zr 0.52Ti0.48)O3 - 15% Pb(Zn1/3Nb 2/3)O3 [PZT - 15 PZN] - 20% Ni0.8Zn 0.2Fe2O4 was found to be around 186 mV/cm.Oe. Thridly, soft magnetic phase with lower coercivity and higher magnetization was found to be suitable for high ME coefficient. Zinc doped Ni-ferrite has higher resistivity, permeability, magnetization and it was found that with increasing Zn concentration the ME coefficient increases exhibiting maxima near 30 at% Zn (138 mV/cm.Oe). Fourthly, if the connectivity was changed from (0-3) to (2-2) which is a bilayer geometry, improved piezoelectric (d33 ˜ 80 pC/N), ferroelectric (polarization = 60 muC/cm2), magnetization (25 emu/gm) and lower coercive field (2.8 Oe) were measured. The bilayer shows an enhancement of 67% increase in ME coefficient compared to bulk

  20. Adjustability of resonance frequency by external magnetic field and bias electric field of sandwich magnetoelectric PZT/NFO/PZT composites

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ling-Fang; Feng, Xing; Sun, Kang; Liang, Ze-Yu; Xu, Qian; Liang, Jia-Yu; Yang, Chang-Ping [Hubei University, Hubei Key Laboratory of Ferro and Piezoelectric Materials and Devices, Faculty of Physics and Electronic Science, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Wuhan (China)

    2017-07-15

    Sandwich magnetoelectric composites of PZT/NFO/PZT (PNP) have been prepared by laminating PZT5, NiFe{sub 2}O{sub 4}, and PZT5 ceramics in turn with polyvinyl alcohol (PVA) paste. A systematic study of structural, magnetic and ferroelectric properties is undertaken. Structural studies carried out by X-ray diffraction indicate formation of cubic perovskite phase of PZT5 ceramic and cubic spinel phase of NiFe{sub 2}O{sub 4} ceramic. As increasing the content of PZT5 phase, ferroelectric loops and magnetic loops of PNP composites showed increasing remnant electric polarizations and decreasing remnant magnetic moments separately. Both external magnetic fields and bias voltages could regulate the basal radial resonance frequency of the composites, which should be originated with the transformation and coupling of the stress between the piezoelectric phase and magnetostrictive phase. Such magnetoelectric composite provides great opportunities for electrostatically tunable devices. (orig.)

  1. New Content Addressable Memory (CAM) Technologies for Big Data and Intelligent Electronics Enabled by Magneto-Electric Ternary CAM

    Science.gov (United States)

    2017-12-11

    AFRL-RY-WP-TR-2017-0198 NEW CONTENT ADDRESSABLE MEMORY (CAM) TECHNOLOGIES FOR BIG DATA AND INTELLIGENT ELECTRONICS ENABLED BY MAGNETO-ELECTRIC...MEMORY (CAM) TECHNOLOGIES FOR BIG DATA AND INTELLIGENT ELECTRONICS ENABLED BY MAGNETO-ELECTRIC TERNARY CAM 5a. CONTRACT NUMBER FA8650-16-1-7655 5b... electronic applications, such as internet of things, big data, wireless sensors, and mobile devices, have begun to focus on the importance of energy

  2. Magnetic reconstruction induced magnetoelectric coupling and spin-dependent tunneling in Ni/KNbO_3/Ni multiferroic tunnel junctions

    International Nuclear Information System (INIS)

    Zhang, Hu; Dai, Jian-Qing; Song, Yu-Min

    2016-01-01

    We investigate the magnetoelectric coupling and spin-polarized tunneling in Ni/KNbO_3/Ni multiferroic tunnel junctions with asymmetric interfaces based on density functional theory. The junctions have two stable polarization states. We predict a peculiar magnetoelectric effect in such junctions originating from the magnetic reconstruction of Ni near the KO-terminated interface. This reconstruction is induced by the reversal of the ferroelectric polarization of KNbO_3. Furthermore, the change in the magnetic ordering filters the spin-dependent current. This effect leads to a change in conductance by about two orders of magnitude. As a result we obtain a giant tunneling electroresistance effect. In addition, there exist sizable tunneling magnetoresistance effects for two polarization states. - Highlights: • We study the ME coupling and electron tunneling in Ni/KNbO_3/Ni junctions. • There is magnetic reconstruction of Ni atoms near the KO-terminated interface. • A peculiar magnetoelectric coupling effect is obtained. • Predicted giant tunneling electroresistance effects.

  3. Externally controlled on-demand release of anti-HIV drug using magneto-electric nanoparticles as carriers.

    Science.gov (United States)

    Nair, Madhavan; Guduru, Rakesh; Liang, Ping; Hong, Jeongmin; Sagar, Vidya; Khizroev, Sakhrat

    2013-01-01

    Although highly active anti-retroviral therapy has resulted in remarkable decline in the morbidity and mortality in AIDS patients, inadequately low delivery of anti-retroviral drugs across the blood-brain barrier results in virus persistence. The capability of high-efficacy-targeted drug delivery and on-demand release remains a formidable task. Here we report an in vitro study to demonstrate the on-demand release of azidothymidine 5'-triphosphate, an anti-human immunodeficiency virus drug, from 30 nm CoFe2O4@BaTiO3 magneto-electric nanoparticles by applying a low alternating current magnetic field. Magneto-electric nanoparticles as field-controlled drug carriers offer a unique capability of field-triggered release after crossing the blood-brain barrier. Owing to the intrinsic magnetoelectricity, these nanoparticles can couple external magnetic fields with the electric forces in drug-carrier bonds to enable remotely controlled delivery without exploiting heat. Functional and structural integrity of the drug after the release was confirmed in in vitro experiments with human immunodeficiency virus-infected cells and through atomic force microscopy, spectrophotometry, Fourier transform infrared and mass spectrometry studies.

  4. THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE MAGNETOELECTRIC SYSTEM, WHICH RECOGNIZES THE LARGE OF SUNS OF A SINGLE-SPIRAL CLASSIFIER

    Directory of Open Access Journals (Sweden)

    A. N. Matsui

    2018-02-01

    Full Text Available Purpose. The aim of the work is to create a magnetoelectric system with permanent magnets, which perceives the coarse size of the sand of a single-helix classifier, by establishing the connection of the output signal with the measured quantity, eliminating the effect of disturbances on the result and justifying its parameters. Methodology. The studies carried out on the basis of the use of methods of the theory of electrical engineering, magnetic systems with permanent magnets, galvanomagnetic transducers, probabilities, random processes, statistics, regression analysis, sensitivity, differential calculus, rock magnetism, determination of the physical properties of matrix material when impurities are added to it with others explicitly expressed properties, the classification of enrichment products. Findings. The process of the rate of change of the volume of solid in a controlled volume of space through which the sand material moves is described mathematically. The limits of the volume of the controlled volume at which the sensitivity is still sufficient are determined. The theoretical dependences of the rate of change of the solid volume in the controlled volume on the size of the sands at different speeds are obtained. It is established that the state of the controlled volume is best estimated by the magnetic method. A magnetoelectric system with permanent magnets has been developed, which has optimal parameter values and an induction winding containing up to 25,000 turns, and in one of the pole pieces of which a Hall transducer is installed in a continuous slot. The magnetic system near the air gap creates in the material a magnetic field 5 × 20 × 60 mm in size with almost the same intensity. Ed. The magnetoelectric system practically changes linearly with the increase in the size of the material. It depends on the content of magnetic iron in the solid, which is compensated by the use of the signal from the Hall converter. Correlation

  5. Resonance line shape, strain and electric potential distributions of composite magnetoelectric sensors

    Directory of Open Access Journals (Sweden)

    Martina Gerken

    2013-06-01

    Full Text Available Multiferroic composite magnetoelectric (ME sensors are based on the elastic coupling of a magnetostrictive phase and a piezoelectric phase. A deformation of the magnetostrictive phase causes strain in the piezoelectric phase and thus an induced voltage. Such sensors may be applied both for static as well as for dynamic magnetic field measurements. Particularly high sensitivities are achieved for operation at a mechanical resonance. Here, the resonance line shape of layered (2-2 composite cantilever ME sensors at the first bending-mode resonance is investigated theoretically. Finite element method (FEM simulations using a linear material model reveal an asymmetric resonance profile and a zero-response frequency for the ME coefficient. Frequency-dependent strain and electric potential distributions inside the magnetoelectric composite are studied for the case of a magnetostrictive-piezoelectric bilayer. It is demonstrated that a positive or a negative voltage may be induced across the piezoelectric layer depending on the position of the neutral plane. The frequency-dependent induced electric potential is investigated for structured cantilevers that exhibit magnetostriction only at specific positions. For static operation an induced voltage is obtained locally at positions with magnetostriction. In addition to this direct effect a resonance-assisted effect is observed for dynamic operation. Magnetostriction in a limited area of the cantilever causes a global vibration of the cantilever. Thus, deformation of the piezoelectric layer and an induced electric potential also occur in areas of the cantilever without magnetostriction. The direct and the resonance-assisted pathway may induce voltages of equal or of opposite sign. The net induced voltage results from the superposition of the two effects. As the resonance-assisted induced voltage changes sign upon passing the resonance frequency, while the direct component is constant, an asymmetric line

  6. Growth and Characterization of Magnetoelectric Fe2TeO6 Thin Films

    Science.gov (United States)

    Wang, Junlei; Colon Santana, Juan; Wu, Ning; Dowben, Peter; Binek, Christian

    2013-03-01

    Voltage-controlled spintronics is of vital importance in information technology where power consumption and Joule heating restrict progress through scaling. Motivated by spintronic concepts and specifically by device applications utilizing electrically controlled interface or boundary magnetization (BM) in magnetic thin film heterostructures, we report on growth, structural, magnetic and magnetoelectric (ME) characterization of the antiferromagnet Fe2TeO6. Magnetometry of synthesized Fe2TeO6 powder, in combination with ME susceptibility data reveals 3D Heisenberg criticality in striking similarity to the archetypical ME chromia. X-ray diffraction shows (110) texture of the PLD grown films. Measurements of the magnetic susceptibility of the latter confirm in-plane magnetic anisotropy. X-ray photoemission spectroscopy indicates a Te-O terminated (110) surface. We interpret it in terms of surface reconstruction. Measurements of X-ray magnetic circular dichroism combined with photoemission electron microscopy support the presence of electrically controllable BM in the PLD-grown Fe2TeO6 thin film. We acknowledge financial support by NSF-MRSEC & Nanoelectronics Research Initiative.

  7. Ferroelectric domain switching dynamics and memristive behaviors in BiFeO3-based magnetoelectric heterojunctions

    Science.gov (United States)

    Huang, Weichuan; Liu, Yukuai; Luo, Zhen; Hou, Chuangming; Zhao, Wenbo; Yin, Yuewei; Li, Xiaoguang

    2018-06-01

    The ferroelectric domain reversal dynamics and the corresponding resistance switching as well as the memristive behaviors in epitaxial BiFeO3 (BFO, ~150 nm) based multiferroic heterojunctions were systematically investigated. The ferroelectric domain reversal dynamics could be described by the nucleation-limited-switching model with the Lorentzian distribution of logarithmic domain-switching times. By engineering the domain states, multi and even continuously tunable resistances states, i.e. memristive states, could be non-volatilely achieved. The resistance switching speed can be as fast as 30 ns in the BFO-based multiferroic heterojunctions with a write voltage of ~20 V. By reducing the thickness of BFO, the La0.6Sr0.4MnO3/BFO (~5 nm)/La0.6Sr0.4MnO3 multiferroic tunnel junction (MFTJ) shows an even a quicker switching speed (20 ns) with a much lower operation voltage (~4 V). Importantly, the MFTJ exhibits a tunable interfacial magnetoelectric coupling related to the ferroelectric domain switching dynamics. These findings enrich the potential applications of multiferroic BFO based devices in high-speed, low-power, and high-density memories as well as future neuromorphic computational architectures.

  8. Magnetoelectric Transverse Gradient Sensor with High Detection Sensitivity and Low Gradient Noise.

    Science.gov (United States)

    Zhang, Mingji; Or, Siu Wing

    2017-10-25

    We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME) transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG) technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites having a transverse orientation and an axial separation. The output voltage of the gradient sensor is directly obtained from the transverse MFG-induced difference in ME voltage between the two ME composites and is calibrated against transverse MFGs to give a high detection sensitivity of 0.4-30.6 V/(T/m), a strong common-mode magnetic field noise rejection rate of gradient noise of 0.16-620 nT/m/ Hz in a broad frequency range of 1 Hz-170 kHz under a small baseline of 35 mm. An analysis of experimental gradient noise spectra obtained in a magnetically-unshielded laboratory environment reveals the domination of the pink (1/ f ) noise, dielectric loss noise, and power-frequency noise below 3 kHz, in addition to the circuit noise above 3 kHz, in the gradient sensor. The high detection performance, together with the added merit of passive and direct ME conversion by the large ME effect in the ME composites, makes the gradient sensor suitable for the passive, direct, and broadband detection of transverse MFGs.

  9. Magnetoelectric effect in nanogranular FeCo-MgF films at GHz frequencies

    Science.gov (United States)

    Ikeda, Kenji; Kobayashi, Nobukiyo; Arai, Ken-Ichi; Yabukami, Shin

    2018-01-01

    The magnetoelectric effect is a key issue for material science and is particularly significant in the high frequency band, where it is indispensable in industrial applications. Here, we present for the first time, a study of the high frequency tunneling magneto-dielectric (TMD) effect in nanogranular FeCo-MgF films, consisting of nanometer-sized magnetic FeCo granules dispersed in an MgF insulator matrix. Dielectric relaxation and the TMD effect are confirmed at frequencies over 10 MHz. The frequency dependence of dielectric relaxation is described by the Debye-Fröhlich model, taking relaxation time dispersion into account, which reflects variations in the nature of the microstructure, such as granule size, and the inter-spacing between the granules that affect the dielectric response. The TMD effect reaches a maximum at a frequency that is equivalent to the inverse of the relaxation time. The frequency where the peak TMD effect is observed varies between 12 MHz and 220 MHz, depending on the concentration of magnetic metal in the nanogranular films. The inter-spacing of the films decreases with increasing magnetic metal concentration, in accordance with the relaxation time. These results indicate that dielectric relaxation is controlled by changing the nanostructure, using the deposition conditions. A prospective application of these nanogranular films is in tunable impedance devices for next-generation mobile communication systems, at frequencies over 1 GHz, where capacitance is controlled using the applied magnetic field.

  10. General point dipole theory for periodic metasurfaces: magnetoelectric scattering lattices coupled to planar photonic structures.

    Science.gov (United States)

    Chen, Yuntian; Zhang, Yan; Femius Koenderink, A

    2017-09-04

    We study semi-analytically the light emission and absorption properties of arbitrary stratified photonic structures with embedded two-dimensional magnetoelectric point scattering lattices, as used in recent plasmon-enhanced LEDs and solar cells. By employing dyadic Green's function for the layered structure in combination with the Ewald lattice summation to deal with the particle lattice, we develop an efficient method to study the coupling between planar 2D scattering lattices of plasmonic, or metamaterial point particles, coupled to layered structures. Using the 'array scanning method' we deal with localized sources. Firstly, we apply our method to light emission enhancement of dipole emitters in slab waveguides, mediated by plasmonic lattices. We benchmark the array scanning method against a reciprocity-based approach to find that the calculated radiative rate enhancement in k-space below the light cone shows excellent agreement. Secondly, we apply our method to study absorption-enhancement in thin-film solar cells mediated by periodic Ag nanoparticle arrays. Lastly, we study the emission distribution in k-space of a coupled waveguide-lattice system. In particular, we explore the dark mode excitation on the plasmonic lattice using the so-called array scanning method. Our method could be useful for simulating a broad range of complex nanophotonic structures, i.e., metasurfaces, plasmon-enhanced light emitting systems and photovoltaics.

  11. Magneto-optic and converse magnetoelectric effects in a ferromagnetic liquid crystal.

    Science.gov (United States)

    Mertelj, Alenka; Osterman, Natan; Lisjak, Darja; Copič, Martin

    2014-12-07

    We have studied the response of ferromagnetic liquid crystals to external magnetic and electric fields, and compared it to the usual response of nematic liquid crystals (NLCs). We have observed effects, which are not present in a pure NLC and are a consequence of the coupling between the nematic director and the magnetization. The electro-optic effect, which is in the ferromagnetic phase the same as in the pure NLC, is accompanied by a converse magnetoelectric effect. The magneto-optic effect differs completely from the one observed in the pure NLC, where it is a quadratic effect and it only appears when a magnetic field larger than a critical field is applied perpendicular to the director. In the ferromagnetic NLC in addition to the response to the perpendicular field, there is also a qualitatively different response to the parallel field. Contrary to the pure NLC no critical field needs to be exceeded for the system to respond to a perpendicular field, but a critical field needs to be exceeded to observe a response to the field parallel to the director and antiparallel to the magnetization. The critical field is in this case two orders of magnitude smaller than the critical field of the magnetic Frederiks transition in the pure NLC. The experimental observations are well described by a simple macroscopic theory.

  12. Quantum percolation phase transition and magnetoelectric dipole glass in hexagonal ferrites

    Science.gov (United States)

    Rowley, S. E.; Vojta, T.; Jones, A. T.; Guo, W.; Oliveira, J.; Morrison, F. D.; Lindfield, N.; Baggio Saitovitch, E.; Watts, B. E.; Scott, J. F.

    2017-07-01

    Hexagonal ferrites not only have enormous commercial impact (£2 billion/year in sales) due to applications that include ultrahigh-density memories, credit-card stripes, magnetic bar codes, small motors, and low-loss microwave devices, they also have fascinating magnetic and ferroelectric quantum properties at low temperatures. Here we report the results of tuning the magnetic ordering temperature in PbF e12 -xG axO19 to zero by chemical substitution x . The phase transition boundary is found to vary as TN˜(1-x /xc ) 2 /3 with xc very close to the calculated spin percolation threshold, which we determine by Monte Carlo simulations, indicating that the zero-temperature phase transition is geometrically driven. We find that this produces a form of compositionally tuned, insulating, ferrimagnetic quantum criticality. Close to the zero-temperature phase transition, we observe the emergence of an electric dipole glass induced by magnetoelectric coupling. The strong frequency behavior of the glass freezing temperature Tm has a Vogel-Fulcher dependence with Tm finite, or suppressed below zero in the zero-frequency limit, depending on composition x . These quantum-mechanical properties, along with the multiplicity of low-lying modes near the zero-temperature phase transition, are likely to greatly extend applications of hexaferrites into the realm of quantum and cryogenic technologies.

  13. Dynamic magnetoelectric effects in bulk and layered composites of cobalt zinc ferrite and lead zirconate titanate

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, G.; Hayes, R.; DeVreugd, C.P. [Oakland University, Physics Department, Rochester, MI (United States); Laletsin, V.M.; Paddubnaya, N. [National Academy of Sciences, Institute of Technical Acoustics, Vitebsk (Belarus)

    2005-02-01

    Low-frequency magnetoelectric (ME) coupling is investigated in bulk samples and multilayers of cobalt zinc ferrite, Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0-0.6), and lead zirconate titanate. In bulk samples, the transverse and longitudinal couplings are weak and of equal magnitude. A substantial strengthening of ME interactions is evident in layered structures, with the ME voltage coefficient a factor of 10-30 higher than in bulk samples. Important findings of our studies of layered composites are as follows. (i) The transverse coupling is stronger than the longitudinal coupling. (ii) The strength of ME interactions is dependent on Zn substitution, with a maximum for x=0.4. (iii) A weak coupling exists at the ferromagnetic-piezoelectric interface, as revealed by an analysis of the volume and static magnetic field dependence of ME voltage coefficients. (iv) The interface coupling k increases with Zn substitution and the k versus x profile shows a maximum centered at x=0.4. (v) The Zn-assisted enhancement can be attributed to efficient magneto-mechanical coupling in the ferrite. (orig.)

  14. Y3Fe5O12/Na,Bi,Sr-doped PZT particulate magnetoelectric composites

    Science.gov (United States)

    Lisnevskaya, I. V.; Bobrova, I. A.; Lupeiko, T. G.; Agamirzoeva, M. R.; Myagkaya, K. V.

    2016-05-01

    Magnetoelectric (ME) composites of Na, Bi, Sr substituted lead zirconate titanate (PZT) and yttrium iron garnet having representative formula (100-x) wt% Na,Bi,Sr-doped PZT (PZTNB-1)+x wt% Y3Fe5O12 (YIG) with x=10-90 were manufactured using powdered components obtained through sol-gel processes. It is shown that the decrease in sintering temperature provided by the use of finely dispersed PZTNB-1 and YIG powders allows to significantly reduce content of fluorite-like foreign phase based on zirconium oxide, which forms due to the interfacial interaction during heat treatment and becomes stabilized by yttrium oxide. Connectivity has considerable effect on the value of ME coefficient of composite ceramics. With the same x value, ΔE/ΔH characteristic decreases when changing from 0-3-type structured composites (PZT grains embedded in ferrite matrix) to 3-3-(interpenetrating network of two phases) and especially 3-0-type samples (YIG grains embedded in PZT matrix); in the last case this can be attributed to the substrate clamping effect when ferrite grains are clamped with piezoelectric matrix. ΔE/ΔH value of 0-3 composites with x=40-60 wt% was found to be ∼1.6 mV/(cm Oe).

  15. Magnetoelectric coupling characteristics in multiferroic heterostructures with different thickness of nanocrystalline soft magnetic alloy

    Science.gov (United States)

    Chen, Lei; Wang, Yao

    2016-05-01

    Magnetoelectric(ME) coupling characteristics in multiferroic heterostructures with different thickness of nanocrystalline soft magnetic alloy has been investigated at low frequency. The ME response with obvious hysteresis, self-biased and dual-peak phenomenon is observed for multiferroic heterostructures, which results from strong magnetic interactions between two ferromagnetic materials with different magnetic properties, magnetostrictions and optimum bias magnetic fields Hdc,opti. The proposed multiferroic heterostructures not only enhance ME coupling significantly, but also broaden dc magnetic bias operating range and overcomes the limitations of narrow bias range. By optimizing the thickness of nanocrystalline soft magnetic alloy Tf, a significantly zero-biased ME voltage coefficient(MEVC) of 14.8mV/Oe (185 mV/cmṡ Oe) at Tf = 0.09 mm can be obtained, which is about 10.8 times as large as that of traditional PZT/Terfenol-D composite with a weak ME coupling at zero bias Hdc,zero. Furthermore, when Tf increases from 0.03 mm to 0.18 mm, the maximum MEVC increases nearly linearly with the increased Tf at Hdc,opti. Additionally, the experimental results demonstrate the ME response for multiferroic heterostructures spreads over a wide magnetic dc bias operating range. The excellent ME performance provides a promising and practicable application for both highly sensitive magnetic field sensors without bias and ME energy harvesters.

  16. A Simple Ultra-Wideband Magneto-Electric Dipole Antenna With High Gain

    Science.gov (United States)

    Shuai, Chen-yang; Wang, Guang-ming

    2017-12-01

    A simple ultra-wideband magneto-electric dipole antenna utilizing a differential-fed structure is designed. The antenna mainly comprises three parts, including a novel circular horned reflector, two vertical semicircular shorted patches as a magnetic dipole, and a horizontal U-shaped semicircular electric dipole. A differential feeding structure working as a perfect balun excites the designed antenna. The results of simulation have a good match with the ones of measurement. Results indicate that the designed antenna achieves a wide frequency bandwidth of 107 % which is 3.19 10.61 GHz, when VSWR is below 2. Via introducing the circular horned reflector, the designed antenna attains a steady and high gain of 12±1.5dBi. Moreover, settled broadside direction main beam, high front-to-back ratio, low cross polarization, and the symmetrical and relatively stable radiation patterns in the E-and H-plane are gotten in the impedance bandwidth range. In the practical applications, the proposed antenna that is dc grounded and has a simple structure satisfies the requirement of many outdoor antennas.

  17. High-field magnetic phase transitions and spin excitations in magnetoelectric LiNiPO4

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Jensen, Jens; Jensen, Thomas Bagger Stibius

    2011-01-01

    The magnetically ordered phases and spin dynamics of magnetoelectric LiNiPO4 have been studied in fields up to 17.3 T along the c axis. Using neutron diffraction, we show that a previously proposed linearly polarized incommensurate (IC) structure exists only for temperatures just below the Neel...... temperature T-N. The ordered IC structure at the lowest temperatures is shown instead to be an elliptically polarized canted spiral for fields larger than 12 T. The transition between the two IC phases is of second order and takes place about 2 K below T-N. For mu H-0 > 16 T and temperatures below 10 K......, the spiral structure is found to lock in to a period of five crystallographic unit cells along the b axis. Based on the neutron-diffraction data, combined with detailed magnetization measurements along all three crystallographic axes, we establish the magnetic phase diagrams for fields up to 17.3 T along c...

  18. Highly-ordered wide bandgap materials for quantized anomalous Hall and magnetoelectric effects

    Science.gov (United States)

    Otrokov, M. M.; Menshchikova, T. V.; Vergniory, M. G.; Rusinov, I. P.; Vyazovskaya, A. Yu; Koroteev, Yu M.; Bihlmayer, G.; Ernst, A.; Echenique, P. M.; Arnau, A.; Chulkov, E. V.

    2017-06-01

    An interplay of spin-orbit coupling and intrinsic magnetism is known to give rise to the quantum anomalous Hall and topological magnetoelectric effects under certain conditions. Their realization could open access to low power consumption electronics as well as many fundamental phenomena like image magnetic monopoles, Majorana fermions and others. Unfortunately, being realized very recently, these effects are only accessible at extremely low temperatures and the lack of appropriate materials that would enable the temperature increase is a most severe challenge. Here, we propose a novel material platform with unique combination of properties making it perfectly suitable for the realization of both effects at elevated temperatures. The key element of the computational material design is an extension of a topological insulator (TI) surface by a thin film of ferromagnetic insulator, which is both structurally and compositionally compatible with the TI. Following this proposal we suggest a variety of specific systems and discuss their numerous advantages, in particular wide band gaps with the Fermi level located in the gap.

  19. Tuning the competition between ferromagnetism and antiferromagnetism in a half-doped manganite through magnetoelectric coupling

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Di [University of California; Liu, Jian [University of California, Berkeley & LBNL; Okamoto, Satoshi [ORNL; Jagannatha, Suresha [Lawrence Berkeley National Laboratory (LBNL); Chen, Yi-Chun [National Cheng Kung University, Tainan, Taiwan; Yu, Pu [Tsinghua University; Chu, Ying-Hao [National Chiao Tung University, Hsinchu, Taiwan; Arenholz, Elke [Lawrence Berkeley National Laboratory (LBNL); Ramesh, Ramamoorthy [University of California, Berkeley

    2013-01-01

    We investigate the possibility of controlling the magnetic phase transition of the heterointerface between a half-doped manganite La0:5Ca0:5MnO3 and a multiferroic BiFeO3 (BFO) through magnetoelectric coupling. Using macroscopic magnetometry and element-selective x-ray magnetic circular dichroism at the Mn and Fe L edges, we discover that the ferroelectric polarization of BFO controls simultaneously the magnetization of BFO and La0.5Ca0.5MnO3 (LCMO). X-ray absorption spectra at the oxygen K edge and linear dichroism at the Mn L edge suggest that the interfacial coupling is mainly derived from the superexchange between Mn and Fe t2g spins. The combination of x-ray absorption spectroscopy and mean-field theory calculations reveals that the d-electron modulation of Mn cations changes the magnetic coupling in LCMO, which controls the enhanced canted moments of interfacial BFO via the interfacial coupling. Our results demonstrate that the competition between ferromagnetic and antiferromagnetic instability can be modulated by an electric field at the heterointerface, providing another pathway for the electrical field control of magnetism.

  20. Raman spectra, photoluminescence, magnetism and magnetoelectric coupling in pure and Fe doped BaTiO{sub 3} nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Kuldeep Chand, E-mail: kuldeep0309@yahoo.co.in [Akal School of Physics, Eternal University, Baru Sahib, Sirmour, Himachal Pradesh 173 101 (India); Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Kaur, Jaspreet [Akal School of Physics, Eternal University, Baru Sahib, Sirmour, Himachal Pradesh 173 101 (India); Kotnala, R.K. [National Physical Laboratory, New Delhi 110 012 (India)

    2013-11-25

    Highlights: •Multiferroic nanostructures by surfactant free hydrothermal method. •Stoichiometric effect on nanostructures. •Raman spectroscopy and Photoluminescence. •Transmission electron microscopy. •Magnetoelectric coupling. -- Abstract: Structural, microstructural, Raman spectroscopy, photoluminescence, saturation magnetization and magnetoelectric (ME) measurement of BaTiO{sub 3} (BFT0) and BaFe{sub 0.01}Ti{sub 0.99}O{sub 3} (BFT1) nanostructures have been studied. BFT0 and BFT1 were prepared by a hydrothermal method of processing temperature 180 °C/48 h. The X-ray diffraction pattern shows the coexistence of cubic/tetragonal and hexagonal phases for BFT0 and cubic/tetragonal for BFT1. The Raman spectra confirm the coexistence of tetragonal and hexagonal phases in BFT0 and cubic in BFT1. Transmission electron microscopy images show nanorods of hexagonal shaped faces for BFT0 and cubic shaped nanowires for BFT1. The resulting mechanism of the formation of these nanostructures is discussed. The experimental and theoretical results by photoluminescence are related to the degree of disorder existing in both BFT0 and BFT1 and suggest the presence of localized states existing inside of the band gap which are directly affected for degree of order–disorder. A strong ferromagnetism in BFT1 and diamagnetism in BFT0 is observed by magnetic hysteresis. As BFT1 is ferromagnetic, the value of linear coefficient, α called Magnetoelectric (ME) coefficient is calculated as ∼16 mV/Oe cm at a fixed frequency of 850 Hz. This ME coefficient α corresponds to induction of polarization by a magnetic field or of magnetization by an electric field. The observed optimum dc bias field at which the maximum ME coupling occurs is ∼750 Oe.

  1. Raman spectra, photoluminescence, magnetism and magnetoelectric coupling in pure and Fe doped BaTiO3 nanostructures

    International Nuclear Information System (INIS)

    Verma, Kuldeep Chand; Gupta, Vinay; Kaur, Jaspreet; Kotnala, R.K.

    2013-01-01

    Highlights: •Multiferroic nanostructures by surfactant free hydrothermal method. •Stoichiometric effect on nanostructures. •Raman spectroscopy and Photoluminescence. •Transmission electron microscopy. •Magnetoelectric coupling. -- Abstract: Structural, microstructural, Raman spectroscopy, photoluminescence, saturation magnetization and magnetoelectric (ME) measurement of BaTiO 3 (BFT0) and BaFe 0.01 Ti 0.99 O 3 (BFT1) nanostructures have been studied. BFT0 and BFT1 were prepared by a hydrothermal method of processing temperature 180 °C/48 h. The X-ray diffraction pattern shows the coexistence of cubic/tetragonal and hexagonal phases for BFT0 and cubic/tetragonal for BFT1. The Raman spectra confirm the coexistence of tetragonal and hexagonal phases in BFT0 and cubic in BFT1. Transmission electron microscopy images show nanorods of hexagonal shaped faces for BFT0 and cubic shaped nanowires for BFT1. The resulting mechanism of the formation of these nanostructures is discussed. The experimental and theoretical results by photoluminescence are related to the degree of disorder existing in both BFT0 and BFT1 and suggest the presence of localized states existing inside of the band gap which are directly affected for degree of order–disorder. A strong ferromagnetism in BFT1 and diamagnetism in BFT0 is observed by magnetic hysteresis. As BFT1 is ferromagnetic, the value of linear coefficient, α called Magnetoelectric (ME) coefficient is calculated as ∼16 mV/Oe cm at a fixed frequency of 850 Hz. This ME coefficient α corresponds to induction of polarization by a magnetic field or of magnetization by an electric field. The observed optimum dc bias field at which the maximum ME coupling occurs is ∼750 Oe

  2. Electronic and magnetic properties of magnetoelectric compound Ca2CoSi2O7: An ab initio study

    Science.gov (United States)

    Chakraborty, Jayita

    2018-05-01

    The detailed first principle density functional theory calculations are carried out to investigate the electronic and magnetic properties of magnetoelectric compound Ca2CoSi2O7. The magnetic properties of this system are analyzed by calculating various hopping integrals as well as exchange interactions and deriving the relevant spin Hamiltonian. The dominant exchange path is visualized with Wannier functions plotting. Only intra planer nearest neighbor exchange interaction is strong in this system. The magnetocrystalline anisotropy is calculated for this system, and the results of the calculation reveal that the spin quantization axis lies in the ab plane.

  3. Interface engineered ferrite@ferroelectric core-shell nanostructures: A facile approach to impart superior magneto-electric coupling

    Science.gov (United States)

    Abraham, Ann Rose; Raneesh, B.; Das, Dipankar; Oluwafemi, Oluwatobi Samuel; Thomas, Sabu; Kalarikkal, Nandakumar

    2018-04-01

    The electric field control of magnetism in multiferroics is attractive for the realization of ultra-fast and miniaturized low power device applications like nonvolatile memories. Room temperature hybrid multiferroic heterostructures with core-shell (0-0) architecture (ferrite core and ferroelectric shell) were developed via a two-step method. High-Resolution Transmission Electron Microscopy (HRTEM) images confirm the core-shell structure. The temperature dependant magnetization measurements and Mossbauer spectra reveal superparamagnetic nature of the core-shell sample. The ferroelectric hysteresis loops reveal leaky nature of the samples. The results indicate the promising applications of the samples for magneto-electric memories and spintronics.

  4. Magnetic-Field-Orientation Dependent Magnetoelectric Effect in FeBSiC/PZT/FeBSiC Composites

    Directory of Open Access Journals (Sweden)

    Jun-Xian Ye

    2014-01-01

    Full Text Available We investigate the magnetic-field-orientation dependent magnetoelectric (ME effect in the FeBSiC/Pb(Zr,TiO3(PZT/FeBSiC laminates. It is shown that, by only using the bias-magnetic-field dependent ME response measured with the magnetic-field parallel to the surface plane of PZT slab, the magnetic-field-orientation dependent ME coefficient upon magnetic-fields of various amplitudes can be obtained via computer simulations. The simulation results match well the experimental measurements, demonstrating the applicability of the ME laminates-based sensors in detecting magnetic-fields with uncertain amplitudes and/or orientations in environment.

  5. Magnetoelectric properties of Pb free Bi2FeTiO6: A theoretical investigation

    Science.gov (United States)

    Patra, Lokanath; Ravindran, P.

    2018-05-01

    The structural, electronic, magnetic and ferroelectric properties of Pb free double perovskite multiferroic Bi2FeTiO6 are investigated using density functional theory within the general gradient approximation (GGA) method. Our structural optimization using total energy calculations for different potential structures show a minimum energy for a non-centrosymmetric rhombohedral structure with R3c space group. Bi2FeTiO6 is found to be an antiferromagnetic insulator with C-type magnetic ordering with bandgap value of 0.3 eV. The calculated magnetic moment of 3.52 μB at Fe site shows the high spin arrangement of 3d electrons which is also confirmed by our orbital projected density of states analysis. We have analyzed the characteristics of bonding present between the constituents of Bi2FeTiO6 with the help of calculated partial density of states and Born effective charges. The ground state of the nearest centrosymmetric structure is found to be a G-type antiferromagnet with half metallicity showing that by the application of external electric field we can not only get a polarized state but also change the magnetic ordering and electronic structure in the present compound indicating strong magnetoelectric coupling. The cation sites the coexistence of Bi 6s lone pair (bring disproportionate charge distribution) and Ti4+ d0 ions which brings covalency produces off-center displacement and favors a non-centrosymmetric ground state and thus ferroelectricity. Our Berry phase calculation gives a polarization of 48 µCcm-2 for Bi2FeTiO6.

  6. Gradient-Type Magnetoelectric Current Sensor with Strong Multisource Noise Suppression.

    Science.gov (United States)

    Zhang, Mingji; Or, Siu Wing

    2018-02-14

    A novel gradient-type magnetoelectric (ME) current sensor operating in magnetic field gradient (MFG) detection and conversion mode is developed based on a pair of ME composites that have a back-to-back capacitor configuration under a baseline separation and a magnetic biasing in an electrically-shielded and mechanically-enclosed housing. The physics behind the current sensing process is the product effect of the current-induced MFG effect associated with vortex magnetic fields of current-carrying cables (i.e., MFG detection) and the MFG-induced ME effect in the ME composite pair (i.e., MFG conversion). The sensor output voltage is directly obtained from the gradient ME voltage of the ME composite pair and is calibrated against cable current to give the current sensitivity. The current sensing performance of the sensor is evaluated, both theoretically and experimentally, under multisource noises of electric fields, magnetic fields, vibrations, and thermals. The sensor combines the merits of small nonlinearity in the current-induced MFG effect with those of high sensitivity and high common-mode noise rejection rate in the MFG-induced ME effect to achieve a high current sensitivity of 0.65-12.55 mV/A in the frequency range of 10 Hz-170 kHz, a small input-output nonlinearity of <500 ppm, a small thermal drift of <0.2%/℃ in the current range of 0-20 A, and a high common-mode noise rejection rate of 17-28 dB from multisource noises.

  7. Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivas Puli, Venkata, E-mail: pvsri123@gmail.com [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Kumar Pradhan, Dhiren [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Gollapudi, Sreenivasulu [Department of Physics, Oakland University, Rochester, MI 48309-4401 (United States); Coondoo, Indrani [Department of Materials and Ceramic and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Panwar, Neeraj [Department of Physics, Central University of Rajasthan, Bandar Sindri, Kishangarh 305801, Rajasthan (India); Adireddy, Shiva; Chrisey, Douglas B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Katiyar, Ram S. [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States)

    2014-11-15

    Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO{sub 3} (BFO) thin films have been deposited on Pt/TiO{sub 2}/SiO{sub 2}/Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d{sub 33}) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO{sub 3} thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO{sub 3} thin films. • High magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO{sub 3} thin films. • A notable piezoelectric constant d{sub 33} ∼94 pm/V was found in BiFeO{sub 3} thin films.

  8. 360° deterministic magnetization rotation in a three-ellipse magnetoelectric heterostructure

    Science.gov (United States)

    Kundu, Auni A.; Chavez, Andres C.; Keller, Scott M.; Carman, Gregory P.; Lynch, Christopher S.

    2018-03-01

    A magnetic dipole-coupled magnetoelectric heterostructure comprised of three closely spaced ellipse shapes was designed and shown to be capable of achieving deterministic in-plane magnetization rotation. The design approach used a combination of conventional micromagnetic simulations to obtain preliminary configurations followed by simulations using a fully strain-coupled, time domain micromagnetic code for a detailed assessment of performance. The conventional micromagnetic code has short run times and was used to refine the ellipse shape and orientation, but it does not accurately capture the effects of the strain gradients present in the piezoelectric and magnetostrictive layers that contribute to magnetization reorientation. The fully coupled code was used to assess the effects of strain and magnetic field gradients on precessional switching in the side ellipses and on the resulting dipole-field driven magnetization reorientation in the center ellipse. The work led to a geometry with a CoFeB ellipse (125 nm × 95 nm × 4 nm) positioned between two smaller CoFeB ellipses (75 nm × 50 nm × 4 nm) on a 500 nm PZT-5H film substrate clamped at its bottom surface. The smaller ellipses were oriented at 45° and positioned at 70° and 250° about the central ellipse due to the film deposition on a thick substrate. A 7.3 V pulse applied to the PZT for 0.22 ns produced 180° switching of the magnetization in the outer ellipses that then drove switching in the center ellipse through dipole-dipole coupling. Full 360° deterministic rotation was achieved with a second pulse. The temporal response of the resulting design is discussed.

  9. Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO3 thin films

    International Nuclear Information System (INIS)

    Sreenivas Puli, Venkata; Kumar Pradhan, Dhiren; Gollapudi, Sreenivasulu; Coondoo, Indrani; Panwar, Neeraj; Adireddy, Shiva; Chrisey, Douglas B.; Katiyar, Ram S.

    2014-01-01

    Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO 3 (BFO) thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d 33 ) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO 3 thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO 3 thin films. • High magnetization ∼35 emu/cm 3 at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO 3 thin films. • A notable piezoelectric constant d 33 ∼94 pm/V was found in BiFeO 3 thin films

  10. Fabrication and properties of SmFe2-PZT magnetoelectric thin films

    KAUST Repository

    Giouroudi, Ioanna

    2013-05-17

    Magnetoelectric (ME) thin film composites are attracting a continually increasing interest due to their unique features and potential applications in multifunctional microdevices and integrated units such as sensors, actuators and energy harvesting modules. By combining piezoelectric and highly magnetostrictive thin films, the potentialities of these materials increase. In this paper we report the fabrication of SmFe2 and PZT thin films and the investigation of their properties. First of all, a ~ 400 nm thin SmFe film was deposited on top of Si/SiO2 substrate by magnetron sputter deposition. Afterwards, a 140 nm Pt bottom electrode was sputtered on top of the SmFe film forming a bottom electrode. Spin coating was employed for the deposition of the 150 nm thin PZT layer. A PZT solution with 10 %Pb excess was utilized for this fabrication step. Finally, circular Pt top electrodes were sputtered as top electrodes. This paper focuses on the microstructure of the individual films characterized by X-Ray diffractometer (XRD) and scanning electron microscopy (SEM). A piezoelectric evaluation system, aixPES, with TF2000E analyzer component was used for the electric hysteresis measurements of PZT thin films and a vibrating sample magnetometer (VSM) was employed for the magnetic characterization of the SmFe. The developed thin films and the fabricated double layer SmFe-PZT exhibit both good ferromagnetic and piezoelectric responses which predict a promising ME composite structure. The quantitative chemical composition of the samples was confirmed by energy dispersive spectroscopy (EDX). © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  11. Gradient-Type Magnetoelectric Current Sensor with Strong Multisource Noise Suppression

    Science.gov (United States)

    2018-01-01

    A novel gradient-type magnetoelectric (ME) current sensor operating in magnetic field gradient (MFG) detection and conversion mode is developed based on a pair of ME composites that have a back-to-back capacitor configuration under a baseline separation and a magnetic biasing in an electrically-shielded and mechanically-enclosed housing. The physics behind the current sensing process is the product effect of the current-induced MFG effect associated with vortex magnetic fields of current-carrying cables (i.e., MFG detection) and the MFG-induced ME effect in the ME composite pair (i.e., MFG conversion). The sensor output voltage is directly obtained from the gradient ME voltage of the ME composite pair and is calibrated against cable current to give the current sensitivity. The current sensing performance of the sensor is evaluated, both theoretically and experimentally, under multisource noises of electric fields, magnetic fields, vibrations, and thermals. The sensor combines the merits of small nonlinearity in the current-induced MFG effect with those of high sensitivity and high common-mode noise rejection rate in the MFG-induced ME effect to achieve a high current sensitivity of 0.65–12.55 mV/A in the frequency range of 10 Hz–170 kHz, a small input-output nonlinearity of <500 ppm, a small thermal drift of <0.2%/℃ in the current range of 0–20 A, and a high common-mode noise rejection rate of 17–28 dB from multisource noises. PMID:29443920

  12. Fabrication and properties of SmFe2-PZT magnetoelectric thin films

    KAUST Repository

    Giouroudi, Ioanna; Alnassar, Mohammed; Kosel, Jü rgen

    2013-01-01

    Magnetoelectric (ME) thin film composites are attracting a continually increasing interest due to their unique features and potential applications in multifunctional microdevices and integrated units such as sensors, actuators and energy harvesting modules. By combining piezoelectric and highly magnetostrictive thin films, the potentialities of these materials increase. In this paper we report the fabrication of SmFe2 and PZT thin films and the investigation of their properties. First of all, a ~ 400 nm thin SmFe film was deposited on top of Si/SiO2 substrate by magnetron sputter deposition. Afterwards, a 140 nm Pt bottom electrode was sputtered on top of the SmFe film forming a bottom electrode. Spin coating was employed for the deposition of the 150 nm thin PZT layer. A PZT solution with 10 %Pb excess was utilized for this fabrication step. Finally, circular Pt top electrodes were sputtered as top electrodes. This paper focuses on the microstructure of the individual films characterized by X-Ray diffractometer (XRD) and scanning electron microscopy (SEM). A piezoelectric evaluation system, aixPES, with TF2000E analyzer component was used for the electric hysteresis measurements of PZT thin films and a vibrating sample magnetometer (VSM) was employed for the magnetic characterization of the SmFe. The developed thin films and the fabricated double layer SmFe-PZT exhibit both good ferromagnetic and piezoelectric responses which predict a promising ME composite structure. The quantitative chemical composition of the samples was confirmed by energy dispersive spectroscopy (EDX). © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  13. Giant Magnetoelectric Energy Conversion Utilizing Inter-Ferroelectric Phase Transformations in Ferroics

    Science.gov (United States)

    Finkel, Peter; Staruch, Margo

    Phase transition-based electromechanical transduction permits achieving a non-resonant broadband mechanical energy conversion see (Finkel et al Actuators, 5 [1] 2. (2015)) , the idea is based on generation high energy density per cycle , at least 100x of magnitude larger than linear piezoelectric type generators in stress biased [011]cut relaxor ferroelectric Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystal can generate reversible strain >0.35% at remarkably low fields (0.1 MV/m) for tens of millions of cycles. Recently we demonstrated that large strain and polarization rotation can be generated for over 40 x 106cycles with little fatigue by realization of reversible ferroelectric-ferroelectric phase transition in [011] cut PIN-PMN-PT relaxor ferroelectric single crystal while sweeping through the transition with a low applied electric field <0.18 MV/m under mechanical stress. This methodology was extended in the present work to propose magnetoelectric (ME) composite hybrid system comprised of highly magnetostrictive alloymFe81.4Ga18.6 (Galfenol), and lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT) domain engineered relaxor ferroelectric single crystal. A small time-varying magnetic field applied to this system causes the magnetostrictive element to expand, and the resulting stress forces the phase change in the relaxor ferroelectric single crystal. ME coupling coefficient was fond to achieve 80 V/cm Oe near the FR-FO phase transition that is at least 100X of magnitude higher than any currently reported values.

  14. Study of magnetization and magnetoelectricity in CoFe2O4/BiFeO3 core-shell composites

    Science.gov (United States)

    Kuila, S.; Tiwary, Sweta; Sahoo, M. R.; Barik, A.; Babu, P. D.; Siruguri, V.; Birajdar, B.; Vishwakarma, P. N.

    2018-02-01

    CoFe2O4 (core)/BiFeO3 (shell) nanoparticles are prepared by varying the relative molar concentration of core and shell materials (40%CoFe2O4-60%BiFeO3, 50%CoFe2O4-50%BiFeO3, and 60%CoFe2O4-40%BiFeO3). The core-shell nature is confirmed from transmission electron microscopy on these samples. A plot of ΔM (=MFC-MZFC) vs temperature suggests the presence of two types of spin dynamics: (a) particle size dependent spin blocking and (b) spin-disorder. These two spin dynamic processes are found to contribute independently to the generation of magnetoelectric voltage. Very clear first order and second order magnetoelectric voltages are recorded. The resemblance of the first order magnetoelectric coefficient vs temperature plot to that of building up of order parameters in the mean field theory suggests that spin disorder can act like one of the essential ingredients in building the magnetoelectric coupling. The best result is obtained for the 50-50 composition sample, which may be due to better coupling of magnetostrictive CoFe2O4, and piezoelectric BiFeO3, because of the optimum thickness of shell and core.

  15. Effect of double layer thickness on magnetoelectric coupling in multiferroic BaTiO3-Bi0.95Gd0.05FeO3 multilayers

    Science.gov (United States)

    Hohenberger, S.; Lazenka, V.; Temst, K.; Selle, S.; Patzig, C.; Höche, T.; Grundmann, M.; Lorenz, M.

    2018-05-01

    The effect of double-layer thickness and partial substitution of Bi3+ by Gd3+ is demonstrated for multiferroic BaTiO3–BiFeO3 2–2 heterostructures. Multilayers of 15 double layers of BaTiO3 and Bi0.95Gd0.05FeO3 were deposited onto (0 0 1) oriented SrTiO3 substrates by pulsed laser deposition with various double layer thicknesses. X-ray diffraction and high resolution transmission electron microscopy investigations revealed a systematic strain tuning with layer thickness via coherently strained interfaces. The multilayers show increasingly enhanced magnetoelectric coupling with reduced double layer thickness. The maximum magnetoelectric coupling coefficient was measured to be as high as 50.8 V cm‑1 Oe‑1 in 0 T DC bias magnetic field at room temperature, and 54.9 V cm‑1 Oe‑1 above 3 T for the sample with the thinnest double layer thickness of 22.5 nm. This enhancement is accompanied by progressively increasing perpendicular magnetic anisotropy and compressive out-of-plane strain. To understand the origin of the enhanced magnetoelectric coupling in such multilayers, the temperature and magnetic field dependency of is discussed. The magnetoelectric performance of the Gd3+ substituted samples is found to be slightly enhanced when compared to unsubstituted BaTiO3–BiFeO3 multilayers of comparable double-layer thickness.

  16. Magnetoelectric coupling and spin-dependent tunneling in Fe/PbTiO3/Fe multiferroic heterostructure with a Ni monolayer inserted at one interface

    International Nuclear Information System (INIS)

    Dai, Jian-Qing; Zhang, Hu; Song, Yu-Min

    2015-01-01

    We report on first-principles calculations of a Ni monolayer inserted at one interface in the epitaxial Fe/PbTiO 3 /Fe multiferroic heterostructure, focusing on the magnetoelectric coupling and the spin-dependent transport properties. The results of magnetoelectric coupling calculations reveal an attractive approach to realize cumulative magnetoelectric effects in the ferromagnetic/ferroelectric/ferromagnetic superlattices. The underlying physics is attributed to the combinations of several different magnetoelectric coupling mechanisms such as interface bonding, spin-dependent screening, and different types of magnetic interactions. We also demonstrate that inserting a Ni monolayer at one interface in the Fe/PbTiO 3 /Fe multiferroic tunnel junction is an efficient method to produce considerable tunneling electroresistance effect by modifying the tunnel potential barrier and the interfacial electronic structure. Furthermore, coexistence of tunneling magnetoresistance and tunneling electroresistance leads to the emergence of four distinct resistance states, which can be served as a multistate-storage device. The complicated influencing factors including bulk properties of the ferromagnetic electrodes, decay rates of the evanescent states in the tunnel barrier, and the specific interfacial electronic structure provide us promising opportunities to design novel multiferroic tunnel junctions with excellent performances

  17. Magnetoelectric coupling and spin-dependent tunneling in Fe/PbTiO{sub 3}/Fe multiferroic heterostructure with a Ni monolayer inserted at one interface

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jian-Qing, E-mail: djqkust@sina.com; Zhang, Hu; Song, Yu-Min [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

    2015-08-07

    We report on first-principles calculations of a Ni monolayer inserted at one interface in the epitaxial Fe/PbTiO{sub 3}/Fe multiferroic heterostructure, focusing on the magnetoelectric coupling and the spin-dependent transport properties. The results of magnetoelectric coupling calculations reveal an attractive approach to realize cumulative magnetoelectric effects in the ferromagnetic/ferroelectric/ferromagnetic superlattices. The underlying physics is attributed to the combinations of several different magnetoelectric coupling mechanisms such as interface bonding, spin-dependent screening, and different types of magnetic interactions. We also demonstrate that inserting a Ni monolayer at one interface in the Fe/PbTiO{sub 3}/Fe multiferroic tunnel junction is an efficient method to produce considerable tunneling electroresistance effect by modifying the tunnel potential barrier and the interfacial electronic structure. Furthermore, coexistence of tunneling magnetoresistance and tunneling electroresistance leads to the emergence of four distinct resistance states, which can be served as a multistate-storage device. The complicated influencing factors including bulk properties of the ferromagnetic electrodes, decay rates of the evanescent states in the tunnel barrier, and the specific interfacial electronic structure provide us promising opportunities to design novel multiferroic tunnel junctions with excellent performances.

  18. Magnetoelectric effect in (BiFeO3x–(BaTiO31-x solid solutions

    Directory of Open Access Journals (Sweden)

    Kowal Karol

    2015-03-01

    Full Text Available The aim of the present work was to study magnetoelectric effect (ME in (BiFeO3x-(BaTiO31-x solid solutions in terms of technological conditions applied in the samples fabrication process. The rapidly growing interest in these materials is caused by their multiferroic behaviour, i.e. coexistence of both electric and magnetic ordering. It creates possibility for many innovative applications, e.g. in steering the magnetic memory by electric field and vice versa. The investigated samples of various chemical compositions (i.e. x = 0.7, 0.8 and 0.9 were prepared by the solid-state sintering method under three sets of technological conditions differing in the applied temperature and soaking time. Measurements of the magnetoelectric voltage coefficient αME were performed using a dynamic lock-in technique. The highest value of αME was observed for 0.7BiFeO3-0.3BaTiO3 solid solution sintered at the highest temperature (T = 1153 K after initial electrical poling despite that the soaking time was reduced 10 times in this case.

  19. Nonlinear magnetoelectric effect and magnetostriction in piezoelectric CsCuCl{sub 3} in paramagnetic and antiferromagnetic states

    Energy Technology Data Exchange (ETDEWEB)

    Kharkovskiy, A. I., E-mail: akharkovskiy@inbox.ru [International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, 53-421 Wrocław (Poland); L.F. Vereshchagin Institute for High Pressure Physics RAS, 142190 Troitsk, Moscow (Russian Federation); Shaldin, Yu. V. [International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, 53-421 Wrocław (Poland); Institute for Crystallography RAS, Lenin' s Avenue 59, 119333 Moscow (Russian Federation); Nizhankovskii, V. I. [International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, 53-421 Wrocław (Poland)

    2016-01-07

    The direct nonlinear magnetoelectric (ME) effect and the magnetostriction of piezoelectric CsCuCl{sub 3} single crystals were comprehensively studied over a wide temperature range in stationary magnetic fields of up to 14 T. The direct nonlinear ME effect measurements were also performed in pulsed magnetic fields up to 31 T, at liquid helium temperature in the antiferromagnetic (AF) state for the crystallographic direction in which effect has the maximum value. The nonlinear ME effect was quadratic in the paramagnetic state for the whole range of magnetic fields. In the AF state the phase transition between different configurations of spins manifested itself as plateau-like peculiarity on the nonlinear ME effect. The nonlinear ME effect was saturated by the phase transition to the spin-saturated paramagnetic state. Two contributions to the nonlinear ME effects in CsCuCl{sub 3} were extracted from the experimental data: the intrinsic ME effect originated from the magnetoelectric interactions, and the extrinsic one, which resulted from a magnetostriction-induced piezoelectric effect.

  20. Resonant magnetoelectric response of composite cantilevers: Theory of short vs. open circuit operation and layer sequence effects

    Directory of Open Access Journals (Sweden)

    Matthias C. Krantz

    2015-11-01

    Full Text Available The magnetoelectric effect in layered composite cantilevers consisting of strain coupled layers of magnetostrictive (MS, piezoelectric (PE, and substrate materials is investigated for magnetic field excitation at bending resonance. Analytic theories are derived for the transverse magnetoelectric (ME response in short and open circuit operation for three different layer sequences and results presented and discussed for the FeCoBSi-AlN-Si and the FeCoBSi-PZT-Si composite systems. Response optimized PE-MS layer thickness ratios are found to greatly change with operation mode shifting from near equal MS and PE layer thicknesses in the open circuit mode to near vanishing PE layer thicknesses in short circuit operation for all layer sequences. In addition the substrate layer thickness is found to differently affect the open and short circuit ME response producing shifts and reversal between ME response maxima depending on layer sequence. The observed rich ME response behavior for different layer thicknesses, sequences, operating modes, and PE materials can be explained by common neutral plane effects and different elastic compliance effects in short and open circuit operation.

  1. Magnetic and magnetoelectric properties of NdCrTiO5 revealed by systematically rare-earth doping

    Science.gov (United States)

    Li, Qing; Feng, Zhenjie; Cheng, Cheng; Wang, Bojie; Chu, Hao; Huang, Ping; Wang, Difei; Qian, Xiaolong; Yu, Chuan; Wang, Guohua; Deng, Dongmei; Jing, Chao; Cao, Shixun; Zhang, Jincang

    2018-01-01

    We have systematically synthesized polycrystalline samples of Nd0.9A0.1CrTiO5 (A = Pr, Nd, Gd, Dy, Er, Tm, and Yb), and have investigated their crystal structure, polarization and magnetic susceptibility. The polarization values of doped samples are suppressed comparing to pure NdCrTiO5 sample, which indicates that the polarization is highly dependence with the magnetic moments of doping ions. The TN of Cr-Cr in Nd0.9A0.1CrTiO5 are dominated by both the suppression effect caused by doped magnetic moment increment and the enhancement effect caused by c axis contracting. We conclude that the magnetic moments in the rare-earth Nd sites play an important role in the magnetoelectric effect in NdCrTiO5 family. The substitution effect discussion here can help us well understand the intrinsic mechanism and provide a possible guidance in exploring new magnetoelectric coupling systems.

  2. Surface and bulk polaritons in a PML-type magnetoelectric multiferroic with canted spins: TE and TM polarization

    Energy Technology Data Exchange (ETDEWEB)

    Gunawan, V; Stamps, R L, E-mail: slamev01@student.uwa.edu.au [School of Physics M013, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

    2011-03-16

    We present a theory for surface polaritons on ferroelectric-antiferromagnetic materials with canted spin structure. A small uniform canted moment is allowed, resulting in a weak ferromagnetism directed in the plane parallel to the surface. Surface and bulk polariton modes for a semi-infinite film are calculated for the case of transverse electric (TE) and transverse magnetic (TM) polarization. Example results are presented using parameters appropriate for BaMnF{sub 4}. We find that the surface modes are non-reciprocal for the TE polarization due to the magnetoelectric interaction, and the non-reciprocity can be controlled by an applied electric field. Example results for attenuated total reflection (ATR) are calculated. The magnetoelectric interaction also gives rise to 'leaky' surface modes in the case of TM polarization. These are pseudo-surface waves that exist in the pass band, and dissipate energy into the bulk of the material. We show that these pseudo-surface mode frequencies and properties can be modified by temperature and the application of external electric or magnetic fields.

  3. Effect of annealing temperature on the magnetoelectric properties of CoFe{sub 2}O{sub 4}/Pt/Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Eum, You Jeong; Hwang, Sung Ok; Koo, Chang Young; Lee, Jai Yeoul; Lee, Hee Young [Yeungnam University, Gyeongsan (Korea, Republic of); Ryu, Jung Ho [Korea Institute of Materials Science, Changwon (Korea, Republic of); Park, Jung Min [Osaka University, Osaka (Japan)

    2014-08-15

    CoFe{sub 2}O{sub 4}(CoFO)/Pt/Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) multilayer films were grown on Pt/Ti/SiO{sub 2}/Si substrates. A thin Pt layer was inserted between the ferrimagnetic and the ferroelectric layers in order to suppress diffusion at high temperatures and thereby to prevent possible interfacial reactions. The effect of annealing on the film's microstructure and multiferroic properties was then investigated using thin film stacks heat-treated at temperatures ranging from 550 to 650 .deg. C. The magnetoelectric coefficients were calculated from the magnetoelectric voltages measured using a magnetoelectric measurement system. The effect of annealing temperature on the magnetoelectric coupling in the CoFO/Pt/PZT multilayer thin film is discussed in detail.

  4. The Magnetoelectric Effect of a Ni0.3Zn0.62Cu0.08Fe2O4 - PbFe0.5Nb0.5O3 Multilayer Composite

    Directory of Open Access Journals (Sweden)

    Guzdek P.

    2014-10-01

    Full Text Available The magnetoelectric effect in multiferroic materials has been widely studied for its fundamental interest and practical applications. The magnetoelectric effect observed for single phase materials like Cr2O3, BiFeO3, and Pb(Fe0.5Nb0.5O3 is usually small. A much larger effect can be obtained in composites consisting of magnetostrictive and piezoelectric phases. This paper investigates the magnetoelectric effect of a multilayer (laminated structure consisting of 6 nickel ferrite and 7 PFN relaxor layers. It describes the synthesis and tape casting process for Ni0.3Zn0.62Cu0.08Fe2O4 ferrite and relaxor PbFe0.5Nb0.5O3 (PFN. Magnetic hysteresis, ZFC - FC curves and dependencies of magnetization versus temperature for PFN relaxor and magnetoelectric composite were measured with a vibrating sample magnetometer (VSM in an applied magnetic field up to 85 kOe at a temperature range of 10 – 400 K. Magnetoelectric effect at room temperature was investigated as a function of a static magnetic field (0.3 - 6.5 kOe and the frequency of sinusoidal magnetic field (0.01 - 6.5 kHz. At lower magnetic field, the magnetoelectric coefficient increases slightly before reaching a maximum and then decreases. The magnetoelectric coefficient aME increases continuously as the frequency is raised, although this increase is less pronounced in the 1-6.5 kHz range. Maximum values of the magnetoelectric coefficient attained for the layered composites exceed about 50 mV/(Oe cm.

  5. Magnetoelectric(ME) Composites and Functional Devices Based on ME Effect

    Science.gov (United States)

    Gao, Junqi

    Magnetoelectric (ME) effect, a cross-coupling effect between magnetic and electric orders, has stimulated lots of investigations due to the potential for applications as multifunctional devices. In this thesis, I have investigated and optimized the ME effect in Metglas/piezo-fibers ME composites with a multi-push pull configuration. Moreover, I have also proposed several devices based on such composites. In this thesis, several methods for ME composites optimization have been investigated. (i) the ME coefficients can be enhanced greatly by using single crystal fibers with high piezoelectric properties; (ii) the influence of volume ratio between Metglas and piezo-fibers on ME coefficients has been studied both experimentally and theoretically. Modulating the volume ratio can increase the ME coefficient greatly; and (iii) the annealing process can change the properties of Metglas, which can enhance the ME response as well. Moreover, one differential structure for ME composites has been proposed, which can reject the external vibration noise by a factor of 10 to 20 dB. This differential structure may allow for practical applications of such sensors in real-world environments. Based on optimized ME composites, two types of AC magnetic sensor have been developed. The objective is to develop one alternative type of magnetic sensor with low noise, low cost and room-temperature operation; that makes the sensor competitive with the commercially available magnetic sensor, such as Fluxgate, GMR, SQUID, etc. Conventional passive sensors have been fully investigated, including the design of sensor working at specific frequency range, sensitivity, noise density characterization, etc. Furthermore, the extremely low frequency (man-portable multi-axial geomagnetic sensor has been developed which has the highest resolution of 10 nT for DC magnetic field. Based on the geomagnetic sensor, some demonstrations have been finished, such as orientation monitor, magnetic field mapping, and

  6. The large magnetoelectric effect in Ni-lead zirconium titanate-Ni trilayers derived by electroless deposition

    International Nuclear Information System (INIS)

    Bi, K; Wang, Y G; Wu, W; Pan, D A

    2010-01-01

    Magnetoelectric (ME) Ni-lead zirconium titanate-Ni trilayers with neither electrodes nor bonding layers have been derived by electroless deposition. The structure and magnetic properties of the electroless deposited Ni layers with different pH values are characterized by x-ray diffraction and vibrating sample magnetometer. The influence of the bias magnetic field and the magnetic field frequency (f) on ME coupling is discussed. It is seen that α E,31 depends strongly on H dc and f. The value of the ME coefficient increases as the thickness of the Ni layer and the pH of the bath increase. A maximum of the ME voltage coefficient α E,31 = 5.77 V cm -1 Oe -1 at resonance frequency with a deposited Ni layer thickness t Ni = 302 μm is obtained. The large ME coefficient makes these Ni-PZT-Ni trilayers suitable for applications in sensors, actuators and transducers. (fast track communication)

  7. Phase-dependent deterministic switching of magnetoelectric spin wave detector in the presence of thermal noise via compensation of demagnetization

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Sourav, E-mail: sdutta38@gatech.edu; Naeemi, Azad [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A. [Components Research, Intel Corporation, Hillsboro, Oregon 97124 (United States)

    2015-11-09

    The possibility of achieving phase-dependent deterministic switching of the magnetoelectric spin wave detector in the presence of thermal noise has been discussed. The proposed idea relies on the modification of the energy landscape by partially canceling the out-of-plane demagnetizing field and the resultant change in the intrinsic magnetization dynamics to drive the nanomagnet towards a preferential final magnetization state. The remarkable increase in the probability of successful switching can be accounted for by the shift in the location of the saddle point in the energy landscape and a resultant change in the nature of the relaxation dynamics of the magnetization from a highly precessional to a fairly damped one and an increased dependence on the initial magnetization values, a crucial requirement for phase-dependent spin wave detection.

  8. Structural, dielectric and magnetic studies of magnetoelectric trirutile Fe{sub 2}TeO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Kaushik, S. D., E-mail: sdkaushik@csr.res.in [UGC-DAE-Consortium for Scientific Research Mumbai Centre, R-5 Shed, BARC, Mumbai-400085 (India); Sahu, B.; Mohapatra, S. R.; Singh, A. K. [Department of Physics and Astronomy, National Institute of Technology, Rourkela-769008, Odisha (India)

    2016-05-23

    We have investigated structural, magnetic and dielectric properties of Fe{sub 2}TeO{sub 6} which is a magnetoelectric antiferromagnet with the trirutile lattice. Rietveld analysis of room temperature X-ray diffraction data shows the phase purity of the sample with tetragonal trirutile structure (space group P4{sub 2}/mnm). The DC susceptibility measurement performed on polycrystalline powders exhibits antiferromagnetic ordering below transition temperature ~ 210K. The employment of Curie-Weiss law to inverse magnetic susceptibility only in the temperature range 350-260 K indicates the magnetic ordering starts developing before the transition temperature. The temperature dependent dielectric measurements show an intrinsic behavior of dielectric constant below 150 K while a continuous increase in dielectric constant with temperature above 150 K may be attributed to a small increase in electrical conduction, known commonly in the literatures.

  9. Biological cell as a soft magnetoelectric material: Elucidating the physical mechanisms underpinning the detection of magnetic fields by animals

    Science.gov (United States)

    Krichen, S.; Liu, L.; Sharma, P.

    2017-10-01

    Sharks, birds, bats, turtles, and many other animals can detect magnetic fields. Aside from using this remarkable ability to exploit the terrestrial magnetic field map to sense direction, a subset is also able to implement a version of the so-called geophysical positioning system. How do these animals detect magnetic fields? The answer to this rather deceptively simple question has proven to be quite elusive. The currently prevalent theories, while providing interesting insights, fall short of explaining several aspects of magnetoreception. For example, minute magnetic particles have been detected in magnetically sensitive animals. However, how is the detected magnetic field converted into electrical signals given any lack of experimental evidence for relevant electroreceptors? In principle, a magnetoelectric material is capable of converting magnetic signals into electricity (and vice versa). This property, however, is rare and restricted to a rather small set of exotic hard crystalline materials. Indeed, such elements have never been detected in the animals studied so far. In this work we quantitatively outline the conditions under which a biological cell may detect a magnetic field and convert it into electrical signals detectable by biological cells. Specifically, we prove the existence of an overlooked strain-mediated mechanism and show that most biological cells can act as nontrivial magnetoelectric materials provided that the magnetic permeability constant is only slightly more than that of a vacuum. The enhanced magnetic permeability is easily achieved by small amounts of magnetic particles that have been experimentally detected in magnetosensitive animals. Our proposed mechanism appears to explain most of the experimental observations related to the physical basis of magnetoreception.

  10. Prediction of two-dimensional electron gas mediated magnetoelectric coupling at ferroelectric PbTiO3/SrTiO3 heterostructures

    Science.gov (United States)

    Wei, Lan-ying; Lian, Chao; Meng, Sheng

    2017-05-01

    First-principles calculations predict the emergence of magnetoelectric coupling mediated by two-dimensional electron gas (2DEG) at the ferroelectric PbTiO3/SrTiO3 heterostructure. Free electrons endowed by naturally existing oxygen vacancies in SrTiO3 are driven to the heterostructure interface under the polarizing field of ferroelectric PbTiO3 to form a 2DEG. The electrons are captured by interfacial Ti atoms, which surprisingly exhibits ferromagnetism even at room temperature with a small critical density of ˜15.5 μ C /cm2 . The ferroelectricity-controlled ferromagnetism mediated by interfacial 2DEG shows strong magnetoelectric coupling strength, enabling convenient control of magnetism by electric field and vice versa. The PbTiO3/SrTiO3 heterostructure is cheap, easily grown, and controllable, promising future applications in low-cost spintronics and information storage at ambient condition.

  11. Multiferroic and magnetoelectric properties of Ba{sub 0.85}Ca{sub 0.15}Zr{sub 0.1}Ti{sub 0.9}O{sub 3}–CoFe{sub 2}O{sub 4} core–shell nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ajith S; Lekha, C.S. Chitra; Vivek, S. [Department of Physics, Central University of Kerala, Kasaragod 671314 (India); Saravanan, Venkata [Department of Physics, Central University of Tamil Nadu, Thiruvarur 610101 (India); Nandakumar, K. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Nair, Swapna S., E-mail: swapna.s.nair@gmail.com [Department of Physics, Central University of Kerala, Kasaragod 671314 (India)

    2016-11-15

    Lead-free magnetoelectric (ME) composites with remarkable ME coupling are required for the realization of eco-friendly multifunctional devices. This work demonstrates the ME properties of Ba{sub 0.85}Ca{sub 0.15}Zr{sub 0.1}Ti{sub 0.9}O{sub 3}–CoFe{sub 2}O{sub 4} (BCZT–CFO) core–shell composites synthesized via co-sol–gel technique. Room temperature ferroelectric and ferromagnetic characterization have shown that the samples are magnetic and ferroelectric along with an adequate magnetoelectric coupling of 12.15 mV/(cm Oe). The strong dependence of electric parameters on applied magnetic DC bias fields demonstrated in ferroelectric and magnetoelectric measurements provide a framework for the development of potential magnetoelectric devices. Also, the high sensitivity of magnetoelectric coupling towards the applied AC magnetic field can be used for its application in magnetoelectric sensors. - Highlights: • The magnetoelectric multiferroic BCZT–CFO nanocomposite is synthesized via sol–gel route. • The XRD measurements show no phases other than BCZT and CFO. • The microstructure analysis employing TEM indicates that the majority of particles formed are having core–shell structure. • The capacitance, resistance and ferroelectric polarization are magnetically tunable. • The composite showed a high magnetoelectric response.

  12. Transition metal modified bulk BiFeO{sub 3} with improved magnetization and linear magneto-electric coupling

    Energy Technology Data Exchange (ETDEWEB)

    Puli, Venkata Sreenivas, E-mail: pvsri123@gmail.com [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (Puerto Rico); Kumar, A.; Panwar, N.; Panwar, I.C.; Katiyar, R.S. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (Puerto Rico)

    2011-08-11

    Highlights: > Present composition (Bi{sub 0.9}Sm{sub 0.10}Fe{sub 0.95}Co{sub 0.05}O{sub 3} (BSFCO) have shown very high magnetization compared to parent BFO. > The magnetic hysteresis loops are well saturated with high saturation magnetization 2.89 emu/gm (unpoled and unleached) and 2.18 emu/gm (poled and unleached) respectively. > Converse ME coupling were found 0.8e-10 s m{sup -1} (H||E) and 0.6-0.8 x 10{sup -10} s m{sup -1} (H-perpendicular E) which are better than the single phase multiferroic obeying linear ME coupling. - Abstract: At present BiFeO{sub 3} (BFO) is the most attractive and sole example, which possesses low magnetization value, high leakage current and low polarization in ceramic form. Single-phase room temperature multiferroics are rare in nature. This paper deals with the improved magnetic and observed linear magneto-electric coupling in Co and Sm co-doped BiFeO{sub 3} ceramics synthesized by sol-gel process at low temperature {approx}600 deg. C. As synthesized Bi{sub 0.9}Sm{sub 0.10}Fe{sub 0.95}Co{sub 0.05}O{sub 3} (BSFCO) showed high impurities phases (20%) over wide range of calcination temperatures. Impurity phases reduced drastically from 20% to 5% after leaching with nitric acid. However the electrical and the magnetic properties were almost the same for both phases. Well-defined magnetic hysteresis with high magnetic moment was found at room temperature. Ferroelectric polarization studies demonstrated similar values and shape as reported in literature for the pure bulk BFO. Linear magneto-electric (ME) coupling and weak ME coefficient ({alpha}) {approx} 0.6 e-10 s m{sup -1} were observed in the co-doped BFO. The origin of the strong ferromagnetic property in our samples may be due to the presence of rare earth and transition metal ions at the lattice sites of BFO or due to impurity phase, since we have not seen any change in magnetization with reduction of impurity phase the later effect is more unlikely.

  13. Composition-driven enhanced magnetic properties and magnetoelectric coupling in Gd substituted BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Vijayasundaram, S.V., E-mail: vijayasundaramsv@gmail.com [Department of Physics, Presidency College, Chennai 600005 (India); Suresh, G. [Department of Physics, Park College of Engineering and Technology, Coimbatore 641659 (India); Department of Urology, Singapore General Hospital, Singapore 169856 (Singapore); Mondal, R.A. [Department of Physics, Hindustan University, Chennai 603103 (India); Kanagadurai, R. [Department of Physics, Presidency College, Chennai 600005 (India)

    2016-11-15

    Bi{sub 1-x}Gd{sub x}FeO{sub 3} (x=0, 0.05 and 0.1) samples were synthesized by modified sol–gel process. X-ray diffraction studies confirmed that the crystal structures of Gd substituted samples remain stable for x<0.1, while compositional-driven structural phase transition from rhombohedral to orthorhombic was observed in the case of x=0.1. The average particle sizes of pure and Gd substituted BiFeO{sub 3} nanoparticles were found to be in the range 62–46 nm. The size of the oblate spherical particles decreased with increasing Gd concentration. XPS studies revealed the trivalent oxidation states of Bi and Fe ions along with sample purity. Pure BiFeO{sub 3} exhibited linear M–H loop indicating its antiferromagnetic characteristics, whereas obvious non-linear M–H loops were observed in Gd substituted samples. In contrast to the observed room temperature magnetization (0.36 emu/g) under 40 kOe for BiFeO{sub 3}, the sample with 10% Gd exhibited appreciable enhancement of magnetization (1.88 emu/g). A leaky type P–E hysteresis loop was observed for the pure one, whereas concave-like ferroelectric loops were obtained for Gd substituted samples. The possible origins of enhanced multiferroic properties have been explained on the basis of substituent, its concentration, phase purity, particle size, structural distortion and the modified magnetic structure. The measurement of magnetoelectric studies at room temperature revealed the coupling between magnetic and ferroelectric ordering, which is desirable for multifunctional device applications of multiferroics. - Highlights: • The substitution of Gd in BiFeO{sub 3} (BFO) nanoparticles led to structural distortion. • Average sizes of the substituted samples are less than the spin period of BFO. • Gd-substitution altered the original magnetic structure of BFO (AFM – FM). • M{sub r} of a substituted sample is an order of magnitude higher than that of BFO. • All the samples show magnetoelectric coupling

  14. Enhanced magnetoelectric effects in composite of piezoelectric ceramics, rare-earth iron alloys, and shape-optimized nanocrystalline alloys.

    Science.gov (United States)

    Zhang, Jitao; Li, Ping; Wen, Yumei; He, Wei; Yang, Aichao; Lu, Caijiang

    2014-03-01

    An enhancement for magnetoelectric (ME) effects is studied in a three-phase ME architecture consisting of two magnetostrictive Terfenol-D (Tb(0.3)Dy(0.7)Fe(1.92)) plates, a piezoelectric PZT (Pb(Zr,Ti)O3) plate, and a pair of shape-optimized FeCuNbSiB nanocrystalline alloys. By modifying the conventional shape of the magnetic flux concentrator, the shape-optimized flux concentrator has an improved effective permeability (μ(eff)) due to the shape-induced demagnetizing effect at its end surface. The flux concentrator concentrates and amplifies the external magnetic flux into Terfenol-D plate by means of changing its internal flux concentrating manner. Consequently, more flux lines can be uniformly concentrated into Terfenol-D plates. The effective piezomagnetic coefficients (d(33m)) of Terfenol-D plate and the ME voltage coefficients (α(ME)) can be further improved under a lower magnetic bias field. The dynamic magneto-elastic properties and the effective magnetic induction of Terfenol-D are taken into account to derive the enhanced effective ME voltage coefficients (α(ME,eff)), the consistency of experimental results and theoretical analyses verifies this enhancement. The experimental results demonstrate that the maximum d(33m) in our proposed architecture achieves 22.48 nm/A under a bias of 114 Oe. The maximum α(ME) in the bias magnetic range 0-900 Oe reaches 84.73 mV/Oe under the low frequency of 1 kHz, and 2.996 V/Oe under the resonance frequency of 102.3 kHz, respectively. It exhibits a 1.43 times larger piezomagnetic coefficient and a 1.87 times higher ME voltage coefficient under a smaller magnetic bias of 82 Oe than those of a conventional Terfenol-D/PZT/Terfenol-D composite. These shape-induced magnetoelectric behaviors provide the possibility of using this ME architecture in ultra-sensitive magnetic sensors.

  15. Transition metal modified bulk BiFeO3 with improved magnetization and linear magneto-electric coupling

    International Nuclear Information System (INIS)

    Puli, Venkata Sreenivas; Kumar, A.; Panwar, N.; Panwar, I.C.; Katiyar, R.S.

    2011-01-01

    Highlights: → Present composition (Bi 0.9 Sm 0.10 Fe 0.95 Co 0.05 O 3 (BSFCO) have shown very high magnetization compared to parent BFO. → The magnetic hysteresis loops are well saturated with high saturation magnetization 2.89 emu/gm (unpoled and unleached) and 2.18 emu/gm (poled and unleached) respectively. → Converse ME coupling were found 0.8e-10 s m -1 (H||E) and 0.6-0.8 x 10 -10 s m -1 (H-perpendicular E) which are better than the single phase multiferroic obeying linear ME coupling. - Abstract: At present BiFeO 3 (BFO) is the most attractive and sole example, which possesses low magnetization value, high leakage current and low polarization in ceramic form. Single-phase room temperature multiferroics are rare in nature. This paper deals with the improved magnetic and observed linear magneto-electric coupling in Co and Sm co-doped BiFeO 3 ceramics synthesized by sol-gel process at low temperature ∼600 deg. C. As synthesized Bi 0.9 Sm 0.10 Fe 0.95 Co 0.05 O 3 (BSFCO) showed high impurities phases (20%) over wide range of calcination temperatures. Impurity phases reduced drastically from 20% to 5% after leaching with nitric acid. However the electrical and the magnetic properties were almost the same for both phases. Well-defined magnetic hysteresis with high magnetic moment was found at room temperature. Ferroelectric polarization studies demonstrated similar values and shape as reported in literature for the pure bulk BFO. Linear magneto-electric (ME) coupling and weak ME coefficient (α) ∼ 0.6 e-10 s m -1 were observed in the co-doped BFO. The origin of the strong ferromagnetic property in our samples may be due to the presence of rare earth and transition metal ions at the lattice sites of BFO or due to impurity phase, since we have not seen any change in magnetization with reduction of impurity phase the later effect is more unlikely.

  16. Magnetoelectric Bi3.15Nd0.85Ti3O12–NiFe2O4 bilayer films derived by a SOL–GEL method

    Directory of Open Access Journals (Sweden)

    Feng Yang

    2015-08-01

    Full Text Available Magnetoelectric Bi3.15Nd0.85Ti3O12–NiFe2O4 (BNT–NFO bilayer films were deposited on Pt/Ti/SiO2/Si(100 substrates by a simple SOL–GEL method and spin-coating process with different growth sequences of BNT and NFO yielding the following layered structures: BNT/NFO/substrate (BNS and NFO/BNT/substrate (NBS. Such heterostructures present simultaneously strong ferroelectric and ferromagnetic responses, as well as magnetoelectric effects at room temperature. BNS thin films showed larger ME voltage coefficient than NBS films, revealing that the layer sequences have a significant influence on the magnetoelectric coupling behavior of these bilayer structures, which may be caused by a interfacial effect.

  17. Sensor Applications of Soft Magnetic Materials Based on Magneto-Impedance, Magneto-Elastic Resonance and Magneto-Electricity

    Directory of Open Access Journals (Sweden)

    Alfredo García-Arribas

    2014-04-01

    Full Text Available The outstanding properties of selected soft magnetic materials make them successful candidates for building high performance sensors. In this paper we present our recent work regarding different sensing technologies based on the coupling of the magnetic properties of soft magnetic materials with their electric or elastic properties. In first place we report the influence on the magneto-impedance response of the thickness of Permalloy films in multilayer-sandwiched structures. An impedance change of 270% was found in the best conditions upon the application of magnetic field, with a low field sensitivity of 140%/Oe. Second, the magneto-elastic resonance of amorphous ribbons is used to demonstrate the possibility of sensitively measuring the viscosity of fluids, aimed to develop an on-line and real-time sensor capable of assessing the state of degradation of lubricant oils in machinery. A novel analysis method is shown to sensitively reveal the changes of the damping parameter of the magnetoelastic oscillations at the resonance as a function of the oil viscosity. Finally, the properties and performance of magneto-electric laminated composites of amorphous magnetic ribbons and piezoelectric polymer films are investigated, demonstrating magnetic field detection capabilities below 2.7 nT.

  18. Investigations of magnetoelectric behavior in BiFe0.95Co0.05O3 nanoparticles

    Science.gov (United States)

    Shrimali, V. G.; Gadani, Keval; Rathod, K. N.; Boricha, Hetal; Prajapati, Pooja; Keshvani, M. J.; Kataria, B. R.; Joshi, A. D.; Pandya, D. D.; Shah, N. A.; Solanki, P. S.

    2017-05-01

    Nanophasic BiFe0.95Co0.05O3 (BFCO) particles were synthesized using low cost, easy, simple, environment friendly and low temperature acetate precursor based modified sol-gel method. Influence of particle size and magnetic field on the structural, dielectric, impedance and a.c. conductivity of BFCO is investigated. X-ray diffraction (XRD) measurement has been performed to understand the structural modifications in the samples upon increasing the sintering temperature. Crystallite size (CS) increases from 33.62nm to 39.56nm due to agglomeration effect between the smaller crystallites. Effect of sintering temperature on the dielectric, impedance and conductivity has been studied and understood in the context of the creation of crystallite (particle) size and oxygen vacancies created due to high temperature sintering process. Magnetic field induced modifications in all these electrical properties [magnetoelectric (ME) effects] for the presently studied BFCO samples have been discussed on the basis of magnetostriction effect and charge mobility across the Fe-O lattice in the samples.

  19. Voltage Control of Two-Magnon Scattering and Induced Anomalous Magnetoelectric Coupling in Ni–Zn Ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Xu [Electronic Materials; amp,; Dong, Guohua [Electronic Materials; amp,; Zhou, Ziyao [Electronic Materials; amp,; Xian, Dan [Collaborative Innovation Center of High-End Manufacturing; Hu, Zhongqiang [Electronic Materials; amp,; Ren, Wei [Electronic Materials; amp,; Collaborative Innovation Center of High-End Manufacturing; Ye, Zuo-Guang [Electronic Materials; amp,; Department; Chen, Wei [Materials; Jiang, Zhuang-De [Collaborative Innovation Center of High-End Manufacturing; Liu, Ming [Electronic Materials; amp,; Collaborative Innovation Center of High-End Manufacturing

    2017-12-01

    Controlling spin dynamics through modulation of spin interactions in a fast, compact, and energy-efficient way is compelling for its abundant physical phenomena and great application potential in next-generation voltage controllable spintronic devices. In this work, we report electric field manipulation of spin dynamics-the two-magnon scattering (TMS) effect in Ni0.5Zn0.5Fe2O4 (NZFO)/Pb(Mg2/3Nb1/3)-PbTiO3 (PMN-PT) multiferroic heterostructures, which breaks the bottleneck of magnetostatic interaction-based magnetoelectric (ME) coupling in multiferroics. An alternative approach allowing spin-wave damping to be controlled by external electric field accompanied by a significant enhancement of the ME effect has been demonstrated. A two-way modulation of the TMS effect with a large magnetic anisotropy change up to 688 Oe has been obtained, referring to a 24 times ME effect enhancement at the TMS critical angle at room temperature. Furthermore, the anisotropic spin-freezing behaviors of NZFO were first determined via identifying the spatial magnetic anisotropy fluctuations. A large spin-freezing temperature change of 160 K induced by the external electric field was precisely determined by electron spin resonance.

  20. Development of a contactless DC current sensor with high linearity and sensitivity based on the magnetoelectric effect

    Science.gov (United States)

    Castro, N.; Reis, S.; Silva, M. P.; Correia, V.; Lanceros-Mendez, S.; Martins, P.

    2018-06-01

    The magnetoelectric (ME) effect is increasingly being considered an attractive alternative for magnetic field and smart current sensing, being able to sense static and dynamic magnetic fields. This work reports on a contactless DC current sensor device based on a ME PVDF/Metglas composite, a solenoid and the corresponding electronic instrumentation. The ME sample shows a maximum resonant ME coefficient (α 33) of 34.48 V cm‑1 Oe‑1, a linear response (R 2 = 0.998) and a sensitivity of 6.7 mV A‑1. With the incorporation of a charge amplifier, an AC-RMS converter and a microcontroller the linearity is maintained (R 2 = 0.997), the ME output voltage increases to a maximum of 2320 mV and the sensitivity rises to 476.5 mV A‑1. Such features allied to the highest sensitivity reported in the literature on polymer-based ME composites provide to the reported ME sensing device suitable characteristics to be used in non-contact electric current measurement, motor operational status checking, and condition monitoring of rechargeable batteries, among others.

  1. Enhanced tunability of magneto-impedance and magneto-capacitance in annealed Metglas/PZT magnetoelectric composites

    Science.gov (United States)

    Leung, Chung Ming; Zhuang, Xin; Xu, Junran; Li, Jiefang; Zhang, Jitao; Srinivasan, G.; Viehland, D.

    2018-05-01

    This report is on a new class of magnetostatically tunable magneto-impedance and magneto-capacitance devices based on a composite of ferromagnetic Metglas and ferroelectric lead zirconate titanate (PZT). Layered magneto-electric (ME) composites with annealed Metglas and PZT were studied in a longitudinal in-plane magnetic field-transverse electric field (L-T) mode. It was found that the degree of tunability was dependent on the annealing temperature of Metglas. An impedance tunability (ΔZ/Z0) of ≥400% was obtained at the electromechanical resonance (EMR) frequency (fr) for a sample with Metglas layers annealed at Ta = 500oC. This tunability is a factor of two higher than for composites with Metglas annealed at 350oC. The tunability of the capacitance, (ΔC/C0), was found to be 290% and -135k% at resonance and antiresonance, respectively, for Ta = 500oC. These results provide clear evidence for improvement in static magnetic field tunability of impedance and capacitance of ME composites with the use of annealed Metglas and are of importance for their potential use in tunable electronic applications.

  2. Determination of the distribution of air and water in porous media by electrical impedance tomography and magneto-electrical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Haegel, Franz-Hubert, E-mail: f.h.haegel@fz-juelich.de [Forschungszentrum Juelich GmbH, Institut fuer Chemie und Dynamik der Geosphaere, ICG-4 Agrosphaere, 52425 Juelich (Germany); Zimmermann, Egon [Forschungszentrum Juelich GmbH, Zentralinstitut fuer Elektronik, 52425 Juelich (Germany); Esser, Odilia; Breede, Katrin; Huisman, Johan Alexander [Forschungszentrum Juelich GmbH, Institut fuer Chemie und Dynamik der Geosphaere, ICG-4 Agrosphaere, 52425 Juelich (Germany); Glaas, Walter; Berwix, Joachim [Forschungszentrum Juelich GmbH, Zentralinstitut fuer Elektronik, 52425 Juelich (Germany); Vereecken, Harry [Forschungszentrum Juelich GmbH, Institut fuer Chemie und Dynamik der Geosphaere, ICG-4 Agrosphaere, 52425 Juelich (Germany)

    2011-06-15

    Monitoring the distribution of water content is essential for understanding hydrological processes in the lithosphere and the pedosphere. The movement of water in unsaturated rock formations and in the vadose zone is influenced by different processes (mainly infiltration, evaporation, percolation and capillary flow) which may be rate determining depending on the actual conditions. The interdependence of these processes also strongly influences the transport and distribution of solutes in the pore space. In order to gain a better understanding of the movement and distribution of water in unsaturated media, systematic investigations with non-invasive or minimal invasive methods appear to be most suitable. Studies on the distribution of electrical conductivity can improve risk analysis concerning waste disposals in general and nuclear waste repositories in particular. Induced polarization and magnetic flux density determined with two highly sensitive accessories yield additional information and may allow for better discrimination of coupled flow processes. Electrical impedance tomography (EIT) with 20 current injection and 48 voltage electrodes was used here to monitor the evaporation of tap water from a container filled with sand under laboratory conditions at 20 deg. C. The results are compared with data obtained by determining spectral induced polarization (SIP) of sand during desaturation in a multi-step outflow equipment. Infiltration processes and evaporation from sand saturated with 0.01 M CaCl{sub 2} were determined by magneto-electrical resistivity imaging technique (MERIT). The results were obtained from a long-term experiment under controlled conditions.

  3. Enhanced off-resonance magnetoelectric response in laser annealed PZT thick film grown on magnetostrictive amorphous metal substrate

    Energy Technology Data Exchange (ETDEWEB)

    Palneedi, Haribabu [Materials Interface Laboratory, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of); Functional Ceramics Group, Korea Institute of Materials Science (KIMS), Changwon 641-831 (Korea, Republic of); Maurya, Deepam; Priya, Shashank [Bio-inspired Materials and Devices Laboratory (BMDL), Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Kim, Gi-Yeop; Choi, Si-Young, E-mail: youngchoi@kims.re.kr [Materials Modeling and Characterization Department, Korea Institute of Materials Science (KIMS), Changwon 641-831 (Korea, Republic of); Kang, Suk-Joong L. [Materials Interface Laboratory, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of); Kim, Kwang-Ho [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Ryu, Jungho, E-mail: jhryu@kims.re.kr [Functional Ceramics Group, Korea Institute of Materials Science (KIMS), Changwon 641-831 (Korea, Republic of)

    2015-07-06

    A highly dense, 4 μm-thick Pb(Zr,Ti)O{sub 3} (PZT) film is deposited on amorphous magnetostrictive Metglas foil (FeBSi) by granule spray in vacuum process at room temperature, followed by its localized annealing with a continuous-wave 560 nm ytterbium fiber laser radiation. This longer-wavelength laser radiation is able to anneal the whole of thick PZT film layer without any deteriorative effects, such as chemical reaction and/or atomic diffusion, at the interface and crystallization of amorphous Metglas substrate. Greatly enhanced dielectric and ferroelectric properties of the annealed PZT are attributed to its better crystallinity and grain growth induced by laser irradiation. As a result, a colossal off-resonance magnetoelectric (ME) voltage coefficient that is two orders of magnitude larger than previously reported output from PZT/Metglas film-composites is achieved. The present work addresses the problems involved in the fabrication of PZT/Metglas film-composites and opens up emerging possibilities in employing piezoelectric materials with low thermal budget substrates (suitable for integrated electronics) and designing laminate composites for ME based devices.

  4. Bath temperature effect on magnetoelectric performance of Ni-lead zirconate titanate-Ni laminated composites synthesized by electroless deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, W. [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wang, Y.G., E-mail: yingang.wang@nuaa.edu.c [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Bi, K. [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2011-03-15

    Magnetoelectric (ME) Ni-lead zirconate titanate-Ni laminated composites have been prepared by electroless deposition at various bath temperatures. The structure of the Ni layers deposited at various bath temperatures was characterized by X-ray diffraction, and microstructures were investigated by transmission electron microscopy. The magnetostrictive coefficients were measured by means of a resistance strain gauge. The transverse ME voltage coefficient {alpha}{sub E,31} was measured with the magnetic field applied parallel to the sample plane. The deposition rate of Ni increases with bath temperature. Ni layer with smaller grain size is obtained at higher bath temperature and shows higher piezomagnetic coefficient, promoting the ME effect of corresponding laminated composites. It is advantageous to increase the bath temperature, while trying to avoid the breaking of bath constituents. - Research Highlights: Laminated composites without interlayer are prepared by electroless deposition. Bath temperature affects the grain size of the deposited Ni layers. Higher bath temperature is beneficial to obtain stronger ME response.

  5. Note: Resonance magnetoelectric interactions in laminate of FeCuNbSiB and multilayer piezoelectric stack for magnetic sensor

    Science.gov (United States)

    Li, Jianqiang; Lu, Caijiang; Xu, Changbao; Zhong, Ming

    2015-09-01

    This paper develops a simple miniature magnetoelectric (ME) laminate FeCuNbSiB/PZT-stack made up of magnetostrictive Fe73.5Cu1Nb3Si13.5B9 (FeCuNbSiB) foils and piezoelectric Pb(Zr, Ti)O3 (PZT) multilayer stack vibrator. Resonant ME interactions of FeCuNbSiB/PZT-stack with different layers of FeCuNbSiB foil (L) are investigated in detail. The experimental results show that the ME voltage coefficient reaches maximum value of 141.5 (V/cm Oe) for FeCuNbSiB/PZT-stack with L = 6. The AC-magnetic sensitivities can reach 524.29 mV/Oe and 1.8 mV/Oe under resonance 91.6 kHz and off-resonance 1 kHz, respectively. The FeCuNbSiB/PZT-stack can distinguish small dc-magnetic field of ˜9 nT. The results indicate that the proposed ME composites are very promising for the cheap room-temperature magnetic field sensing technology.

  6. Analytical modeling of demagnetizing effect in magnetoelectric ferrite/PZT/ferrite trilayers taking into account a mechanical coupling

    Science.gov (United States)

    Loyau, V.; Aubert, A.; LoBue, M.; Mazaleyrat, F.

    2017-03-01

    In this paper, we investigate the demagnetizing effect in ferrite/PZT/ferrite magnetoelectric (ME) trilayer composites consisting of commercial PZT discs bonded by epoxy layers to Ni-Co-Zn ferrite discs made by a reactive Spark Plasma Sintering (SPS) technique. ME voltage coefficients (transversal mode) were measured on ferrite/PZT/ferrite trilayer ME samples with different thicknesses or phase volume ratio in order to highlight the influence of the magnetic field penetration governed by these geometrical parameters. Experimental ME coefficients and voltages were compared to analytical calculations using a quasi-static model. Theoretical demagnetizing factors of two magnetic discs that interact together in parallel magnetic structures were derived from an analytical calculation based on a superposition method. These factors were introduced in ME voltage calculations which take account of the demagnetizing effect. To fit the experimental results, a mechanical coupling factor was also introduced in the theoretical formula. This reflects the differential strain that exists in the ferrite and PZT layers due to shear effects near the edge of the ME samples and within the bonding epoxy layers. From this study, an optimization in magnitude of the ME voltage is obtained. Lastly, an analytical calculation of demagnetizing effect was conducted for layered ME composites containing higher numbers of alternated layers (n ≥ 5). The advantage of such a structure is then discussed.

  7. Magnetoelectric coupling in multiferroic BaTiO3-CoFe2O4 composite nanofibers via electrospinning

    Science.gov (United States)

    Fu, Bi; Lu, Ruie; Gao, Kun; Yang, Yaodong; Wang, Yaping

    2015-07-01

    Magnetoelectric (ME) coupling in Pb-based multiferroic composites has been widely investigated due to the excellent piezoelectric property of lead zirconate titanate (PZT). In this letter, we report a strategy to create a hybrid Pb-free ferroelectric and ferromagnetic material and detect its ME coupling at the nanoscale. Hybrid Pb-free multiferroic BaTiO3-CoFe2O4 (BTO-CFO) composite nanofibers (NFs) were generated by sol-gel electrospinning. The perovskite structure of BTO and the spinel structure of CFO nanograins were homogenously distributed in the composite NFs and verified by bright-field transmission electron microscopy observations along the perovskite [111] zone axis. Multiferroicity was confirmed by amplitude-voltage butterfly curves and magnetic hysteresis loops. ME coupling was observed in terms of a singularity on a dM/dT curve at the ferroelectric Curie temperature (TC) of BaTiO3. The lateral ME coefficient was investigated by the evolution of the piezoresponse under an external magnetic field of 1000 Oe and was estimated to be α31 =0.78× 104 \\text{mV cm}-1 \\text{Oe}-1 . These findings could enable the creation of nanoscale Pb-free multiferroic composite devices.

  8. Analysis of the low-frequency magnetoelectric performance in three-phase laminate composites with Fe-based nanocrystalline ribbon

    International Nuclear Information System (INIS)

    Chen, Lei; Li, Ping; Wen, Yumei; Zhu, Yong

    2013-01-01

    The theoretical analysis of magnetoelectric (ME) performance in three-phase Terfenol-D/PZT/FeCuNbSiB (MPF) laminate composite is presented in this paper. The ME couplings at low frequency for ideal and less than ideal interface couplings are studied, respectively, and our analysis predicts that (i) the ME voltage coefficient for ideal interface coupling increases with the increasing layers (n) of Fe-based nanocrystalline ribbon FeCuNbSiB (Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ) while the sizes of PZT (Pb(Zr 1−x Ti x )O 3 ) and Terfenol-D (Tb 1−x Dy x Fe 2−y ) are kept constant, and then it tends to be a constant when the layers of FeCuNbSiB are >100; (ii) by introducing the interface coupling factor k and considering the degradation of d 33m,f with n, the ME voltage coefficient for a less than ideal interface condition is predicted. As the FeCuNbSiB layer increases, it first increases and reaches to a maximum value, and then slowly decreases. Various MPF laminates are fabricated and tested. It is found that the theoretical predictions for the consideration of actual boundary conditions at the interface are in agreement with the experimental observations. This study plays a guiding role for the design of MPF composite in real applications. (paper)

  9. Voltage Control of Two-Magnon Scattering and Induced Anomalous Magnetoelectric Coupling in Ni-Zn Ferrite.

    Science.gov (United States)

    Xue, Xu; Dong, Guohua; Zhou, Ziyao; Xian, Dan; Hu, Zhongqiang; Ren, Wei; Ye, Zuo-Guang; Chen, Wei; Jiang, Zhuang-De; Liu, Ming

    2017-12-13

    Controlling spin dynamics through modulation of spin interactions in a fast, compact, and energy-efficient way is compelling for its abundant physical phenomena and great application potential in next-generation voltage controllable spintronic devices. In this work, we report electric field manipulation of spin dynamics-the two-magnon scattering (TMS) effect in Ni 0.5 Zn 0.5 Fe 2 O 4 (NZFO)/Pb(Mg 2/3 Nb 1/3 )-PbTiO 3 (PMN-PT) multiferroic heterostructures, which breaks the bottleneck of magnetostatic interaction-based magnetoelectric (ME) coupling in multiferroics. An alternative approach allowing spin-wave damping to be controlled by external electric field accompanied by a significant enhancement of the ME effect has been demonstrated. A two-way modulation of the TMS effect with a large magnetic anisotropy change up to 688 Oe has been obtained, referring to a 24 times ME effect enhancement at the TMS critical angle at room temperature. Furthermore, the anisotropic spin-freezing behaviors of NZFO were first determined via identifying the spatial magnetic anisotropy fluctuations. A large spin-freezing temperature change of 160 K induced by the external electric field was precisely determined by electron spin resonance.

  10. Discovery of Enhanced Magnetoelectric Coupling through Electric Field Control of Two-Magnon Scattering within Distorted Nanostructures.

    Science.gov (United States)

    Xue, Xu; Zhou, Ziyao; Dong, Guohua; Feng, Mengmeng; Zhang, Yijun; Zhao, Shishun; Hu, Zhongqiang; Ren, Wei; Ye, Zuo-Guang; Liu, Yaohua; Liu, Ming

    2017-09-26

    Electric field control of dynamic spin interactions is promising to break through the limitation of the magnetostatic interaction based magnetoelectric (ME) effect. In this work, electric field control of the two-magnon scattering (TMS) effect excited by in-plane lattice rotation has been demonstrated in a La 0.7 Sr 0.3 MnO 3 (LSMO)/Pb(Mn 2/3 Nb 1/3 )-PbTiO 3 (PMN-PT) (011) multiferroic heterostructure. Compared with the conventional strain-mediated ME effect, a giant enhancement of ME effect up to 950% at the TMS critical angle is precisely determined by angular resolution of the ferromagnetic resonance (FMR) measurement. Particularly, a large electric field modulation of magnetic anisotropy (464 Oe) and FMR line width (401 Oe) is achieved at 173 K. The electric-field-controllable TMS effect and its correlated ME effect have been explained by electric field modulation of the planar spin interactions triggered by spin-lattice coupling. The enhancement of the ME effect at various temperatures and spin dynamics control are promising paradigms for next-generation voltage-tunable spintronic devices.

  11. Absence of strain-mediated magnetoelectric coupling at fully epitaxial Fe/BaTiO{sub 3} interface (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Radaelli, G., E-mail: greta.radaelli@gmail.com; Petti, D.; Cantoni, M.; Rinaldi, C.; Bertacco, R. [LNESS Center - Dipartimento di Fisica del Politecnico di Milano, Como 22100 (Italy)

    2014-05-07

    Interfacial MagnetoElectric coupling (MEC) at ferroelectric/ferromagnetic interfaces has recently emerged as a promising route to achieve electrical writing of magnetic information in spintronic devices. For the prototypical Fe/BaTiO{sub 3} (BTO) system, various MEC mechanisms have been theoretically predicted. Experimentally, it is well established that using BTO single crystal substrates MEC is dominated by strain-mediated mechanisms. In case of ferromagnetic layers epitaxially grown onto BTO films, instead, no direct evidence for MEC has been provided, apart from the results obtained on tunneling junction sandwiching a BTO tunneling barrier. In this paper, MEC at fully epitaxial Fe/BTO interface is investigated by Magneto-Optical Kerr Effect and magnetoresistance measurements on magnetic tunnel junctions fabricated on BTO. We find no evidence for strain-mediated MEC mechanisms in epitaxial systems, likely due to clamping of BTO to the substrate. Our results indicate that pure electronic MEC is the route of choice to be explored for achieving the electrical writing of information in epitaxial ferromagnet-ferroelectric heterostructures.

  12. Absence of strain-mediated magnetoelectric coupling at fully epitaxial Fe/BaTiO3 interface (invited)

    International Nuclear Information System (INIS)

    Radaelli, G.; Petti, D.; Cantoni, M.; Rinaldi, C.; Bertacco, R.

    2014-01-01

    Interfacial MagnetoElectric coupling (MEC) at ferroelectric/ferromagnetic interfaces has recently emerged as a promising route to achieve electrical writing of magnetic information in spintronic devices. For the prototypical Fe/BaTiO 3 (BTO) system, various MEC mechanisms have been theoretically predicted. Experimentally, it is well established that using BTO single crystal substrates MEC is dominated by strain-mediated mechanisms. In case of ferromagnetic layers epitaxially grown onto BTO films, instead, no direct evidence for MEC has been provided, apart from the results obtained on tunneling junction sandwiching a BTO tunneling barrier. In this paper, MEC at fully epitaxial Fe/BTO interface is investigated by Magneto-Optical Kerr Effect and magnetoresistance measurements on magnetic tunnel junctions fabricated on BTO. We find no evidence for strain-mediated MEC mechanisms in epitaxial systems, likely due to clamping of BTO to the substrate. Our results indicate that pure electronic MEC is the route of choice to be explored for achieving the electrical writing of information in epitaxial ferromagnet-ferroelectric heterostructures

  13. A multi-scale and multi-field coupling nonlinear constitutive theory for the layered magnetoelectric composites

    Science.gov (United States)

    Xu, Hao; Pei, Yongmao; Li, Faxin; Fang, Daining

    2018-05-01

    The magnetic, electric and mechanical behaviors are strongly coupled in magnetoelectric (ME) materials, making them great promising in the application of functional devices. In this paper, the magneto-electro-mechanical fully coupled constitutive behaviors of ME laminates are systematically studied both theoretically and experimentally. A new probabilistic domain switching function considering the surface ferromagnetic anisotropy and the interface charge-mediated effect is proposed. Then a multi-scale multi-field coupling nonlinear constitutive model for layered ME composites is developed with physical measureable parameters. The experiments were performed to compare the theoretical predictions with the experimental data. The theoretical predictions have a good agreement with experimental results. The proposed constitutive relation can be used to describe the nonlinear multi-field coupling properties of both ME laminates and thin films. Several novel coupling experimental phenomena such as the electric-field control of magnetization, and the magnetic-field tuning of polarization are observed and analyzed. Furthermore, the size-effect of the electric tuning behavior of magnetization is predicted, which demonstrates a competition mechanism between the interface strain-mediated effect and the charge-driven effect. Our study offers deep insight into the coupling microscopic mechanism and macroscopic properties of ME layered composites, which is benefit for the design of electromagnetic functional devices.

  14. Magnetoelectric properties of microwave sintered BiFeO{sub 3} and Bi{sub 0.90}La{sub 0.10}Fe{sub 0.95}Mn{sub 0.05}O{sub 3} nanoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kolte, Jayant, E-mail: jayantkolte@gmail.com [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai (India); Daryapurkar, A.S., E-mail: asdarypaurkar@gmail.com [Department of Basic Sciences, Indian Institute of Information Technology, Nagpur (India); Agarwal, Mohit, E-mail: mohit2705@gmail.com [Department of Electronics and Communication Engineering, Thapar University, Patiala, Punjab (India); Gulwade, D.D., E-mail: devidasgulwade@gmail.com [Department of Physics, V.E.S. College of Arts, Commerce and Science, Chembur, Mumbai (India); Gopalan, P., E-mail: pgopalan@iitb.ac.in [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai (India)

    2017-06-01

    Multiferroic materials have attracted the attention of scientific community all over the world due to smart functionality and attractive applications such as in magnetoelectric memory and magnetoelectric sensors. In this paper, we report on the ferroelectric, magnetic and magnetoelectric properties of microwave sintered BiFeO{sub 3} (BFO) and Bi{sub 0.90}La{sub 0.10}Fe{sub 0.95}Mn{sub 0.05}O{sub 3} (BLFMO) ceramics. The ferromagnetic and paramagnetic components have been deconvoluted using standard magnetization equation. The ferromagnetic saturation and paramagnetic susceptibility for BFO are found to be 0.046 emu/g and 1.17 × 10{sup -5} emu/g·Oe respectively. The magnetization in BLFMO increases enormously as compared to BFO due to suppression of cycloid spin. The magnetoelectric voltage coefficient for BFO is 3.37 mV/cm·Oe, while for BLFMO it is 10.11 mV/cm·Oe. As compared to BFO, BLFMO exhibits improved ferroelectric, magnetic and magnetoelectric properties. - Highlights: • Ferromagnetic and paramagnetic components calculated from total magnetization. • Magnetoelectric and magnetodielectric coefficients of BFO and BLFMO were measured. • BFO shows linear change in magnetoelectric voltage coefficient with ac magnetic field. • Both BFO and BLFMO follows Ginzburg Landau equation for multiferroics. • Relative to BFO, BLFMO exhibits leakage current that is three order lower.

  15. Y{sub 3}Fe{sub 5}O{sub 12}/Na,Bi,Sr-doped PZT particulate magnetoelectric composites

    Energy Technology Data Exchange (ETDEWEB)

    Lisnevskaya, I.V., E-mail: liv@sfedu.ru; Bobrova, I.A.; Lupeiko, T.G.; Agamirzoeva, M.R.; Myagkaya, K.V.

    2016-05-01

    Magnetoelectric (ME) composites of Na, Bi, Sr substituted lead zirconate titanate (PZT) and yttrium iron garnet having representative formula (100−x) wt% Na,Bi,Sr-doped PZT (PZTNB-1)+x wt% Y{sub 3}Fe{sub 5}O{sub 12} (YIG) with x=10–90 were manufactured using powdered components obtained through sol–gel processes. It is shown that the decrease in sintering temperature provided by the use of finely dispersed PZTNB-1 and YIG powders allows to significantly reduce content of fluorite-like foreign phase based on zirconium oxide, which forms due to the interfacial interaction during heat treatment and becomes stabilized by yttrium oxide. Connectivity has considerable effect on the value of ME coefficient of composite ceramics. With the same x value, ΔE/ΔH characteristic decreases when changing from 0–3-type structured composites (PZT grains embedded in ferrite matrix) to 3-3-(interpenetrating network of two phases) and especially 3-0-type samples (YIG grains embedded in PZT matrix); in the last case this can be attributed to the substrate clamping effect when ferrite grains are clamped with piezoelectric matrix. ΔE/ΔH value of 0–3 composites with x=40–60 wt% was found to be ∼1.6 mV/(cm Oe). - Highlights: • Y{sub 3}Fe{sub 5}O{sub 12}/Na,Bi,Sr-doped PZT particulate magnetoelectric composites were prepared. • The decrease in sintering temperature reduces the content of foreign phase of ZrO{sub 2}. • Connectivity pattern is important factor for magnetoelectric response. • The value of ME coefficient reaches ~1,6 mV/(cm Oe) in 0–3 composites.

  16. Magnetoelectric coupling in multiferroic heterostructure of rf-sputtered Ni–Mn–Ga thin film on PMN–PT

    International Nuclear Information System (INIS)

    Teferi, M.Y.; Amaral, V.S.; Lounrenco, A.C.; Das, S.; Amaral, J.S.; Karpinsky, D.V.; Soares, N.; Sobolev, N.A.; Kholkin, A.L.; Tavares, P.B.

    2012-01-01

    In this paper, we report a preparation of multiferroic heterostructure from thin film of Ni–Mn–Ga (NMG) alloy and lead magnesium niobate–lead titanate (PMN–PT) with effective magnetoelectric (ME) coupling between the film as ferromagnetic material and PMN–PT as piezoelectric material. The heterostructure was prepared by relatively low temperature (400 °C) deposition of the film on single crystal of piezoelectric PMN–PT substrate using rf magnetron co-sputtering of Ni 50 Mn 50 and Ni 50 Ga 50 targets. Magnetic measurements by Superconducting Quantum Interference Design (SQIUD) Magnetometer and Vibrating Sample Magnetometer (VSM) on the film revealed that the film is in ferromagnetically ordered martensitic state at room temperature with saturation magnetization of ∼240 emu/cm 3 and Curie temperature of ∼337 K. Piezoresponse force microscopy (PFM) measurement done at room temperature on the substrate showed the presence of expected hysteresis loop confirming the stability of the piezoelectric state of the substrate after deposition. Room temperature ME voltage coefficient (α ME ) of the heterostructure was measured as a function of applied bias dc magnetic field in Longitudinal–Transverse (L–T) ME coupling mode by lock-in technique. A maximum ME coefficient α ME of 3.02 mV/cm Oe was measured for multiferroic NMG/PMN–PT heterostructure which demonstrates that there is ME coupling between the film as ferromagnetic material and PMN–PT as piezoelectric material. - Highlights: ► Multiferroic NMG/PMN–PT heterostructure prepared by depositing NMG alloy thin film on PMN–PT substrate. ► The film is in ferromagnetically ordered martensite state at room temperature. ► The substrate maintains its piezoelectric state after deposition. ► The heterostructure exhibits ME effect with maximum of α ME of 3.02 mV/cm Oe.

  17. Room-temperature paramagnetoelectric effect in magnetoelectric multiferroics Pb(Fe.sub.1/2./sub.Nb.sub.1/2./sub.)O.sub.3./sub. and its solid solution with PbTiO.sub.3./sub.

    Czech Academy of Sciences Publication Activity Database

    Laguta, Valentyn; Morozovska, A. N.; Eliseev, E. A.; Raevski, I. P.; Raevskaya, S. I.; Sitalo, E.I.; Prosandeev, S. A.; Bellaiche, L.

    2016-01-01

    Roč. 51, č. 11 (2016), s. 5330-5342 ISSN 0022-2461 R&D Projects: GA ČR GA13-11473S Institutional support: RVO:68378271 Keywords : multiferroic * antiferromagnetic * ferroelectrics * magnetoelectric effect * Landau theory Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.599, year: 2016

  18. Impedance and magnetoelectric characteristics of (1 - x)BaTiO3- xLa0.7Sr0.3MnO3 ( x = 0.1 and 0.3) nano-composites

    Science.gov (United States)

    Nayek, C.; Murugavel, P.; Dinesh Kumar, S.; Subramanian, V.

    2015-08-01

    We have synthesized the phase-pure (1 - x)BaTiO3- xLa0.7Sr0.3MnO3 ( x = 0.1 and 0.3) magnetoelectric composites without interdiffusion among the existing phases. The magnetic measurements revealed an anomaly at the ferroelectric Curie temperature (393 K) of BaTiO3, and the dielectric data revealed an anomaly at the ferromagnetic transition temperature (360 K) of La0.7Sr0.3MnO3 ascertaining the magnetoelectric coupling in the composite. Impedance analysis indicated dipolar polarization contributions to the dielectric spectrum with two non-Debye-type relaxations. Both the grain and grain boundary contributions were present in the system with dominant grain boundary effect in all the composites. The composites show semiconducting behavior with the barrier hopping-type conducting mechanism. To avoid the free charge carrier and the space charge contributions, the magnetoelectric response was measured at high frequency range. The maximum values of magnetoelectric voltage coefficient measured at 100 kHz were 221 and 219 mV/Oe-cm for x = 0.1 and 0.3 samples, respectively.

  19. Dielectric and polarization studies of magnetoelectric coupling in non-relaxor Pb(Fe.sub.1/2./sub.Ta.sub.1/2./sub.)O.sub.3./sub. multiferroic ceramics

    Czech Academy of Sciences Publication Activity Database

    Savinov, Maxim; Bednyakov, Petr; Raevskaya, S. I.; Gusev, A.A.; Isupov, V.P.; Raevski, I. P.; Titov, V.V.; Chen, H.; Kovrigina, S.A.; Chou, C.-C.; Minasyan, T.A.; Malitskaya, M. A.

    2017-01-01

    Roč. 509, č. 1 (2017), s. 80-91 ISSN 0015-0193 Institutional support: RVO:68378271 Keywords : lead iron tantalate * PFT * dielectric permittivity * phase transition * hysteresis loops * magnetoelectric coupling Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.551, year: 2016

  20. A Dual-Wideband Double-Layer Magnetoelectric Dipole Antenna with a Modified Horned Reflector for 2G/3G/LTE Applications

    Directory of Open Access Journals (Sweden)

    Botao Feng

    2013-01-01

    Full Text Available A novel dual-wideband double-layer magnetoelectric dipole unidirectional antenna with a modified horned reflector for 2G/3G/LTE applications is proposed. Firstly, a double-layer electric dipole structure is presented to provide a dualwideband, whose folded lower layer mainly serves the lower frequency band while the inclined upper layer works for the upper frequency band. In addition, to reduce the size of the antenna and improve impedance matching, a new feeding structure designed with inverted U-shaped and tapered line is introduced. Finally, a modified horn-shaped reflector, instead of a ground plane, is employed to achieve stable and high gains. The antenna prototype can achieve a bandwidth of 24.4% (790 MHz–1010 MHz with a stable gain of 7.2 ± 0.6 dBi for the lower band, and a bandwidth of 67.3% (1.38 GHz–2.78 GHz with a gain of 7.5 ± 0.8 dBi for the upper band covering all the frequency bands for 2G/3G/LTE systems. To the best of our knowledge, it is the first double-layer magnetoelectric dipole antenna proposed. Compared with the existing ME dipole antennas, the proposed antenna, which is completely made of copper, can be easily fabricated at low cost and thus is practicable for 2G/3G/LTE applications.

  1. Local manifestations of a static magnetoelectric effect in nanostructured BaTiO3-BaFe12O9 composite multiferroics

    Science.gov (United States)

    Trivedi, Harsh; Shvartsman, Vladimir V.; Lupascu, Doru C.; Medeiros, Marco S. A.; Pullar, Robert C.; Kholkin, Andrei L.; Zelenovskiy, Pavel; Sosnovskikh, Andrey; Shur, Vladimir Ya.

    2015-02-01

    A study on magnetoelectric phenomena in the barium titanate-barium hexaferrite (BaTiO3-BaFe12O19) composite system, using high resolution techniques including switching spectroscopy piezoresponse force microscopy (SSPFM) and spatially resolved confocal Raman microscopy (CRM), is presented. It is found that both the local piezoelectric coefficient and polarization switching parameters change on the application of an external magnetic field. The latter effect is rationalized by the influence of magnetostrictive stress on the domain dynamics. Processing of the Raman spectral data using principal component analysis (PCA) and self-modelling curve resolution (SMCR) allowed us to achieve high resolution phase distribution maps along with separation of average and localized spectral components. A significant effect of the magnetic field on the Raman spectra of the BaTiO3 phase has been revealed. The observed changes are comparable with the classical pressure dependent studies on BaTiO3, confirming the strain mediated character of the magnetoelectric coupling in the studied composites.

  2. Room temperature large self-biased magnetoelectric effect in non-lead based piezoelectric and magnetostrictive (0−3) particulate composite system

    International Nuclear Information System (INIS)

    Kumari, Mukesh; Prakash, Chandra; Chatterjee, Ratnamala

    2017-01-01

    In this work, room temperature magnetoelectric properties of (0−3) particulate composites of non lead based piezoelectric BNTKNNLTS [0.97(Bi 0.5 Na 0.5 TiO 3 )–0.03(K 0.47 Na 0.47 Li 0.06 Nb 0.74 Sb 0.06 Ta 0.2 O 3 ) and magnetostrictive CZFMO (Co 0.6 Zn 0.4 Fe 1.7 Mn 0.3 O 4 ) are presented. Composite samples of (1-x)(BNTKNNLTS)-x(CZFMO) , with x=0.1 and 0.5, are synthesized by solid state reaction route. X-ray diffraction confirms the single phase formation of parent phases and the presence of two phases in the composites. Similar sintering conditions of the two individual components lead to optimal ferroelectric and ferromagnetic properties in the composites. A large self-biased magnetoelectric (ME) coupling ~74 mV/cm.Oe for the sample with x=0.1 (measured in longitudinally magnetized-transversely polarized configuration) is observed at room temperature. - Highlights: • Modified BNT-CFO based (0−3) particulate composites have been synthesized. • Similar sintering conditions of two components lead to optimal multiferroicity. • A large self-biased ME coupling ~74 mV/cm. Oe is obtained at room temperature.

  3. Magnetoelectric coupling mechanisms in YMn2-xFexO5 and NdFe3(BO3)4 revealed by resonant X-ray diffraction

    International Nuclear Information System (INIS)

    Partzsch, Sven

    2014-01-01

    Multiferroic materials with a coupled ordering of electric and magnetic moments could be used to build energy-efficient, magnetic computer memory that is written with an electrical field. To understand the interaction between the magnetic and electric ordering in such materials, two examples, namely yttrium manganate YMn 2 O 5 and neodymium iron borate NdFe 3 (BO 3 ) 4 , are studied by means of resonant x-ray diffraction. The important role of a pure electronic contribution to the ferroelectric polarization is shown in YMn 2 O 5 . Furthermore, substitution of Fe can change the magnetic order of YMn 2 O 5 from antiferromagnetic into ferrimagnetic, allowing the storage of easily readable magnetic information. Therefore the change of the magnetic structure upon small Fe substitution is studied. Although most of the magnetic structure of the parent compound is kept, the Fe moments have larger components along the c-direction. In NdFe 3 (BO 3 ) 4 the microscopic origin of the magnetoelectric coupling is addressed as the consequence of the frustration of the Fe and Nd magnetic sublattices. The application of an electrical field shifts the balance from the helical to the collinear magnetic domains, revealing again the strong magnetoelectric coupling.

  4. Peak divergence in the curve of magnetoelectric coefficient versus dc bias magnetic field at resonance region for bi-layer magnetostrictive/piezoelectric composites

    Directory of Open Access Journals (Sweden)

    Z. J. Zuo

    2013-12-01

    Full Text Available Magnetoelectric (ME coefficient dependence on the bias magnetic field at resonance frequencies for the bi-layered bonded Terfenol-D/Pb(Zr,TiO3 composite was investigated. The resonance frequency decreases first and then increases with the bias magnetic field (HDC, showing a “V” shape in the range of 0 ∼ 5 kOe. Below the resonance frequency, the pattern of ME coefficient dependence on the HDC shows a single peak, but splits into a double-peak pattern when the testing frequency increases into a certain region. With increasing the frequency, a divergent evolution of the HDC patterns was observed. Domain motion and ΔE effect combined with magnetostriction-piezoelectric coupling effect were employed to explain this experimental result.

  5. Extending the magnetoelectric efficiency of an MFC/brass/NdFeB energy harvester by coupling a pair of movable magnets

    Science.gov (United States)

    Leung, Chung Ming; Wang, Ya

    2017-10-01

    In this letter, an MFC/brass/NdFeB tip magnet three-phase cantilever beam was coupled with a pair of movable magnets to harness energy from alternating magnetic fields. By coupling with a pair of moveable magnets, both bandwidth and magnetoelectric (ME) voltage coefficient (α\\text{V}) were largely increased by 25% and 87.5%, respectively, in comparison with the same harvester coupled with stationary magnets. Such improvements were attributed to magnetic energy introduced by the moving magnets. Experiments also revealed the boundary positions of external magnets (movable and stationary) where the repulsive magnetic forces jumped to the attractive ones, and the stiffness hardening switched to the softening process. These results provided a wide-band nonlinear approach to efficiently harvest/detect the low-frequency alternating magnetic field energies.

  6. Enhanced Magnetoelectric Effect in Permendur/Pb(Zr0.52Ti0.48O3 Laminated Magnetostrictive/Piezoelectric Composite

    Directory of Open Access Journals (Sweden)

    Yanmin Jia

    2015-09-01

    Full Text Available In this work, after investigating three typical magneto-electric (ME composites, Permendur/Pb(Zr0.52Ti0.48O3(PZT, Metglas/PZT, and Tefenol-D/PZT, with the same dimensions and different saturation magnetostriction and magnetic permeability, the most excellent ME performance is observed in the Permendur/PZT laminates, which agrees well with the predicted results from the figure of merit. The low-frequency and resonance ME coefficients of Permendur/PZT composite are ~23.1 V/Oe.cm and ~309 V/Oe.cm at the optimal dc bias magnetic field of ~250 Oe, respectively. The strong ME effect of Permendur/PZT composite gives it potential in practical magnetic sensitive device applications.

  7. A flexible, high-performance magnetoelectric heterostructure of (001) oriented Pb(Zr0.52Ti0.48)O3 film grown on Ni foil

    Science.gov (United States)

    Palneedi, Haribabu; Yeo, Hong Goo; Hwang, Geon-Tae; Annapureddy, Venkateswarlu; Kim, Jong-Woo; Choi, Jong-Jin; Trolier-McKinstry, Susan; Ryu, Jungho

    2017-09-01

    In this study, a flexible magnetoelectric (ME) heterostructure of PZT/Ni was fabricated by depositing a (001) oriented Pb(Zr0.52Ti0.48)O3 (PZT) film on a thin, flexible Ni foil buffered with LaNiO3/HfO2. Excellent ferroelectric properties and large ME voltage coefficient of 3.2 V/cmṡOe were realized from the PZT/Ni heterostructure. The PZT/Ni composite's high performance was attributed to strong texturing of the PZT film, coupled with the compressive stress in the piezoelectric film. Besides, reduced substrate clamping in the PZT film due to the film on the foil structure and strong interfacial bonding in the PZT/LaNiO3/HfO2/Ni heterostructure could also have contributed to the high ME performance of PZT/Ni.

  8. Converse magnetoelectric effect in laminated composite of Metglas and Pb(Zr,TiO3 with screen-printed interdigitated electrodes

    Directory of Open Access Journals (Sweden)

    Yuan Zhang

    2014-06-01

    Full Text Available In this study, we investigate the converse magnetoelectric (CME effect in a laminated composite consisting of Metglas ribbons and Pb(Zr,TiO3 (PZT plate with screen-printed interdigitated electrodes and operating in longitudinal magnetization and longitudinal polarization (L-L mode. Large CME coefficients of 0.134 G·cm/V at frequency of 1 kHz and 2.75 G·cm/V at resonance frequency of 43.5 kHz under a small bias magnetic field of 7 Oe are achieved. The large CME effect can be attributed to the L-L mode and low mechanical loss of the Metglas/PZT laminated composite.

  9. Orientation dependence of magnetoelectric coefficient in 1-3-type BaTiO3/CoFe2O4

    Science.gov (United States)

    Jian, Gang; Shao, Hui; Zhang, Cheng; Yan, Chao; Zhao, Ning; Song, Bo; Wong, C. P.

    2018-03-01

    Orientation dependence of magnetoelectric coefficient αE33 in 1-3-type BaTiO3/CoFe2O4 composites was calculated in arbitrary directions by three-dimensional coordinate transformation method. The space distributions of pc11‧, pc12‧, e31‧ for piezoelectric phase and mc11‧, mc12‧, q31‧ for magnetic phase were obtained independently using relative experimental data and original matrices for 4mm BaTiO3 and m3m CoFe2O4. Elastic stiffness coefficients show little orientation differences, while e31‧ and q31‧ exhibit high dependence on crystal orientation, with the MAX absolute e31‧ = 2.96 C/m2 and the MAX q31‧ = 556 × 10-12 m/A are found at θ = 0° and θ = 0°, ϕ = 45°, respectively. For space distribution of αE33‧, BaTiO3||[0 0 1]/CoFe2O4||[0 0 1] combination has the maximum value which applies to both 1-3 p/m (1.485 V/A) and 1-3 m/p composites (1.529 V/A). Volume fraction is quite independent of orientations of both piezoelectric and magnetic phases and the volume fraction for magnetic phase f around 0.5 obtains the largest αE33. The results suggest an approach to significantly enhancing magnetoelectric coefficient of composite multiferroic materials through crystal orientation controls of single crystals and textured ceramics.

  10. Room temperature large self-biased magnetoelectric effect in non-lead based piezoelectric and magnetostrictive (0−3) particulate composite system

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Mukesh [Magnetics & Advanced Ceramics Laboratory, Indian Institute of Technology, Delhi-110016 India (India); Prakash, Chandra [Solid State Physics Laboratory Timarpur, Delhi-110054 India (India); Chatterjee, Ratnamala, E-mail: rmala@physics.iitd.ac.in [Magnetics & Advanced Ceramics Laboratory, Indian Institute of Technology, Delhi-110016 India (India)

    2017-05-01

    In this work, room temperature magnetoelectric properties of (0−3) particulate composites of non lead based piezoelectric BNTKNNLTS [0.97(Bi{sub 0.5}Na{sub 0.5}TiO{sub 3})–0.03(K{sub 0.47}Na{sub 0.47}Li{sub 0.06}Nb{sub 0.74}Sb{sub 0.06}Ta{sub 0.2}O{sub 3}) and magnetostrictive CZFMO (Co{sub 0.6}Zn{sub 0.4}Fe{sub 1.7}Mn{sub 0.3}O{sub 4}) are presented. Composite samples of (1-x)(BNTKNNLTS)-x(CZFMO){sub ,} with x=0.1 and 0.5, are synthesized by solid state reaction route. X-ray diffraction confirms the single phase formation of parent phases and the presence of two phases in the composites. Similar sintering conditions of the two individual components lead to optimal ferroelectric and ferromagnetic properties in the composites. A large self-biased magnetoelectric (ME) coupling ~74 mV/cm.Oe for the sample with x=0.1 (measured in longitudinally magnetized-transversely polarized configuration) is observed at room temperature. - Highlights: • Modified BNT-CFO based (0−3) particulate composites have been synthesized. • Similar sintering conditions of two components lead to optimal multiferroicity. • A large self-biased ME coupling ~74 mV/cm. Oe is obtained at room temperature.

  11. Enhanced Self-Biased Magnetoelectric Coupling in Laser-Annealed Pb(Zr,Ti)O3 Thick Film Deposited on Ni Foil.

    Science.gov (United States)

    Palneedi, Haribabu; Maurya, Deepam; Geng, Liwei D; Song, Hyun-Cheol; Hwang, Geon-Tae; Peddigari, Mahesh; Annapureddy, Venkateswarlu; Song, Kyung; Oh, Yoon Seok; Yang, Su-Chul; Wang, Yu U; Priya, Shashank; Ryu, Jungho

    2018-04-04

    Enhanced and self-biased magnetoelectric (ME) coupling is demonstrated in a laminate heterostructure comprising 4 μm-thick Pb(Zr,Ti)O 3 (PZT) film deposited on 50 μm-thick flexible nickel (Ni) foil. A unique fabrication approach, combining room temperature deposition of PZT film by granule spray in vacuum (GSV) process and localized thermal treatment of the film by laser radiation, is utilized. This approach addresses the challenges in integrating ceramic films on metal substrates, which is often limited by the interfacial chemical reactions occurring at high processing temperatures. Laser-induced crystallinity improvement in the PZT thick film led to enhanced dielectric, ferroelectric, and magnetoelectric properties of the PZT/Ni composite. A high self-biased ME response on the order of 3.15 V/cm·Oe was obtained from the laser-annealed PZT/Ni film heterostructure. This value corresponds to a ∼2000% increment from the ME response (0.16 V/cm·Oe) measured from the as-deposited PZT/Ni sample. This result is also one of the highest reported values among similar ME composite systems. The tunability of self-biased ME coupling in PZT/Ni composite has been found to be related to the demagnetization field in Ni, strain mismatch between PZT and Ni, and flexural moment of the laminate structure. The phase-field model provides quantitative insight into these factors and illustrates their contributions toward the observed self-biased ME response. The results present a viable pathway toward designing and integrating ME components for a new generation of miniaturized tunable electronic devices.

  12. Effects of Al substitution and thermal annealing on magnetoelectric Ba0.5Sr1.5Zn2Fe12O22 investigated by the enhancement factor of 57Fe nuclear magnetic resonance.

    Science.gov (United States)

    Kwon, Sangil; Kang, Byeongki; Kim, Changsoo; Jo, Euna; Lee, Soonchil; Chai, Yi Sheng; Chun, Sae Hwan; Kim, Kee Hoon

    2014-04-09

    The magnetoelectric properties of hexaferrite Ba0.5Sr1.5Zn2Fe12O22 are significantly improved by Al substitution and thermal annealing. Measuring the enhancement factor of 57Fe NMR, we found direct microscopic evidence that the magnetic moments of the L and S blocks are rotated by a magnetic field in such a way as to increase the net magnetic moment of a magnetic unit, even after the field is removed. Al substitution makes magnetoelectric property arise easily by suppressing the easy-plane anisotropy. The effect of thermal annealing is to stabilize the multiferroic state by reducing the number of pinning sites and the electron spin fluctuation. The transverse conic structure gradually changes to the alternating longitudinal conic structure where spins fluctuate more severely.

  13. Thickness dependence of magnetoelectric response for composites of Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films on CoFe{sub 2}O{sub 4} ceramic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing, E-mail: wang-jing@nuaa.edu.cn; Zhu, Kongjun [State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wu, Xia; Deng, Chaoyong [School of Electronics and Information Engineering, Guizhou University, Guiyang 550025 (China); Peng, Renci; Wang, Jianjun [School of Materials Science and Engineering, and State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

    2014-08-15

    Using chemical solution spin-coating we grew Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films of different thicknesses on highly dense CoFe{sub 2}O{sub 4} ceramics. X-ray diffraction revealed no other phases except Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} and CoFe{sub 2}O{sub 4}. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} film was important in obtaining strong magnetoelectric coupling.

  14. Magnetically tunable dielectric, impedance and magnetoelectric response in MnFe{sub 2}O{sub 4}/(Pb{sub 1−x}Sr{sub x})TiO{sub 3} composites thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bala, Kanchan, E-mail: bala.kanchan1987@gmail.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Kotnala, R.K. [CSIR, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Negi, N.S., E-mail: nsn_phy_hpu@yahoo.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India)

    2017-02-15

    We have synthesized piezomagnetic–piezoelectric composites thin films MnFe{sub 2}O{sub 4}/(Pb{sub 1−x}Sr{sub x})TiO{sub 3}, where x=0.1, 0.2, and 0.3, using the metalorganic deposition (MOD) reaction method. The structural and microstructural analysis using the X-ray diffraction (XRD), AFM, and SEM reveals the presence of homogenous growth of both pervoskite and spinel phases in the composite films. Our results show that all the composites films exhibit good multiferroic as well as considerable magnetoelectric coupling. The impedance (Z′ and Z″) and electrical modulus (M′ and M″) Nyquist plots show distinct electrical responses with the magnetic field. Our analyses suggest that this electrical response arises due to the coexistence of the high resistive phase and the comparatively conductive phase in the MFO/PST composite films. The maximum magnetoelectric coefficient (α) is found to be 4.29 V Oe{sup −1} cm{sup −1} and 2.82 V Oe{sup −1} cm{sup −1} for compositions x=0.1 and 0.2. These values are substantially larger than those reported for bilayer composites thin films in literature and make them interesting for room temperature device applications. - Highlights: • Influence of Sr doping on multiferroic and magnetoelectric properties composites thin films of MnFe{sub 2}O{sub 4} and (Pb, Sr)TiO{sub 3}. • Dielectric constant and dielectric loss with application of magnetic field. • Magnetically tunable AC electrical properties. • Magnetoelectric coupling in MnFe{sub 2}O{sub 4}/(Pb, Sr)TiO{sub 3} composite films by passive method.

  15. Magnetoelectric effect in antiferromagnetic multiferroic Pb(Fe.sub.1/2./sub. N b.sub.1/2./sub.)O.sub.3./sub. and its solid solutions with PbTi O.sub.3./sub.

    Czech Academy of Sciences Publication Activity Database

    Laguta, Valentyn; Stephanovich, V. A.; Raevski, I. P.; Raevskaya, S. I.; Titov, V.V.; Smotrakov, V. G.; Eremkin, V. V.

    2017-01-01

    Roč. 95, č. 1 (2017), 1-13, č. článku 014207. ISSN 1098-0121 R&D Projects: GA MŠk LO1409; GA MŠk LM2015088; GA ČR GA13-11473S Institutional support: RVO:68378271 Keywords : multiferroic * antiferromagnetic * ferroelectrics * magnetoelectric effect * Landau theory Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.)

  16. Thickness dependence of La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/PbZr{sub 0.2}Ti{sub 0.8}O{sub 3} magnetoelectric interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jinling; Trappen, Robbyn; Frye, Charles; Wolfe, Evan; Holcomb, Mikel Barry, E-mail: mikel.holcomb@mail.wvu.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Tra, Vu Thanh; Lin, Jiunn-Yuan [Institute of Physics, National Chiao Tung University, 30010 Hsinchu, Taiwan (China); Dong, Shuai [Department of Physics, Southeast University, 211189 Nanjing (China); Marcus, Matthew A.; Jenkins, Catherine [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); White, Ryan [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Polisetty, Srinivas [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Department of Chemical Engineering and Material Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States); LeBeau, James M. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Chu, Ying-Hao [Department of Materials Science and Engineering, National Chiao Tung University, 30010 Hsinchu, Taiwan (China); Institute of Physics, Academia Sinica, 105 Taipei, Taiwan (China)

    2015-10-05

    Magnetoelectric materials have great potential to revolutionize electronic devices due to the coupling of their electric and magnetic properties. Thickness varying La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO)/PbZr{sub 0.2}Ti{sub 0.8}O{sub 3} (PZT) heterostructures were built and measured in this article by valence sensitive x-ray absorption spectroscopy. The sizing effects of the heterostructures on the LSMO/PZT magnetoelectric interfaces were investigated through the behavior of Mn valence, a property associated with the LSMO magnetization. We found that Mn valence increases with both LSMO and PZT thickness. Piezoresponse force microscopy revealed a transition from monodomain to polydomain structure along the PZT thickness gradient. The ferroelectric surface charge may change with domain structure and its effects on Mn valence were simulated using a two-orbital double-exchange model. The screening of ferroelectric surface charge increases the electron charges in the interface region, and greatly changes the interfacial Mn valence, which likely plays a leading role in the interfacial magnetoelectric coupling. The LSMO thickness dependence was examined through the combination of two detection modes with drastically different attenuation depths. The different length scales of these techniques' sensitivity to the atomic valence were used to estimate the depth dependence Mn valence. A smaller interfacial Mn valence than the bulk was found by globally fitting the experimental results.

  17. Thickness dependence of La0.7Sr0.3MnO3/PbZr0.2Ti0.8O3 magnetoelectric interfaces

    Science.gov (United States)

    Zhou, Jinling; Tra, Vu Thanh; Dong, Shuai; Trappen, Robbyn; Marcus, Matthew A.; Jenkins, Catherine; Frye, Charles; Wolfe, Evan; White, Ryan; Polisetty, Srinivas; Lin, Jiunn-Yuan; LeBeau, James M.; Chu, Ying-Hao; Holcomb, Mikel Barry

    2015-10-01

    Magnetoelectric materials have great potential to revolutionize electronic devices due to the coupling of their electric and magnetic properties. Thickness varying La0.7Sr0.3MnO3 (LSMO)/PbZr0.2Ti0.8O3 (PZT) heterostructures were built and measured in this article by valence sensitive x-ray absorption spectroscopy. The sizing effects of the heterostructures on the LSMO/PZT magnetoelectric interfaces were investigated through the behavior of Mn valence, a property associated with the LSMO magnetization. We found that Mn valence increases with both LSMO and PZT thickness. Piezoresponse force microscopy revealed a transition from monodomain to polydomain structure along the PZT thickness gradient. The ferroelectric surface charge may change with domain structure and its effects on Mn valence were simulated using a two-orbital double-exchange model. The screening of ferroelectric surface charge increases the electron charges in the interface region, and greatly changes the interfacial Mn valence, which likely plays a leading role in the interfacial magnetoelectric coupling. The LSMO thickness dependence was examined through the combination of two detection modes with drastically different attenuation depths. The different length scales of these techniques' sensitivity to the atomic valence were used to estimate the depth dependence Mn valence. A smaller interfacial Mn valence than the bulk was found by globally fitting the experimental results.

  18. Equivalent Circuit Model of Low-Frequency Magnetoelectric Effect in Disk-Type Terfenol-D/PZT Laminate Composites Considering a New Interface Coupling Factor.

    Science.gov (United States)

    Lou, Guofeng; Yu, Xinjie; Lu, Shihua

    2017-06-15

    This paper describes the modeling of magnetoelectric (ME) effects for disk-type Terfenol-D (Tb 0.3 Dy 0.7 Fe 1.92 )/PZT (Pb(Zr,Ti)O₃) laminate composite at low frequency by combining the advantages of the static elastic model and the equivalent circuit model, aiming at providing a guidance for the design and fabrication of the sensors based on magnetoelectric laminate composite. Considering that the strains of the magnetostrictive and piezoelectric layers are not equal in actual operating due to the epoxy resin adhesive bonding condition, the magnetostrictive and piezoelectric layers were first modeled through the equation of motion separately, and then coupled together with a new interface coupling factor k c , which physically reflects the strain transfer between the phases. Furthermore, a theoretical expression containing k c for the transverse ME voltage coefficient α v and the optimum thickness ratio n optim to which the maximum ME voltage coefficient corresponds were derived from the modified equivalent circuit of ME laminate, where the interface coupling factor acted as an ideal transformer. To explore the influence of mechanical load on the interface coupling factor k c , two sets of weights, i.e., 100 g and 500 g, were placed on the top of the ME laminates with the same thickness ratio n in the sample fabrication. A total of 22 T-T mode disk-type ME laminate samples with different configurations were fabricated. The interface coupling factors determined from the measured α v and the DC bias magnetic field H bias were 0.11 for 500 g pre-mechanical load and 0.08 for 100 g pre-mechanical load. Furthermore, the measured optimum thickness ratios were 0.61 for k c = 0.11 and 0.56 for k c = 0.08. Both the theoretical ME voltage coefficient α v and optimum thickness ratio n optim containing k c agreed well with the measured data, verifying the reasonability and correctness for the introduction of k c in the modified equivalent circuit model.

  19. Equivalent Circuit Model of Low-Frequency Magnetoelectric Effect in Disk-Type Terfenol-D/PZT Laminate Composites Considering a New Interface Coupling Factor

    Directory of Open Access Journals (Sweden)

    Guofeng Lou

    2017-06-01

    Full Text Available This paper describes the modeling of magnetoelectric (ME effects for disk-type Terfenol-D (Tb0.3Dy0.7Fe1.92/PZT (Pb(Zr,TiO3 laminate composite at low frequency by combining the advantages of the static elastic model and the equivalent circuit model, aiming at providing a guidance for the design and fabrication of the sensors based on magnetoelectric laminate composite. Considering that the strains of the magnetostrictive and piezoelectric layers are not equal in actual operating due to the epoxy resin adhesive bonding condition, the magnetostrictive and piezoelectric layers were first modeled through the equation of motion separately, and then coupled together with a new interface coupling factor kc, which physically reflects the strain transfer between the phases. Furthermore, a theoretical expression containing kc for the transverse ME voltage coefficient αv and the optimum thickness ratio noptim to which the maximum ME voltage coefficient corresponds were derived from the modified equivalent circuit of ME laminate, where the interface coupling factor acted as an ideal transformer. To explore the influence of mechanical load on the interface coupling factor kc, two sets of weights, i.e., 100 g and 500 g, were placed on the top of the ME laminates with the same thickness ratio n in the sample fabrication. A total of 22 T-T mode disk-type ME laminate samples with different configurations were fabricated. The interface coupling factors determined from the measured αv and the DC bias magnetic field Hbias were 0.11 for 500 g pre-mechanical load and 0.08 for 100 g pre-mechanical load. Furthermore, the measured optimum thickness ratios were 0.61 for kc = 0.11 and 0.56 for kc = 0.08. Both the theoretical ME voltage coefficient αv and optimum thickness ratio noptim containing kc agreed well with the measured data, verifying the reasonability and correctness for the introduction of kc in the modified equivalent circuit model.

  20. Strong magnetoelectric coupling in CoFe2O4-BaTiO3 composites prepared by molten-salt synthesis method

    International Nuclear Information System (INIS)

    Nie Junwu; Xu Guoyue; Yang Ying; Cheng Chuanwei

    2009-01-01

    Magnetoelectric nano-composites (1 - x)CoFe 2 O 4 + (x)BaTiO 3 with x varies as 0, 0.5, 0.65 and 1.0 in molar ratio were prepared by molten-salt synthesis method. The structural analysis carried out by X-ray diffraction (XRD) technique has confirmed that both phases are present in all the nano-composites powders and ceramic composites. The TEM images show that the nano-particle crystallite size is about 50-80 nm, which is consistent to the result calculated by XRD. The dielectric constant was studied as a function of frequency for ceramic composites sintered by using those nano-composite powders. The saturation magnetization (Ms) and remnant polarization (Pr) were calculated from the magnetic hysteresis loop and electric hysteresis loop, respectively. And a large ME coefficient of about 17.04 mV cm -1 Oe -1 was observed for 0.5CoFe 2 O 4 + 0.5BaTiO 3 ME composite under the ac superimposed magnetic signal with 20 kHz frequency by using the lock-in technique

  1. Magnetoelectric coupling study in multiferroic Pb(Fe0.5Nb0.5)O3 ceramics through small and large electric signal standard measurements

    International Nuclear Information System (INIS)

    Raymond, Oscar; Siqueiros, Jesus M.; Font, Reynaldo; Portelles, Jorge

    2011-01-01

    Multifunctional multiferroic materials such as the single phase compound Pb(Fe 0.5 Nb 0.5 )O 3 (PFN), where ferroelectric and antiferromagnetic order coexist, are very promising and have great interest from the academic and technological points of view. In this work, coupling of the ferroelectric and magnetic moments is reported. For this study, a combination of the small signal response using the impedance spectroscopy technique and the electromechanical resonance method with the large signal response through standard ferroelectric hysteresis measurement, has been used with and without an applied magnetic field. The measurements to determine the electrical properties of the ceramic were performed as functions of the bias and poling electric fields. A simultaneous analysis of the complex dielectric constant ε-tilde, impedance Z-tilde, electric modulus M-tilde, admittance Y-tilde, and the electromechanical parameters and coupling factors is presented. The results are correlated with a previous study of structural, morphological, small signal dielectric frequency-temperature response, and the ferroelectric hysteretic, magnetic and magnetodielectric behaviors. The observed shifts of the resonance and antiresonance frequency values can be associated with change of the ferroelectric domain size favored by the readjustment of the oxygen octahedron when the magnetic field is applied. From P-E hysteresis loops obtained without and with an external applied magnetic field, a dc magnetoelectric coupling effect with maximum value of 4 kV/cm T (400 mV/cm Oe) was obtained.

  2. First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

    International Nuclear Information System (INIS)

    Lee, Jun Hee; Fishman, Randy S; Kézsmáki, István

    2016-01-01

    Due to the complicated magnetic and crystallographic structures of BiFeO 3 , its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a first-principles approach, we uncover all possible ME couplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO 3 . First-principles calculations are used to understand the microscopic origins of the ME couplings. We find that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamic ME effects in BiFeO 3 . A model motivated by first principles reproduces the absorption difference of counter-propagating light beams called non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic ME couplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hidden ME couplings on the atomic scale and for exploiting optical ME effects in the next generation of technological devices such as optical diodes. (paper)

  3. Polycrystalline La1-xSrxMnO3 films on silicon: Influence of post-Deposition annealing on structural, (Magneto-)Optical, and (Magneto-)Electrical properties

    Science.gov (United States)

    Thoma, Patrick; Monecke, Manuel; Buja, Oana-Maria; Solonenko, Dmytro; Dudric, Roxana; Ciubotariu, Oana-Tereza; Albrecht, Manfred; Deac, Iosif G.; Tetean, Romulus; Zahn, Dietrich R. T.; Salvan, Georgeta

    2018-01-01

    The integration of La1-xSrxMnO3 (LSMO) thin film technology into established industrial silicon processes is regarded as challenging due to lattice mismatch, thermal expansion, and chemical reactions at the interface of LSMO and silicon. In this work, we investigated the physical properties of thin La0.73Sr0.27MnO3 films deposited by magnetron sputtering on silicon without a lattice matching buffer layer. The influence of a post-deposition annealing treatment on the structural, (magneto-)optical, and (magneto-)electrical properties was investigated by a variety of techniques. Using Rutherford backscattering spectroscopy, atomic force microscopy, Raman spectroscopy, and X-ray diffraction we could show that the thin films exhibit a polycrystalline, rhombohedral structure after a post-deposition annealing of at least 700 °C. The dielectric tensor in the spectral range from 1.7 eV to 5 eV determined from spectroscopic ellipsometry in combination with magneto-optical Kerr effect spectroscopy was found to be comparable to that of lattice matched films on single crystal substrates reported in literature [1]. The values of the metal-isolator transition temperature and temperature-dependent resistivities also reflect a high degree of crystalline quality of the thermally treated films.

  4. Magnetoelectric and electric measurements of the (1-x)BiFeO{sub 3}–(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bochenek, D., E-mail: dariusz.bochenek@us.edu.pl [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Niemiec, P. [University of Silesia, Faculty of Computer Science and Material Science, Institute of Technology and Mechatronics, 12, Żytnia St., 41–200, Sosnowiec (Poland); Guzdek, P. [Institute of Electron Technology Cracow Division, 39, Zabłocie St., Cracow, 30-701 (Poland); Wzorek, M. [Institute of Electron Technology, Al. Lotników 32/46, 02-668, Warsaw (Poland)

    2017-07-01

    In the paper ferro–electro–magnetic (1-x)BiFeO{sub 3}-(x)Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3} (BF-PFN) solid solutions were obtained (containing the percentage BF/PFN: 60/40 and 70/30). Individual components of the solid solution were prepared by follows methods: synthesizing a powder BF was performed by calcining the simple oxides (Bi{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}), and synthesizing a powder PFN was carried out by calcining a mixture of complex oxides (FeNbO{sub 4}, PbO). Compaction of synthesized and mixed BiFeO{sub 3}, PbFe{sub 1/2}Nb{sub 1/2}O{sub 3} powders was carried out by free sintering methods. X–ray, microstructure, dielectric, magnetic and magnetoelectric studies, DC electrical conductivity and electrical hysteresis loop were carried out. Magnetoelectric effect measurements performed at room temperature showed coupling between electric and magnetic subsystem of the BF–PFN solid solutions. - Highlights: • BF-PFN samples have a densely packed microstructure, with well crystallized grains. • Bi atoms possibly migrate from BF toward PFN component during sintering. • BF-PFN have a diffuse character of the ferroelectric–paraelectric phase transition. • Magnetoelectric coefficient (α{sub ME}) for BF-PFN is higher, than for pure BF. • The α{sub ME} for BF-PFN is about three times higher than for 0.75BiFeO{sub 3}–0.25BaTiO{sub 3}.

  5. Room temperature magneto-electric coupling in La-Zn doped Ba{sub 1-x}La{sub x}Fe{sub 12-x}Zn{sub x}O{sub 19} (x = 0.0-0.4) hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pawan; Gaur, Anurag [National Institute of Technology, Department of Physics, Kurukshetra (India)

    2017-12-15

    Barium hexaferrite powder samples with substitution of La{sup +3} at Ba{sup +2} and Zn{sup +2} at Fe{sup +3} site, according to the series formula Ba{sub 1-x}La{sub x}Fe{sub 12-x}Zn{sub x}O{sub 19} (x = 0.0, 0.1, 0.2, 0.3, 0.4) have been prepared by the co-precipitation method. These samples were characterized by X-ray diffractometer (XRD), scanning electron microscopy, Polarization versus electric field loop tracer and vibrating sample magnetometer techniques. XRD patterns and Rietveld refinement indicate the single-phase formation of the magneto-plumbite barium hexaferrite for all the samples. Significant changes in dielectric properties are obtained by the different doping concentration of La and Zn. Ferroelectric loop for all the samples shows the lossy ferroelectric behaviour. Large spontaneous polarization is observed for x = 0.2 sample at room temperature. With increasing La and Zn doping content, the value of saturation magnetization and retentivity increases, and reaches a maximum value of 40.0 emu/gm and 24.0 emu/gm, respectively, for x = 0.2 sample and then decreases. To confirm the magneto-electric coupling, the second-order magneto-electric coupling coefficient β is measured through the dynamic method with the maximum value of ∝ 1.69 x 10{sup -6} mV/cm.Oe{sup 2} for x = 0.2 sample at room temperature. The observations of room temperature magneto-electric coupling in these samples are useful for evolution of new multifunctional devices. (orig.)

  6. First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

    Science.gov (United States)

    Lee, Jun Hee; Kézsmáki, István; Fishman, Randy S.

    2016-04-01

    Due to the complicated magnetic and crystallographic structures of BiFeO3, its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a first-principles approach, we uncover all possible ME couplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO3. First-principles calculations are used to understand the microscopic origins of the ME couplings. We find that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamic ME effects in BiFeO3. A model motivated by first principles reproduces the absorption difference of counter-propagating light beams called non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic ME couplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hidden ME couplings on the atomic scale and for exploiting optical ME effects in the next generation of technological devices such as optical diodes. This manuscript has been written by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan.

  7. Piezoelectric control of magnetoelectric coupling driven non-volatile memory switching and self cooling effects in FE/FSMA multiferroic heterostructures

    Science.gov (United States)

    Singh, Kirandeep; Kaur, Davinder

    2017-02-01

    The manipulation of magnetic states and materials' spin degree-of-freedom via a control of an electric (E-) field has been recently pursued to develop magnetoelectric (ME) coupling-driven electronic data storage devices with high read/write endurance, fast dynamic response, and low energy dissipation. One major hurdle for this approach is to develop reliable materials which should be compatible with prevailing silicon (Si)-based complementary metal-oxide-semiconductor (CMOS) technology, simultaneously allowing small voltage for the tuning of magnetization switching. In this regard, multiferroic heterostructures where ferromagnetic (FM) and ferroelectric (FE) layers are alternatively grown on conventional Si substrates are promising as the piezoelectric control of magnetization switching is anticipated to be possible by an E-field. In this work, we study the ferromagnetic shape memory alloys based PbZr0.52Ti0.48O3/Ni50Mn35In15 (PZT/Ni-Mn-In) multiferroic heterostructures, and investigate their potential for CMOS compatible non-volatile magnetic data storage applications. We demonstrate the voltage-impulse controlled nonvolatile, reversible, and bistable magnetization switching at room temperature in Si-integrated PZT/Ni-Mn-In thin film multiferroic heterostructures. We also thoroughly unveil the various intriguing features in these materials, such as E-field tuned ME coupling and magnetocaloric effect, shape memory induced ferroelectric modulation, improved fatigue endurance as well as Refrigeration Capacity (RC). This comprehensive study suggests that these novel materials have a great potential for the development of unconventional nanoscale memory and refrigeration devices with self-cooling effect and enhanced refrigeration efficiency, thus providing a new venue for their applications.

  8. Strong and anisotropic magnetoelectricity in composites of magnetostrictive Ni and solid-state grown lead-free piezoelectric BZT–BCT single crystals

    Directory of Open Access Journals (Sweden)

    Haribabu Palneedi

    2017-03-01

    Full Text Available Aimed at developing lead-free magnetoelectric (ME composites with performances as good as lead (Pb-based ones, this study employed (001 and (011 oriented 82BaTiO3-10BaZrO3-8CaTiO3 (BZT–BCT piezoelectric single crystals, fabricated by the cost-effective solid-state single crystal growth (SSCG method, in combination with inexpensive, magnetostrictive base metal Nickel (Ni. The off-resonance, direct ME coupling in the prepared Ni/BZT–BCT/Ni laminate composites was found to be strongly dependent on the crystallographic orientation of the BZT–BCT single crystals, as well as the applied magnetic field direction. Larger and anisotropic ME voltage coefficients were observed for the composite made using the (011 oriented BZT–BCT single crystal. The optimized ME coupling of 1 V/cm Oe was obtained from the Ni/(011 BZT–BCT single crystal/Ni composite, in the d32 mode of the single crystal, when a magnetic field was applied along its [100] direction. This performance is similar to that reported for the Ni/Pb(Mg1/3Nb2/3O3-Pb(Zr,TiO3 (PMN–PZT single crystal/Ni, but larger than that obtained from the Ni/Pb(Zr,TiO3 ceramic/Ni composites. The results of this work demonstrate that the use of lead-free piezoelectric single crystals with special orientations permits the selection of desired anisotropic properties, enabling the realization of customized ME effects in composites.

  9. Electrical, magnetic, and direct and converse magnetoelectric properties of (1−x)Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3}−(x)CoFe{sub 2}O{sub 4} (PZT–CFO) magnetoelectric composites

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Jian-hong, E-mail: pjhhj@sohu.com [College of Physics and Electronic Information Engineering, Qinghai University for Nationalities, Xining 810007 (China); College of Physics and Information Technology, Shaanxi Normal University, Xi' an 710062 (China); Hojamberdiev, Mirabbos, E-mail: hmirabbos@gmail.com [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama, Kanagawa 226-8503 (Japan); Li, Hai-qing; Mao, Duo-lu; Zhao, Yuan-juan [College of Physics and Electronic Information Engineering, Qinghai University for Nationalities, Xining 810007 (China); Liu, Peng; Zhou, Jian-ping; Zhu, Gang-qiang [College of Physics and Information Technology, Shaanxi Normal University, Xi' an 710062 (China)

    2015-03-15

    In this work, hydrothermal synthesis and ceramic sintering process were applied to fabricate (1−x)Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3}−(x)CoFe{sub 2}O{sub 4} (PZT–CFO) (x=0.20, 0.35, and 0.50) magnetoelectric (ME) composites. The X-ray diffraction (XRD) studies revealed that no chemical reaction occurred between individual PZT and CFO phases and confirmed the manifestation of PZT and CFO phases within the ME composite. Scanning electron microscopy (SEM) was used to investigate the microstructure and connectivity scheme in the ME composites. The dielectric constant (ε) and loss tangent (tan δ) were determined as functions of frequency and temperature for all the composites prepared. The polarization–electric field (P–E) and magnetization–magnetic field (M–H) hysteresis loops obtained indicate that both ferroelectric and ferromagnetic properties coexist in the ME composites prepared. The direct (DME) and converse magnetoelectric effects (CME) were measured only for the PZT–CFO20 (20 mol% CoFe{sub 2}O{sub 4}) composite sintered at 1100 °C for 4 h. The maximum values of ME voltage coefficient α{sub ME}(dE/dH) and ME susceptibility coefficient α{sub me} (dH/dE) were 226 mV cm{sup −1} Oe{sup −1} at frequency of 75.1 kHz and 1.15×10{sup −8} s/m at frequency of 66.8 kHz, respectively. - Highlights: • PZT–CFO composite was prepared by hydrothermal method and ceramic sintering process. • Effect of CoFe{sub 2}O{sub 4} content on the electrical and magnetic properties is studied. • CoFe{sub 2}O{sub 4} particles are uniformly distributed in the PZT matrix. • P–E and M–H hysteresis loops confirm room-temperature multiferroic characteristics. • T{sub m} shifts to higher values with the increase in the measurement frequency.

  10. Investigation on magnetoelectric behavior of (80Bi0.5Na0.5TiO3-20Bi0.5K0.5TiO3)-CoFe2O4 particulate composites

    Science.gov (United States)

    Liu, Sheng; Yan, Shuoqing; Yao, Lingling; He, Jun; He, Longhui; Hu, Zhaowen; Huang, Shengxiang; Deng, Lianwen

    2017-12-01

    Particulate magnetoelectric (ME) ceramics constituted by (1-x)(80Bi0.5Na0.5TiO3-20Bi0.5K0.5TiO3)-xCoFe2O4 [(1-x)BNKT-xCFO] (x = 0, 0.1, 0.2, 0.3, 0.4 and 1.0) were synthesized by an powder-in-sol precursor hybrid processing method and their structure, magnetic, ferroelectric, magnetodielectric (MD) and ME properties have been investigated. Results showed that the ceramics consisted of only two chemically separated phases and had homogeneous microstructure. The introduction of CFO into BNKT matrix led to the weakening of ferroelectric and dielectric properties whereas the strengthening magnetic and MD properties. The observation of the MD effect revealed the evidence of the strain-induced ME coupling and the MD value is well scaled with M2. A maximum value of ME output of 25.07 mV/cm·Oe was achieved for the 0.7BNKT-0.3CFO composite. The improved ME response together with the linear MD effect makes the ceramics promise for use in magnetic field controllable devices or magneto-electric transducers.

  11. Structural, multiferroic, dielectric and magnetoelectric properties of (1-x)Ba0.85Ca0.15Ti0.90Zr0.10O3-(x)CoFe2O4 lead-free composites

    Science.gov (United States)

    Negi, N. S.; Kumar, Rakesh; Sharma, Hakikat; Shah, J.; Kotnala, R. K.

    2018-06-01

    High performance lead-free multiferroic composites with strong magnetoelectric coupling effect are desired to replace lead-based ceramics in multifunctional device applications due to increasing environmental issues. We report crystal structure, ferroelectric, magnetic, dielectric and magnetoelectric properties of (1-x)Ba0.85Ca0.15Ti0.90Zr0.10O3-(x)CoFe2O4 (BCTZ-CFO) lead-free composites with x = 0.1, 0.3, 0.5, 0.7 and 0.9 synthesized by chemical solution method. BCTZ power was synthesized by sol-gel method while CFO was prepared by metallo-organic decomposition (MOD) method. The XRD results confirm successful formation of the BCTZ-CFO composites without presence of any impurity phase. At room temperature, the BCTZ-CFO composites show multiferroic behavior characterized by ferroelectric and ferromagnetic hysteresis curves. The composite having 10 wt% of CFO exhibited maximum polarization, remnant polarization and coercive field of Ps ∼ 5.1 μC/cm2, Pr ∼ 1.4 μC/cm2 and Ec ∼ 11.6 kV/cm respectively. The BCTZ-CFO composite with 90 wt% of CFO incorporation exhibits improved ferromagnetic properties with Ms ∼ 32 emu/g, Mr ∼ 11.7 emu/g and Hc ∼ 504 Oe. Mӧssbauer spectra analysis show two sets of six-line hyperfine patterns for BCTZ-CFO composites, indicating the presence of Fe3+ ions in both A and B sites. Increasing BCTZ content was found to decrease the hyperfine field strength at both sites and is consistent with the decreasing magnetic moment observed for the samples. The maximum dielectric constant value ε‧ ∼ 678 is obtained at 1 MHz for composite with 10 wt% of CFO phase. The results indicate that the BCTZ-CFO composites are potential lead-free room temperature multiferroic systems.

  12. Mesoscale Design of Magnetoelectric Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Viehland, Dwight [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Priya, Shashank [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2016-09-09

    This is a final report for a transient program that was issued to Virginia Tech as a new program (DE-SC0001450), rather than as a renewal to our existing program (DE-FG02-06ER46290). The renewal proposal was submitted in November 2014, but because of confusion in the negotiations got issued as a new program. Subsequently, a correction was made where the new program (DE-SC0001450) was terminated, and a renewal to the existing program (DE-FG02-06ER46290) issued. About $8,000 was expended on the new program before the mistake was discovered, and actions begun to correct it. The Department of Materials Science and Engineering at Virginia Tech issued a ‘Letter of Guarantee’ to the University to continue work while the issues were sorted out. The renewal proposal (DE-FG02-06ER46290) that was eventually funded was the same one as the new proposal (DE-SC0001450) that was initially funded. The $8,000 expended on the new proposal was subtracted from the eventual amount given in the renewal proposal. Here, we submit the final report for this new program (DE-SC0001450) that was terminated. Since the Statement of Work was identical to the renewal proposal (DE-FG02-06ER46290), we submit to you as the final report for the new program (DE-SC0001450) the same information that we submitted as our annual report for DE-FG02-06ER46290 that was submitted to the program manager (Refik Kortan) in June 2016.

  13. Magnetoelectric Nanocomposites for Flexible Electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-01-01

    inside anodic aluminum oxide membranes is discussed. Characterization of electrodeposited iron, nickel and highly magnetostrictive iron-gallium alloy NWs was done using XRD, electron and magnetic force microscopy. Second, different nanocomposite films

  14. Evidence for two spin-glass transitions with magnetoelastic and magnetoelectric couplings in the multiferroic (B i1 -xB ax) (F e1 -xT ix ) O3 system

    Science.gov (United States)

    Kumar, Arun; Kaushik, S. D.; Siruguri, V.; Pandey, Dhananjai

    2018-03-01

    For disordered Heisenberg systems with small single ion anisotropy (D ), two spin-glass (SG) transitions below the long-range ordered (LRO) phase transition temperature (Tc) have been predicted theoretically for compositions close to the percolation threshold. Experimental verification of these predictions is still controversial for conventional spin glasses. We show that multiferroic spin-glass systems can provide a unique platform for verifying these theoretical predictions via a study of change in magnetoelastic and magnetoelectric couplings, obtained from an analysis of diffraction data, at the spin-glass transition temperatures (TSG). Results of macroscopic (dc M (H , T ), M(t ), ac susceptibility [χ (ω, T )], and specific heat (Cp)) and microscopic (x-ray and neutron scattering) measurements are presented on disordered BiFe O3 , a canonical Heisenberg system with small single ion anisotropy, which reveal appearance of two spin-glass phases, SG1 and SG2, in coexistence with the LRO phase below the Almeida-Thouless (A-T) and Gabey-Toulouse (G-T) lines. It is shown that the temperature dependence of the integrated intensity of the antiferromagnetic (AFM) peak shows dips with respect to the Brillouin function behavior around the SG1 and SG2 transition temperatures. The temperature dependence of the unit cell volume departs from the Debye-Grüneisen behavior below the SG1 transition and the magnitude of departure increases significantly with decreasing temperature up to the electromagnon driven transition temperature below which a small change of slope occurs followed by another similar change of slope at the SG2 transition temperature. The ferroelectric polarization also changes significantly at the two spin-glass transition temperatures. These results, obtained using microscopic techniques, clearly demonstrate that the SG1 and SG2 transitions occur on the same magnetic sublattice and are intrinsic to the system. We also construct a phase diagram showing all

  15. Strain mediated magnetoelectric coupling induced in (x) Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-(1−x) MgFe{sub 2}O{sub 4} composites

    Energy Technology Data Exchange (ETDEWEB)

    Manjusha [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Yadav, K.L., E-mail: klyadav35@yahoo.com [Smart Materials Research Laboratory, Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Adhlakha, Nidhi [Elettra-Sincrotrone Trieste S.C.p.A, Area Science Park, I-34012 Trieste (Italy); Shah, Jyoti; Kotnala, R.K. [CSIR-National Physical Laboratory, New Delhi 110012 (India)

    2017-06-01

    Particulate composites of ferroelectric and ferrite phases having general formula (x)Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-(1−x)MgFe{sub 2}O{sub 4} (x=0, 0.5, 0.6, 0.7, 0.8 and 1.0), equivalently denoted as (x)BNT-(1−x)MgFO were synthesized by solid state reaction method. From X-ray diffraction analysis, the structural transformation from tetragonal to rhombohedral corresponding to BNT phase was observed in composites with x=0.5 to x=0.8. Shifting of (012) BNT peak towards left (x=0.5, 0.8) and right side (x=0.6, 0.7) observed due to occupation of Bi{sup 3+} ions at interstitial and substitutional sites into host MgFO lattice respectively. BNT produced strain in MgFO lattice. Scanning electron micrographs show closely packed microstructure with grain size variations from 0.62 to 2.90 µm. The value of magnetoelectric (ME) coupling coefficient increases from 2.42 (x=0.5) to 4.79 (x=0.8) mV/cm. Oe due to strain produced in MgFO and BNT lattices.

  16. Emergent odd-parity multipoles and magnetoelectric effects on a diamond structure: Implication for the 5 d transition metal oxides A OsO4 (A =K ,Rb, and Cs)

    Science.gov (United States)

    Hayami, Satoru; Kusunose, Hiroaki; Motome, Yukitoshi

    2018-01-01

    We report our theoretical predictions on the linear magnetoelectric (ME) effects originating from odd-parity multipoles associated with spontaneous spin and orbital ordering on a diamond structure. We derive a two-orbital model for d electrons in eg orbitals by including the effective spin-orbit coupling which arises from the mixing between eg and t2 g orbitals. We show that the model acquires a net antisymmetric spin-orbit coupling once staggered spin and orbital orders occur spontaneously. The staggered orders are accompanied by odd-parity multipoles: magnetic monopole, quadrupoles, and toroidal dipoles. We classify the types of the odd-parity multipoles according to the symmetry of the spin and orbital orders. Furthermore, by computing the ME tensor using the linear response theory, we show that the staggered orders induce a variety of the linear ME responses. We elaborate all possible ME responses for each staggered order, which are useful to identify the order parameter and to detect the odd-parity multipoles by measuring the ME effects. We also elucidate the effect of lowering symmetry by a tetragonal distortion, which leads to richer ME responses. The implications of our results are discussed for the 5 d transition metal oxides, A OsO4 (A =K,Rb, and Cs) , in which the order parameters are not fully identified.

  17. Large self-biased and multi-peak magnetoelectric coupling in transducer of Pb(Zr,Ti)O3 plates and H-type magnetization-graded ferromagnetic fork

    Science.gov (United States)

    Shen, Yongchun; Ling, Zhihao; Lu, Caijiang

    2015-12-01

    This paper develops a self-biased magnetoelectric (ME) composite Metglas/H-type-FeNi/PZT (MHFP) of H-type magnetization-graded Metglas/H-type-FeNi fork and piezoelectric Pb(Zr,Ti)O3 (PZT) plate. By using the magnetization-graded magnetostrictive layer and symmetrical H-type structure, giant self-biased ME coupling and multi-peak phenomenon are observed. The zero-biased ME voltage coefficient of MHFP composite reaches ˜63.8 V/cm Oe, which is ˜37.5 times higher than that of traditional FeNi/PZT laminate. The output ME voltage has a good near linear relation with Hac and is determined to be ˜5.1 V/Oe and ˜10.6 mV/Oe at ˜65 kHz and 1 kHz, respectively. These indicate that the proposed composite show promising applications for ME transducers and high-sensitivity self-biased magnetic sensors.

  18. Multiferroic magnetoelectric coupling effect of bilayer La1.2Sr1.8Mn2O7/PbZr0.3Ti0.7O3 complex thin film

    Science.gov (United States)

    Liang, K.; Zhou, P.; Ma, Z. J.; Qi, Y. J.; Mei, Z. H.; Zhang, T. J.

    2017-05-01

    Magnetoelectric (ME) coupling effect of 2-2-type ferromagnetic/ferroelectric bi-layer multiferroic epitaxial thin film (La1.2Sr1.8Mn2O7/PbZr0.3Ti0.7O3, LSMO/PZT) on SrRuO3 (SRO) substrate is investigated systematically by using Landau-Ginzburg-Devonshire (LGD) thermodynamic theory and modified constitutive equations. The calculating results clarify the detail relationships between ME coupling response and the residual strain, the volume fraction of constituent phases, the interface coupling coefficients, the magnetic field and the temperature. It also shows that improved ME coupling response can be modulated by these parameters. External magnetic fields (H1) induced ME coupling effect could be enhanced around Curie Temperature (Tc) of ferromagnetic phase and ME voltage coefficient (αE31) approaches a maximum at H1 ∼ 4.5 kOe near Tc. The remarkable variations of ME coupling response can be used to provide useful guidelines on the design of multifunctional devices.

  19. Strong Nonvolatile Magnon-Driven Magnetoelectric Coupling in Single-Crystal Co /[PbMg1/3Nb2/3O3] 0.71[PbTiO3]0.29 Heterostructures

    Science.gov (United States)

    Zhou, Cai; Shen, Lvkang; Liu, Ming; Gao, Cunxu; Jia, Chenglong; Jiang, Changjun

    2018-01-01

    The ability to manipulate the magnetism on interfacing ferromagnetic and ferroelectric materials via electric fields to achieve an emergent multiferroic response has enormous potential for nanoscale devices with novel functionalities. Herein, a strong electric-field control of the magnetism modulation is reported for a single-crystal Co (14 nm )/(001 )Pb (Mg1/3Nb2/3) 0.7Ti0.3O3 (PMN-PT) heterostructure by fabricating an epitaxial Co layer on a PMN-PT substrate. Electric-field-tuned ferromagnetic resonance exhibits a large resonance field shift, with a 120-Oe difference between that under positive and negative remanent polarizations, which demonstrates nonvolatile electric-field control of the magnetism. Further, considering the complexity of the twofold symmetry magnetic anisotropy, the linear change of the fourfold symmetry magnetic anisotropy, relating to the single-crystal cubic magnetocrystal anisotropy of the Co thin film, is resolved and quantified to exert a magnon-driven, strong direct magnetoelectric effect on the Co /PMN -PT interface. These results are promising for future multiferroic devices.

  20. Investigating the effect of multiple grain-grain interfaces on electric transport behavior of [50 wt% BaFe12O19-50 wt% Na0.5Bi0.5TiO3] magnetoelectric nanocomposite system

    Science.gov (United States)

    Pattanayak, Ranjit; Raut, Subhajit; Dash, Tapan; Mohapatra, Soumyaranjan; Muduli, Rakesh; Panigrahi, Simanchala

    2017-05-01

    Polycrystalline [50 wt% BaFe12O19 (BaM)-50 wt% Na0.5Bi0.5TiO3 (NBT)] particulate novel magnetoelectric nanocomposite system was successfully fabricated by solid state reaction technique. The Rietveld refinement of X-ray diffraction pattern was provided the evidence about the pure phase formation of desired nanocomposite system as well as the presence of both ferrimagnetic (FM) BaM & ferroelectric (FE) NBT phases separately. The Field Scanning Electron Micrograph (FESEM) and Scanning Tunneling Electron Micrograph (STEM) explored the information about grain size and connectivity of the composite system. The XPS study was helped to examine the presence of oxygen vacancy (Ov) as well as multi oxidation states of transition metal ions for nanocomposite system. In this report we have systematically examined the conduction mechanism of different interfaces (BaM-BaM, BaM-NBT and NBT-NBT) by the help of complex impedance spectroscopy technique. From our investigation it was observed that, different interfaces activates at different temperature ranges. Due to absence of OV, BaM-NBT interfaces conduction dominants over BaM-BaM interfaces conduction even at room temperature (RT). The mechanism behind the appeared high dielectric loss (tanδ) at RT which was reduced when NBT-NBT interfaces were activates at higher temperature was explained by Maxwell-Wagner type interfacial polarization concept.

  1. Study of magnetic properties and magnetoelectric effect in (x) Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}+(1-x)PZT composites

    Energy Technology Data Exchange (ETDEWEB)

    Bammannavar, B.K. [Department of Studies in Physics, Karnatak University, Dharwad 580003 (India); Naik, L.R., E-mail: naik_36@rediffmail.com [Department of Studies in Physics, Karnatak University, Dharwad 580003 (India)

    2012-03-15

    Magnetoelectric (ME) composites consisting of ferrite phase (x) Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}+ferroelectric phase (1-x)Pb Zr{sub 0.8}Ti{sub 0.2}O{sub 3} (Lead Zirconate Titanate-PZT) in which x (mol%) varies between 0 and 1 (0.0{<=}x{<=}1.0) was synthesized by double sintering ceramic method. The presence of constituent phases of ferrite, ferroelectric and their composites was confirmed by X-ray diffraction studies. The hysteresis measurement was used to study magnetic properties such as saturation magnetization (M{sub S}) and magnetic moment ({mu}{sub B}). The existence of single domain (SD) particle in the ferrite phase and mixed (SD+MD) particle in the composites was studied from AC susceptibility measurements. ME voltage coefficient for each mol% of ferrite phase was measured as a function of applied DC magnetic field and at the same time influence of magnetic field on ME response and resistivity of composites was studied. The maximum ME voltage coefficient of 0.84 mV/cm Oe was observed for 15% of ferrite phase and 85% of ferroelectric phase in the composites. - Highlights: Black-Right-Pointing-Pointer AC susceptibility measurement shows SD particles of the ferrite phase and mixed (SD+MD) particles in the composites. Black-Right-Pointing-Pointer Maximum ME voltage coefficient of 0.84 mV/cm Oe was observed 15 % of ferrite phase and 85 % of ferroelectric phase in composites. Black-Right-Pointing-Pointer These composites are useful in preparing ME devices as they show better ME voltage coefficients.

  2. Study of xCo{sub 0.8}Ni{sub 0.2}Fe{sub 2}O{sub 4}+(1−x) Pb{sub 0.99625} La{sub 0.0025}Zr{sub 0.55}Ti{sub 0.45}O{sub 3} magnetoelectric composites

    Energy Technology Data Exchange (ETDEWEB)

    Dipti [Electroceramics Research Lab, G.V.M. Girls College, Sonepat 131001 (India); School of Physics & Materials Science, Thapar University, Patiala 147004 (India); Singh, Sangeeta, E-mail: Sangeetaasingh@gmail.com [Department of Physics, G.V.M. Girls College, Sonepat 131001 (India); Juneja, J.K. [Department of Physics, Hindu College, Sonepat 131001 (India); Raina, K.K. [School of Physics & Materials Science, Thapar University, Patiala 147004 (India); Dehradun Institute of Technology, DIT University, Dehradun 248009 (India); Kotnala, R.K. [National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Prakash, Chandra [Solid State Physics Laboratory, Lucknow Road, Delhi 110054 (India)

    2016-06-01

    We are reporting here, the studies of the structural, dielectric, ferroelectric and magnetic properties of magnetoelectric composites of La modified lead zirconate titanate (PLZT) and Ni modified cobalt ferrite (CNFO) with compositional formula xCo{sub 0.8}Ni{sub 0.2}Fe{sub 2}O{sub 4}+(1−x) Pb{sub 0.99625}La{sub 0.0025}Zr{sub 0.55}Ti{sub 0.45}O{sub 3} (x=0.00, 0.05, 0.10, 0.15 and 1.00 by weight) prepared by the solid state reaction method. Coexistence of both the phases in composites was confirmed by X-Ray diffraction technique. The microstructure and average grain size were determined from Scanning Electron Micrograph (SEM) in backscattered mode. Both the phases could be observed clearly. The variations of dielectric properties with frequency and temperature were also studied. P–E and M–H hysteresis measurements were carried. Magnetoelectric coupling (ME) coefficient for samples with x=0.05 and 0.10 were measured as a function of DC magnetic field. Maximum value of ME coefficient (1.2 mV/cm Oe) and piezoelectric coefficient (96 pC/N) for x=0.05 were observed. - Highlights: • ME composites PLZT–CNFO were studied for various properties. • Substitution of Ni and La in CFO and in PZT phase improves ME Coefficient. • The samples are good for various application due to high ME coeff. of PLZT-CNFO.

  3. Dielectric and magnetoelectric properties of Li{sub 0.5}Ni{sub 0.75-x/2}Zn{sub x/2}Fe{sub 2}O{sub 4} + Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} ME composites

    Energy Technology Data Exchange (ETDEWEB)

    Durgadsimi, S.U. [Department of Physics, Basaveshwara Engineering College, Bagalkot 587 102 (India); Chougule, S.S.; Chougule, B.K.; Bhosale, C.H. [Department of Physics, Shivaji University, Kolhapur 416 004 (India); Bellad, S.S., E-mail: ssbellad@rediffmail.com [Department of Physics, Maharani' s Science College for Women, Bangalore 560 001 (India)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The magnetoelectric composites Y[Li{sub 0.5}Ni{sub 0.75-x/2}Zn{sub x/2}Fe{sub 2}O{sub 4}] + (1 - Y)[Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3}] are prepared by standard ceramic technique. Black-Right-Pointing-Pointer The XRD patterns confirmed the coexistence of piezomagnetic and piezoelectric phases. Black-Right-Pointing-Pointer Both dielectric constant ({epsilon} Prime ) and loss tangent (tan {delta}) decrease with increase in frequency. Black-Right-Pointing-Pointer The linearity in the log {sigma}{sub ac} vs. log {omega}{sup 2} plots confirmed small polaron hopping type of conduction mechanism. Black-Right-Pointing-Pointer ME output showed direct relation with the resistivity of the composites. - Abstract: The magnetoelectric composites with the composition Y[Li{sub 0.5}Ni{sub 0.75-x/2}Zn{sub x/2}Fe{sub 2}O{sub 4}] + (1 - Y)[Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3}] where x = 0.1, 0.2. 0.3 and Y = 0.1, 0.2, 0.3 were prepared by standard double sintering ceramic technique. The XRD patterns confirmed the coexistence of piezomagnetic and piezoelectric phases. Both dielectric constant ({epsilon} Prime ) and loss tangent (tan {delta}) decrease with increase in frequency exhibiting normal dielectric behaviour. The linearity in the log {sigma}{sub ac} vs. log {omega}{sup 2} plots confirmed the small polaron hopping type of conduction mechanism in the composites studied. Flat curves in the ME output vs. dc magnetic field are obtained which may be due to the presence of strontium in the composites. ME output showed direct relation with the resistivity of the composites.

  4. Magnetoelectric effect of (1-x) Ba0.5Sr0.5Zr0.5Ti0.5O3+(x) Ni0.12Mg0.18Cu0.2Zn0.5Fe2O4 composites

    Science.gov (United States)

    Rahaman, Md. D.; Saha, S. K.; Ahmed, T. N.; Saha, D. K.; Hossain, A. K. M. Akther

    2014-12-01

    The magnetoelectric composites with chemical compositions (1-x) Ba0.5Sr0.5Zr0.5Ti0.5O3+(x) Ni0.12Mg0.18Cu0.2Zn0.5Fe2O4 (x=20, 40, 60 and 80 wt%) was prepared by the conventional solid state reaction method. The presence of a biphase composition was confirmed by X-ray diffraction while the microstructure of the composites was studied by scanning electron microscopy revealing a good mixing of the two phases and a good densification of the bulk ceramics. The dielectric dispersion is observed at lower frequencies due to interfacial polarization arising from the interface of the two phases. At higher frequencies, the dielectric constant is almost constant due to the inability of electric dipoles to follow the first variation of the alternating applied electric field. The dielectric loss shows maxima which are attributed when the hopping frequency of electrons between different ionic sites becomes nearly equal to the frequency of the applied field. The linearity in the log(σAC) vs. log(ω2) plots confirmed the small polaron hopping type of conduction mechanism. The composite materials are found to exhibit an excellent frequency dependence of magnetic properties. In the high frequency range, with increasing ferrite concentration the initial permeability increases and cut-off frequency decreases. An optimal magnetoelectric coupling responding voltage of about 600 μV cm-1 Oe-1 is obtained for x=20 wt% at room temperature.

  5. Magnetoelectric Jones spectroscopy of alkali atoms

    International Nuclear Information System (INIS)

    Chernushkin, V V; Mironova, P V; Ovsiannikov, V D

    2008-01-01

    The Jones effect in a medium of free atoms exposed to static electric and magnetic fields is a useful tool for determining details of an atomic structure. For atoms in their nS ground states irradiated by a monochromatic wave in resonance with a single-photon transition to an n' D state, the bilinear Jones effect is not shaded by the quadratic Kerr and Cotton-Mouton effects, nor by the linear in magnetic field Faraday effect. The position and shape of the amplitude resonance may provide information on spectroscopic properties of atomic levels. We generalize equations for the Jones-effect amplitude to the case of a doublet structure of energy levels and calculate corresponding parameters for alkali atoms. General equations are derived for the amplitude dependence on the relative orientation of the static electric and magnetic fields and on the angle between the static field and the major axis of the wave polarization vector. These equations demonstrate explicitly that the three bilinear-in-static-fields optical birefringence effects-(i) the Jones birefringence (in parallel fields), (ii) the linear birefringence and (iii) the directional birefringence (the last two in perpendicular fields)-correspond to particular cases of the bilinear-in-static-fields correction to the amplitude of Rayleigh forward scattering

  6. Topological magnetoelectric pump in three dimensions

    Science.gov (United States)

    Fukui, Takahiro; Fujiwara, Takanori

    2017-11-01

    We study the topological pump for a lattice fermion model mainly in three spatial dimensions. We first calculate the U(1) current density for the Dirac model defined in continuous space-time to review the known results as well as to introduce some technical details convenient for the calculations of the lattice model. We next investigate the U(1) current density for a lattice fermion model, a variant of the Wilson-Dirac model. The model we introduce is defined on a lattice in space but in continuous time, which is suited for the study of the topological pump. For such a model, we derive the conserved U(1) current density and calculate it directly for the (1 +1 )-dimensional system as well as (3 +1 )-dimensional system in the limit of the small lattice constant. We find that the current includes a nontrivial lattice effect characterized by the Chern number, and therefore the pumped particle number is quantized by the topological reason. Finally, we study the topological temporal pump in 3 +1 dimensions by numerical calculations. We discuss the relationship between the second Chern number and the first Chern number, the bulk-edge correspondence, and the generalized Streda formula which enables us to compute the second Chern number using the spectral asymmetry.

  7. Multiferroics and magnetoelectrics: thin films and nanostructures

    NARCIS (Netherlands)

    Martin, L.W.; Crane, S.P.; Chu, Y.H.; Holcomb, M.B.; Gajek, M.; Huijben, Mark; Yang, C.H.; Balke, N.; Ramesh, R.

    2008-01-01

    Multiferroic materials, or materials that simultaneously possess two or more ferroic order parameters, have returned to the forefront of materials research. Driven by the desire to achieve new functionalities—such as electrical control of ferromagnetism at room temperature—researchers have

  8. Designing asymmetric multiferroics with strong magnetoelectric coupling

    Science.gov (United States)

    Lu, Xuezeng; Xiang, Hongjun; Rondinelli, James; Materials Theory; Design Group Team

    2015-03-01

    Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the ``asymmetric multiferroic.'' In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.

  9. Structural, dielectric and ferroelectric studies of (x) Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4} + (1-x) BaTiO{sub 3} magnetoelectric nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Khader, S. Abdul, E-mail: khadersku@gmail.com; Sankarappa, T., E-mail: sankarappa@rediffmail.com [Department of Physics, Gulbarga University, Gulbarga-585106, Karnataka (India); Muneeswaran, M.; Giridharan, N. V. [Department of Physics, National Institute of Technology, Tiruchirapalli-620015 (India)

    2016-05-06

    The Particulate nano-composites of ferrite and ferroelectric phases having the general formula (x) Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4} + (1-x) BaTiO{sub 3} (x=15%, 30% and 45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO{sub 3} (BT) and highly magneto-strictive magnetic component Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4}(MCZF). The presence of constituent phases of ferrite, ferroelectric and their composites were probed and confirmed by X-ray diffraction (XRD) studies. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM). The variation of dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz at room temperature were carried out using a Hioki LCR Hi-Tester. The dielectric constant and dielectric loss were found to decrease rapidly in the low frequency region and became almost constant in the high frequency region. The electrical conductivity deduced from the measured dielectric data has been thoroughly analyzed and found that the conduction mechanism in these composites is in conformity with small polaron hopping model. The ferroelectric properties of synthesized magneto-electric nano-composites were measured using P-E loop tracer.

  10. Magnetoelectric effect in two-layered self-biased composites Tb{sub 0.12}Dy{sub 0.2}Fe{sub 0.68}/epoxy - PbZr{sub 0.53}Ti{sub 0.47}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kalgin, A.V.; Gridnev, S.A.; Popov, I.I. [Voronezh State Technical University, Voronezh (Russian Federation)

    2017-03-15

    Direct magnetoelectric (ME) effect in two-layered Tb{sub 0.12}Dy{sub 0.2}Fe{sub 0.68}/Epoxy - PbZr{sub 0.53}Ti{sub 0.47}O{sub 3} composites containing magnetostrictive layers of the epoxy with distributed in it Tb{sub 0.12}Dy{sub 0.2}Fe{sub 0.68} granules and piezoelectric layers of the PbZr{sub 0.53}Ti{sub 0.47}O{sub 3} ceramics was studied. It was found, that the gradient distribution of Tb{sub 0.12}Dy{sub 0.2}Fe{sub 0.68} granules in magnetostrictive layers induces the internal (self-biased) magnetic field. This field leads to the increase in ME responses in composites with the gradient distribution of Tb{sub 0.12}Dy{sub 0.2}Fe{sub 0.68} granules in magnetostrictive layers as compared with ME responses in composites with the random distribution of Tb{sub 0.12}Dy{sub 0.2}Fe{sub 0.68} granules in magnetostrictive layers, which does not induce the internal magnetic field. We revealed the possibility of controlling and determining values of the internal magnetic field in composites and conditions for obtaining optimal ME responses. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Magnetoelectric effect in lead free piezoelectric Bi{sub 1/2}Na{sub 1/2}TiO{sub 3}–modified CFO based magnetostrictive (Co{sub 0.6}Zn{sub 0.4}Fe{sub 1.7} Mn{sub 0.3}O{sub 4}) particulate nanocomposite prepared by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Megha [Nanotechnology Research Laboratory, Desh Bhagat University, Mandi Govindgarh 147330, Punjab (India); Sharma, Puneet [School of Physics & Materials Science, Thapar University, Patiala 147004, Punjab (India); Kumari, Mukesh; Singh, Anoop Pratap [Magnetics & Advanced ceramics laboratory, Department of Physics, Indian Institute of Technology, Delhi 110016 (India); Tyagi, Mintu, E-mail: mintutyagi@deshbhagatuniversity.in [Nanotechnology Research Laboratory, Desh Bhagat University, Mandi Govindgarh 147330, Punjab (India)

    2017-03-15

    Lead free magnetoelectric composites that comprise Co{sub 0.6}Zn{sub 0.4}Fe{sub 1.7}Mn{sub 0.3}O{sub 4} (CZFMO) and Bi{sub 1/2}Na{sub 1/2}TiO{sub 3} (BNT) were synthesized using sol-gel method and it's structural, dielectric, magnetic, ferroelectric and magnetoelectric (ME) properties were studied. The X-ray diffraction displayed the single phase formation of parent phases and the presence of two phases in the composites. The temperature dependent dielectric spectra of samples indicates two anomalies at ~220 °C and ~320 °C were ascribed to ferroelectric to antiferroelectric, and anti-ferroelectric to paraelectric phase transitions respectively. Room temperature (RT) magnetic measurements show that composites are soft magnetic. The composite with x=0.2, showed the large value of ME voltage coefficient (α{sub E})~58 mV/cmOe. Moreover, these ME composites provide a great opportunity as potential lead free systems for multifunctional devices. - Highlights: • In this work, Modified CFO based lead free particulate nanocomposites with significantly high value of ME coupling coefficient α{sub E} ~52 mV/cmOe have been prepared. • This sufficient high value of α{sub E} in such composites is obtained by manipulating/improving the piezomagnetic component. • The studies on BNT based particulate ME composites are very scarce in literature. However, no report is available in on the modified CFO based lead free particulate composites.

  12. Weak ferromagnetism and magnetoelectric effect in multiferroic xBa{sub 0.95}Sr{sub 0.05}TiO{sub 3}–(1−x)BiFe{sub 0.9}Gd{sub 0.1}O{sub 3} relaxors

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M.J. [Department of Physics, Bangladesh University of Engineering and Technology (Bangladesh); Department of Physics, Comilla University, Comilla (Bangladesh); Khan, M.N.I. [Materials Science Division, Atomic Energy Center, Dhaka (Bangladesh); Hossain, A.K.M. Akther, E-mail: akmhossain@phy.buet.ac.bd [Department of Physics, Bangladesh University of Engineering and Technology (Bangladesh)

    2016-03-01

    Multiferroic xBa{sub 0.95}Sr{sub 0.05}TiO{sub 3}–(1−x)BiFe{sub 0.9}Gd{sub 0.1}O{sub 3} [xBST–(1−x)BFGO], where x=0.00−0.40, have been synthesized by the conventional solid-state reaction method. The crystalline phase, microstructure, relaxor behavior, ac conductivity, impedance spectroscopy, dc magnetic properties, complex initial permeability and magnetoelectric coefficient of these solid solutions have been investigated. The crystal structure is found to change from rhombohedral in BFGO rich compositions to cubic when x≥0.30. Room temperature dielectric properties are investigated within the frequency range from 1 kHz to 1 MHz and found to increase with BST content. The frequency dependence of high temperature dielectric measurements indicated that the composites with x≥0.20, exhibit relaxor ferroelectric behavior. The ac conductivity obeys the Jonscher’s universal power law and BST helps to enhance the electrical conductivity of the composites. Studies of impedance spectroscopy suggest that only grains have the contribution to the conductivity mechanism in this material. Magnetizations as a function of applied magnetic field measurements show weak ferromagnetism for 0.10≤x≤0.30 composites. The maximum value of remnant magnetization is found to be 0.565×10{sup 3} A/m (=0.08 emu/g) for x=0.25 which is better than previously reported BaTiO{sub 3}–BiFeO{sub 3} systems. The complex initial permeability is found to improve with the increase in BST concentration due to the reduction of oxygen vacancies. In addition, an enhanced magnetoelectric (ME) coupling is also observed and determined by the ME coefficient. The maximum value of ME coefficient is found to be 21.71×10{sup −4} V/A (=1.67 mV/cm Oe) for the x=0.25 composition. The BST–BFGO solid solutions show high-performance multiferroic properties and can be selected for further investigation. - Highlights: • Phase pure multiferroic xBa{sub 0.95}Sr{sub 0.05}TiO{sub 3}–(1−x)BiFe{sub 0

  13. Equivalent magnetic noise reduction at high frequency range due to polarized direction optimization in Terfenol-D/Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} magnetoelectric laminate sensors

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Cong, E-mail: fangcong86@gmail.com [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Ma, Jiashuai; Yao, Meng [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Di, Wenning; Lin, Di; Xu, Haiqing; Wang, Wei [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); Luo, Haosu, E-mail: hsluo@mail.sic.ac.cn [Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2017-02-01

    In this paper, we investigate the responsivities and output voltage noise power spectral densities of magnetoelectric (ME) laminate sensors, consisting of length magnetized Terfenol-D alloys and transverse/width poled Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} (PMNT) crystals (i.e. L-T mode and L-W mode respectively), which are directly integrated with custom-build low noise charge amplifier circuits. Both the theoretical analyses and experimental results prove that the L-W mode sensor with the optimized polarized direction of the PMNT plate possesses lower magnetic detection limit at the interested high frequency range of 10 kHz≤f≤50 kHz. The equivalent magnetic noise (EMN) of the L-W mode sensor is 0.78 pT/Hz{sup 1/2} at 30 kHz, which is about 1.7 times lower than the 1.35 pT/Hz{sup 1/2} for conventional L-T mode sensor. Furthermore, an effective method of using operational amplifiers with low equivalent input noise voltage and employing ME laminate composites with high voltage coefficient to reduce the EMNs of the ME laminate sensors at high frequency range has been established. - Highlights: • We present fabrications and properties of the L-T and L-T mode ME composites. • The equivalent magnetic noise levels at high frequency are measured. • The equivalent magnetic noise of the L-W mode sensor is 0.78 pT/Hz{sup 1/2} at 30 kHz. • The dominated noise source can be confirmed from OPA at high frequency range.

  14. Magnetoelectric effect of (1−x) Ba{sub 0.5}Sr{sub 0.5}Zr{sub 0.5}Ti{sub 0.5}O{sub 3}+(x) Ni{sub 0.12}Mg{sub 0.18}Cu{sub 0.2}Zn{sub 0.5}Fe{sub 2}O{sub 4} composites

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Md. D., E-mail: dalilurrahaman1976@gmail.com [Department of Physics, University of Dhaka, Dhaka-1000 (Bangladesh); Saha, S.K.; Ahmed, T.N. [Department of Physics, University of Dhaka, Dhaka-1000 (Bangladesh); Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh); Saha, D.K. [Materials Science Division, Atomic Energy Centre, PO Box 164, Dhaka 1000 (Bangladesh); Hossain, A.K.M. Akther [Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh)

    2014-12-15

    The magnetoelectric composites with chemical compositions (1−x) Ba{sub 0.5}Sr{sub 0.5}Zr{sub 0.5}Ti{sub 0.5}O{sub 3}+(x) Ni{sub 0.12}Mg{sub 0.18}Cu{sub 0.2}Zn{sub 0.5}Fe{sub 2}O{sub 4} (x=20, 40, 60 and 80 wt%) was prepared by the conventional solid state reaction method. The presence of a biphase composition was confirmed by X-ray diffraction while the microstructure of the composites was studied by scanning electron microscopy revealing a good mixing of the two phases and a good densification of the bulk ceramics. The dielectric dispersion is observed at lower frequencies due to interfacial polarization arising from the interface of the two phases. At higher frequencies, the dielectric constant is almost constant due to the inability of electric dipoles to follow the first variation of the alternating applied electric field. The dielectric loss shows maxima which are attributed when the hopping frequency of electrons between different ionic sites becomes nearly equal to the frequency of the applied field. The linearity in the log(σ{sub AC}) vs. log(ω{sup 2}) plots confirmed the small polaron hopping type of conduction mechanism. The composite materials are found to exhibit an excellent frequency dependence of magnetic properties. In the high frequency range, with increasing ferrite concentration the initial permeability increases and cut-off frequency decreases. An optimal magnetoelectric coupling responding voltage of about 600 μV cm{sup −1} Oe{sup −1} is obtained for x=20 wt% at room temperature. - Highlights: • XRD patterns confirmed the coexistence of ferroelectric and ferrimagnetic phases. • Dielectric dispersion observed at low frequencies due to interfacial polarization. • Linearity in logσ{sub ac} vs. logω{sup 2} is due to small polaron hopping mechanism. • Maximum ME voltage coefficient 600 μV cm{sup −1} Oe{sup −1} observed for 20% of ferrite.

  15. Composition dependent room temperature structure, electric and magnetic properties in magnetoelectric Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3}−Pb(Fe{sub 2/3}W{sub 1/3})O{sub 3} solid-solutions

    Energy Technology Data Exchange (ETDEWEB)

    Matteppanavar, Shidaling [Department of Physics, Jnanabharathi Campus, Bangalore University, Bangalore, 560056 (India); Rayaprol, Sudhindra [UGC-DAE-Consortium for Scientific Research, Mumbai Centre, B A R C Campus, Mumbai, 400085 (India); Angadi, Basavaraj, E-mail: brangadi@gmail.com [Department of Physics, Jnanabharathi Campus, Bangalore University, Bangalore, 560056 (India); Sahoo, Balaram [Materials Research Centre, Indian Institute of Science, Bangalore, 560012 (India)

    2016-08-25

    Fe in 3+ state and on increasing x, the spectra changes from doublet to sextet. The ferroelectric (P-E) study confirms the existence of ferroelectric ordering with leaky behaviour. The reasonable ferroelectric loops with antiferromagnetic properties indicate samples with x = 0.2–0.6 show good magnetoelectric characteristics and may find applications in multiferroics. - Highlights: • RT neutron diffraction studies on PFN{sub 1−x}-PFW{sub x} (x = 0.0 to1.0) multiferroics. • Composition dependent changes in nuclear and magnetic structure. • On increasing x, system exhibit a gradual phase transition from monoclinic to cubic. • Supporting Raman, magnetic, Mössbauer and ferroelectric studies. • Augmentation of Néel temperature (T{sub N}) from 155 K to 350 K on increasing x.

  16. Optical properties of two-dimensional magnetoelectric point scattering lattices

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Sersic, Ivana; Koenderink, A. Femius

    2013-01-01

    of split ring resonators and provide a quantitative comparison of measured and calculated transmission spectra at normal incidence as a function of lattice density, showing excellent agreement. We further show angle-dependent transmission calculations for circularly polarized light and compare...... with the angle-dependent response of a single split ring resonator, revealing the importance of cross coupling between electric dipoles and magnetic dipoles for quantifying the pseudochiral response under oblique incidence of split ring lattices....

  17. Polarizability properties of bianisotropic spheres with noncomplete magnetoelectric dyadics

    Science.gov (United States)

    Sihvola, A. H.

    1994-02-01

    The polarizability expressions for bianisotropic scatterers are often complicated expressions of the material parameters. The communication treats the question how the dyadic inversion operations needed in the expressions can be carried out in a well-behaving way. Also, the particular polarizabilities of biaxial chiral spheres are studied in detail.

  18. Implanting Strong Spin-Orbit Coupling at Magnetoelectric Interfaces

    Science.gov (United States)

    2017-12-19

    drawback is that including both spin and orbital is computationally more expensive than the conventional method and consume significantly longer time...superlattices in Fig. 6. Right: The remnant magnetization anisotropy between the in- plane and out-of- plane directions for the 1/1-SL, which is...canted antiferromagnet. The out-of- plane canting of the spin-orbit moments is significantly enhanced (Fig. 10) compared with the nonpolar structure

  19. Inducing magneto-electric response in topological insulator

    International Nuclear Information System (INIS)

    Zeng, Lunwu; Song, Runxia; Zeng, Jing

    2013-01-01

    Utilizing electric potential and magnetic scalar potential formulas, which contain zero-order Bessel functions of the first kind and the constitutive relations of topological insulators, we obtained the induced magnetic scalar potentials and induced magnetic monopole charges which are induced by a point charge in topological insulators. The results show that infinite image magnetic monopole charges are generated by a point electric charge. The magnitude of the induced magnetic monopole charges are determined not only by the point electric charge, but also by the material parameters. - Highlights: ► Electric potential and magnetic scalar potential which contain zero-order Bessel function of the first kind were derived. ► Boundary conditions of topological insulator were built. ► Induced monopole charges were worked out.

  20. Magnetoelectric effect in concentric quantum rings induced by shallow donor

    Science.gov (United States)

    Escorcia, R.; García, L. F.; Mikhailov, I. D.

    2018-05-01

    We study the alteration of the magnetic and electric properties induced by the off-axis donor in a double InAs/GaAs concentric quantum ring. To this end we consider a model of an axially symmetrical ring-like nanostructure with double rim, in which the thickness of the InAs thin layer is varied smoothly in the radial direction. The energies and of contour plots of the density of charge for low-lying levels we find by using the adiabatic approximation and the double Fourier-Bessel series expansion method and the Kane model. Our results reveal a possibility of the formation of a giant dipole momentum induced by the in-plane electric field, which in addition can be altered by of the external magnetic field applied along the symmetry axis.

  1. Magnetoelectric effect in cobalt ferrite–barium titanate composites ...

    Indian Academy of Sciences (India)

    relaxation process and resistivity of the materials. However, the conductivity behavior in. CoFe2O4–BaTiO3 composites has not been studied. In this paper we report the dc electrical conductivity and thermoelectric power (TEP) as a function of temperature for this system. Dielectric behavior is also studied to understand the ...

  2. Spin-polarized current generated by magneto-electrical gating

    International Nuclear Information System (INIS)

    Ma Minjie; Jalil, Mansoor Bin Abdul; Tan, Seng Ghee

    2012-01-01

    We theoretically study spin-polarized current through a single electron tunneling transistor (SETT), in which a quantum dot (QD) is coupled to non-magnetic source and drain electrodes via tunnel junctions, and gated by a ferromagnetic (FM) electrode. The I–V characteristics of the device are investigated for both spin and charge currents, based on the non-equilibrium Green's function formalism. The FM electrode generates a magnetic field, which causes a Zeeman spin-splitting of the energy levels in the QD. By tuning the size of the Zeeman splitting and the source–drain bias, a fully spin-polarized current is generated. Additionally, by modulating the electrical gate bias, one can effect a complete switch of the polarization of the tunneling current from spin-up to spin-down current, or vice versa. - Highlights: ► The spin polarized transport through a single electron tunneling transistor is systematically studied. ► The study is based on Keldysh non-equilibrium Green's function and equation of motion method. ► A fully spin polarized current is observed. ► We propose to reverse current polarization by the means of gate voltage modulation. ► This device can be used as a bi-polarization current generator.

  3. Multiple broadband magnetoelectric response in Terfenol-D/PZT structure

    Science.gov (United States)

    Wen, Jian-Biao; Zhang, Juan-Juan; Gao, Yuan-Wen

    2018-02-01

    Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 11702120, 11372120, 11421062, and 11572143) and the Fundamental Research Funds for the Central Universities, China (Grant No. lzujbky-2016-106).

  4. Inducing magneto-electric response in topological insulator

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Lunwu, E-mail: 163.sin@163.com [Jiangsu Key Laboratory for Intelligent Agricultural Equipment, College of Engineering, Nanjing Agricultural University, Nanjing 210031 (China); Song, Runxia [Jiangsu Key Laboratory for Intelligent Agricultural Equipment, College of Engineering, Nanjing Agricultural University, Nanjing 210031 (China); Zeng, Jing [Faculty of Business and Economics, Macquarie University, NSW 2122 (Australia)

    2013-02-15

    Utilizing electric potential and magnetic scalar potential formulas, which contain zero-order Bessel functions of the first kind and the constitutive relations of topological insulators, we obtained the induced magnetic scalar potentials and induced magnetic monopole charges which are induced by a point charge in topological insulators. The results show that infinite image magnetic monopole charges are generated by a point electric charge. The magnitude of the induced magnetic monopole charges are determined not only by the point electric charge, but also by the material parameters. - Highlights: Black-Right-Pointing-Pointer Electric potential and magnetic scalar potential which contain zero-order Bessel function of the first kind were derived. Black-Right-Pointing-Pointer Boundary conditions of topological insulator were built. Black-Right-Pointing-Pointer Induced monopole charges were worked out.

  5. Inhomogeneous field induced magnetoelectric effect in Mott insulators

    Energy Technology Data Exchange (ETDEWEB)

    Boulaevskii, Lev N [Los Alamos National Laboratory; Batista, Cristian D [Los Alamos National Laboratory

    2008-01-01

    We consider a Mott insulator like HoMnO{sub 3} whose magnetic lattice is geometrically frustrated and comprises a 3D array of triangular layers with magnetic moments ordered in a 120{sup o} structure. We show that the effect of a uniform magnetic field gradient, {gradient}H, is to redistribute the electronic charge of the magnetically ordered phase leading to a unfirom electric field gradient. The resulting voltage difference between the crystal edges is proportional to the square of the crystal thickness, or inter-edge distance, L. It can reach values of several volts for |{gradient}H| {approx} 0.01 T/cm and L {approx_equal} 1mm, as long as the crystal is free of antiferromagnetic domain walls.

  6. Magneto-Electric Conversion of Optical Energy to Electricity

    Science.gov (United States)

    2015-07-06

    polarizability can be induced and depolarization may take place by a third order all-electric torque interaction [1]. Thus the cross- polarized scattering...an additional, unprecedented result, a milestone for this project. They show that in solid GGG, where anisotropic polarizability does not exist to... Argon laser beam (in green). Measurement structures are shown in Figure 5. nullify energy extraction. So great care is needed in matching

  7. One-Dimensional Rydberg Gas in a Magnetoelectric Trap

    International Nuclear Information System (INIS)

    Mayle, Michael; Hezel, Bernd; Lesanovsky, Igor; Schmelcher, Peter

    2007-01-01

    We study the quantum properties of Rydberg atoms in a magnetic Ioffe-Pritchard trap which is superimposed by a homogeneous electric field. Trapped Rydberg atoms can be created in long-lived electronic states exhibiting a permanent electric dipole moment of several hundred Debye. The resulting dipole-dipole interaction in conjunction with the radial confinement is demonstrated to give rise to an effectively one-dimensional ultracold Rydberg gas with a macroscopic interparticle distance. We derive analytical expressions for the electric dipole moment and the required linear density of Rydberg atoms

  8. A simple model for the magnetoelectric interaction in multiferroics

    International Nuclear Information System (INIS)

    Filho, Cesar J Calderon; Barberis, Gaston E

    2011-01-01

    The (anti)ferromagnetic and ferroelectric transitions in some multiferroic compounds seem to be strongly correlated. Even for systems that do not show spontaneous ferroelectricity such as the LiMPO 4 (M = Mn, Fe, Co, Ni) compounds, the coupling between magnetic and electric degrees of freedom is evident experimentally. Here, we present a simple numerical calculation to simulate this coupling that leads to the two transitions. We assume a magnetic sublattice consisting of classical magnetic moments coupled to a separated nonmagnetic sublattice consisting of classical electric dipoles. The coupling between them is realized through a phenomenological spin-lattice Hamiltonian, and the solution is obtained using the Monte Carlo technique. In the simplest version, the magnetic system is 2D Ising (anti)ferromagnetic lattice, with nearest neighbors interactions only, and the electric moments are permanent moments, coupled electrically. Within this approximation, the second order magnetic transition induces ferroelectricity in the electric dipoles. We show that these calculations can be extended to other magnetic systems, (x-y model and 3D Heisenberg) and to systems where the electric moments are created by strains, generated via spin-lattice coupling, so the model can be applied to model realistic systems such as the olivines mentioned above.

  9. Thermal effects in magnetoelectric memories with stress-mediated switching

    International Nuclear Information System (INIS)

    Giordano, S; Dusch, Y; Tiercelin, N; Pernod, P; Preobrazhensky, V

    2013-01-01

    Heterostructures with magneto-electro-elastic coupling (e.g. multiferroics) are of paramount importance for developing new sensors, actuators and memories. With the progressive miniaturization of these systems it is necessary to take into account possible thermal effects, which may influence the normal operating regime. As a paradigmatic example we consider a recently introduced non-volatile memory element composed of a magnetostrictive nanoparticle embedded in a piezoelectric matrix. The distributions of the physical fields in this matrix/inclusion configuration are determined by means of the Eshelby theory, the magnetization dynamics is studied through the Landau–Lifshitz–Gilbert formalism, and the statistical mechanics is introduced with the Langevin and Fokker–Planck methodologies. As result of the combination of such techniques we determine the switching time between the states of the memory, the error probability and the energy dissipation of the writing process. They depend on the ratio k B T/v where T is the absolute temperature and v is the volume of the magnetoelastic particle. (paper)

  10. Influence of magneto-electric coefficient for magnetic and electric charge injection properties in magneto-electric MIS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, T; Tsuboi, Y; Imura, R; Kito, S; Gomi, M, E-mail: yokota.takeshi@nitech.ac.jp [Department of Material Science and Engineering, Graduate School of Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya City, Aichi, 466-8555 (Japan)

    2011-10-29

    We investigated the electric charge injection properties of a floating-gate type metal-insulator Si capacitor having different-ME gate insulators. The samples showed charge-injection type behaviour in capacitance-voltage curves, and it was revealed that the amount of injected charges can be controlled by the application of an external magnetic field. The sample having a high-ME-coefficient gate insulator showed stepwise capacitance-voltage curves unlike the normal one. These results indicate that this capacitor, which employs a magnetic gate insulator, has the potential to be used in multilevel memory by the application of an external magnetic field.

  11. Magnetoelectric versus thermal actuation characteristics of shear force AFM probes with piezoresistive detection

    International Nuclear Information System (INIS)

    Sierakowski, Andrzej; Janus, Paweł; Dobrowolski, Rafał; Grabiec, Piotr; Kopiec, Daniel; Majstrzyk, Wojciech; Kunicki, Piotr; Gotszalk, Teodor; Rangelow, Ivo W

    2017-01-01

    In this paper the authors compare methods used for piezoresistive microcantilevers actuation for the atomic force microscopy (AFM) imaging in the dynamic shear force mode. The piezoresistive detection is an attractive technique comparing the optical beam detection of deflection. The principal advantage is that no external alignment of optical source and detector are needed. When the microcantilever is deflected, the stress is transferred into a change of resistivity of piezoresistors. The integration of piezoresistive read-out provides a promising solution in realizing a compact non-contact AFM. Resolution of piezoresistive read-out is limited by three main noise sources: Johnson, 1/ f and thermomechanical noise. In the dynamic shear force mode measurement the method used for cantilever actuation will also affect the recorded noise in the piezoresistive detection circuit. This is the result of a crosstalk between an aluminium path (current loop used for actuation) and piezoresistors located near the base of the beam. In this paper authors described an elaborated in ITE (Institute of Electron Technology) technology of fabrication cantilevers with piezoresistive detection of deflection and compared efficiency of two methods used for cantilever actuation. (paper)

  12. Highly efficient conductance control in a topological insulator based magnetoelectric transistor

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Xiaopeng; Li, Xi-Lai; Li, Xiaodong; Semenov, Yuriy G. [Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Kim, Ki Wook, E-mail: kwk@ncsu.edu [Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2015-12-14

    The spin-momentum interlocked properties of the topological insulator (TI) surface states are exploited in a transistor-like structure for efficient conductance control in the TI-magnet system. Combined with the electrically induced magnetization rotation as part of the gate function, the proposed structure takes advantage of the magnetically modulated TI electronic band dispersion in addition to the conventional electrostatic barrier. The transport analysis coupled with the magnetic simulation predicts super-steep current-voltage characteristics near the threshold along with the GHz operating frequencies. Potential implementation to a complementary logic is also examined. The predicted characteristics are most suitable for applications requiring low power or those with small signals.

  13. Dielectric and thermodynamic measurements on the magnetoelectric perovskite EuTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Engelmayer, Johannes; Grams, Christoph; Hemberger, Joachim; Lorenz, Thomas [II. Physikalisches Institut, Universitaet zu Koeln (Germany)

    2016-07-01

    Various perovskite titanates ATiO{sub 3} are known to undergo ferroelectric phase transitions, e.g., for A=Ba,Pb,Cd. BaTiO{sub 3} is the only ferroelectric alkaline-earth titanate, since ferroelectric long-range order is suppressed in CaTiO{sub 3} and SrTiO{sub 3} by quantum fluctuations, which is referred to as quantum paraelectric behavior. The rare-earth titanate EuTiO{sub 3} is similar to SrTiO{sub 3}, since it has the same valencies (Eu{sup 2+},Ti{sup 4+}) and the same ionic radii. Both are cubic at room temperature and undergo a structural phase transition to tetragonal upon cooling. In contrast to the nonmagnetic Sr{sup 2+}, the half-filled 4f shell of Eu{sup 2+} with S=7/2 has a large magnetic moment of 7μ{sub B}. Below T{sub N}=5.5 K the localized 4f moments order antiferromagnetically, while rather small fields of 1.5 T are sufficient to saturate the magnetization. Here we present field- and temperature-dependent measurements of magnetization, specific heat, and thermal expansion, exhibiting characteristic anomalies at T{sub N}. Broadband measurements of the permittivity reveal the dynamics of polar domain walls at the onset of the structural phase transition, as well as the materials quantum paraelectric nature that is masked by high conductivity for low frequencies.

  14. Radiation losses in the microwave Ku band in magneto-electric nanocomposites

    Directory of Open Access Journals (Sweden)

    Talwinder Kaur

    2015-08-01

    Full Text Available A study on radiation losses in conducting polymer nanocomposites, namely La–Co-substituted barium hexaferrite and polyaniline, is presented. The study was performed by means of a vector network analyser, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, electron spin resonance spectroscopy and a vibrating sample magnetometer. It is found that the maximum loss occurs at 17.9 GHz (−23.10 dB, 99% loss which is due to the composition of a conducting polymer and a suitable magnetic material. A significant role of polyaniline has been observed in ESR. The influence of the magnetic properties on the radiation losses is explained. Further studies revealed that the prepared material is a nanocomposite. FTIR spectra show the presence of expected chemical structures such as C–H bonds in a ring system at 1512 cm−1.

  15. Magnetoelectric effects in the spin-1/2 XXZ model with Dzyaloshinskii-Moriya interaction

    International Nuclear Information System (INIS)

    Thakur, Pradeep; Durganandini, P.

    2015-01-01

    We study the 1D spin-1/2 XXZ chain in the presence of the Dzyaloshinskii-Moriya (D-M) interaction and with longitudinal and transverse magnetic fields. We assume the spin-current mechanism of Katsura-Nagaosa-Balatsky at play and interpret the D-M interaction as a coupling between the local electric polarization and an external electric field. We study the interplay of electric and magnetic order in the ground state using the numerical density matrix renormalization group(DMRG) method. Specifically, we investigate the dependences of the magnetization and electric polarization on the external electric and magnetic fields. We find that for transverse magnetic fields, there are two different regimes of polarization while for longitudinal magnetic fields, there are three different regimes of polarization. The different regimes can be tuned by the external magnetic fields

  16. Magnetoelectric excitations in multiferroic Ni.sub.3./sub.TeO.sub.6./sub.

    Czech Academy of Sciences Publication Activity Database

    Skiadopoulou, Styliani; Borodavka, Fedir; Kadlec, Christelle; Kadlec, Filip; Retuerto, M.; Deng, Z.; Greenblatt, M.; Kamba, Stanislav

    2017-01-01

    Roč. 95, č. 18 (2017), 1-6, č. článku 184435. ISSN 2469-9950 R&D Projects: GA MŠk(CZ) LH15122; GA ČR GA15-08389S Institutional support: RVO:68378271 Keywords : multiferroics * electromagnons * THz * Raman * IR spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016

  17. Magnetoelectric control of valley and spin in a silicene nanoribbon modulated by the magnetic superlattices

    Energy Technology Data Exchange (ETDEWEB)

    An, Xing-Tao, E-mail: anxt@hku.hk

    2015-03-20

    The control of valley and spin degrees of freedom and the transport properties of electrons in a zigzag silicene nanoribbon modulated by the magnetic superlattices are investigated theoretically. Due to the valley–spin locking effect in silicene, the valley degree of freedom can be controlled by magnetic means. The valley or/and spin selection induced by the exchange field result in the perfect spin–valley filter and tunneling magnetoresistance effect in the double ferromagnetic barriers on the surface of the silicene nanoribbon. It is more interesting that there are valley-resolved minigaps and minibands in the zigzag silicene nanoribbon modulated by the magnetic superlattices which give rise to the periodically modulated spin (or/and valley) polarization and tunneling magnetoresistance. The results obtained may have certain practical significance in applications for future valleytronic and spintronic devices. - Highlights: • The valley can be controlled by a magnetic field in silicene. • The valley-resolved miniband transport is studied in the silicene superlattices. • There are the perfect spin–valley filter and tunneling magnetoresistance effect.

  18. Multi-channel spintronic transistor design based on magnetoelectric barriers and spin-orbital effects

    International Nuclear Information System (INIS)

    Fujita, T; Jalil, M B A; Tan, S G

    2008-01-01

    We present a spin transistor design based on spin-orbital interactions in a two-dimensional electron gas, with magnetic barriers induced by a patterned ferromagnetic gate. The proposed device overcomes certain shortcomings of previous spin transistor designs such as long device length and degradation of conductance modulation for multi-channel transport. The robustness of our device for multi-channel transport is unique in spin transistor designs based on spin-orbit coupling. The device is more practical in fabrication and experimental respects compared to previously conceived single-mode spin transistors

  19. Magnetic phase diagram of magnetoelectric LiMnPO4

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Andersen, Niels Hessel; Li, Haifeng

    2012-01-01

    to the a axis to be nearly along the c axis at magnetic fields between 4 and 4.7 T, depending on temperature. The low-field antiferromagnetic phase boundary is shown to join the spin-flop line tangentially at the so-called bicritical point, where there is a suppression of the ordering temperature....... At the bicritical field, we observe an increased intensity of the Lorentz broadened elastic scattering at magnetic Bragg peaks above TN as compared to zero field and 10 T, without an increase in peak width. This suggests an increased density of fluctuations at the bicritical field as compared to zero field....

  20. Free vibration analysis of magneto-electro-elastic microbeams subjected to magneto-electric loads

    Science.gov (United States)

    Vaezi, Mohamad; Shirbani, Meisam Moory; Hajnayeb, Ali

    2016-01-01

    Different types of actuating and sensing mechanisms are used in new micro and nanoscale devices. Therefore, a new challenge is modeling electromechanical systems that use these mechanisms. In this paper, free vibration of a magnetoelectroelastic (MEE) microbeam is investigated in order to obtain its natural frequencies and buckling loads. The beam is simply supported at both ends. External electric and magnetic potentials are applied to the beam. By using the Hamilton's principle, the governing equations and boundary conditions are derived based on the Euler-Bernoulli beam theory. The equations are solved, analytically to obtain the natural frequencies of the MEE microbeam. Furthermore, the effects of external electric and magnetic potentials on the buckling of the beam are analyzed and the critical values of the potentials are obtained. Finally, a numerical study is conducted. It is found that the natural frequency can be tuned directly by changing the magnetic and electric potentials. Additionally, a closed form solution for the normalized natural frequency is derived, and buckling loads are calculated in a numerical example.

  1. Electronic structure, Born effective charges and spontaneous polarization in magnetoelectric gallium ferrite

    International Nuclear Information System (INIS)

    Roy, Amritendu; Garg, Ashish; Mukherjee, Somdutta; Gupta, Rajeev; Prasad, Rajendra; Auluck, Sushil

    2011-01-01

    We present a theoretical study of the structure-property correlation in gallium ferrite, based on first-principles calculations followed by a subsequent comparison with experiments. The local spin density approximation (LSDA + U) of the density functional theory has been used to calculate the ground state structure, electronic band structure, density of states and Born effective charges. The calculations reveal that the ground state structure is orthorhombic Pc 2 1 n having A-type antiferromagnetic spin configuration, with lattice parameters matching well with those obtained experimentally. Plots of the partial density of states of constituent ions exhibit noticeable hybridization of Fe 3d, Ga 4s, Ga 4p and O 2p states. However, the calculated charge density and electron localization function show a largely ionic character of the Ga/Fe-O bonds which is also supported by a lack of any significant anomaly in the calculated Born effective charges with respect to the corresponding nominal ionic charges. The calculations show a spontaneous polarization of ∼ 59 μC cm -2 along the b-axis which is largely due to asymmetrically placed Ga1, Fe1, O1, O2 and O6 ions.

  2. Magnetoelectric Response in Multiferroic SrFe12O19 Ceramics.

    Directory of Open Access Journals (Sweden)

    Guolong Tan

    Full Text Available We report here realization of ferroelectricity, ferromagnetism and magnetocapacitance effect in singleSrFe12O19ceramic at room temperature. The ceramics demonstrate a saturated polarization hysteresis loop, two nonlinear I-V peaks and large anomaly of dielectric constant near Curie temperature, which confirm the intrinsic ferroelectricity of SrFe12O19 ceramicswith subsequent heat-treatment in O2atmosphere. The remnant polarization of the SrFe12O19 ceramic is estimated to be 103μC/cm2. The ceramic also exhibits strong ferromagnetic characterization, the coercive field and remnant magnetic moment are 6192Oe and 35.8emu/g, respectively. Subsequent annealing SrFe12O19 ceramics in O2 plays a key role on revealing its intrinsic ferroelectricity and improving the ferromagnetism through transforming Fe2+ into Fe3+. By applying a magnetic field, the capacitance demonstrates remarkable change along with B field, the maximum rate of change in ε (Δε(B/ε(0 is 1174%, which reflects a giant magnetocapacitance effect in SrFe12O19. XPS and molecular magnetic moment measurements confirmed the transformation of Fe2+ into Fe3+ and removal of oxygen vacancies upon O2 heat treatment. These combined functional responses in SrFe12O19 ceramics opens substantial possibilities for applications in novel electric devices.

  3. Advanced nanoscopic studies in magneto-electric manganites and high T$_c$ superconductors

    CERN Document Server

    Melo Mendonça, Tânia Manuela; Martins Correia, João Guilherme

    2012-05-01

    Technological advances in materials synthesis and the development of new experimental techniques have created a wealth of information with remarkable implications for understanding the macroscopic properties of systems with strongly correlated electronic properties. These advances allowed the observation of a wide range of exotic phenomena such as high T$_c$ superconductivity, colossal magneto-resistance or, more recently, multiferroic behavior, which are known to be strongly dependent on the nanoscale phenomenology. In fact, several experimental and theoretical studies demonstrated that strongly correlated electron systems are not homogeneous at a local scale due to simultaneously active spin, charge, lattice and/or orbital interactions. Consequently, these systems show nanoscale chemical and electronic disorder, which lead to a rich variety of macroscopic properties. It is under this scope that the nuclear hyperfine techniques are introduced, being particularly useful to infer the local lattice structure, e...

  4. Domain Engineered Magnetoelectric Thin Films for High Sensitivity Resonant Magnetic Field Sensors

    Science.gov (United States)

    2012-02-28

    increas small at low uency shift ur hypothes former: Sin (output), w tion. Materia ansducer. Th e transform voltage gai rmer. Furth ansformer p ded...90 min, r 0 Oe to 300 ith increasin ity (GH-G0/G tic field. Th dels. The d agnetic fiel ion of actua rent materia se with high nce and new r. This

  5. Domain Engineered Magnetoelectric Thin Films for High Sensitivity Resonant Magnetic Field Sensors

    Science.gov (United States)

    2011-12-01

    band gap of highly textured PZT thin films. The deposition process variables were - argon and oxygen flows, chamber pressure, RF power (DC Bias...needed another parameter to equate with the number of unknowns in the resultant model equations. From Figure 24, electronic polarizability affects the... Polarizability and Optical dielectric response of a thin.film , ., ,__~--~---\\- 000 01’ "󈧶 Ots Tncnt.re"’°l Effective Polarizability = Reddy

  6. Hidden magnetic states emergent under electric field, in a room temperature composite magnetoelectric multiferroic

    Czech Academy of Sciences Publication Activity Database

    Clarkson, J.D.; Fina, I.; Liu, Z.Q.; Lee, Y.; Kim, J.; Frontera, C.; Cordero, K.; Wisotzki, S.; Sánchez, F.; Sort, J.; Hsu, S.L.; Ko, C.; Aballe, L.; Foerster, M.; Wu, J.; Christen, H.M.; Heron, J.T.; Schlom, D. G.; Salahuddin, S.; Kioussis, N.; Fontcuberta, J.; Martí, Xavier; Ramesh, R.

    2017-01-01

    Roč. 7, č. 1 (2017), s. 1-7, č. článku 15460. ISSN 2045-2322 R&D Projects: GA ČR GB14-37427G Institutional support: RVO:68378271 Keywords : antiferromagnetic phase-transition * total-energy calculations * wave basis-set Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 4.259, year: 2016

  7. Porous InP as piezoelectric matrix material in 1-3 magnetoelectric composite sensors

    International Nuclear Information System (INIS)

    Gerngross, M.-D.; Leisner, M.; Carstensen, J.; Foell, H.

    2011-01-01

    This work shows the results of the fabrication of semi-insulating piezoelectric porous InP structures by electrochemical etching and subsequent purely chemical post-etching in an isotropic HF, HNO 3 , EtOH and HAc containing electrolyte. The piezoelectric modulus d 14 of porous InP is measured to around |60| pm / V, which larger by a factor of 30 compared to bulk InP.

  8. Resistive switching via the converse magnetoelectric effect in ferromagnetic multilayers on ferroelectric substrates.

    Science.gov (United States)

    Pertsev, N A; Kohlstedt, H

    2010-11-26

    A voltage-controlled resistive switching is predicted for ferromagnetic multilayers and spin valves mechanically coupled to a ferroelectric substrate. The switching between low- and high-resistance states results from the strain-driven magnetization reorientations by about 90°, which are shown to occur in ferromagnetic layers with a high magnetostriction and weak cubic magnetocrystalline anisotropy. Such reorientations, not requiring external magnetic fields, can be realized experimentally by applying moderate electric field to a thick substrate (bulk or membrane type) made of a relaxor ferroelectric having ultrahigh piezoelectric coefficients. The proposed multiferroic hybrids exhibiting giant magnetoresistance may be employed as electric-write nonvolatile magnetic memory cells with nondestructive readout.

  9. Rich magnetoelectric phase diagrams of multiferroic single-crystal α -NaFeO2

    Science.gov (United States)

    Terada, Noriki; Ikedo, Yuta; Sato, Hirohiko; Khalyavin, Dmitry D.; Manuel, Pascal; Miyake, Atsushi; Matsuo, Akira; Tokunaga, Masashi; Kindo, Koichi

    2017-07-01

    The magnetic and dielectric properties of the multiferroic triangular lattice magnet compound α -NaFeO2 were studied by magnetization, specific heat, dielectric permittivity, and pyroelectric current measurements and by neutron diffraction experiments using single crystals grown by a hydrothermal synthesis method. This work produced magnetic field (in the monoclinic a b -plane, Ba b, and along the c*-axis, Bc) versus temperature magnetic phase diagrams, including five and six magnetically ordered phases in Ba b and along Bc, respectively. In zero magnetic field, two spin-density-wave orderings with different k vectors—(0 ,q ,1/2 ) in phase I and (qa,qb,qc ) in phase II—appeared at T =9.5 and 8.25 K, respectively. Below T =5 K, a commensurate order with k =(0.5 ,0 ,0.5 ) was stabilized as the ground state in phase III. Both Ba b≥3 T and Bc≥5 T were found to induce ferroelectric phases at the lowest temperature (2 K), with an electric polarization that was not confined to any highly symmetric directions in phases IVa b (3.3 ≤Ba b≤8.5 T), Va b (8.5 ≤Ba b≤13.6 T), IVc (5.0 ≤Bc≤8.5 T), and Vc (8.5 ≤Bc≤13.5 T). In phase VIc, within a narrow temperature region in Bc, the polarization was confined to the a b plane. For each of the ferroelectric phases, the k vector was (qa,qb,qc ), and noncollinear structures were identified, including a general spiral in IVa b an a b cycloid in IVc and Vc, and a proper screw in VIc, along with a triclinic 11' magnetic point group allowing polarization in the general direction. Comparing the polarization direction to the magnetic structures in the ferroelectric phases, we conclude that the extended inverse Dzyaloshinskii-Moriya mechanism expressed by the orthogonal components p1∝ri j×(Si×Sj) and p2∝Si×Sj can explain the polarization directions. Based on calculations incorporating exchange interactions up to fourth-nearest-neighbor (NN) couplings, we infer that competition among antiferromagnetic second NN interactions in the triangular lattice plane, as well as weak interplane antiferromagnetic interactions, are responsible for the rich phase diagrams of α -NaFeO2 .

  10. Electric dipole spin resonance in a quantum spin dimer system driven by magnetoelectric coupling

    Science.gov (United States)

    Kimura, Shojiro; Matsumoto, Masashige; Akaki, Mitsuru; Hagiwara, Masayuki; Kindo, Koichi; Tanaka, Hidekazu

    2018-04-01

    In this Rapid Communication, we propose a mechanism for electric dipole active spin resonance caused by spin-dependent electric polarization in a quantum spin gapped system. This proposal was successfully confirmed by high-frequency electron spin resonance (ESR) measurements of the quantum spin dimer system KCuCl3. ESR measurements by an illuminating linearly polarized electromagnetic wave reveal that the optical transition between the singlet and triplet states in KCuCl3 is driven by an ac electric field. The selection rule of the observed transition agrees with the calculation by taking into account spin-dependent electric polarization. We suggest that spin-dependent electric polarization is effective in achieving fast control of quantum spins by an ac electric field.

  11. Size effect study in magnetoelectric BiFeO3 system

    Indian Academy of Sciences (India)

    ... for phase determination and lattice parameter calculations (figure 1). The coherently diffracting domain size dXRD is calculated from X- ray line broadening using Scherrer's formula. Scanning electron microscopy (SEM) is used to find out grain size and morphology (figure 2). Differential scanning calorimeter (DSC). 1028.

  12. Anomalous magnetic structure and spin dynamics in magnetoelectric LiFePO4

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Reehuis, Manfred; Jensen, Thomas Bagger Stibius

    2015-01-01

    We report significant details of the magnetic structure and spin dynamics of LiFePO4 obtained by single-crystal neutron scattering. Our results confirm a previously reported collinear rotation of the spins away from the principal b axis, and they determine that the rotation is toward the a axis...

  13. Investigation of magneto-electric properties of BCZT-NFO particulate composite

    Energy Technology Data Exchange (ETDEWEB)

    Sowmya, N. Shara, E-mail: sowmya.shara@gmail.com; Srinivas, A., E-mail: adirajs@gmail.com [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad, 500 058 (India); Praveen, Paul J.; Das, Dibakar [School of Engineering Science and Technology, University of Hyderabad, Hyderabad, 500 046 (India); Reddy, K. Venu Gopal [National Institute of Technology, Warangal, 506004 (India)

    2016-05-06

    :Synthesis and characterizations for ferroelectric, ferromagnetic properties of 50BCZT - 50NFO particulate composite have been investigated. Phase pure BCZT (tetragonal) and NFO (cubic inverse spinel) have been observed in powder XRD pattern of 50BCZT-50NFO composite. Average grain size of 12µm for BCZT and 4µm for NFO have been observed in the back scattered electron diffraction (BSE) image of the sintered sample. Hysteresis loop measurement reveals typical ferroelectric nature of the sample with remnant and saturation polarizations of 8.34µC/cm{sup 2} and 17.4µC/cm{sup 2}, respectively. Furthermore, sintered BCZT-NFO sample also showed good ferromagnetic M-H hysteresis loop with saturation magnetization upto ~14.6emu/g. Magnetostriction measurements showed a value of ~ - 20ppm for pure NFO and ~ - 8ppm for the composite.

  14. The toroidal moment in condensed-matter physics and its relation to the magnetoelectric effect

    NARCIS (Netherlands)

    Spaldin, Nicola A.; Fiebig, Manfred; Mostovoy, Maxim

    2008-01-01

    The concept of toroidal moments in condensed-matter physics and their long-range ordering in a so-called ferrotoroidic state is reviewed. We show that ferrotoroidicity as a form of primary ferroic order can be understood both from microscopic (multipole expansion) and macroscopic (symmetry-based

  15. Optically resonant magneto-electric cubic nanoantennas for ultra-directional light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Sikdar, Debabrata, E-mail: debabrata.sikdar@monash.edu; Premaratne, Malin [Advanced Computing and Simulation Laboratory (A chi L), Department of Electrical and Computer Systems Engineering, Monash University, Clayton 3800, Victoria (Australia); Cheng, Wenlong [Department of Chemical Engineering, Faculty of Engineering, Monash University, Clayton 3800, Victoria (Australia); The Melbourne Centre for Nanofabrication, 151 Wellington Road, Clayton 3168, Victoria (Australia)

    2015-02-28

    Cubic dielectric nanoparticles are promising candidates for futuristic low-loss, ultra-compact, nanophotonic applications owing to their larger optical coefficients, greater packing density, and relative ease of fabrication as compared to spherical nanoparticles; besides possessing negligible heating at nanoscale in contrast to their metallic counterparts. Here, we present the first theoretical demonstration of azimuthally symmetric, ultra-directional Kerker's-type scattering of simple dielectric nanocubes in visible and near-infrared regions via simultaneous excitation and interference of optically induced electric- and magnetic-resonances up to quadrupolar modes. Unidirectional forward-scattering by individual nanocubes is observed at the first generalized-Kerker's condition for backward-scattering suppression, having equal electric- and magnetic-dipolar responses. Both directionality and magnitude of these unidirectional-scattering patterns get enhanced where matching electric- and magnetic-quadrupolar responses spectrally overlap. While preserving azimuthal-symmetry and backscattering suppression, a nanocube homodimer provides further directionality improvement for increasing interparticle gap, but with reduced main-lobe magnitude due to emergence of side-scattering lobes from diffraction-grating effect. We thoroughly investigate the influence of interparticle gap on scattering patterns and propose optimal range of gap for minimizing side-scattering lobes. Besides suppressing undesired side-lobes, significant enhancement in scattering magnitude and directionality is attained with increasing number of nanocubes forming a linear chain. Optimal directionality, i.e., the narrowest main-scattering lobe, is found at the wavelength of interfering quadrupolar resonances; whereas the largest main-lobe magnitude is observed at the wavelength satisfying the first Kerker's condition. These unique optical properties of dielectric nanocubes thus can revolutionize their applications at visible and near-infrared regions in the fields of nanoantennas, nanolasers, photovoltaics, and even in biomedicine.

  16. Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Bahniman, E-mail: bghosh@utexas.edu; Dey, Rik; Register, Leonard F.; Banerjee, Sanjay K. [Microelectronics Research Center, University of Texas at Austin, 10100 Burnet Road, Bldg. 160, Austin, Texas 78758 (United States)

    2016-07-21

    In this article, we consider through simulation low-energy switching of nanomagnets via electrostatically gated inter-magnet Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions on the surface of three-dimensional topological insulators, for possible memory and nonvolatile logic applications. We model the possibility and dynamics of RKKY-based switching of one nanomagnet by coupling to one or more nanomagnets of set orientation. Potential applications to both memory and nonvolatile logic are illustrated. Sub-attojoule switching energies, far below conventional spin transfer torque (STT)-based memories and even below CMOS logic appear possible. Switching times on the order of a few nanoseconds, comparable to times for STT switching, are estimated for ferromagnetic nanomagnets, but the approach also appears compatible with the use of antiferromagnets which may allow for faster switching.

  17. Magnetoelectric and transport properties of (GaMn)Sb thin films: A ferrimagnetic phase in dilute alloys

    Energy Technology Data Exchange (ETDEWEB)

    Calderón, Jorge A. [Universidad Nacional de Colombia – Bogotá, Dpto. de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Cra. 30 No. 45-03 Edificio 404 Lab. 121C Ciudad Universitaria, Bogotá (Colombia); Mesa, F., E-mail: fredy.mesa@urosario.edu.co [Grupo NanoTech, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Cra. 24 No. 63C-69, Bogotá (Colombia); Dussan, A. [Universidad Nacional de Colombia – Bogotá, Dpto. de Física, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Cra. 30 No. 45-03 Edificio 404 Lab. 121C Ciudad Universitaria, Bogotá (Colombia)

    2017-02-28

    Highlights: • (GaMn)Sb thin films were fabricated using the direct current (DC) magnetron co-sputtering. • Presence of ferrimagnetic (Mn{sub 2}Sb) and ferromagnetic (Mn{sub 2}Sb{sub 2}) phases. • A minor difference of 1% was found with respect to percolation theory, which confirmed the validity of the diffusional model in semiconductor alloys with magnetic properties. • Increase in the localized states density (N{sub F}) with increasing substrate temperature. - Abstract: We studied the electrical, magnetic, and transport properties of (GaMn)Sb thin films fabricated by the direct current magnetron co-sputtering method. Using X-ray powder diffraction measurements, we identified the presence of ferrimagnetic (Mn{sub 2}Sb) and ferromagnetic (Mn{sub 2}Sb{sub 2}) phases within the films. We also measured the magnetization of the films versus an applied magnetic field as well as their hysteresis curves at room temperature. We determined the electrical and transport properties of the films through temperature-dependent resistivity measurements using the Van Der Pauw method. The main contribution to the transport process was variable range hopping. Hopping parameters were calculated using percolation theory and refined using the diffusional model. In addition, we determined that all samples had p type semiconductor behavior, that there was an increase in the density of localized states near the Fermi level, and that the binary magnetic phases influenced the electrical properties and transport mechanisms.

  18. A Physics Experiment Concerning the Measurement of the Torque of a Rotating Body Using a Magnetoelectrical Technique

    Science.gov (United States)

    Sakon, Takuo; Nakagawa, Keisuke

    2016-01-01

    A physical experiment concerning the moment of inertia of a rigid disk is described. Basic physical quantities such as the moment of inertia and torque are very important in elementary physics courses. This experiment was designed to improve students' understanding of the relation between the rigid moment of inertia and torque. The moment of…

  19. Magnetic and magneto-dielectric properties of magneto-electric field effect capacitor using Cr2O3

    OpenAIRE

    Takeshi, Yokota; Shotaro, Murata; Takaaki, Kuribayashi; Manabu, Gomi

    2008-01-01

    We investigated the magnetic and dielectric properties of a metal (Pt)/insulator (Cr_2O_3)/magnetic floating gate (Fe)/tunnel layer (CeO_2)/semiconductor (Si) capacitor. This capacitor shows capacitance-voltage (C-V) properties typical of a Si Metal-Insulator-Semiconductor (MIS) capacitor with hysteresis, which indicates that electrons have been injected into the Fe layer. The capacitor also shows ferromagnetic properties. The C-V curve has a hysteresis window with a clockwise trace. This hys...

  20. Method and Apparatus for High-Permeability Magnetostrictive/Piezo-Fiber Laminates Having Colossal, Near-Ideal Magnetoelectricity

    OpenAIRE

    2007-01-01

    An ME composite laminate of at least one (1-3) piezo-fiber layer coupled with high-permeability alloy magnetostrictive layers, optionally formed of FeBSiC or equivalent. The composite laminate alternates the (1-3) piezo-fiber and high-permeability alloy magnetostrictive layers in a stacked manner. Optionally, the magnetization direction of the high-permeability alloy magnetostrictive layers and polarization direction of the piezo-fiber layer are an (L-L) arrangement. Optionally, thin film pol...

  1. Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications

    International Nuclear Information System (INIS)

    Ghosh, Bahniman; Dey, Rik; Register, Leonard F.; Banerjee, Sanjay K.

    2016-01-01

    In this article, we consider through simulation low-energy switching of nanomagnets via electrostatically gated inter-magnet Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions on the surface of three-dimensional topological insulators, for possible memory and nonvolatile logic applications. We model the possibility and dynamics of RKKY-based switching of one nanomagnet by coupling to one or more nanomagnets of set orientation. Potential applications to both memory and nonvolatile logic are illustrated. Sub-attojoule switching energies, far below conventional spin transfer torque (STT)-based memories and even below CMOS logic appear possible. Switching times on the order of a few nanoseconds, comparable to times for STT switching, are estimated for ferromagnetic nanomagnets, but the approach also appears compatible with the use of antiferromagnets which may allow for faster switching.

  2. Tuning magnetic properties of magnetoelectric BiFeO 3-NiFe 2O 4 nanostructures

    Science.gov (United States)

    Crane, S. P.; Bihler, C.; Brandt, M. S.; Goennenwein, S. T. B.; Gajek, M.; Ramesh, R.

    2009-02-01

    Multifunctional thin film nanostructures containing soft magnetic materials such as nickel ferrite are interesting for potential applications in microwave signal processing because of the possibility to shrink the size of device architecture and limit device power consumption. An essential prerequisite to future applications of such a system is a firm understanding of its magnetic properties. We show that nanostructures composed of ferrimagnetic NiFe 2O 4 pillars in a multiferroic BiFeO 3 matrix can be tuned magnetically by altering the aspect ratio of the pillars by depositing films of varying thickness. Magnetic anisotropy is studied using ferromagnetic resonance, which shows that the uniaxial magnetic anisotropy in the growth direction changes sign upon increasing the film thickness. The magnitude of this anisotropy contribution can be explained via a combination of shape and magnetostatic effects, using the object-oriented micromagnetic framework (OOMMF). The key factors determining the magnetic properties of the films are shown to be the aspect ratio of individual pillars and magnetostatic interactions between neighboring pillars.

  3. Tuning magnetic properties of magnetoelectric BiFeO3-NiFe2O4 nanostructures

    International Nuclear Information System (INIS)

    Crane, S.P.; Bihler, C.; Brandt, M.S.; Goennenwein, S.T.B.; Gajek, M.; Ramesh, R.

    2009-01-01

    Multifunctional thin film nanostructures containing soft magnetic materials such as nickel ferrite are interesting for potential applications in microwave signal processing because of the possibility to shrink the size of device architecture and limit device power consumption. An essential prerequisite to future applications of such a system is a firm understanding of its magnetic properties. We show that nanostructures composed of ferrimagnetic NiFe 2 O 4 pillars in a multiferroic BiFeO 3 matrix can be tuned magnetically by altering the aspect ratio of the pillars by depositing films of varying thickness. Magnetic anisotropy is studied using ferromagnetic resonance, which shows that the uniaxial magnetic anisotropy in the growth direction changes sign upon increasing the film thickness. The magnitude of this anisotropy contribution can be explained via a combination of shape and magnetostatic effects, using the object-oriented micromagnetic framework (OOMMF). The key factors determining the magnetic properties of the films are shown to be the aspect ratio of individual pillars and magnetostatic interactions between neighboring pillars

  4. Evidence of a New Current-Induced Magnetoelectric Effect in a Toroidal Magnetic Ordered State of UNi4B

    Science.gov (United States)

    Saito, Hiraku; Uenishi, Kenta; Miura, Naoyuki; Tabata, Chihiro; Hidaka, Hiroyuki; Yanagisawa, Tatsuya; Amitsuka, Hiroshi

    2018-03-01

    Magnetization measurements under direct electric current were performed in a toroidal magnetic ordered state of UNi4B to test a recent theoretical prediction of current-induced magnetization in a metallic system lacking local-inversion symmetry. We found that electric current parallel to [2\\bar{1}\\bar{1}0] and [0001] in the hexagonal 4-index notation induces a uniform magnetization along the [01\\bar{1}0] direction. The observed behavior of the induced magnetization is essentially consistent with the theoretical prediction; however, it also shows an inconsistency suggesting that the antiferromagnetic state of UNi4B could not be simply regarded as a uniform toroidal order in the ideal honeycomb layered structure.

  5. Ferroelectricity and magnetoelectric coupling in h-YbMnO{sub 3}: Spin reorientation and defect effect

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Gang; Fang, Yifei; Lu, Xiaowen; Cao, Shixun; Zhang, Jincang, E-mail: jczhang@shu.edu.cn [Materials Genome Institute and Department of Physics, Shanghai University, Shanghai 200444 (China)

    2016-01-11

    Low-temperature magnetic and electric properties in hexagonal multiferroic compound YbMnO{sub 3} were studied. The Mn{sup 3+} spin moments order at T{sub N} = 85 K and reoriented around 43.5 K, leading to the magnetic phase transition from B{sub 2}(P6{sub 3}cm) → A{sub 2}(P6{sub 3}cm). The concomitant ferroelectric polarization is observed and explained microscopically by the destruction of initial symmetric relationship of the polarization between the upper and lower half of the magnetic unit cell. The asymmetry of the polarization vs temperature curves under opposite poling voltage revealed the pinning effect of the defects on the electrical polarization.

  6. TE and TM modes polaritons in multilayer system comprise of a PML-type magnetoelectric multiferroics and ferroelectrics

    International Nuclear Information System (INIS)

    Gunawan, Vincensius; Widiyandari, Hendri

    2016-01-01

    In this paper, we report our study on both bulk and surface polaritons generated in Multilayer system. The multilayer consists of ferroelectric and multiferroic with canted spins structure. The effective medium approximation is employed to derive the dispersion relation for both bulk and surface modes. Surface and bulk polaritons are calculated numerically for the case of Transverse electric (TE) and Transverse magnetic (TM) modes. Example results are presented using parameters appropriate for BaMnF 4 /BaAl 2 O 4 . We found in both TE and TM modes, that the region where the surface modes may exist is affected by the volume fraction of the multiferroics. The region of the surface modes decrease when the volume fraction of the multiferroic is reduced. This region decrement suppress the surface polariton curves which result in shortening the surface modes curves. (paper)

  7. On separation of exchange term from the coefficient of the ...

    Indian Academy of Sciences (India)

    Magnetoelectroelastics; exchange coefficient; magnetoelectric effect; piezoelectric effect; piezomagnetic effect. PACS Nos 51.40.+p; 72.55.+s. Magnetoelectroelastics, also known as piezoelectromagnetic smart materials, actually possess magnetoelectric, piezomagnetic, and piezoelectric effects. In this class of mag-.

  8. Magneto-electrical transport through MBE-grown III-V semiconductor nanostructures. From zero- to one-dimensional type of transport

    Energy Technology Data Exchange (ETDEWEB)

    Storace, Eleonora

    2009-07-08

    From the development of the first transistor in 1947, great interest has been directed towards the technological development of semiconducting devices and the investigation of their physical properties. A very vital field within this topic focuses on the electrical transport through low-dimensional structures, where the quantum confinement of charge carriers leads to the observation of a wide variety of phenomena that, in their turn, can give an interesting insight on the fundamental properties of the structures under examination. In the present thesis, we will start analyzing zero-dimensional systems, focusing on how electrons localized onto an island can take part in the transport through the whole system; by precisely tuning the tunnel coupling strength between this island and its surroundings, we will then show how it is possible to move from a zero- to a one-dimensional system. Afterwards, the inverse path will be studied: a one-dimensional system is electrically characterized, proving itself to split up due to disorder into several zero-dimensional structures. (orig.)

  9. Structural order, magnetic and intrinsic dielectric properties of magnetoelectric La.sub.2./sub.CoMnO.sub.6./sub.

    Czech Academy of Sciences Publication Activity Database

    Silva, R.X.; de Menezes, A.S.; Almeida, R.M.; Moreira, R.L.; Paniago, R.; Martí, Xavier; Reichlová, Helena; Maryško, Miroslav; Rezende, M.V.S.; Paschoal, C.W.A.

    2016-01-01

    Roč. 661, Mar (2016), s. 541-552 ISSN 0925-8388 Institutional support: RVO:68378271 Keywords : La 2 CoMnO 6 * double perovskite * structural order * magnetodielectric * Raman spectroscopy * infrared spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.133, year: 2016

  10. Comment on 'Calculated chiral and magneto-electric dichroic signals for copper metaborate (CuB2O4) in an applied magnetic field'

    International Nuclear Information System (INIS)

    Arima, T; Saito, M

    2009-01-01

    Contrary to a claim by Lovesey and Staub (2009 J. Phys.: Condens. Matter 21 142201), a careful treatment of symmetry shows that the application of a magnetic field along a twofold axis can induce the crystallographic chirality in a tetragonal system with the point group 4-bar2m like CuB 2 O 4 . The chirality is reversed by a 90 deg. rotation of the magnetic field around the c axis. (comment)

  11. Magneto-electric coupling in NdFe{sub 3}(BO{sub 3}){sub 4} studied by resonant x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hamann-Borrero, J.E.; Partzsch, S.; Hess, C.; Buechner, B.; Geck, J. [IFW Dresden, 01171 Dresden (Germany); Valencia, S.; Feyerherm, R. [Helmholtz Zentrum Berlin, Albert Einstein Str. 15, 12489 Berlin (Germany); Mazzoli, C.; Herrero-Martin, J. [ESRF, Boite Postale 220, 38043 Grenoble (France); Vasiliev, A. [Faculty of Physics, Moscow State University (Russian Federation); Bezmaternykh, L. [Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk (Russian Federation)

    2011-07-01

    Resonant x-ray magnetic scattering (RXS) experiments on NdFe{sub 3}(BO{sub 3}){sub 4} were performed at the Nd L{sub 2,3} and Fe K edges in order to determine its magnetic structure as a function of temperature (T) as well as applied magnetic (B) and electric (E) fields. Results of the T dependent measurements show that the magnetic structure changes from a commensurate collinear structure to an incommensurate spin helix structure. Moreover, the analysis of the resonant intensities shows that the T dependence of the magnetic order is different for the Nd and for the Fe sublattice. A mean field analysis implies that the magnetization of the Nd sublattice is induced by the Fe magnetization. When a B field is applied along the a-direction, the spin helix is destroyed and a collinear structure is formed where the moments align perpendicular to B. Since the critical B at which the spin helix is destroyed is the same at which the magnetic induced electric polarization is maximum. This shows that the spin helix is not the origin of the electric polarization in NdFe{sub 3}(BO{sub 3}){sub 4}.

  12. Structural order, magnetic and intrinsic dielectric properties of magnetoelectric La.sub.2./sub.CoMnO.sub.6./sub.

    Czech Academy of Sciences Publication Activity Database

    Silva, R.X.; de Menezes, A.S.; Almeida, R.M.; Moreira, R.L.; Paniago, R.; Martí, Xavier; Reichlová, Helena; Maryško, Miroslav; Rezende, M.V.S.; Paschoal, C.W.A.

    2015-01-01

    Roč. 661, Mar (2015), s. 541-552 ISSN 0925-8388 Institutional support: RVO:68378271 Keywords : La 2 CoMnO 6 * double perovskite * structural order * magnetodielectric * Raman spectroscopy * infrared spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.014, year: 2015

  13. Magneto-electrical transport through MBE-grown III-V semiconductor nanostructures. From zero- to one-dimensional type of transport

    International Nuclear Information System (INIS)

    Storace, Eleonora

    2009-01-01

    From the development of the first transistor in 1947, great interest has been directed towards the technological development of semiconducting devices and the investigation of their physical properties. A very vital field within this topic focuses on the electrical transport through low-dimensional structures, where the quantum confinement of charge carriers leads to the observation of a wide variety of phenomena that, in their turn, can give an interesting insight on the fundamental properties of the structures under examination. In the present thesis, we will start analyzing zero-dimensional systems, focusing on how electrons localized onto an island can take part in the transport through the whole system; by precisely tuning the tunnel coupling strength between this island and its surroundings, we will then show how it is possible to move from a zero- to a one-dimensional system. Afterwards, the inverse path will be studied: a one-dimensional system is electrically characterized, proving itself to split up due to disorder into several zero-dimensional structures. (orig.)

  14. Local Probing of Magnetoelectric Coupling and Magnetoelastic Control of Switching in BiFeO3-CoFe2O4 Thin-Film Nanocomposite

    Science.gov (United States)

    2013-07-25

    at remanent state (Fig. 4(d)). The obtained ME coefficient (the highest value we measure is 102 mV/ cm/Oe) and is comparable to that of bulk PZT -CFO...For a large field (H > Hc), a mag- netostrictive strain (k) must be already saturated and the ME coefficient estimated (Fig. 4) should be nearly...zero at high field (as a function of piezomagnetic coefficient (dk=dH), leading to a maximum in the ME response near Hc. That this is not observed can be

  15. Evidence for a New Magnetoelectric Effect of Current-Induced Magnetization in a Toroidal Magnetic Ordered State of UNi$_4$B

    OpenAIRE

    Saito, Hiraku; Uenishi, Kenta; Miura, Naoyuki; Tabata, Chihiro; Hidaka, Hiroyuki; Yanagisawa, Tatsuya; Amitsuka, Hiroshi

    2018-01-01

    Magnetization measurements under direct electric currents were performed for toroidal magnetic ordered state of UNi$_4$B to test a recent theoretical prediction of current-induced magnetization in a metallic system lacking local inversion symmetry.We found that each of the electric currents parallel to [$2\\bar{1}\\bar{1}0$] and [$0001$] in the hexagonal 4-index notation induces uniform magnetization in the direction of [$01\\bar{1}0$].The observed behavior of the induced magnetization is essent...

  16. A density functional theory study of magneto-electric Jones birefringence of noble gases, furan homologues, and mono-substituted benzenes

    International Nuclear Information System (INIS)

    Fahleson, Tobias; Norman, Patrick; Coriani, Sonia; Rizzo, Antonio; Rikken, Geert L. J. A.

    2013-01-01

    We report on the results of a systematic ab initio study of the Jones birefringence of noble gases, of furan homologues, and of monosubstituted benzenes, in the gas phase, with the aim of analyzing the behavior and the trends within a list of systems of varying size and complexity, and of identifying candidates for a combined experimental/theoretical study of the effect. We resort here to analytic linear and nonlinear response functions in the framework of time-dependent density functional theory. A correlation is made between the observable (the Jones constant) and the atomic radius for noble gases, or the permanent electric dipole and a structure/chemical reactivity descriptor as the para Hammett constant for substituted benzenes

  17. Cluster superconductivity in the magnetoelectric Pb(Fe.sub.1/2./sub.Sb.sub.1/2./sub.)O.sub.3./sub. ceramics

    Czech Academy of Sciences Publication Activity Database

    Laguta, Valentyn; Maryško, Miroslav; Stephanovich, V. A.; Raevsky, I.P.; Olekhnovich, N.M.; Pushkarev, A.V.; Radyush, Yu.V.; Raevskaya, S. I.; Kuzian, R. O.; Chlan, V.; Štěpánková, H.

    2017-01-01

    Roč. 131, č. 6 (2017), s. 1534-1539 ISSN 0587-4246 R&D Projects: GA MŠk LO1409; GA MŠk LM2015088; GA ČR GA13-11473S Institutional support: RVO:68378271 Keywords : multiferroics * superconductivity Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.469, year: 2016

  18. Single magnetic chirality in the magnetoelectric NdFe.sub.3./sub.(.sup.11./sup.BO.sub.3./sub.).sub.4./sub..

    Czech Academy of Sciences Publication Activity Database

    Janoschek, M.; Fischer, P.; Schefer, J.; Roessli, B.; Pomjakushin, V.; Mews, M.; Petříček, Václav; Petrakovskii, G.; Bezmaternikh, L.

    2010-01-01

    Roč. 81, č. 9 (2010), 094429/1-094429/13 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : magnetic structure * neutron diffraction * phase transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  19. Gigantic magnetoelectric effect caused by magnetic-field-induced canted antiferromagnetic-paramagnetic transition in quasi-two-dimensional Ca2CoSi2O7 crystal

    Science.gov (United States)

    Akaki, M.; Tozawa, J.; Akahoshi, D.; Kuwahara, H.

    2009-05-01

    We have investigated the magnetic and dielectric properties of Ca2CoSi2O7 crystal. The dielectricity and magnetism of Ca2CoSi2O7 are strongly coupled below a canted antiferromagnetic transition temperature (TN). Magnetic fields induce electric polarization below TN. Interestingly, the magnetic-field-induced electric polarization is detected even without poling electric fields. Below TN, a canted antiferromagnetic-paramagnetic transition is induced by magnetic fields. The large magnetocapacitance is observed around TN. The origin of the large magnetocapacitance is due to the magnetic-field-induced the canted antiferromagnetic-paramagnetic transition.

  20. Amorphous FeCoSiB for exchange bias coupled and decoupled magnetoelectric multilayer systems: Real-structure and magnetic properties

    International Nuclear Information System (INIS)

    Hrkac, V.; Strobel, J.; Kienle, L.; Lage, E.; Köppel, G.; McCord, J.; Quandt, E.; Meyners, D.

    2014-01-01

    The effect of field annealing for exchanged biased multilayer films is studied with respect to the resultant structural and magnetic film properties. The presented multilayer stacks comprise repeating sequences of Ta/Cu/(1 1 1) textured antiferromagnetic Mn 70 Ir 30 /amorphous ferromagnetic Fe 70.2 Co 7.8 Si 12 B 10 . Within the ferromagnetic layers crystalline filaments are observed. An additional Ta layer between the antiferromagnet and ferromagnet is used in order to investigate and separate the influence of the common Mn 70 Ir 30 /Fe 70.2 Co 7.8 Si 12 B 10 interface on the occurring filaments and structural changes. In situ and ex situ transmission electron microscopy is used for a comprehensive structure characterization of multilayer stacks for selected temperature stages. Up to 250 °C, the multilayers are structurally unaltered and preserve the as-deposited condition. A deliberate increase to 350 °C exhibits different crystallization processes for the films, depending on the presence of crystal nuclei within the amorphous ferromagnetic layer. The influence of volume-to-surface ratio of the multilayer stacks to the crystallization process is emphasized by the comparison of in situ and ex situ investigations as the respective specimen thickness is changed. Complementary magnetic studies reveal a defined exchange bias obtained at the first annealing step and a decrease of total anisotropy field with partial crystallization after the subsequent annealing at 350 °C.

  1. Tuning magnetic properties of magnetoelectric BiFeO{sub 3}-NiFe{sub 2}O{sub 4} nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Crane, S.P. [Department of Materials Science and Engineering, University of California, Berkeley, CA 94720 (United States)], E-mail: scrane@berkeley.edu; Bihler, C.; Brandt, M.S. [Walter Schottky Institut, Technische Universitaet Muenchen, D-85748 Garching (Germany); Goennenwein, S.T.B. [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching (Germany); Gajek, M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Ramesh, R. [Department of Materials Science and Engineering, University of California, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States)

    2009-02-15

    Multifunctional thin film nanostructures containing soft magnetic materials such as nickel ferrite are interesting for potential applications in microwave signal processing because of the possibility to shrink the size of device architecture and limit device power consumption. An essential prerequisite to future applications of such a system is a firm understanding of its magnetic properties. We show that nanostructures composed of ferrimagnetic NiFe{sub 2}O{sub 4} pillars in a multiferroic BiFeO{sub 3} matrix can be tuned magnetically by altering the aspect ratio of the pillars by depositing films of varying thickness. Magnetic anisotropy is studied using ferromagnetic resonance, which shows that the uniaxial magnetic anisotropy in the growth direction changes sign upon increasing the film thickness. The magnitude of this anisotropy contribution can be explained via a combination of shape and magnetostatic effects, using the object-oriented micromagnetic framework (OOMMF). The key factors determining the magnetic properties of the films are shown to be the aspect ratio of individual pillars and magnetostatic interactions between neighboring pillars.

  2. High frequency and magnetoelectrical properties of magnetoresistive memory element based on FeCoNi/TiN/FeCoNi film

    Directory of Open Access Journals (Sweden)

    Kurlyandskaya, G. V.

    2000-08-01

    Full Text Available A miniaturised memory device for information recording and readout processes have been designed on the basis of anisotropic magnetoresistive effect in Fe15Co20Ni65(160Å/ TiN(50Å/Fe15Co20Ni65(160Å three-layered film done by rf diode sputtering. Stable recording and readout processes were available for 32 rectangular element column, where each element had μm dimensions convenient to fabricate memory chip with 106 bits capacity. Rectangles of different sizes with removed corners were used in order to define the geometry of most of all stable recording and readout processes. Magnetoresistance and magnetoimpedance effects of a magnetic memory device have been comparatively analysed. We suggest that the decrease of the absolute value of the magnetoimpedance of the memory device comes from the reduction of the real part via the magnetoresistance.

    Se ha diseñado un dispositivo de memoria para la grabación y lectura de información basado en el efecto de la anisotropía magnetorresistiva de una multicapa fabricada por sputtering mediante diodo de rf. El elemento de memoria se compone de tres películas delgadas, de composición Fe15Co20Ni65(160Å/ TiN(50Å/Fe15Co20Ni65(160Å. El dispositivo permite procesos de grabación y lectura estables, y se compone de 32 elementos de memoria rectangulares por columna, donde cada elemento tiene dimensiones de μm lo que permite la fabricación de memorias integradas con capacidades del orden de 106 bits. Se han ensayado elementos de memoria rectangulares de diferentes tamaños, con las esquinas redondeadas con objeto de conseguir procesos de lectura-escritura lo más estable posible. Se han analizado comparativamente los efectos de magnetorresistencia y magnetoimpedancia de los elementos de memoria de diferentes dimensiones. Sugerimos que la disminución del valor absoluto de la magnetoimpedancia del elemento de memoria es consecuencia de la reducción de la parte real, de origen magnetorresistivo.

  3. The effect of annealing atmosphere on magnetoelectric coupling of the La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/BaTiO{sub 3} layered heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tingxian, E-mail: wxlltx@126.com [College of Physics and Electrical Engineering, Anyang Normal University, Anyang 455002 (China); Wang, Hongwei [School of Mathematics and Statistics, Anyang Normal University, Anyang 455002 (China); Ju, Lin; Tang, Zhenjie; Ma, Dongwei [College of Physics and Electrical Engineering, Anyang Normal University, Anyang 455002 (China); Li, Kuoshe [National Engineering Research Central for Rare earth Materials, Beijing 100088 (China)

    2015-10-15

    The epitaxial La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/BaTiO{sub 3} (LSMO/BTO) layered heterostructure was grown on (001) oriented LaAlO{sub 3} single-crystal substrate by pulsed laser deposition. Our results showed that the in-situ annealing process in oxygen made the LSMO/BTO interface possess higher oxygen content than that of the one annealing in vacuum, which leaded to the LSMO film presented higher magnetic permeability and higher saturated magnetization. The P–E hystersis loop only could be detected in the sample annealing in oxygen. The ME voltage coefficient of the LSMO/BTO heterostructure annealing in oxygen was higher than that of the one annealing in vacuum, which suggested a more effective ME coupling. It was a combined effect of the two main ME coupling mechanisms, including strain mediation, and polarized carrier mediation.

  4. Magneto-electric properties and magnetic entropy change in perovskite La{sub 0.7}Sr{sub 0.3}Mn{sub 1−x}Ti{sub x}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Bau, Le Viet, E-mail: levietbau@hdu.edu.vn; An, Nguyen Manh

    2016-12-15

    The ceramic samples of La{sub 0.7}Sr{sub 0.3}Mn{sub 1−x}Ti{sub x}O{sub 3}(x=0; 0.05; 0.1; 0.2 and 0.3) were synthesized by the conventional solid state reaction method. Their electric, magnetic and magnetocaloric properties have been investigated. The transition temperature declines and a significant influence on the width of the ferro-paramagnetic phase transition is observed as increasing Ti concentration. Moreover, the sign of spin-glass is expected to exist in the high concentration samples. For fully replacing Ti{sup 4+} for Mn{sup 4+}, the canted spin state is formed. The substitution Ti for Mn increases resistivity quickly and the insulating–metallic transition temperature shifts toward lower temperature. For x>0.1 samples, the insulating state is observed even in ferromagnetic phase. The substitution Ti shifts the CME to room temperature while almost persists the value of entropy change. Although the maximum value of CME reduces slightly, the temperature range happening MCE is expended and then improves the relative cooling power. These properties could be explained in term of DE interaction and phase separation phenomenon. - Highlights: • Electro-magnetic properties and CME of La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Ti{sub x}O{sub 3} have been investigated. • T{sub C} declines and the width of the F-M phase transition is observed as increasing Ti concentration. • For fully replacing Ti{sup 4+} for Mn{sup 4+}, the canted spin state is formed. • The substitution Ti for Mn increases resistivity quickly and T{sub P} shifts toward lower temperature. • The substitution Ti shifts CME to 300 K while almost persists the value of entropy change. • Relative cooling power (RCP) increases with substitution 5% Ti for Mn.

  5. High electron mobility and large magnetoresistance in the half-Heusler semimetal LuPtBi

    KAUST Repository

    Hou, Zhipeng; Wang, Wenhong; Xu, Guizhou; Zhang, Xiaoming; Wei, Zhiyang; Shen, Shipeng; Liu, Enke; Yao, Yuan; Chai, Yisheng; Sun, Young; Xi, Xuekui; Wang, Wenquan; Liu, Zhongyuan; Wu, Guangheng; Zhang, Xixiang

    2015-01-01

    Materials with high carrier mobility showing large magnetoresistance (MR) have recently received much attention because of potential applications in future high-performance magnetoelectric devices. Here, we report on an electron-hole

  6. Anisotropic modulation of magnetic properties and the memory effect in a wide-band (011)-Pr0.7Sr0.3MnO3/PMN-PT heterostructure

    KAUST Repository

    Zhao, Ying-Ying; Wang, Jing; Kuang, Hao; Hu, Feng-Xia; Liu, Yao; Wu, Rong-Rong; Zhang, Xixiang; Sun, Ji-Rong; Shen, Bao-Gen

    2015-01-01

    Memory effect of electric-field control on magnetic behavior in magnetoelectric composite heterostructures has been a topic of interest for a long time. Although the piezostrain and its transfer across the interface of ferroelectric

  7. Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state.

    Science.gov (United States)

    Okada, Ken N; Takahashi, Youtarou; Mogi, Masataka; Yoshimi, Ryutaro; Tsukazaki, Atsushi; Takahashi, Kei S; Ogawa, Naoki; Kawasaki, Masashi; Tokura, Yoshinori

    2016-07-20

    Electrodynamic responses from three-dimensional topological insulators are characterized by the universal magnetoelectric term constituent of the Lagrangian formalism. The quantized magnetoelectric coupling, which is generally referred to as topological magnetoelectric effect, has been predicted to induce exotic phenomena including the universal low-energy magneto-optical effects. Here we report the experimental indication of the topological magnetoelectric effect, which is exemplified by magneto-optical Faraday and Kerr rotations in the quantum anomalous Hall states of magnetic topological insulator surfaces by terahertz magneto-optics. The universal relation composed of the observed Faraday and Kerr rotation angles but not of any material parameters (for example, dielectric constant and magnetic susceptibility) well exhibits the trajectory towards the fine structure constant in the quantized limit.

  8. Influence of Na-doping in La{sub 0.67}Pb{sub 0.33-x}Na{sub x}MnO{sub 3} (0 ≤ x ≤ 0.15) on its structural, magnetic and magneto-electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Zaidi, Asma; Cherif, Karima [Laboratoire de la Matière Condensée et des Nanosciences, Université de Monastir, 5019 (Tunisia); Dhahri, J., E-mail: dhahri.jemai@yahoo.fr [Laboratoire de la Matière Condensée et des Nanosciences, Université de Monastir, 5019 (Tunisia); Hlil, E.K. [Institut Neel, CNRS et Université Joseph Fourier, B.P.166, 38042 Grenoble (France); Zaidi, M.; Alharbi, T. [College of Science of Zulfi, Majmaah University (Saudi Arabia)

    2015-11-25

    We have studied the effect of Na substitution on structural, magnetic and electrical properties in La{sub 0.67}Pb{sub 0.33-x}Na{sub x}MnO{sub 3} (0 ≤ x ≤ 0.15). All compositions were synthesized using the sol–gel technique. X-ray diffraction and structure refinement show that they crystallize in the rhombohedra structure with the R − 3c space group. All the samples exhibit a paramagnetic (PM)-ferromagnetic (FM) phase transition (T{sub C}) at 363, 328, 305 and 285 K for x = 0, x = 0.05, x = 0.1 and x = 0.15 respectively. The replacement of Pb ion by Na results in a decrease of the metal-semiconductor transition temperature T{sub M-Sc} and the magnetoresistance (MR) as well as the resistivity are found to increase. The electrical resistivity in the entire temperature range fit well with the phenomenological percolation theory based on the phase segregation mechanism. - Graphical abstract: Temperature dependence of MR under several magnetic applied field values for the samples La{sub 0.67}Pb{sub 0.18-x}Na{sub 0.15}MnO{sub 3}. - Highlights: • The samples exhibit PM-FM phase transition. • The electrical transport is investigated. • Low temperature minimum resistivity is observed. • The electrical resistivity in the entire temperature range fit well with the phenomenological percolation model.

  9. Comprehension of the Electric Polarization as a Function of Low Temperature

    Science.gov (United States)

    Liu, Changshi

    2017-01-01

    Polarization response to warming plays an increasingly important role in a number of ferroelectric memory devices. This paper reports on the theoretical explanation of the relationship between polarization and temperature. According to the Fermi-Dirac distribution, the basic property of electric polarization response to temperature in magnetoelectric multiferroic materials is theoretically analyzed. The polarization in magnetoelectric multiferroic materials can be calculated by low temperature using a phenomenological theory suggested in this paper. Simulation results revealed that the numerically calculated results are in good agreement with experimental results of some inhomogeneous multiferroic materials. Numerical simulations have been performed to investigate the influences of both electric and magnetic fields on the polarization in magnetoelectric multiferroic materials. Furthermore, polarization behavior of magnetoelectric multiferroic materials can be predicted by low temperature, electric field and magnetic induction using only one function. The calculations offer an insight into the understanding of the effects of heating and magnetoelectric field on electrical properties of multiferroic materials and offer a potential to use similar methods to analyze electrical properties of other memory devices.

  10. DOE-EPSCoR Final Report Period: September 1, 2008- August 31, 2016

    International Nuclear Information System (INIS)

    Katiyar, Ram; Gomez, M.; Morell, G.; Fonseca, L.; Ishikawa, Y.; Palai, R.; Thomas, R.; Kumar, A.; Velev, J.; Makarov, V.; Perales, O.; Tomar, M. S.; Otano, W.

    2016-01-01

    In this project, multifunctional nanostructured spintronic and magnetoelectric materials were investigated by experimental and computational efforts for applications in energy efficient electronic systems that integrate functionalities and thus have the potential to enable a new generation of faster responding devices and increased integration densities. The team systematically investigated transition metal (TM)-doped ZnO nanostructures, silicide nanorods, magnetoelectric oxides, and ferroelectric/ferromagnetic heterostructures. In what follows, we report the progress made by researchers during the above period in developing and understanding of 1) Spintronics nanostructures; 2) Resistive switching phenomenon in oxides for memory devices; 3) Magnetoelectric multiferroics; 4) Novel high-k gate oxides for logic devices; 5) Two dimensional (2D) materials; and 6) Theoretical studies in the above fields.

  11. DOE-EPSCoR Final Report Period: September 1, 2008- August 31, 2016

    Energy Technology Data Exchange (ETDEWEB)

    Katiyar, Ram [Univ. of Puerto Rico, Rio Piedras, PR (United States); Gomez, M. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Morell, G. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Fonseca, L. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Ishikawa, Y. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Palai, R. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Thomas, R. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Kumar, A. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Velev, J. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Makarov, V. [Univ. of Puerto Rico, Rio Piedras, PR (United States); Perales, O. [Univ. of Puerto Rico, Mayaguez, PR (United States); Tomar, M. S. [Univ. of Puerto Rico, Mayaguez, PR (United States); Otano, W. [Univ. of Puerto Rico, Cayey, PR (United States)

    2016-10-31

    In this project, multifunctional nanostructured spintronic and magnetoelectric materials were investigated by experimental and computational efforts for applications in energy efficient electronic systems that integrate functionalities and thus have the potential to enable a new generation of faster responding devices and increased integration densities. The team systematically investigated transition metal (TM)-doped ZnO nanostructures, silicide nanorods, magnetoelectric oxides, and ferroelectric/ferromagnetic heterostructures. In what follows, we report the progress made by researchers during the above period in developing and understanding of 1) Spintronics nanostructures; 2) Resistive switching phenomenon in oxides for memory devices; 3) Magnetoelectric multiferroics; 4) Novel high-k gate oxides for logic devices; 5) Two dimensional (2D) materials; and 6) Theoretical studies in the above fields.

  12. Reversible control of magnetic interactions by electric field in a single-phase material.

    Science.gov (United States)

    Ryan, P J; Kim, J-W; Birol, T; Thompson, P; Lee, J-H; Ke, X; Normile, P S; Karapetrova, E; Schiffer, P; Brown, S D; Fennie, C J; Schlom, D G

    2013-01-01

    Intrinsic magnetoelectric coupling describes the interaction between magnetic and electric polarization through an inherent microscopic mechanism in a single-phase material. This phenomenon has the potential to control the magnetic state of a material with an electric field, an enticing prospect for device engineering. Here, we demonstrate 'giant' magnetoelectric cross-field control in a tetravalent titanate film. In bulk form, EuTiO(3), is antiferromagnetic. However, both anti and ferromagnetic interactions coexist between different nearest europium neighbours. In thin epitaxial films, strain was used to alter the relative strength of the magnetic exchange constants. We not only show that moderate biaxial compression precipitates local magnetic competition, but also demonstrate that the application of an electric field at this strain condition switches the magnetic ground state. Using first-principles density functional theory, we resolve the underlying microscopic mechanism resulting in G-type magnetic order and illustrate how it is responsible for the 'giant' magnetoelectric effect.

  13. Chiral magnetic effect of light

    Science.gov (United States)

    Hayata, Tomoya

    2018-05-01

    We study a photonic analog of the chiral magnetic (vortical) effect. We discuss that the vector component of magnetoelectric tensors plays a role of "vector potential," and its rotation is understood as "magnetic field" of a light. Using the geometrical optics approximation, we show that "magnetic fields" cause an anomalous shift of a wave packet of a light through an interplay with the Berry curvature of photons. The mechanism is the same as that of the chiral magnetic (vortical) effect of a chiral fermion, so that we term the anomalous shift "chiral magnetic effect of a light." We further study the chiral magnetic effect of a light beyond geometric optics by directly solving the transmission problem of a wave packet at a surface of a magnetoelectric material. We show that the experimental signal of the chiral magnetic effect of a light is the nonvanishing of transverse displacements for the beam normally incident to a magnetoelectric material.

  14. Casimir-Polder forces on atoms in the presence of magnetoelectronic bodies

    International Nuclear Information System (INIS)

    Buhmann, S.Y.

    2007-01-01

    In this work, the CP force between a single neutral atom or molecule and neutral magnetoelectric bodies is studied. The focus lies on the pure vacuum CP force, i.e., the electromagnetic field is in general understood to be in its ground state. Furthermore, we assume that the atom-body separation is sufficiently large to ensure that the atom is adequately characterised as an electric dipole, while the body can be described by its macroscopic magnetoelectric properties; and that repulsive exchange forces due to the overlap between the electronic wave functions of the atom and the bodies can be neglected. Interactions due to non-vanishing net charges, permanent electric dipole moments, magnetisability, quadrupole (or higher multipole) polarisabilities of the atom and those resulting from non-local or anisotropic magnetoelectric properties of the bodies are ignored. (orig.)

  15. Origin of the magnetic-field controlled polarization reversal in multiferroic TbMn2 O 5

    Science.gov (United States)

    Leo, N.; Meier, D.; Pisarev, R. V.; Park, S.; Cheong, S.-W.; Fiebig, M.

    2011-03-01

    The interplay of multi-dimensional complex magnetic order parameters leads to interesting effects like magnetically induced ferroelectricity. A particular interesting example is TbMn 2 O5 because of the associated magnetic-field controllable electric polarization. By optical second harmonic generation we show that the gigantic magnetoelectric effect originates in three independent ferroelectric contributions. Two of these are manganese-generated. The third contribution is related to the magnetism of the Tb 3+ sublattice and has not been identified so far. It mediates the remarkable magnetic-field induced polarization reversal. This model is verified by experiments on the isostructural YMn 2 O5 where Y3+ ions are nonmagnetic and only two polarization contributions are present and no magnetoelectric coupling is observed. These results underline the importance of the 3 d - 4 f -interaction for the intricate magnetoelectric coupling in the class of isostructural RMn 2 O5 compounds. This work was supported by the DFG through SFB 608.

  16. Casimir-Polder forces on atoms in the presence of magnetoelectronic bodies

    Energy Technology Data Exchange (ETDEWEB)

    Buhmann, S Y

    2007-07-05

    In this work, the CP force between a single neutral atom or molecule and neutral magnetoelectric bodies is studied. The focus lies on the pure vacuum CP force, i.e., the electromagnetic field is in general understood to be in its ground state. Furthermore, we assume that the atom-body separation is sufficiently large to ensure that the atom is adequately characterised as an electric dipole, while the body can be described by its macroscopic magnetoelectric properties; and that repulsive exchange forces due to the overlap between the electronic wave functions of the atom and the bodies can be neglected. Interactions due to non-vanishing net charges, permanent electric dipole moments, magnetisability, quadrupole (or higher multipole) polarisabilities of the atom and those resulting from non-local or anisotropic magnetoelectric properties of the bodies are ignored. (orig.)

  17. Electrical percolation threshold of magnetostrictive inclusions in a piezoelectric matrix composite as a function of relative particle size

    Science.gov (United States)

    Barbero, Ever J.; Bedard, Antoine Joseph

    2018-04-01

    Magnetoelectric composites can be produced by embedding magnetostrictive particles in a piezoelectric matrix derived from a piezoelectric powder precursor. Ferrite magnetostrictive particles, if allowed to percolate, can short the potential difference generated in the piezoelectric phase. Modeling a magnetoelectric composite as an aggregate of bi-disperse hard shells, molecular dynamics was used to explore relationships among relative particle size, particle affinity, and electrical percolation with the goal of maximizing the percolation threshold. It is found that two factors raise the percolation threshold, namely the relative size of magnetostrictive to piezoelectric particles, and the affinity between the magnetostrictive and piezoelectric particles.

  18. Large microwave tunability of GaAs-based multiferroic heterostructure for applications in monolithic microwave integrated circuits

    International Nuclear Information System (INIS)

    Chen Yajie; Gao Jinsheng; Vittoria, C; Harris, V G; Heiman, D

    2010-01-01

    Microwave magnetoelectric coupling in a ferroelectric/ferromagnetic/semiconductor multiferroic (MF) heterostructure, consisting of a Co 2 MnAl epitaxial film grown on a GaAs substrate bonded to a lead magnesium niobate-lead titanate (PMN-PT) crystal, is reported. Ferromagnetic resonance measurements were carried out at X-band under the application of electric fields. Results indicate a frequency tuning of 125 MHz for electric field strength of 8 kV cm -1 resulting in a magnetoelectric coupling coefficient of 3.4 Oe cm kV -1 . This work explores the potential of electronically controlled MF devices for use in future monolithic microwave integrated circuits.

  19. Dynamic response in a finite size composite multiferroic thin film

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zidong, E-mail: Zidong.Wang@auckland.ac.nz; Grimson, Malcolm J. [Department of Physics, The University of Auckland, Auckland 1010 (New Zealand)

    2016-03-28

    Composite multiferroics, heterostructures of ferromagnetic and ferroelectric materials, are characterized by a remarkable magnetoelectric effect at the interface. Previous work has supported the ferromagnetic structure with magnetic spins and the ferroelectric with pseudospins which act as electric dipoles in a microscopic model, coupled with a magnetoelectric interaction [Wang and Grimson, J. Appl. Phys. 118, 124109 (2015)]. In this work, by solving the stochastic Landau-Lifshitz-Gilbert equation, the electric-field-induced magnetization switching in a twisted boundary condition has been studied, and a behavior of domain wall in the ferromagnetic structure is discussed.

  20. Filho et al., Afr J Tradit Complement Altern Med. (2014) 11(3):30-37 30

    African Journals Online (AJOL)

    cadewumi

    Background: Chinese meridian system of acupuncture has recently been deciphered as the fractal continuum of neurovascular bundles and its smaller branches. The corresponding acupuncture mechanism of therapeutics has been attributed to the magneto-electric inductive effects of the meridian system via chaotic wave ...

  1. Various properties of the 0.6BaTiO3–0.4Ni0.5Zn0.5Fe2O4 ...

    Indian Academy of Sciences (India)

    2016-09-06

    Sep 6, 2016 ... This property pro- motes the magnetoelectric energy conversion and thus ... Wet mixing was done with ethanol to obtain a homogeneous powder mix- ... rite was prepared by mixing NiO, ZnO and Fe2O3 in. 0.5:0.5:1 molar ...

  2. Anomalous spin waves and the commensurate-incommensurate magnetic phase transition in LiNiPO4

    DEFF Research Database (Denmark)

    Jensen, Thomas Bagger Stibius; Christensen, Niels Bech; Kenzelmann, M.

    2009-01-01

    Detailed spin-wave spectra of magnetoelectric LiNiPO4 have been measured by neutron scattering at low temperatures in the commensurate (C) antiferromagnetic (AF) phase below T-N=20.8 K. An anomalous shallow minimum is observed at the modulation vector of the incommensurate (IC) AF phase appearing...

  3. The Mechanism Of Auriculotherapy: A Case Report Based On The ...

    African Journals Online (AJOL)

    The Mechanism Of Auriculotherapy: A Case Report Based On The Fractal Structure Of Meridian System. ... The corresponding acupuncture mechanism of therapeutics has been attributed to the magneto-electric inductive effects of the meridian system via chaotic wave of nerve innervations and blood flow. Hence, based on ...

  4. The local density of optical states of a metasurface

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Koenderink, A. Femius

    2016-01-01

    -dimensional (2D) lattice composed of arbitrary magnetoelectric dipole scatterers. The method takes into account radiation damping as well as all retarded electrodynamic interactions in a self-consistent manner. We show that a lattice of magnetic scatterers evidences characteristic Drexhage oscillations. However...

  5. On the Huygens principle for bianisotropic mediums with symmetric permittivity and permeability dyadics

    Energy Technology Data Exchange (ETDEWEB)

    Faryad, Muhammad, E-mail: muhammad.faryad@lums.edu.pk [Department of Physics, Lahore University of Management Sciences, Lahore 54792 (Pakistan); Lakhtakia, Akhlesh [Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2017-02-19

    Mathematical statements of the Huygens principle relate the electric and magnetic field phasors at an arbitrary location in a source-free region enclosed by a surface to the tangential components of the electric and magnetic field phasors over that surface, via the dyadic Green functions applicable to the linear homogeneous medium occupying that region. We have mathematically formulated the Huygens principle for the electric and magnetic field phasors when the permittivity and permeability dyadics of the medium are symmetric, the symmetric parts of the two magnetoelectric dyadics of the medium are negative of each other, and both magnetoelectric dyadics also contain anti-symmetric terms. We have also formulated the Huygens principle for the electric (resp. magnetic) field phasor in a medium whose permittivity (resp. permeability) is scalar, the permeability (resp. permittivity) is symmetric, the symmetric parts of the two magnetoelectric dyadics reduce to dissimilar scalars, and anti-symmetric parts of the two magnetoelectric dyadics are identical. - Highlights: • The Huygens principle was formulated for bianistropic mediums when the permittivity and permeability dyadics of the medium are symmetric. • The formulation covers isotropic, biisotropic, and gyrotropic-like uniaxial mediums for which the Huygens principle is already available. • The formulation also covers new mediums like biaxial, chiro-omega, pseudo chiral, gyrotropic-like biaxial, and Lorentz reciprocal mediums.

  6. Synthesis of BiFeO 3 by carbonate precipitation

    Indian Academy of Sciences (India)

    Magnetoelectric multiferroic BiFeO3 (BFO) was synthesized by a simple carbonate precipitation technique of metal nitrate solutions. X-ray powder diffraction and thermo-gravimetric analysis (TGA) revealed that the precipitate consists of an intimate mixture of crystalline bismuth carbonate and an amorphous hydroxide of ...

  7. Magnetic and dielectric properties of hexagonal InMnO.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Belik, A.A.; Kamba, Stanislav; Savinov, Maxim; Nuzhnyy, Dmitry; Tachibana, M.; Takayama-Muromachi, E.; Goian, Veronica

    2009-01-01

    Roč. 79, č. 5 (2009), 054411/1-054411/7 ISSN 1098-0121 R&D Projects: GA ČR(CZ) GA202/09/0682 Institutional research plan: CEZ:AV0Z10100520 Keywords : magnetoelectric multiferroics * phase transitions * dielectric spectroscopy * magnetic properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.475, year: 2009

  8. Ferroelectricity Induced by Acentric Spin-Density Waves in YMn2O5

    NARCIS (Netherlands)

    Chapon, L.C.; Radaelli, P.G.; Blake, G.R.; Park, S.; Cheong, S.-W.

    2006-01-01

    The commensurate and incommensurate magnetic structures of the magnetoelectric system YMn2O5, as determined from neutron diffraction, were found to be spin-density waves lacking a global center of symmetry. We propose a model, based on a simple magnetoelastic coupling to the lattice, which enables

  9. Characterization of energy conversion of multiferroic PFN and PFN:Mn

    Directory of Open Access Journals (Sweden)

    Lucjan Kozielski

    2013-12-01

    Full Text Available Characterization of energy conversion of multiferroic materials is concerned with multifunctional properties of materials, a topic that is fascinating from the scientific point of view and important for the modern technology. The complex characterization of multiferroic structures suffers at present from lack of a systematic experimental approach and deficiency of multifunctional magnetoelectric properties testing capabilities. Compactness and high frequency energy conversion capacity are the main reasons of invention and improvement of sophisticated materials which are prepared for high-speed computer memories and broadband transducer devices. As a consequence, one can easily notice an intense search for new materials for generation, transformation and amplification of magnetic and electric energies. In this scenario, the combination of excellent piezoelectric and magnetic properties makes lead iron niobate Pb(Fe1/2Nb1/2O3 (PFN an attractive host material for application in integrated magnetoelectric energy conversion applications. PFN multiferroic materials are attractive for commercial electroceramics due to high value of dielectric permittivity and magnetoelectric coefficients as well as relatively easy synthesis process. However, synthesis of PFN ceramics is mostly connected with formation of the secondary unwanted pyrochlore phase associated with dramatic decrease of ferroelectric properties. The authors have successfully reduced this negative phenomenon by Mn doping and finally present high piezoelectric and magnetoelectric energy conversion efficiency in fabricated PMFN ceramics.

  10. Exploring Electrical and Magnetic Resonances from Coherently Correlated Long-Lived Radical Pairs towards Development of Negative Refractive-Index Materials

    Science.gov (United States)

    2015-01-03

    Bin Hu Brazil -MRS meeting, Campos do Jordao, September 30 – October 04, 2013 (10) Magneto-Optic, Magneto-Electric, and Magneto-Thermoelectric...Solar Cells Bin Hu 2013 TechConnect World, National Innovation Summit and National SBIR Conference, Gaylord Hotel , National Harbor, Maryland, May

  11. Exploring Novel Spintronic Responses from Advanced Functional Organic Materials

    Science.gov (United States)

    2015-11-12

    States in Organic Semiconductors Bin Hu Brazil -MRS meeting, Campos do Jordao, September 30 – October 04, 2013 (10) Magneto-Optic, Magneto-Electric, and...Photovoltaic Processes in Organic Solar Cells Bin Hu 2013 TechConnect World, National Innovation Summit and National SBIR Conference, Gaylord Hotel , National

  12. Room-temperature multiferroic and magnetocapacitance effects in M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19}

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Rujun, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn; Zhou, Hao; You, Wenlong [Jiangsu Key Laboratory of Thin Films, College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China); Yang, Hao, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 211106 (China)

    2016-08-22

    The room-temperature multiferroic and magnetocapacitance (MC) effects of polycrystalline M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} have been investigated. The results show that the magnetic moments of insulating BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} can be manipulated by the electric field at room temperature, indicating the existence of magnetoelectric coupling. Moreover, large MC effects are also observed around the room temperature. A frequency dependence analysis shows that the Maxwell-Wagner type magnetoresistance effect is the dominant mechanism for MC effects at low frequencies. Both the magnetoelectric-type and non-magnetoelectric-type spin-phonon couplings contribute to the MC effects at high frequencies with the former being the dominant mechanism. The above results show that the hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} is a room-temperature multiferroic material that can be potentially used in magnetoelectric devices.

  13. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Pramana – Journal of Physics; Volume 58; Issue 5-6. Size effect study in magnetoelectric BiFeO3 system. Shwetha Shetty V R Palkar R Pinto. Colossal Magnetoresistance & Other Materials Volume 58 Issue 5-6 May-June 2002 pp 1027-1030 ...

  14. Electric field stimulation setup for photoemission electron microscopes.

    Science.gov (United States)

    Buzzi, M; Vaz, C A F; Raabe, J; Nolting, F

    2015-08-01

    Manipulating magnetisation by the application of an electric field in magnetoelectric multiferroics represents a timely issue due to the potential applications in low power electronics and the novel physics involved. Thanks to its element sensitivity and high spatial resolution, X-ray photoemission electron microscopy is a uniquely suited technique for the investigation of magnetoelectric coupling in multiferroic materials. In this work, we present a setup that allows for the application of in situ electric and magnetic fields while the sample is analysed in the microscope. As an example of the performances of the setup, we present measurements on Ni/Pb(Mg(0.66)Nb(0.33))O3-PbTiO3 and La(0.7)Sr(0.3)MnO3/PMN-PT artificial multiferroic nanostructures.

  15. The Influence of the Optical Phonons on the Non-equilibrium Spin Current in the Presence of Spin-Orbit Couplings

    Science.gov (United States)

    Hasanirokh, K.; Phirouznia, A.; Majidi, R.

    2016-02-01

    The influence of the electron coupling with non-polarized optical phonons on magnetoelectric effects of a two-dimensional electron gas system has been investigated in the presence of the Rashba and Dresselhaus spin-orbit couplings. Numerical calculations have been performed in the non-equilibrium regime. In the previous studies in this field, it has been shown that the Rashba and Dresselhaus couplings cannot generate non-equilibrium spin current and the spin current vanishes identically in the absence of other relaxation mechanisms such as lattice vibrations. However, in the current study, based on a semiclassical approach, it was demonstrated that in the presence of electron-phonon coupling, the spin current and other magnetoelectric quantities have been modulated by the strength of the spin-orbit interactions.

  16. Induced motion of domain walls in multiferroics with quadratic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimchuk, Victor S., E-mail: viktor.gera@gmail.com [National Technical University of Ukraine “Kyiv Polytechnic Institute”, Peremohy Avenue 37, 03056 Kiev (Ukraine); Shitov, Anatoliy A., E-mail: shitov@mail.ru [Donbass National Academy of Civil Engineering, Derzhavina Street 2, 86123 Makeevka, Donetsk Region (Ukraine)

    2013-10-15

    We theoretically study the dynamics of 180-degree domain wall of the ab-type in magnetic materials with quadratic magnetoelectric interaction in external alternating magnetic and electric fields. The features of the oscillatory and translational motions of the domain walls and stripe structures depending on the parameters of external fields and characteristics of the multiferroics are discussed. The possibility of the domain walls drift in a purely electric field is established. - Highlights: • We study DW and stripe DS in multiferroics with quadratic magnetoelectric interaction. • We build up the theory of oscillatory and translational (drift) DW and DS motion. • DW motion can be caused by crossed alternating electric and magnetic fields. • DW motion can be caused by alternating “pure” electric field. • DW drift velocity is formed by the AFM and Dzyaloshinskii interaction terms.

  17. Neutron diffraction and low temperature magnetization study of Tb0.8Y0.2MnO3

    International Nuclear Information System (INIS)

    Chakraborty, Keka R.; Mukadam, M.; Yusuf, S.M.; Shukla, R.; Tyagi, A.K.; Kaushik, S.D.; Siruguri, V.

    2012-01-01

    Multiferroic materials possess mutually correlated magnetic and electric order parameters which are suitable for device applications but scarcity of such materials and the separation of magnetic and electric ordering temperatures are a major hindrance in technological applications. TbMnO 3 is one of the material which is reported to have higher magnetoelectric coupling. Structurally, TbMnO 3 crystallizes in orthorhombically distorted perovskite structure (space group Pbnm). For TbMnO 3 , several reports are available in the literature which further modify the magnetoelectric coupling by selective doping or reducing the particle size to nano dimensions, or preparing thin films. Here, we study the effect of Y doping at Tb site in nanoparticle form in terms of crystal structure and magnetic properties. Nanoparticles of Tb 0.8 Y 0.2 MnO 3 were synthesized using the gel combustion technique. Crystal structure of this sample is studied at 300 K using neutron diffraction

  18. Electric field control of magnetism using BiFeO3-based heterostructures

    International Nuclear Information System (INIS)

    Heron, J. T.; Schlom, D. G.; Ramesh, R.

    2014-01-01

    Conventional CMOS based logic and magnetic based data storage devices require the shuttling of electrons for data processing and storage. As these devices are scaled to increasingly smaller dimensions in the pursuit of speed and storage density, significant energy dissipation in the form of heat has become a center stage issue for the microelectronics industry. By taking advantage of the strong correlations between ferroic orders in multiferroics, specifically the coupling between ferroelectric and magnetic orders (magnetoelectricity), new device functionalities with ultra-low energy consumption can be envisioned. In this article, we review the advances and highlight challenges toward this goal with a particular focus on the room temperature magnetoelectric multiferroic, BiFeO 3 , exchange coupled to a ferromagnet. We summarize our understanding of the nature of exchange coupling and the mechanisms of the voltage control of ferromagnetism observed in these heterostructures

  19. The electric field manipulation of magnetization in La{sub 1−x}Sr{sub x}CoO{sub 3}/Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q. M.; Li, Q.; Zhou, W. P.; Wang, L. Y.; Yang, Y. T.; Wang, D. H., E-mail: wangdh@nju.edu.cn; Lv, L. Y.; Du, Y. W. [Jiangsu Key Laboratory for Nano Technology and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Gao, R. L. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China)

    2014-04-07

    La{sub 1−x}Sr{sub x}CoO{sub 3} (x = 0.18, 0.33, and 0.5) films were grown epitaxially on piezoelectric Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} substrates by pulsed laser deposition. The magnetization of these films varies with the external electric field, showing the magnetoelectric effect. With different doping content of Sr{sup 2+} ions, the change of magnetization for these films show different behaviors with increasing temperature, which can be attributed to the competition between electric-field-induced changes of spin state and double exchange interaction. This work presents an alternative mechanism to investigate the electric field control of magnetism in magnetoelectric heterostructure by tuning the spin state.

  20. Terfenol-D/Pb(Zr,Ti)O{sub 3} disk-ring multiferroic heterostructures coupled through normal stresses

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lei; Chen, Xiang Ming [Zhejiang University, Laboratory of Dielectric Materials, Department of Materials Science and Engineering, Hangzhou (China)

    2010-03-15

    Disk-ring multiferroic heterostructures composed of Terfenol-D and Pb(Zr,Ti)O{sub 3} (PZT) were prepared and characterized, for which the ferromagnetic and ferroelectric phases were coupled through normal stresses instead of the shear stresses that acted in most of the previous multiferroic heterostructures. High low-frequency magnetoelectric coefficients of 0.10-0.75 V cm{sup -1} Oe{sup -1} were attained for the disk-ring heterostructures, which indicated the strong magnetoelectric coupling. Moreover, a symmetrical resonant peak was observed for dE{sub 3}/dH{sub 3} in the frequency range of 1-200 kHz, while another weak peak with asymmetrical shape also existed at a lower frequency for dE{sub 3}/dH{sub 1}, which was due to the combination of two vibration modes. (orig.)

  1. Electric field control of magnon-induced magnetization dynamics in multiferroics.

    Science.gov (United States)

    Risinggård, Vetle; Kulagina, Iryna; Linder, Jacob

    2016-08-24

    We consider theoretically the effect of an inhomogeneous magnetoelectric coupling on the magnon-induced dynamics of a ferromagnet. The magnon-mediated magnetoelectric torque affects both the homogeneous magnetization and magnon-driven domain wall motion. In the domains, we predict a reorientation of the magnetization, controllable by the applied electric field, which is almost an order of magnitude larger than that observed in other physical systems via the same mechanism. The applied electric field can also be used to tune the domain wall speed and direction of motion in a linear fashion, producing domain wall velocities several times the zero field velocity. These results show that multiferroic systems offer a promising arena to achieve low-dissipation magnetization rotation and domain wall motion by exciting spin-waves.

  2. Collaborative Research: Polymeric Multiferroics

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Shenqiang [Temple Univ., Philadelphia, PA (United States). College of Engineering

    2017-04-20

    The goal of this project is to investigate room temperature magnetism and magnetoelectric coupling of polymeric multiferroics. A new family of molecular charge-transfer crystals has been emerged as a fascinating opportunity for the development of all-organic electrics and spintronics due to its weak hyperfine interaction and low spin-orbit coupling; nevertheless, direct observations of room temperature magnetic spin ordering have yet to be accomplished in organic charge-transfer solids. Furthermore, room temperature magnetoelectric coupling effect hitherto known multiferroics, is anticipated in organic donor-acceptor complexes because of magnetic field effects on charge-transfer dipoles, yet this is also unexplored. The PI seeks to fundamental understanding of the control of organic crystals to demonstrate and explore room temperature multiferroicity. The experimental results have been verified through the theoretical modeling.

  3. Concurrent transition of ferroelectric and magnetic ordering near room temperature.

    Science.gov (United States)

    Ko, Kyung-Tae; Jung, Min Hwa; He, Qing; Lee, Jin Hong; Woo, Chang Su; Chu, Kanghyun; Seidel, Jan; Jeon, Byung-Gu; Oh, Yoon Seok; Kim, Kee Hoon; Liang, Wen-I; Chen, Hsiang-Jung; Chu, Ying-Hao; Jeong, Yoon Hee; Ramesh, Ramamoorthy; Park, Jae-Hoon; Yang, Chan-Ho

    2011-11-29

    Strong spin-lattice coupling in condensed matter gives rise to intriguing physical phenomena such as colossal magnetoresistance and giant magnetoelectric effects. The phenomenological hallmark of such a strong spin-lattice coupling is the manifestation of a large anomaly in the crystal structure at the magnetic transition temperature. Here we report that the magnetic Néel temperature of the multiferroic compound BiFeO(3) is suppressed to around room temperature by heteroepitaxial misfit strain. Remarkably, the ferroelectric state undergoes a first-order transition to another ferroelectric state simultaneously with the magnetic transition temperature. Our findings provide a unique example of a concurrent magnetic and ferroelectric transition at the same temperature among proper ferroelectrics, taking a step toward room temperature magnetoelectric applications.

  4. Final Technical Report: Collaborative Research. Polymeric Muliferroics

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Shenqiang [Univ. of Kansas, Lawrence, KS (United States)

    2015-06-05

    The goal of this project is to investigate room temperature magnetism and magnetoelectric coupling of polymeric multiferroics. A new family of organic charge-transfer complexes has been emerged as a fascinating opportunity for the development of all-organic electrics and spintronics due to its weak hyperfine interaction and low spin-orbit coupling; nevertheless, direct observations of room temperature magnetic spin ordering have yet to be accomplished in organic charge-transfer complexes. Furthermore, room temperature magnetoelectric coupling effect hitherto known multiferroics, is anticipated in organic donor-acceptor complexes because of magnetic field effects on charge-transfer dipoles, yet this is also unexplored. The PIs seek to fundamental understanding of the synthetic control of organic complexes to demonstrate and explore room temperature multiferroicity.

  5. Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

    International Nuclear Information System (INIS)

    Ju, S; Chae, S H; Choi, Y; Jun, S; Park, S M; Lee, S; Ji, C-H; Lee, H W

    2013-01-01

    This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken

  6. Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

    Science.gov (United States)

    Ju, S.; Chae, S. H.; Choi, Y.; Jun, S.; Park, S. M.; Lee, S.; Lee, H. W.; Ji, C.-H.

    2013-12-01

    This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken.

  7. Magnetocrystalline anisotropy and its electric-field-assisted switching of Heusler-compound-based perpendicular magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Bai, Zhaoqiang; Wu, Qingyun; Zeng, Minggang; Feng, Yuan Ping; Shen, Lei; Cai, Yongqing; Han, Guchang

    2014-01-01

    Employing density functional theory combined with the non-equilibrium Green's function formalism, we systematically investigate the structural, magnetic and magnetoelectric properties of the Co 2 FeAl(CFA)/MgO interface, as well as the spin-dependent transport characteristics of the CFA/MgO/CFA perpendicular magnetic tunnel junctions (p-MTJs). We find that the structure of the CFA/MgO interface with the oxygen-top FeAl termination has high thermal stability, which is protected by the thermodynamic equilibrium limit. Furthermore, this structure is found to have perpendicular magnetocrystalline anisotropy (MCA). Giant electric-field-assisted modifications of this interfacial MCA through magnetoelectric coupling are demonstrated with an MCA coefficient of up to 10 −7 erg V −1 cm. In addition, our non-collinear spin transport calculations of the CFA/MgO/CFA p-MTJ predict a good magnetoresistance performance of the device. (paper)

  8. Temperature dependence of electric field tunable ferromagnetic resonance lineshape in multiferroic heterostructure

    Directory of Open Access Journals (Sweden)

    Fenglong Wang

    2016-11-01

    Full Text Available Herein, we experimentally investigate the effect of temperature on the electric field tunable ferromagnetic resonance (FMR in a ferroelectric/ferromagnetic heterostructure, and demonstrate the tuning of abnormal change in FMR using the polarization of the ferroelectric layer above 200 K. The FMR was found to be almost unchanged under different electric field strength at 100 K owing to frozen polarization, which causes extremely weak magnetoelectric coupling. More interestingly, negative effective linewidth was observed when an electric field greater than 10 kV/cm was applied above 220 K. The simultaneous electrical control of magnetization and its damping via FMR based on linear magnetoelectric coupling are directly relevant to use of composite multiferroics for a wide range of devices.

  9. Ferroelectricity driven magnetism at domain walls in LaAlO3/PbTiO3 superlattices

    Science.gov (United States)

    Zhou, P. X.; Dong, S.; Liu, H. M.; Ma, C. Y.; Yan, Z. B.; Zhong, C. G.; Liu, J. -M.

    2015-01-01

    Charge dipole moment and spin moment rarely coexist in single-phase bulk materials except in some multiferroics. Despite the progress in the past decade, for most multiferroics their magnetoelectric performance remains poor due to the intrinsic exclusion between charge dipole and spin moment. As an alternative approach, the oxide heterostructures may evade the intrinsic limits in bulk materials and provide more attractive potential to realize the magnetoelectric functions. Here we perform a first-principles study on LaAlO3/PbTiO3 superlattices. Although neither of the components is magnetic, magnetic moments emerge at the ferroelectric domain walls of PbTiO3 in these superlattices. Such a twist between ferroelectric domain and local magnetic moment, not only manifests an interesting type of multiferroicity, but also is possible useful to pursuit the electrical-control of magnetism in nanoscale heterostructures. PMID:26269322

  10. Magnetic Field Control of Cycloidal Domains and Electric Polarization in Multiferroic BiFeO3

    Science.gov (United States)

    Bordács, S.; Farkas, D. G.; White, J. S.; Cubitt, R.; DeBeer-Schmitt, L.; Ito, T.; Kézsmárki, I.

    2018-04-01

    The magnetic field induced rearrangement of the cycloidal spin structure in ferroelectric monodomain single crystals of the room-temperature multiferroic BiFeO3 is studied using small-angle neutron scattering. The cycloid propagation vectors are observed to rotate when magnetic fields applied perpendicular to the rhombohedral (polar) axis exceed a pinning threshold value of ˜5 T . In light of these experimental results, a phenomenological model is proposed that captures the rearrangement of the cycloidal domains, and we revisit the microscopic origin of the magnetoelectric effect. A new coupling between the magnetic anisotropy and the polarization is proposed that explains the recently discovered magnetoelectric polarization perpendicular to the rhombohedral axis.

  11. Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator.

    Science.gov (United States)

    Wu, Liang; Salehi, M; Koirala, N; Moon, J; Oh, S; Armitage, N P

    2016-12-02

    Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi 2 Se 3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry's phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system. Copyright © 2016, American Association for the Advancement of Science.

  12. Magnetocapacitance effects in MnZn ferrites

    Directory of Open Access Journals (Sweden)

    Y. M. Xu

    2015-11-01

    Full Text Available The magnetocapacitance effects of MnZn ferrites with different initial permeabilities have been studied systematically. Both intrinsic effect associated with magnetoelectric coupling and extrinsic effect, which means the combined contribution of magnetoresistance and the Maxwell-Wagner effect, have been observed simultaneously. Analysis shows that the relationship between the origins of both is in competitive equilibrium. Either of both mechanisms plays a dominant role in magnetocapacitance effects under different conditions, respectively, such as permeability and frequency of applied signals.

  13. Ultrafast modulation of near-field heat transfer with tunable metamaterials

    OpenAIRE

    Cui, Longji; Huang, Yong; Wang, Ju; Zhu, Ke-Yong

    2012-01-01

    We propose a mechanism of active near-field heat transfer modulation relying on externally tunable metamaterials. A large modulation effect is observed and can be explained by the coupling of surface modes, which is dramatically varied in the presence of controllable magnetoelectric coupling in metamaterials. We finally discuss how a practical picosecond-scale thermal modulator can be made. This modulator allows manipulating nanoscale heat flux in an ultrafast and noncontact (by optical means...

  14. Introducing Magneto-Optical Functions into Soft Materials

    Science.gov (United States)

    2017-05-03

    including organic and bio materials by using magnetic nanomaterials. This final report includes the successful developments of magneto-optical... successful developments of magneto-optical properties in both organic and bio magnetic nanocomposites during the project period of three years...proteins on the photoluminescence of nanodiamond. J. Appl . Phys. 2011, 109 (3), 034704. 7, Xu, H.; Hung, C.E.; Cheng, C.L.; Hu, B., Magneto-electric

  15. Materials on the brink: unprecedented transforming materials

    Science.gov (United States)

    2013-09-10

    2013 56.00 Shenqiang Ren\\, Manfred Wuttig. Spinodal synthesis of PZT /NFO magnetoelectric, Applied Physics Letters, (08 2007): 83501. doi: 02/06/2013... PZT . This material was discovered through a combinatorial search. Rabe et al. have used first principles methods to show that this morphotropic...temperature. James et al. have suggested a new strategy for energy recovery from waste heat using this alloy. • Discovery of a new fatigue -free shape

  16. Low-frequency characteristics extension for vibration sensors

    Institute of Scientific and Technical Information of China (English)

    杨学山; 高峰; 候兴民

    2004-01-01

    Traditional magneto-electric vibration sensors and servo accelerometers have severe shortcomings when used to measure vibration where low frequency components predominate. A low frequency characteristic extension for velocity vibration sensors is presented in this paper. The passive circuit technology, active compensation technology and the closedcycle pole compensation technology are used to extend the measurable range and to improve low frequency characteristics of sensors. Thses three types of low frequency velocity vibration sensors have been developed and widely adopted in China.

  17. Disclosure of double exchange bias effect in chromium (III) oxide nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Rinaldi-Montes, N.; Gorria, P.; Fuertes, A.B.; Martinez-Blanco, D.; Olivi, L.; Puente-Orench, I.; Alonso, J.M.; Phan, M.-H.; Skrikanth, H.; Martí, Xavier; Blanco, J.A.

    2017-01-01

    Roč. 53, č. 1 (2017), s. 1-4, č. článku 2300204. ISSN 0018-9464 R&D Projects: GA ČR GB14-37427G Institutional support: RVO:68378271 Keywords : antiferromagnetism * exchange bias (EB) * magnetic nanoparticles * magnetoelectric effect Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.243, year: 2016

  18. Spectroscopic studies of the ferroelectric and magnetic phase transitions in multiferroic Sr.sub.1-x./sub.Ba.sub.x./sub.MnO.sub.3./sub.

    Czech Academy of Sciences Publication Activity Database

    Goian, Veronica; Kadlec, Filip; Kadlec, Christelle; Dabrowski, B.; Kolesnik, S.; Chmaissem, O.; Nuzhnyy, Dmitry; Kempa, Martin; Bovtun, Viktor; Savinov, Maxim; Hejtmánek, Jiří; Prokleška, J.; Kamba, Stanislav

    2016-01-01

    Roč. 28, č. 17 (2016), 1-7, č. článku 175901. ISSN 0953-8984 R&D Projects: GA ČR GP14-14122P; GA ČR GA15-08389S; GA MŠk(CZ) LH15122 Institutional support: RVO:68378271 Keywords : multiferroics * soft and central modes * phonons * magnetoelectric effect * spin-phonon effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.649, year: 2016

  19. Ferroelectric control of magnetization in BiFeO3/CoFe heterostructures.

    Science.gov (United States)

    Gajek, Martin; Martin, Lane; Heron, John; Seidel, Jan; Ramesh, Ramamoorthy

    2009-03-01

    The cross coupling between ferroic order parameters in multiferroics opens an alternative for the control of magnetism in magnetoelectric devices by purely electrical means. We first report on the exchange coupling between BiFeO3, an antiferromagnetic ferroelectric , and CoFe. We then show that the domain structure of the ferromagnet can be changed by poling the ferroelectric layer. Finally, we will discuss the implementation of our findings into possible device schemes.

  20. Electric-Field-Induced Magnetization Reversal in a Ferromagnet-Multiferroic Heterostructure

    Science.gov (United States)

    Heron, J. T.; Trassin, M.; Ashraf, K.; Gajek, M.; He, Q.; Yang, S. Y.; Nikonov, D. E.; Chu, Y.-H.; Salahuddin, S.; Ramesh, R.

    2011-11-01

    A reversal of magnetization requiring only the application of an electric field can lead to low-power spintronic devices by eliminating conventional magnetic switching methods. Here we show a nonvolatile, room temperature magnetization reversal determined by an electric field in a ferromagnet-multiferroic system. The effect is reversible and mediated by an interfacial magnetic coupling dictated by the multiferroic. Such electric-field control of a magnetoelectric device demonstrates an avenue for next-generation, low-energy consumption spintronics.

  1. Colossal Magnetoresistance Manganites and Related Prototype Devices

    OpenAIRE

    Liu, Yukuai; Yin, Yuewei; Li, Xiaoguang

    2013-01-01

    We review colossal magnetoresistance in single phase manganites, as related to the field sensitive spin charge interactions and phase separation; the rectifying property and negative/positive magnetoresistance in manganite/Nb:SrTiO3 pn junctions in relation to the special interface electronic structure; magnetoelectric coupling in manganite/ferroelectric structures that takes advantage of strain, carrier density, and magnetic field sensitivity; tunneling magnetoresistance in tunnel junctions ...

  2. The Symmetry of Multiferroics

    OpenAIRE

    Harris, A. Brooks

    2006-01-01

    This paper represents a detailed instruction manual for constructing the Landau expansion for magnetoelectric coupling in incommensurate ferroelectric magnets. The first step is to describe the magnetic ordering in terms of symmetry adapted coordinates which serve as complex valued magnetic order parameters whose transformation properties are displayed. In so doing we use the previously proposed technique to exploit inversion symmetry, since this symmetry had been universally overlooked. Havi...

  3. Giant multiferroic effects in topological GeTe-Sb2Te3 superlattices

    International Nuclear Information System (INIS)

    Tominaga, Junji; Kolobov, Alexander V; Fons, Paul J; Wang, Xiaomin; Saito, Yuta; Nakano, Takashi; Hase, Muneaki; Murakami, Shuichi; Herfort, Jens; Takagaki, Yukihiko

    2015-01-01

    Multiferroics, materials in which both magnetic and electric fields can induce each other, resulting in a magnetoelectric response, have been attracting increasing attention, although the induced magnetic susceptibility and dielectric constant are usually small and have typically been reported for low temperatures. The magnetoelectric response usually depends on d-electrons of transition metals. Here we report that in [(GeTe) 2 (Sb 2 Te 3 ) l ] m superlattice films (where l and m are integers) with topological phase transition, strong magnetoelectric response may be induced at temperatures above room temperature when the external fields are applied normal to the film surface. By ab initio computer simulations, it is revealed that the multiferroic properties are induced due to the breaking of spatial inversion symmetry when the p-electrons of Ge atoms change their bonding geometry from octahedral to tetrahedral. Finally, we demonstrate the existence in such structures of spin memory, which paves the way for a future hybrid device combining nonvolatile phase-change memory and magnetic spin memory. (focus issue paper)

  4. Magnetodielectric coupling in multiferroic holmium iron garnets

    International Nuclear Information System (INIS)

    Malar Selvi, M.; Chakraborty, Deepannita; Venkateswaran, C.

    2017-01-01

    Single phase magneto-electric multiferroics require a large magnetic or electric field for producing magneto-electric (ME) and magnetodielectric (MD) effects. For utilizing these effects in devices investigations on the room temperature and low field MD studies are necessary. Recently, efforts have been largely devoted to the investigation of rare earth iron garnets. In the physical method, the preparation of rare earth iron garnet requires high sintering temperature and processing time. To solve these problems, ball milling assisted microwave sintering technique is used to prepare nanocrystalline holmium iron garnets (Ho_3Fe_5O_1_2). Magnetic and dielectric properties of the prepared sample are investigated. These properties get enhanced in nanocrystalline form when compared to the bulk. The MD coupling of the prepared sample is evident from the anomaly in the temperature dependent dielectric constant plot and the ME coupling susceptibility is derived from the room temperature MD measurements. - Highlights: • Formation of single phase Holmium iron garnet reported. • Ball milling assisted microwave sintering reduces the sintering temperature and time. • Holmium iron garnet shows enhanced magnetic and dielectric properties. • Pyromagnetic and pyroelectric measurements confirm the magnetoelectric coupling. • Room temperature magnetodielectric measurements show the nonlinear behaviour.

  5. An X-ray absorption spectroscopic study of the metal site preference in Al1-xGaxFeO3

    Science.gov (United States)

    Walker, James D. S.; Grosvenor, Andrew P.

    2013-01-01

    Magnetoelectric materials have potential for being introduced into next generation technologies, especially memory devices. The AFeO3 (Pna21; A=Al, Ga) system has received attention to better understand the origins of magnetoelectric coupling. The magnetoelectric properties this system exhibits depend on the amount of anti-site disorder present, which is affected by the composition and the method of synthesis. In this study, Al1-xGaxFeO3 was synthesized by the ceramic method and studied by X-ray absorption spectroscopy. Al L2,3-, Ga K-, and Fe K-edge spectra were collected to examine how the average metal coordination number changes with composition. Examination of XANES spectra from Al1-xGaxFeO3 indicate that with increasing Ga content, Al increasingly occupies octahedral sites while Ga displays a preference for occupying the tetrahedral site. The Fe K-edge spectra indicate that more Fe is present in the tetrahedral site in AlFeO3 than in GaFeO3, implying more anti-site disorder is present in AlFeO3.

  6. Symmetry, incommensurate magnetism and ferroelectricity: The case of the rare-earth manganites RMnO3

    International Nuclear Information System (INIS)

    Ribeiro, J L

    2010-01-01

    The complete irreducible co-representations of the paramagnetic space group provide a simple and direct path to explore the symmetry restrictions of magnetically driven ferroelectricity. The method consists of a straightforward generalization of the method commonly used in the case of displacive modulated systems and allows us to determine, in a simple manner, the full magnetic symmetry of a given phase originated from a given magnetic order parameter. The potential ferroic and magneto-electric properties of that phase can then be established and the exact Landau free energy expansions can be derived from general symmetry considerations. In this work, this method is applied to the case of the orthorhombic rare-earth manganites RMnO 3 . This example will allow us to stress some specific points, such as the differences between commensurate or incommensurate magnetic phases regarding the ferroic and magnetoelectric properties, the possible stabilization of ferroelectricity by a single irreducible order parameter or the possible onset of a polarization oriented parallel to the magnetic modulation. The specific example of TbMnO 3 will be considered in more detail, in order to characterize the role played by the magneto-electric effect in the mechanism for the polarization rotation induced by an external magnetic field.

  7. Landau-Ginzburg description of anomalous properties of novel room temperature multiferroics Pb(Fe{sub 1/2}Ta{sub 1/2}){sub x}(Zr{sub 0.53}Ti{sub 0.47}){sub 1-x}O{sub 3} and Pb(Fe{sub 1/2}Nb{sub 1/2}){sub x}(Zr{sub 0.53}Ti{sub 0.47}){sub 1−x}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Glinchuk, Maya D.; Eliseev, Eugene A. [Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Krjijanovskogo 3, 03142 Kyiv (Ukraine); Morozovska, Anna N., E-mail: anna.n.morozovska@gmail.com [Institute of Physics, National Academy of Sciences of Ukraine, 46, pr. Nauky, 03028 Kyiv (Ukraine)

    2016-01-14

    Landau-Ginzburg thermodynamic formalism is used for the description of the anomalous ferroelectric, ferromagnetic, and magnetoelectric properties of Pb(Fe{sub 1/2}Ta{sub 1/2}){sub x}(Zr{sub 0.53}Ti{sub 0.47}){sub 1−x}O{sub 3} and Pb(Fe{sub 1/2}Nb{sub 1/2}){sub x}(Zr{sub 0.53}Ti{sub 0.47}){sub 1−x}O{sub 3} micro-ceramics. We calculated temperature, composition, and external field dependences of ferroelectric, ferromagnetic, and antiferromagnetic phases transition temperatures, remanent polarization, magnetization, hysteresis loops, dielectric permittivity, and magnetoelectric coupling. Special attention was paid to the comparison of developed theory with experiments. It appeared possible to describe adequately main experimental results including a reasonable agreement between the shape of calculated and measured hysteresis loops and remnant polarization. Since Landau-Ginzburg thermodynamic formalism appertains to single domain properties of a ferroic, we did not aim to describe quantitatively the coercive field under the presence of realistic poly-domain switching. Information about linear and nonlinear magnetoelectric coupling coefficients was extracted from the experimental data. From the fitting of experimental data with theoretical formula, we obtained the composition dependence of Curie-Weiss constant that is known to be inversely proportional to harmonic (linear) dielectric stiffness, as well as the strong nonlinear dependence of anharmonic parameters in free energy. Keeping in mind the essential influence of these parameters on multiferroic properties, the obtained results open the way to govern practically all the material properties with the help of suitable composition choice. A forecast of the strong enough influence of antiferrodistortive order parameter on the transition temperatures and so on the phase diagrams and properties of multiferroics are made on the basis of the developed theory.

  8. Potentials and challenges of integration for complex metal oxides in CMOS devices and beyond

    International Nuclear Information System (INIS)

    Kim, Y; Pham, C; Chang, J P

    2015-01-01

    This review focuses on recent accomplishments on complex metal oxide based multifunctional materials and the potential they hold in advancing integrated circuits. It begins with metal oxide based high-κ materials to highlight the success of their integration since 45 nm complementary metal–oxide–semiconductor (CMOS) devices. By simultaneously offering a higher dielectric constant for improved capacitance as well as providing a thicker physical layer to prevent the quantum mechanical tunnelling of electrons, high-κ materials have enabled the continued down-scaling of CMOS based devices. The most recent technology driver has been the demand to lower device power consumption, which requires the design and synthesis of novel materials, such as complex metal oxides that exhibit remarkable tunability in their ferromagnetic, ferroelectric and multiferroic properties. These properties make them suitable for a wide variety of applications such as magnetoelectric random access memory, radio frequency band pass filters, antennae and magnetic sensors. Single-phase multiferroics, while rare, offer unique functionalities which have motivated much scientific and technological research to ascertain the origins of their multiferroicity and their applicability to potential devices. However, due to the weak magnetoelectric coupling for single-phase multiferroics, engineered multiferroic composites based on magnetostrictive ferromagnets interfacing piezoelectrics or ferroelectrics have shown enhanced multiferroic behaviour from effective strain coupling at the interface. In addition, nanostructuring of the ferroic phases has demonstrated further improvement in the coupling effect. Therefore, single-phase and engineered composite multiferroics consisting of complex metal oxides are reviewed in terms of magnetoelectric coupling effects and voltage controlled ferromagnetic properties, followed by a review on the integration challenges that need to be overcome to realize the

  9. Pulsed Neutron Scattering Studies of Strongly Fluctuating solids, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Collin Broholm

    2006-06-22

    The conventional description of a solid is based on a static atomic structure with small amplitude so-called harmonic fluctuations about it. This is a final technical report for a project that has explored materials where fluctuations are sufficiently strong to severely challenge this approach and lead to unexpected and potentially useful materials properties. Fluctuations are enhanced when a large number of configurations share the same energy. We used pulsed spallation source neutron scattering to obtain detailed microscopic information about structure and fluctuations in such materials. The results enhance our understanding of strongly fluctuating solids and their potential for technical applications. Because new materials require new experimental techniques, the project has also developed new techniques for probing strongly fluctuating solids. Examples of material that were studied are ZrW2O8 with large amplitude molecular motion that leads to negative thermal expansion, NiGa2S4 where competing interactions lead to an anomalous short range ordered magnet, Pr1- xBixRu2O7 where a partially filled electron shell (Pr) in a weakly disordered environment produces anomalous metallic properties, and TbMnO3 where competing interactions lead to a magneto-electric phase. The experiments on TbMnO3 exemplify the relationship between research funded by this project and future applications. Magneto-electric materials may produce a magnetic field when an electric field is applied or vise versa. Our experiments have clarified the reason why electric and magnetic polarization is coupled in TbMnO3. While this knowledge does not render TbMnO3 useful for applications it will focus the search for a practical room temperature magneto-electric for applications.

  10. Domain switching in single-phase multiferroics

    Science.gov (United States)

    Jia, Tingting; Cheng, Zhenxiang; Zhao, Hongyang; Kimura, Hideo

    2018-06-01

    Multiferroics are a time-honoured research subject by reason for their tremendous application potential in the information industry, such as in multi-state information storage devices and new types of sensors. An outburst of studies on multiferroicity has been witnessed in the 21st century, although this field has a long research history since the 19th century. Multiferroicity has now become one of the hottest research topics in condensed matter physics and materials science. Numerous efforts have been made to investigate the cross-coupling phenomena among ferroic orders such as ferroelectricity, (anti-)ferromagnetism, and ferroelasticity, especially the coupling between electric and magnetic orderings that would account for the magnetoelectric (ME) effect in multiferroic materials. The magnetoelectric properties and coupling behavior of single phase multiferroics are dominated by their domain structures. It was also noted that, however, the multiferroic materials exhibit very complicated domain structures. Studies on domain structure characterization and domain switching are a crucial step in the exploration of approaches to the control and manipulation of magnetic (electric) properties using an electric (magnetic) field or other means. In this review, following a concise outline of our current basic knowledge on the magnetoelectric (ME) effect, we summarize some important research activities on domain switching in single-phase multiferroic materials in the form of single crystals and thin films, especially domain switching behavior involving strain and the related physics in the last decade. We also introduce recent developments in characterization techniques for domain structures of ferroelectric or multiferroic materials, which have significantly advanced our understanding of domain switching dynamics and interactions. The effects of a series of issues such as electric field, magnetic field, and stress effects on domain switching are been discussed as well. It

  11. Microscopic Description of Electric and Magnetic Toroidal Multipoles in Hybrid Orbitals

    Science.gov (United States)

    Hayami, Satoru; Kusunose, Hiroaki

    2018-03-01

    We derive the quantum-mechanical operator expressions of multipoles under the space-time inversion group. We elucidate that electric and magnetic toroidal multipoles, in addition to ordinary non-toroidal ones, are fundamental pieces to express arbitrary electronic degrees of freedom. We show that electric (magnetic) toroidal multipoles higher than the dipole (monopole) can become active in a hybridized-orbital system. We also demonstrate emergent cross-correlated couplings between the electric, magnetic, and elastic degrees of freedom, such as magneto-electric and magneto(electro)-elastic coupling, under toroidal multipole orders.

  12. New classical inversion formulas for centrosymmetric electric and magnetic fields; focusing potentials

    International Nuclear Information System (INIS)

    Bogdanov, I.V.; Demkov, Y.N.

    1982-01-01

    New inversion formulas are obtained for the classical scattering of a charged particle by a spherical or axisymmetric electric or magnetic field at a fixed impact parameter or angular momentum. For different cases, focusing fields are obtained similar to those previously considered for scattering by an electric field at a given energy, viz., of the backscattering (cat's eye), Maxwell fish eye, or Luneberg lens type. A magnetoelectric analogy is formulated, namely the existence of equivalent axisymmetric electric and magnetic fields that scatter charged particles in identical fashion

  13. Efectos estructurales y de interfase en capas finas de La₂/₃Ca₁/₃MnO₃

    OpenAIRE

    Abad Muñoz, Llibertat

    2008-01-01

    Consultable des del TDX Títol obtingut de la portada digitalitzada En el desarrollo de esta tesis hemos analizado distintos aspectos preliminares relacionados con la utilización de óxidos complejos, tales como las perovskitas de manganeso, en la implementación de dispositivos con potenciales aplicaciones en magnetoelectrónica. En concreto, hemos abordado a fondo distintos aspectos relacionados con la fabricación de uniones túnel magnéticas basadas en el sistema La2/3Ca1/3MnO3 (LCMO)/SrT...

  14. Efectos Estructurales y de Interfase en Capas Finas de La(2/3)Ca(1/3)MnO(3)

    OpenAIRE

    Abad Muñoz, Libertad

    2007-01-01

    En el desarrollo de esta tesis hemos analizado distintos aspectos preliminares relacionados con la utilización de óxidos complejos, tales como las perovskitas de manganeso, en la implementación de dispositivos con potenciales aplicaciones en magnetoelectrónica. En concreto, hemos abordado a fondo distintos aspectos relacionados con la fabricación de uniones túnel magnéticas basadas en el sistema La2/3Ca1/3MnO3 (LCMO)/SrTiO3 (STO).Nuestro trabajo ha puesto de manifiesto que la técnica de pulve...

  15. Relation between ferroelectric and antiferromagnetic order in RMn2O5

    International Nuclear Information System (INIS)

    Noda, Yukio; Kimura, Hiroyuki; Kamada, Youichi; Osawa, Toshihiro; Fukuda, Yosikazu; Ishikawa, Yoshihisa; Kobayashi, Satoru; Wakabayashi, Yusuke; Sawa, Hiroshi; Ikeda, Naoshi; Kohn, Kay

    2006-01-01

    RMn 2 O 5 (R=Y and rare earth) shows successive magnetic and ferroelectric phase transitions at about 45, 40, 39, 20 and 10K. We have reinvestigated the magnetic structure of YMn 2 O 5 at the commensurate phase (T=25K) using a single crystal four-circle diffractometer in order to discuss the mechanism of magnetoelectric interaction and the origin of ferroelectricity. We also observed the lattice modulation vectors (q L ) to compare the magnetic propagation vectors (q M ) by synchrotron X-ray diffraction. Improved magnetic structure data are compared with the theory recently proposed

  16. Electric polarization of magnetic textures: New horizons of micromagnetism

    International Nuclear Information System (INIS)

    Pyatakov, A.P.; Meshkov, G.A.; Zvezdin, A.K.

    2012-01-01

    A common scenario of magnetoelectric coupling in multiferroics is the electric polarization induced by spatially modulated spin structures. It is shown in this paper that the same mechanism works in magnetic dielectrics with inhomogeneous magnetization distribution: the domain walls and magnetic vortexes can be the sources of electric polarization. The electric field driven magnetic domain wall motion is observed in iron garnet films. The electric field induced nucleation of vortex state of magnetic nanodots is theoretically predicted and numerically simulated. From the practical point of view the electric field control of micromagnetic structures suggests a low-power approach for spintronics and magnonics.

  17. Effect of low transverse magnetic field on the confinement strength in a quasi-1D wire

    International Nuclear Information System (INIS)

    Kumar, Sanjeev; Thomas, K. J.; Smith, L. W.; Farrer, I.; Ritchie, D. A.; Jones, G. A. C.; Griffiths, J.; Pepper, M.

    2013-01-01

    Transport measurements in a quasi-one dimensional (1D) quantum wire are reported in the presence of low transverse magnetic field. Differential conductance shows weak quantised plateaus when the 2D electrons are squeezed electrostatically. Application of a small transverse magnetic field (0.2T) enhances the overall degree of quantisation due to the formation of magneto-electric subbands. The results show the role of magnetic field to fine tune the confinement strength in low density wires when interaction gives rise to double row formation

  18. Topological Invariants and Ground-State Wave functions of Topological Insulators on a Torus

    Directory of Open Access Journals (Sweden)

    Zhong Wang

    2014-01-01

    Full Text Available We define topological invariants in terms of the ground-state wave functions on a torus. This approach leads to precisely defined formulas for the Hall conductance in four dimensions and the topological magnetoelectric θ term in three dimensions, and their generalizations in higher dimensions. They are valid in the presence of arbitrary many-body interactions and disorder. These topological invariants systematically generalize the two-dimensional Niu-Thouless-Wu formula and will be useful in numerical calculations of disordered topological insulators and strongly correlated topological insulators, especially fractional topological insulators.

  19. Magneto- to electroactive transmutation of spin waves in ErMnO3.

    Science.gov (United States)

    Chaix, L; de Brion, S; Petit, S; Ballou, R; Regnault, L-P; Ollivier, J; Brubach, J-B; Roy, P; Debray, J; Lejay, P; Cano, A; Ressouche, E; Simonet, V

    2014-04-04

    The low-energy dynamical properties of the multiferroic hexagonal perovskite ErMnO3 have been studied by inelastic neutron scattering as well as terahertz and far infrared spectroscopies on a synchrotron source. From these complementary techniques, we have determined the magnon and crystal field spectra and identified a zone center magnon excitable only by the electric field of an electromagnetic wave. Using a comparison with the isostructural YMnO3 compound and crystal field calculations, we propose that this dynamical magnetoelectric process is due to the hybridization of a magnon with an electroactive crystal field transition.

  20. Giant tunneling electroresistance effect driven by an electrically controlled spin valve at a complex oxide interface.

    Science.gov (United States)

    Burton, J D; Tsymbal, E Y

    2011-04-15

    A giant tunneling electroresistance effect may be achieved in a ferroelectric tunnel junction by exploiting the magnetoelectric effect at the interface between the ferroelectric barrier and a magnetic La(1-x)Sr(x)MnO3 electrode. Using first-principles density-functional theory we demonstrate that a few magnetic monolayers of La(1-x)Sr(x)MnO3 near the interface act, in response to ferroelectric polarization reversal, as an atomic-scale spin valve by filtering spin-dependent current. This produces more than an order of magnitude change in conductance, and thus constitutes a giant resistive switching effect.

  1. Magnetodielectric effect and optic soft mode behaviour in quantum paraelectric EuTiO.sub.3./sub. ceramics

    Czech Academy of Sciences Publication Activity Database

    Kamba, Stanislav; Nuzhnyy, Dmitry; Vaněk, Přemysl; Savinov, Maxim; Knížek, Karel; Shen, Z.; Šantavá, Eva; Maca, K.; Sadowski, M.; Petzelt, Jan

    2007-01-01

    Roč. 80, č. 2 (2007), 27002/1-27002/6 ISSN 0295-5075 R&D Projects: GA ČR(CZ) GA202/06/0403; GA MŠk OC 101 Grant - others:MŠMT(CZ) OC 102; EU(XE) RITA-CT-2003-505474 Institutional research plan: CEZ:AV0Z10100520 Keywords : magnetomechanical and magnetoelectric effect * magnetostriction * infrared and Raman spectra * phonons in crystal lattices Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.206, year: 2007

  2. Electric Field Tuning Non-volatile Magnetism in Half-Metallic Alloys Co2FeAl/Pb(Mg1/3Nb2/3)O3-PbTiO3 Heterostructure

    Science.gov (United States)

    Dunzhu, Gesang; Wang, Fenglong; Zhou, Cai; Jiang, Changjun

    2018-03-01

    We reported the non-volatile electric field-mediated magnetic properties in the half-metallic Heusler alloy Co2FeAl/Pb(Mg1/3Nb2/3)O3-PbTiO3 heterostructure at room temperature. The remanent magnetization with different applied electric field along [100] and [01-1] directions was achieved, which showed the non-volatile remanent magnetization driven by an electric field. The two giant reversible and stable remanent magnetization states were obtained by applying pulsed electric field. This can be attributed to the piezostrain effect originating from the piezoelectric substrate, which can be used for magnetoelectric-based memory devices.

  3. Electric control of antiferromagnets

    Czech Academy of Sciences Publication Activity Database

    Fina, I.; Martí, Xavier

    2017-01-01

    Roč. 53, č. 2 (2017), 1-7, č. článku 2500107. ISSN 0018-9464 R&D Projects: GA ČR GB14-37427G EU Projects: European Commission(XE) 268066 - 0MSPIN Institutional support: RVO:68378271 Keywords : magnetoelectric effects * perpendicular magnetic anisotropy * magnetic domain walls * magnetic domains * switches * magnetic fields Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.243, year: 2016

  4. FAST TRACK COMMUNICATION: Eight-logic memory cell based on multiferroic junctions

    Science.gov (United States)

    Yang, Feng; Zhou, Y. C.; Tang, M. H.; Liu, Fen; Ma, Ying; Zheng, X. J.; Zhao, W. F.; Xu, H. Y.; Sun, Z. H.

    2009-04-01

    A model is proposed for a device combining a multiferroic tunnel junction with a magnetoelectric (ME) film in which the magnetic configuration is controlled by the electric field. Calculations embodying the Green's function approach show that the magnetic polarization can be switched on and off by an electric field in the ME film due to the effect of elastic coupling interaction. Using a model including the spin-filter effect and screening of polarization charges, we have produced eight logic states of tunnelling resistance in the tunnel junction and have obtained corresponding laws that control them. The results provide some insights into the realization of an eight-logic memory cell.

  5. Colossal magnetoresistance in manganites and related prototype devices

    International Nuclear Information System (INIS)

    Liu Yu-Kuai; Yin Yue-Wei; Li Xiao-Guang

    2013-01-01

    We review colossal magnetoresistance in single phase manganites, as related to the field sensitive spin-charge interactions and phase separation; the rectifying property and negative/positive magnetoresistance in manganite/Nb:SrTiO 3 p—n junctions in relation to the special interface electronic structure; magnetoelectric coupling in manganite/ferroelectric structures that takes advantage of strain, carrier density, and magnetic field sensitivity; tunneling magnetoresistance in tunnel junctions with dielectric, ferroelectric, and organic semiconductor spacers using the fully spin polarized nature of manganites; and the effect of particle size on magnetic properties in manganite nanoparticles. (topical review - magnetism, magnetic materials, and interdisciplinary research)

  6. Multiferroic Properties of o-LuMnO3 Controlled by b-Axis Strain

    Science.gov (United States)

    Windsor, Y. W.; Huang, S. W.; Hu, Y.; Rettig, L.; Alberca, A.; Shimamoto, K.; Scagnoli, V.; Lippert, T.; Schneider, C. W.; Staub, U.

    2014-10-01

    Strain is a leading candidate for controlling magnetoelectric coupling in multiferroics. Here, we use x-ray diffraction to study the coupling between magnetic order and structural distortion in epitaxial films of the orthorhombic (o-) perovskite LuMnO3. An antiferromagnetic spin canting in the E-type magnetic structure is shown to be related to the ferroelectrically induced structural distortion and to a change in the magnetic propagation vector. By comparing films of different orientations and thicknesses, these quantities are found to be controlled by b-axis strain. It is shown that compressive strain destabilizes the commensurate E-type structure and reduces its accompanying ferroelectric distortion.

  7. Giant magneto-optical Kerr effect and universal Faraday effect in thin-film topological insulators.

    Science.gov (United States)

    Tse, Wang-Kong; MacDonald, A H

    2010-07-30

    Topological insulators can exhibit strong magneto-electric effects when their time-reversal symmetry is broken. In this Letter we consider the magneto-optical Kerr and Faraday effects of a topological insulator thin film weakly exchange coupled to a ferromagnet. We find that its Faraday rotation has a universal value at low frequencies θF=tan(-1)α, where α is the vacuum fine structure constant, and that it has a giant Kerr rotation θK=π/2. These properties follow from a delicate interplay between thin-film cavity confinement and the surface Hall conductivity of a topological insulator's helical quasiparticles.

  8. Response of multiferroic composites inferred from a fast-Fourier-transform-based numerical scheme

    International Nuclear Information System (INIS)

    Brenner, Renald; Bravo-Castillero, Julián

    2010-01-01

    The effective response and the local fields within periodic magneto-electric multiferroic composites are investigated by means of a numerical scheme based on fast Fourier transforms. This computational framework relies on the iterative resolution of coupled series expansions for the magnetic, electric and strain fields. By using an augmented Lagrangian formulation, a simple and robust procedure which makes use of the uncoupled Green operators for the elastic, electrostatics and magnetostatics problems is proposed. Its accuracy is assessed in the cases of laminated and fibrous two-phase composites for which analytical solutions exist

  9. Negative refraction using Raman transitions and chirality

    Energy Technology Data Exchange (ETDEWEB)

    Sikes, D. E.; Yavuz, D. D. [Department of Physics, 1150 University Avenue, University of Wisconsin at Madison, Madison, Wisconsin 53706 (United States)

    2011-11-15

    We present a scheme that achieves negative refraction with low absorption in far-off resonant atomic systems. The scheme utilizes Raman resonances and does not require the simultaneous presence of an electric-dipole transition and a magnetic-dipole transition near the same wavelength. We show that two interfering Raman tran-sitions coupled to a magnetic-dipole transition can achieve a negative index of refraction with low absorption through magnetoelectric cross-coupling. We confirm the validity of the analytical results with exact numerical simulations of the density matrix. We also discuss possible experimental implementations of the scheme in rare-earth metal atomic systems.

  10. Spin-orbit torque in 3D topological insulator-ferromagnet heterostructure: crossover between bulk and surface transport

    KAUST Repository

    Ghosh, Sumit; Manchon, Aurelien

    2017-01-01

    Current-driven spin-orbit torques are investigated in a heterostructure composed of a ferromagnet deposited on top of a three dimensional topological insulator using the linear response formalism. We develop a tight-binding model of the heterostructure adopting a minimal interfacial hybridization scheme that promotes induced magnetic exchange on the topological surface states, as well as induced Rashba-like spin-orbit coupling in the ferromagnet. Therefore, our model accounts for spin Hall effect from bulk states together with inverse spin galvanic and magnetoelectric effects at the interface on equal footing. By varying the transport energy across the band structure, we uncover a crossover from surface-dominated to bulk-dominated transport regimes. We show that the spin density profile and the nature of the spin-orbit torques differ substantially in both regimes. Our results, which compare favorably with experimental observations, demonstrate that the large damping torque reported recently is more likely attributed to interfacial magnetoelectric effect, while spin Hall torque remains small even in the bulk-dominated regime.

  11. Electrodynamics of a Cosmic Dark Fluid

    Directory of Open Access Journals (Sweden)

    Alexander B. Balakin

    2016-06-01

    Full Text Available Cosmic Dark Fluid is considered as a non-stationary medium, in which electromagnetic waves propagate, and magneto-electric field structures emerge and evolve. A medium-type representation of the Dark Fluid allows us to involve in its analysis the concepts and mathematical formalism elaborated in the framework of classical covariant electrodynamics of continua, and to distinguish dark analogs of well-known medium-effects, such as optical activity, pyro-electricity, piezo-magnetism, electro- and magneto-striction and dynamo-optical activity. The Dark Fluid is assumed to be formed by a duet of a Dark Matter (a pseudoscalar axionic constituent and Dark Energy (a scalar element; respectively, we distinguish electrodynamic effects induced by these two constituents of the Dark Fluid. The review contains discussions of 10 models, which describe electrodynamic effects induced by Dark Matter and/or Dark Energy. The models are accompanied by examples of exact solutions to the master equations, correspondingly extended; applications are considered for cosmology and space-times with spherical and pp-wave symmetries. In these applications we focused the attention on three main electromagnetic phenomena induced by the Dark Fluid: first, emergence of Longitudinal Magneto-Electric Clusters; second, generation of anomalous electromagnetic responses; third, formation of Dark Epochs in the Universe history.

  12. Transformable ferroelectric control of dynamic magnetic permeability

    Science.gov (United States)

    Jiang, Changjun; Jia, Chenglong; Wang, Fenglong; Zhou, Cai; Xue, Desheng

    2018-02-01

    Magnetic permeability, which measures the response of a material to an applied magnetic field, is crucial to the performance of magnetic devices and related technologies. Its dynamic value is usually a complex number with real and imaginary parts that describe, respectively, how much magnetic power can be stored and lost in the material. Control of permeability is therefore closely related to energy redistribution within a magnetic system or energy exchange between magnetic and other degrees of freedom via certain spin-dependent interactions. To avoid a high power consumption, direct manipulation of the permeability with an electric field through magnetoelectric coupling leads to high efficiency and simple operation, but remains a big challenge in both the fundamental physics and material science. Here we report unambiguous evidence of ferroelectric control of dynamic magnetic permeability in a Co /Pb (Mg1/3Nb2/3) 0.7Ti0.3O3 (Co/PMN-PT) heterostructure, in which the ferroelectric PMN-PT acts as an energy source for the ferromagnetic Co film via an interfacial linear magnetoelectric interaction. The electric field tuning of the magnitude and line shape of the permeability offers a highly localized means of controlling magnetization with ultralow power consumption. Additionally, the emergence of negative permeability promises a new way of realizing functional nanoscale metamaterials with adjustable refraction index.

  13. Sample-size resonance, ferromagnetic resonance and magneto-permittivity resonance in multiferroic nano-BiFeO{sub 3}/paraffin composites at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lei; Li, Zhenyu; Jiang, Jia; An, Taiyu; Qin, Hongwei; Hu, Jifan, E-mail: hujf@sdu.edu.cn

    2017-01-01

    In the present work, we demonstrate that ferromagnetic resonance and magneto-permittivity resonance can be observed in appropriate microwave frequencies at room temperature for multiferroic nano-BiFeO{sub 3}/paraffin composite sample with an appropriate sample-thickness (such as 2 mm). Ferromagnetic resonance originates from the room-temperature weak ferromagnetism of nano-BiFeO{sub 3}. The observed magneto-permittivity resonance in multiferroic nano-BiFeO{sub 3} is connected with the dynamic magnetoelectric coupling through Dzyaloshinskii–Moriya (DM) magnetoelectric interaction or the combination of magnetostriction and piezoelectric effects. In addition, we experimentally observed the resonance of negative imaginary permeability for nano BiFeO{sub 3}/paraffin toroidal samples with longer sample thicknesses D=3.7 and 4.9 mm. Such resonance of negative imaginary permeability belongs to sample-size resonance. - Highlights: • Nano-BiFeO{sub 3}/paraffin composite shows a ferromagnetic resonance. • Nano-BiFeO{sub 3}/paraffin composite shows a magneto-permittivity resonance. • Resonance of negative imaginary permeability in BiFeO{sub 3} is a sample-size resonance. • Nano-BiFeO{sub 3}/paraffin composite with large thickness shows a sample-size resonance.

  14. Fingerprints of surface magnetism in Cr2O3 based exchange bias heterostructures

    Science.gov (United States)

    He, Xi; Wang, Yi; Binek, Ch.

    2009-03-01

    Magnetoelectric materials experienced a recent revival as promising components of novel spintronic devices [1, 2, 3]. Since the magnetoelectric (ME) effect is relativistically small in traditional antiferromagnetic (AF) compounds like Cr2O3 (max. αzz 4ps/m) and also cross-coupling between ferroic order parameters is typically small in the modern multiferroics, it is a challenge to electrically induce sufficient magnetization required for the envisioned device applications. In exchange bias systems the bias field depends critically on the AF interface magnetization. Hence, a strong relation between the latter and the surface magnetization of the free Cr2O3 pinning layer can be expected. Our recent research indicates that there are surface magnetic phase transitions in free Cr2O3 (111) films accompanying surface structural phase transitions. Well defined AF interface magnetization is initialized through ME annealing to T=20K. Subsequently, the interface magnetization is thermally driven through phase transitions at T=120 and 210K. Their effects on the exchange bias are studied in Cr2O3 (111)/CoPt films with the help of polar Kerr and SQUID magnetometry. [1] P. Borisov et al. Phys. Rev. Lett. 94, 117203 (2005). [2] Ch. Binek, B.Doudin, J. Phys. Condens. Matter 17, L39 (2005). [3] R. Ramesh et al. 2007 Nature Materials 6 21. Financial support by NSF through Career DMR-0547887, MRSEC DMR-0820521 and the NRI.

  15. Studies of electrical conductivity and complex initial permeability of multiferroic xBa{sub 0.95}Sr{sub 0.05}TiO{sub 3}-(1-x)BiFe{sub 0.90}Gd{sub 0.10}O{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Miah, Mohammad J., E-mail: mmjulhash@yahoo.com [Department of Physics, Bangladesh University of Engineering & Technology, Dhaka (Bangladesh); Department of Physics, Comilla University, Comilla (Bangladesh); Khan, M. N. I. [Materials Science Division, Atomic Energy Center, Dhaka (Bangladesh); Hossain, A. K. M. Akther [Department of Physics, Bangladesh University of Engineering & Technology, Dhaka (Bangladesh)

    2016-07-12

    Multiferroic xBa{sub 0.95}Sr{sub 0.05}TiO{sub 3}-(1-x)BiFe{sub 0.90}Gd{sub 0.10}O{sub 3} [xBST-(1-x)BFGO] (x = 0.00, 0.10 and 0.20) ceramics were prepared by the standard solid-state reaction technique. Crystal structure of the ceramics was determined by X-ray diffraction pattern. All the compositions exhibited rhombohedral crystal structure. The tolerance factor ‘t’ varied from 0.847 to 0.864. The AC conductivity spectrum followed the Jonscher’s power law. The Nyquist plots indicated that only grains have the contribution to the resistance in this material and the values of grain resistance (R{sub g}) increased with BST content. The real part of complex initial permeability decreased with the increase in frequency and increased with increasing BST content. Magnetoelectric coefficient was determined for all compositions. The maximum value of magnetoelectric coefficient was found to be 1.467 mV.cm{sup −1}.Oe{sup −1} for x = 0.20.

  16. Spin-orbit torque in 3D topological insulator-ferromagnet heterostructure: crossover between bulk and surface transport

    KAUST Repository

    Ghosh, Sumit

    2017-11-29

    Current-driven spin-orbit torques are investigated in a heterostructure composed of a ferromagnet deposited on top of a three dimensional topological insulator using the linear response formalism. We develop a tight-binding model of the heterostructure adopting a minimal interfacial hybridization scheme that promotes induced magnetic exchange on the topological surface states, as well as induced Rashba-like spin-orbit coupling in the ferromagnet. Therefore, our model accounts for spin Hall effect from bulk states together with inverse spin galvanic and magnetoelectric effects at the interface on equal footing. By varying the transport energy across the band structure, we uncover a crossover from surface-dominated to bulk-dominated transport regimes. We show that the spin density profile and the nature of the spin-orbit torques differ substantially in both regimes. Our results, which compare favorably with experimental observations, demonstrate that the large damping torque reported recently is more likely attributed to interfacial magnetoelectric effect, while spin Hall torque remains small even in the bulk-dominated regime.

  17. Analysis and synthesis of bianisotropic metasurfaces by using analytical approach based on equivalent parameters

    Science.gov (United States)

    Danaeifar, Mohammad; Granpayeh, Nosrat

    2018-03-01

    An analytical method is presented to analyze and synthesize bianisotropic metasurfaces. The equivalent parameters of metasurfaces in terms of meta-atom properties and other specifications of metasurfaces are derived. These parameters are related to electric, magnetic, and electromagnetic/magnetoelectric dipole moments of the bianisotropic media, and they can simplify the analysis of complicated and multilayer structures. A metasurface of split ring resonators is studied as an example demonstrating the proposed method. The optical properties of the meta-atom are explored, and the calculated polarizabilities are applied to find the reflection coefficient and the equivalent parameters of the metasurface. Finally, a structure consisting of two metasurfaces of the split ring resonators is provided, and the proposed analytical method is applied to derive the reflection coefficient. The validity of this analytical approach is verified by full-wave simulations which demonstrate good accuracy of the equivalent parameter method. This method can be used in the analysis and synthesis of bianisotropic metasurfaces with different materials and in different frequency ranges by considering electric, magnetic, and electromagnetic/magnetoelectric dipole moments.

  18. Evolution of structure and magnetic properties for BaFe{sub 11.9}Al{sub 0.1}O{sub 19} hexaferrite in a wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Trukhanov, A.V., E-mail: truhanov86@mail.ru [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, S.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Panina, L.V.; Kostishyn, V.G. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); Kazakevich, I.S. [SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, An.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanova, E.L.; Natarov, V.O. [SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Turchenko, V.A. [Joint Institute for Nuclear Research, Joliot-Curie Str., 6, 141980 Dubna (Russian Federation); Donetsk Institute of Physics and Technology named after A.A. Galkin of the NAS of Ukraine, 72 R.Luxemburg Str., 83114 Donetsk (Ukraine); Salem, M.M. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); and others

    2017-03-15

    M-type BaFe{sub 11.9}Al{sub 0.1}O{sub 19} hexaferrite was successfully synthesized by solid state reactions. Precision investigations of crystal and magnetic structures of BaFe{sub 11.9}Al{sub 0.1}O{sub 19} powder by neutron diffraction in the temperature range 4.2–730 K have been performed. Magnetic and electrical properties investigations were carried out in the wide temperature range. Neutron powder diffraction data were successfully refined in approximation for both space groups (SG): centrosymmetric #194 (standard non-polar phase) and non-centrosymmetric #186 (polar phase). It has been shown that at low temperatures (below room temperature) better fitting results (value χ{sup 2}) were for the polar phase (SG: #186) or for the two phases coexistence (SG: #186 and SG: #194). At high temperatures (400–730 K) better fitting results were for SG: #194. It was established coexistence of the dual ferroic properties (specific magnetization and spontaneous polarization) at room temperature. Strong correlation between magnetic and electrical subsystems was demonstrated (magnetoelectrical effect). Temperature dependences of the spontaneous polarization, specific magnetization and magnetoelectrical effect were investigated.

  19. Thermodynamic and neutron diffraction studies on multiferroic NdMn{sub 2}O{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S.; Balédent, V.; Auban-Senzier, P.; Pasquier, C.; Doubrovsky, C. [Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, 91405 Orsay (France); Greenblatt, M. [Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Foury-Leylekian, P., E-mail: pascale.foury@u-psud.fr [Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, 91405 Orsay (France)

    2015-03-01

    Magnetically frustrated RMn{sub 2}O{sub 5} oxides have attracted considerable attention in recent years, because most of the members of this family show spin ordering induced dielectric polarization along with strong magneto-electric coupling. Although the true origin of the ferroelectricity is still a matter of debate, it has been observed that the magneto-electric phase diagram can be substantially tuned with the variation of rare earth elements. In this work, we have chosen NdMn{sub 2}O{sub 5} as the compound of our interest since it lies exactly in between the ferroelectric and non-ferroelectric members of this family and also, because there are few investigations performed on RMn{sub 2}O{sub 5} systems with large rare earth atoms . With the combination of heat capacity, magnetic susceptibility, dielectric permittivity, powder X-ray diffraction, and powder neutron diffraction measurements, it has been found that NdMn{sub 2}O{sub 5} undergoes an incommensurate magnetic ordering around 30 K followed by a possible ferroelectric-like transition at ∼26 K. Another lock-in kind of magnetic transition appears when the temperature is decreased to ∼15 K. With further lowering of temperature, an antiferromagnetic ordering, which is presumably associated with the Nd{sup 3+}, is achieved near 4 K. This study thus sheds light on a new compound of the RMn{sub 2}O{sub 5} series presenting different multiferroic properties.

  20. Nanoscale control of stripe-ordered magnetic domain walls by vertical spin transfer torque in La0.67Sr0.33MnO3 film

    Science.gov (United States)

    Wang, Jing; Wu, Shizhe; Ma, Ji; Xie, Lishan; Wang, Chuanshou; Malik, Iftikhar Ahmed; Zhang, Yuelin; Xia, Ke; Nan, Ce-Wen; Zhang, Jinxing

    2018-02-01

    Stripe-ordered domains with perpendicular magnetic anisotropy have been intensively investigated due to their potential applications in high-density magnetic data-storage devices. However, the conventional control methods (e.g., epitaxial strain, local heating, magnetic field, and magnetoelectric effect) of the stripe-ordered domain walls either cannot meet the demands for miniaturization and low power consumption of spintronic devices or require high strength of the electric field due to the small value of the magnetoelectric effect at room temperature. Here, a domain-wall resistive effect of 0.1% was clarified in La0.67Sr0.33MnO3 thin films between the configurations of current in the plane and perpendicular to the plane of walls. Furthermore, a reversible nanoscale control of the domain-wall re-orientation by vertical spin transfer torque across the probe/film interface was achieved, where a probe voltage of 0.1 V was applied on a manganite-based capacitor. We also demonstrated that the stripe-ordered magnetic domain-wall re-orientation strongly depends on the AC frequency of the scanning probe voltage which was applied on the capacitor.

  1. Structural and magneto-dielectric property of (1-x)SBT-xLSMO nanocomposite thin films

    International Nuclear Information System (INIS)

    Maity, Sarmistha; Bhattacharya, D.; Dhar, A.; Ray, S.K.

    2009-01-01

    Full text: In recent years, interest in multiferroic materials has been increasing due to their potential applications. As single-phase multiferroic materials have very low room temperature magnetoelectric coefficient, recent studies have been concentrated on the possibility of attaining a coupling between the two order parameters by designing composites with magnetostrictive and piezoelectric phases via stress mediation. Composite thin films with homogenous matrix, composition spread with terminal layers being ferromagnetic and ferroelectric, layer-by-layer growth, superlattices, as well as epitaxial growth of ferromagnetic and ferroelectric layers on suitable substrates are been currently considered. In the present work, a nanostructured composite thin film of strontium bismuth tantalate (SBT) (ferroelectric layer) and lanthanum strontium manganese oxide (LSMO) (ferromagnetic layer) were fabricated using pulsed laser deposition. Phase separated multiferroic thin films with thickness varying from 50nm to 150nm were deposited from composite target (1-x)SBT-xLSMO with x=0.2, 0.5, 0.8. Grazing angle X-ray diffraction study combined with photo electron spectroscopy with depth profiling was carried out to study the phase separation. Interface quality of the thin film on silicon substrate was studied by Rutherford backscattering spectroscopy. Influence of film thickness and composition (x) on the electrical property of film was examined using impedance spectroscopy. The composite films exhibited ferroelectric as well as ferromagnetic characteristics at room temperature. A small kink in the dielectric spectra near the Neel temperature of LSMO confirmed the magneto-electric effect in the nanocomposite films

  2. Electric field tuning of magnetism in heterostructure of yttrium iron garnet film/lead magnesium niobate-lead zirconate titanate ceramic

    Science.gov (United States)

    Lian, Jianyun; Ponchel, Freddy; Tiercelin, Nicolas; Chen, Ying; Rémiens, Denis; Lasri, Tuami; Wang, Genshui; Pernod, Philippe; Zhang, Wenbin; Dong, Xianlin

    2018-04-01

    In this paper, the converse magnetoelectric (CME) effect by electric field tuning of magnetization in an original heterostructure composed of a polycrystalline yttrium iron garnet (YIG) film and a lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramic is presented. The magnetic performances of the YIG films with different thicknesses under a DC electric field applied to the PMN-PZT ceramics and a bias magnetic field are investigated. All the magnetization-electric field curves are found to be in good agreement with the butterfly like strain curve of the PMN-PZT ceramic. Both the sharp deformation of about 2.5‰ of PMN-PZT and the easy magnetization switching of YIG are proposed to be the reasons for the strongest CME interaction in the composite at the small electric coercive field of PMN-PZT (4.1 kV/cm) and the small magnetic coercive field of YIG (20 Oe) where the magnetic susceptibility reaches its maximum value. A remarkable CME coefficient of 3.1 × 10-7 s/m is obtained in the system with a 600 nm-thick YIG film. This heterostructure combining multiferroics and partially magnetized ferrite concepts is able to operate under a small or even in the absence of an external bias magnetic field and is more compact and power efficient than the traditional magnetoelectric devices.

  3. Large-eddy simulation, atmospheric measurement and inverse modeling of greenhouse gas emissions at local spatial scales

    Science.gov (United States)

    Nottrott, Anders Andelman

    Multiferroic materials and devices have attracted intensified interests due to the demonstrated strong magnetoelectric coupling in new multiferroic materials, artificial multiferroic heterostructures and devices with unique functionalities and superior performance characteristics. This offers great opportunities for achieving compact, fast, energy-efficient and voltage tunable spintronic devices. In traditional magnetic materials based magnetic random access memories (MRAM) devices, the binary information is stored as magnetization. The high coercivity of the ferromagnetic media requires large magnetic fields for switching the magnetic states thus consuming large amount of energy. In modern MRAM information writing process, spin-torque technique is utilized for minimizing the large energy for generating magnetic field by passing through a spin-polarized current directly to the magnets. However, both methods still need large current/current density to toggle the magnetic bits which consume large amount of energy. With the presence of multiferroic or magnetoelectric materials, spin is controlled by electric field which opens new opportunities for power-efficient voltage control of magnetization in spintronic devices leading to magnetoelectric random access memories (MERAM) with ultra-low energy consumption. However, state of the art multiferroic materials still have difficulty of realizing nonvolatile 180° magnetization reversal, which is desired in realizing MERAM. In a strain-mediated multiferroic system, the typical modification of the magnetism of ferromagnetic phase as a function of bipolar electric field shows a "butterfly" like behavior. This is due to the linear piezoelectricity of ferroelectric phase which has a "butterfly" like piezostrain as a function of electric field curve resulting from ferroelectric domain wall switching. In this case, the magnetization state is volatile because of the vanishing of the piezostrain at zero electric field. However, the

  4. Realization of the Axion Insulator State in Quantum Anomalous Hall Sandwich Heterostructures

    Science.gov (United States)

    Xiao, Di; Jiang, Jue; Shin, Jae-Ho; Wang, Wenbo; Wang, Fei; Zhao, Yi-Fan; Liu, Chaoxing; Wu, Weida; Chan, Moses H. W.; Samarth, Nitin; Chang, Cui-Zu

    2018-02-01

    The "magnetoelectric effect" arises from the coupling between magnetic and electric properties in materials. The Z2 invariant of topological insulators (TIs) leads to a quantized version of this phenomenon, known as the topological magnetoelectric (TME) effect. This effect can be realized in a new topological phase called an "axion insulator" whose surface states are all gapped but the interior still obeys time reversal symmetry. We demonstrate such a phase using electrical transport measurements in a quantum anomalous Hall (QAH) sandwich heterostructure, in which two compositionally different magnetic TI layers are separated by an undoped TI layer. Magnetic force microscopy images of the same sample reveal sequential magnetization reversals of the top and bottom layers at different coercive fields, a consequence of the weak interlayer exchange coupling due to the spacer. When the magnetization is antiparallel, both the Hall resistance and Hall conductance show zero plateaus, accompanied by a large longitudinal resistance and vanishing longitudinal conductance, indicating the realization of an axion insulator state. Our findings thus show evidence for a phase of matter distinct from the established QAH state and provide a promising platform for the realization of the TME effect.

  5. Structural, electrical and multiferroic characteristics of thermo-mechanically fabricated BiFeO3-(BaSr)TiO3 solid solutions

    Science.gov (United States)

    Behera, C.; Choudhary, R. N. P.; Das, Piyush R.

    2018-05-01

    A solid solution consisting of two perovskite compounds (BiFeO3 and (BaSr)TiO3) of chemical composition (Bi1/2Ba1/4Sr1/4)(Fe1/2Ti1/2)O3 has been fabricated in the low dimensional regime by thermo-mechanical (ball milling and heating) approach. The effect of particle size on the structural, micro-structural, relative permittivity, switching (ferroelectric and magnetic) and conduction phenomena of the material has been studied using various experimental techniques such as x-rays diffraction, transmission and scanning electron microscopy, ferroelectric and magnetic hysteresis, dynamic magneto-electric coupling measurement and impedance spectroscopy techniques. All the above extracted properties are found to be particle size dependent. The first order magneto-electric coupling constant is found to be 2.56, 6.6 and 8.7 mV cm‑1.Oe for 30, 60 and 90 h milled calcined (hmc) sample respectively. As the above micro/nano-material with different particle size, has a high relative dielectric constant and low tangent loss, it can be used for some multifunctional devices including capacity energy storage device in nano-electronics.

  6. An analytical solution for the magneto-electro-elastic bimorph beam forced vibrations problem

    International Nuclear Information System (INIS)

    Milazzo, A; Orlando, C; Alaimo, A

    2009-01-01

    Based on the Timoshenko beam theory and on the assumption that the electric and magnetic fields can be treated as steady, since elastic waves propagate very slowly with respect to electromagnetic ones, a general analytical solution for the transient analysis of a magneto-electro-elastic bimorph beam is obtained. General magneto-electric boundary conditions can be applied on the top and bottom surfaces of the beam, allowing us to study the response of the bilayer structure to electromagnetic stimuli. The model reveals that the magneto-electric loads enter the solution as an equivalent external bending moment per unit length and as time-dependent mechanical boundary conditions through the definition of the bending moment. Moreover, the influences of the electro-mechanic, magneto-mechanic and electromagnetic coupling on the stiffness of the bimorph stem from the computation of the beam equivalent stiffness constants. Free and forced vibration analyses of both multiphase and laminated magneto-electro-elastic composite beams are carried out to check the effectiveness and reliability of the proposed analytic solution

  7. Low-power non-volatile spintronic memory: STT-RAM and beyond

    International Nuclear Information System (INIS)

    Wang, K L; Alzate, J G; Khalili Amiri, P

    2013-01-01

    The quest for novel low-dissipation devices is one of the most critical for the future of semiconductor technology and nano-systems. The development of a low-power, universal memory will enable a new paradigm of non-volatile computation. Here we consider STT-RAM as one of the emerging candidates for low-power non-volatile memory. We show different configurations for STT memory and demonstrate strategies to optimize key performance parameters such as switching current and energy. The energy and scaling limits of STT-RAM are discussed, leading us to argue that alternative writing mechanisms may be required to achieve ultralow power dissipation, a necessary condition for direct integration with CMOS at the gate level for non-volatile logic purposes. As an example, we discuss the use of the giant spin Hall effect as a possible alternative to induce magnetization reversal in magnetic tunnel junctions using pure spin currents. Further, we concentrate on magnetoelectric effects, where electric fields are used instead of spin-polarized currents to manipulate the nanomagnets, as another candidate solution to address the challenges of energy efficiency and density. The possibility of an electric-field-controlled magnetoelectric RAM as a promising candidate for ultralow-power non-volatile memory is discussed in the light of experimental data demonstrating voltage-induced switching of the magnetization and reorientation of the magnetic easy axis by electric fields in nanomagnets. (paper)

  8. The local density of optical states of a metasurface

    Science.gov (United States)

    Lunnemann, Per; Koenderink, A. Femius

    2016-02-01

    While metamaterials are often desirable for near-field functions, such as perfect lensing, or cloaking, they are often quantified by their response to plane waves from the far field. Here, we present a theoretical analysis of the local density of states near lattices of discrete magnetic scatterers, i.e., the response to near field excitation by a point source. Based on a pointdipole theory using Ewald summation and an array scanning method, we can swiftly and semi-analytically evaluate the local density of states (LDOS) for magnetoelectric point sources in front of an infinite two-dimensional (2D) lattice composed of arbitrary magnetoelectric dipole scatterers. The method takes into account radiation damping as well as all retarded electrodynamic interactions in a self-consistent manner. We show that a lattice of magnetic scatterers evidences characteristic Drexhage oscillations. However, the oscillations are phase shifted relative to the electrically scattering lattice consistent with the difference expected for reflection off homogeneous magnetic respectively electric mirrors. Furthermore, we identify in which source-surface separation regimes the metasurface may be treated as a homogeneous interface, and in which homogenization fails. A strong frequency and in-plane position dependence of the LDOS close to the lattice reveals coupling to guided modes supported by the lattice.

  9. Tuning the photovoltaic effect of multiferroic CoFe{sub 2}O{sub 4}/Pb(Zr, Ti)O{sub 3} composite films by magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Dan-Feng; Chen, Guang-Yi; Bi, Gui-Feng [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Zhang, Hao [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Liu, Jun-Ming; Wang, Guang-Hou; Wan, Jian-Guo, E-mail: wanjg@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2016-05-30

    The 0–3 type CoFe{sub 2}O{sub 4}-Pb(Zr,Ti)O{sub 3} (CFO-PZT) multiferroic composite films have been prepared by a sol-gel process and spin-coating technique. A confirmable photovoltaic effect is observed under ultraviolet light irradiation. Moreover, this photovoltaic effect can be tuned by external magnetic fields. The maximum magnetic modulation ratios of short-circuit current density and open-circuit voltage can reach as high as 13.7% and 12.8% upon the application of 6 kOe DC magnetic field. Through remnant polarization measurements under various magnetic fields and detailed analysis of the energy band structures, we elucidate the mechanism of tuning photovoltaic effect by magnetic fields and attribute it to the combination of two factors. One is the decreased ferroelectric-polarization-induced depolarization electric field and another is the band structure reconstruction at CFO-PZT interfaces, both of which are dominated by the magnetoelectric coupling via interfacial stress transferring at nanoscale. This work makes some attempts of coupling photo-induced effects with magnetoelectric effect in multiferroic materials and will widen the practical ranges of multiferroic-based applications.

  10. Lattice strain induced multiferroicity in PZT-CFO particulate composite

    Science.gov (United States)

    Pradhan, Lagen Kumar; Pandey, Rabichandra; Kumar, Rajnish; Kar, Manoranjan

    2018-02-01

    Lead Zirconate Titanate [Pb(Zr0.52Ti0.48)O3/PZT] and Cobalt Ferrite [CoFe2O4/CFO] based multiferroic composites [(1-x)PZT-(x)CFO] with (x = 0.10-0.40) have been prepared to study its magnetoelectric (ME) and multiferroic properties. X-ray diffraction method along with the Rietveld refinement technique reveals that the crystal symmetries corresponding to PZT and CFO exist independently in the composites. The effect of interfacial strain on lattice distortion in PZT has been observed. It is well correlated with the magnetoelectric coupling of the composites. Dispersion behavior of dielectric constant with frequency can be explained by the modified Debye model. Different relaxation phenomena have been observed in PZT-CFO particulate composites. The ferroelectric properties of composites decrease with the increase in percentage of CFO in the composite. Both saturation (Ms) and remanent (Mr) magnetization increase with the increase in CFO content in the composite. The maximum ME coupling was found to be 1.339 pC/cm2 Oe for the composition (0.80) PZT-(0.20) CFO at the application of maximum magnetic field of 50 Oe. The multiferroic properties in CFO-PZT can be explained by the lattice strain at the CFO-PZT interfaces.

  11. Modulation of magnetic coercivity in Ni thin films by reversible control of strain

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wen-Chin, E-mail: wclin@ntnu.edu.tw [Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan (China); Huang, Chia-Wei; Ting, Yi-Chieh; Lo, Fang-Yuh [Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan (China); Chern, Ming-Yau [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)

    2015-05-01

    In this study, we demonstrated the magnetoelectric control of magnetic thin films. (111)-textured Pd/Ni/Pd thin films were prepared on mica/lead zirconium titanate (PZT) substrates for the investigation. The reversible modulation of magnetic coercivity in Ni films was observed through the electric-voltage-controlled strain variation from the PZT substrate. For 14 nm Ni film, the applied electric field of ±350 V/m led to ±0.5% strain variation of PZT, which was transferred to ±0.4% strain variation of Pd/Ni/Pd thin films on mica, and resulted in ∓17 Oe (∓5% of the preliminary magnetic coercivity). The reversible modulation of magnetic coercivity is supposed to be caused by the voltage-controlled strain through the magneto-elastic effect. - Highlights: • The magnetoelectric control of the magnetic coercivity of Pd/Ni/Pd thin films was demonstrated. • The ±0.4% strain variation of 14 nm Ni thin films resulted in ±17 Oe change of H{sub c}. • The reversible modulation of H{sub c} is supposed to be caused by the magneto-elastic effect.

  12. "Metamagnetoelectric" effect in multiferroics

    Science.gov (United States)

    Fouokeng, G. C.; Fodouop, F. Kuate; Tchoffo, M.; Fai, L. C.; Randrianantoandro, N.

    2018-05-01

    We present a theoretical calculation of magnetoelectric properties in a quasi-two dimensional spin chain externally controlled by a static electric field in y-direction and magnetic field in z-direction. Given the diversity of properties in functional materials and their applications in physics, the multiferroic model is investigated. By using the Fermi-Dirac statistics of quantum gases and the Landau theory, we assess the effects of the Dzyaloshinskii-Moriya interaction and the electric polarization on the magnetoelectric coupling that induces at low temperature the "metamagnetoelectric" effet, and likewise affects the ferroelectricity induced through symmetry mechanisms and magnetic properties of the multiferroic system. In fact, the variation of the induced polarisation due to spin arrangement through the Dzyaloshinskii-Moriya interaction gives rise to a multistep interdependent metamagnetic and metaelectric transitions which are settled up by the corresponding Dzyaloshinskii-Moriya parameter and the system then exhibits a spin gap that results from an electric and a magnetic demagnetization field range. This metamagnetoelectric effect observed in these multiferroic materials model is seem to be highly tunable via the external electric and magnetic fields and thus can be crucial in the design of new mechanisms for the processing and storage of data and other spintronic applications.

  13. Evidence for multiferroic characteristics in NdCrTiO5

    International Nuclear Information System (INIS)

    Saha, J.; Sharma, G.; Patnaik, S.

    2014-01-01

    We report NdCrTiO 5 to be an unusual multiferroic material with large magnetic field dependent electric polarization. While magneto-electric coupling in this two magnetic sub-lattice oxide is well established, the purpose of this study is to look for spontaneous symmetry breaking at the magnetic transition. The conclusions are based on extensive magnetization, dielectric and polarization measurements around its antiferromagnetic ordering temperature of 18 K. Room temperature X-ray diffraction pattern of NdCrTiO 5 reveals that the sample is single phase with an orthorhombic crystal structure that allows linear magneto-electric coupling. DC magnetization measurement shows magnetization downturn at 11 K together with a small kink corresponding to the Cr +3 sub-lattice ordering at ∼18 K. An anomaly in dielectric constant is observed around the magnetic ordering temperature that increases substantially with increasing magnetic field. Through detailed pyroelectric current measurements at zero magnetic field, particularly as a function of thermal cycling, we establish that NdCrTiO 5 is a genuine multiferroic material that is possibly driven by collinear magneto-striction. - Highlights: • We provide evidence for multiferroicity in NdCrTiO 5 . • Large magnetic field dependent electric polarization is confirmed. • Sign reversal of pyroelectric current upon thermal cycling proves genuine ferroelectricity. • A model based on collinear magneto-striction is proposed. • A new class of multiferroic materials with large ME coupling is established

  14. Electric Field Controlled Magnetism in BiFeO3/Ferromagnet Films

    Science.gov (United States)

    Holcomb, M. B.; Chu, Y. H.; Martin, L. W.; Gajek, M.; Seidel, J.; Ramesh, R.; Scholl, A.; Fraile-Rodriguez, A.

    2008-03-01

    Electric field control of magnetism is a hot technological topic at the moment due to its potential to revolutionize today's devices. Magnetoelectric materials, those having both electric and magnetic order and the potential for coupling between the two, are a promising avenue to approach electric control. BiFeO3, both a ferroelectric and an antiferromagnet, is the only single phase room temperature magnetoelectric that is currently known. In addition to other possibilities, its multiferroic nature has potential in the very active field of exchange bias, where an antiferromagnetic thin film pins the magnetic direction of an adjoining ferromagnetic layer. Since this antiferromagnet is electrically tunable, this coupling could allow electric-field control of the ferromagnetic magnetization. Direction determination of antiferromagnetic domains in BFO has recently been shown using linear and circular dichroism studies. Recently, this technique has been extended to look at the magnetic domains of a ferromagnetic grown on top of BFO. The clear magnetic changes induced by application of electric fields reveal the possibility of electric control.

  15. Strain-mediated magnetic response in La0.67Sr0.33MnO3/SrTiO3/La0.67Sr0.33MnO3/BaTiO3 structure

    Science.gov (United States)

    Swain, Anupama; Komatsu, Katsuyoshi; Itoh, Mitsuru; Taniyama, Tomoyasu; Gorige, Venkataiah

    2018-05-01

    Electric field controlled magnetism is an exciting area of condensed matter physics to explore the device applications at ultra-low power consumption compared to the conventional current controlled or magnetic field controlled devices. In this study, an attempt was made to demonstrate electric field controlled magnetoresistance (MR) in a tri-layer structure consisting of La0.67Sr0.33MnO3 (LSMO) (40 nm)/SrTiO3 (10 nm)/LSMO (10 nm) grown on a 500-μm-thick BaTiO3 (001) (BTO) single crystal substrate by pulsed laser deposition technique. Epitaxial growth of the trilayer structure was confirmed by x-ray diffraction measurements. Jumps observed in the temperature-dependent magnetization curve at around the structural phase transitions of BTO ensure the strain-mediated magnetoelectric coupling between LSMO and BTO layers. A significant change in MR of this structure in applied electric fields does not show any polarity dependence. The findings are related to the lattice strain-mediated magnetoelectric coupling in ferromagnetic LSMO/ferroelectric BTO heterostructures.

  16. Hydrogen Treatment for Superparamagnetic VO2 Nanowires with Large Room-Temperature Magnetoresistance.

    Science.gov (United States)

    Li, Zejun; Guo, Yuqiao; Hu, Zhenpeng; Su, Jihu; Zhao, Jiyin; Wu, Junchi; Wu, Jiajing; Zhao, Yingcheng; Wu, Changzheng; Xie, Yi

    2016-07-04

    One-dimensional (1D) transition metal oxide (TMO) nanostructures are actively pursued in spintronic devices owing to their nontrivial d electron magnetism and confined electron transport pathways. However, for TMOs, the realization of 1D structures with long-range magnetic order to achieve a sensitive magnetoelectric response near room temperature has been a longstanding challenge. Herein, we exploit a chemical hydric effect to regulate the spin structure of 1D V-V atomic chains in monoclinic VO2 nanowires. Hydrogen treatment introduced V(3+) (3d(2) ) ions into the 1D zigzag V-V chains, triggering the formation of ferromagnetically coupled V(3+) -V(4+) dimers to produce 1D superparamagnetic chains and achieve large room-temperature negative magnetoresistance (-23.9 %, 300 K, 0.5 T). This approach offers new opportunities to regulate the spin structure of 1D nanostructures to control the intrinsic magnetoelectric properties of spintronic materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Hybrid supercapacitors for reversible control of magnetism.

    Science.gov (United States)

    Molinari, Alan; Leufke, Philipp M; Reitz, Christian; Dasgupta, Subho; Witte, Ralf; Kruk, Robert; Hahn, Horst

    2017-05-10

    Electric field tuning of magnetism is one of the most intensely pursued research topics of recent times aiming at the development of new-generation low-power spintronics and microelectronics. However, a reversible magnetoelectric effect with an on/off ratio suitable for easy and precise device operation is yet to be achieved. Here we propose a novel route to robustly tune magnetism via the charging/discharging processes of hybrid supercapacitors, which involve electrostatic (electric-double-layer capacitance) and electrochemical (pseudocapacitance) doping. We use both charging mechanisms-occurring at the La 0.74 Sr 0.26 MnO 3 /ionic liquid interface to control the balance between ferromagnetic and non-ferromagnetic phases of La 1-x Sr x MnO 3 to an unprecedented extent. A magnetic modulation of up to ≈33% is reached above room temperature when applying an external potential of only about 2.0 V. Our case study intends to draw attention to new, reversible physico-chemical phenomena in the rather unexplored area of magnetoelectric supercapacitors.

  18. Voltage control of magnetism in multiferroic heterostructures.

    Science.gov (United States)

    Liu, Ming; Sun, Nian X

    2014-02-28

    Electrical tuning of magnetism is of great fundamental and technical importance for fast, compact and ultra-low power electronic devices. Multiferroics, simultaneously exhibiting ferroelectricity and ferromagnetism, have attracted much interest owing to the capability of controlling magnetism by an electric field through magnetoelectric (ME) coupling. In particular, strong strain-mediated ME interaction observed in layered multiferroic heterostructures makes it practically possible for realizing electrically reconfigurable microwave devices, ultra-low power electronics and magnetoelectric random access memories (MERAMs). In this review, we demonstrate this remarkable E-field manipulation of magnetism in various multiferroic composite systems, aiming at the creation of novel compact, lightweight, energy-efficient and tunable electronic and microwave devices. First of all, tunable microwave devices are demonstrated based on ferrite/ferroelectric and magnetic-metal/ferroelectric composites, showing giant ferromagnetic resonance (FMR) tunability with narrow FMR linewidth. Then, E-field manipulation of magnetoresistance in multiferroic anisotropic magnetoresistance and giant magnetoresistance devices for achieving low-power electronic devices is discussed. Finally, E-field control of exchange-bias and deterministic magnetization switching is demonstrated in exchange-coupled antiferromagnetic/ferromagnetic/ferroelectric multiferroic hetero-structures at room temperature, indicating an important step towards MERAMs. In addition, recent progress in electrically non-volatile tuning of magnetic states is also presented. These tunable multiferroic heterostructures and devices provide great opportunities for next-generation reconfigurable radio frequency/microwave communication systems and radars, spintronics, sensors and memories.

  19. Magneto-acousto-electrical Measurement Based Electrical Conductivity Reconstruction for Tissues.

    Science.gov (United States)

    Zhou, Yan; Ma, Qingyu; Guo, Gepu; Tu, Juan; Zhang, Dong

    2018-05-01

    Based on the interaction of ultrasonic excitation and magnetoelectrical induction, magneto-acousto-electrical (MAE) technology was demonstrated to have the capability of differentiating conductivity variations along the acoustic transmission. By applying the characteristics of the MAE voltage, a simplified algorithm of MAE measurement based conductivity reconstruction was developed. With the analyses of acoustic vibration, ultrasound propagation, Hall effect, and magnetoelectrical induction, theoretical and experimental studies of MAE measurement and conductivity reconstruction were performed. The formula of MAE voltage was derived and simplified for the transducer with strong directivity. MAE voltage was simulated for a three-layer gel phantom and the conductivity distribution was reconstructed using the modified Wiener inverse filter and Hilbert transform, which was also verified by experimental measurements. The experimental results are basically consistent with the simulations, and demonstrate that the wave packets of MAE voltage are generated at tissue interfaces with the amplitudes and vibration polarities representing the values and directions of conductivity variations. With the proposed algorithm, the amplitude and polarity of conductivity gradient can be restored and the conductivity distribution can also be reconstructed accurately. The favorable results demonstrate the feasibility of accurate conductivity reconstruction with improved spatial resolution using MAE measurement for tissues with conductivity variations, especially suitable for nondispersive tissues with abrupt conductivity changes. This study demonstrates that the MAE measurement based conductivity reconstruction algorithm can be applied as a new strategy for nondestructive real-time monitoring of conductivity variations in biomedical engineering.

  20. Sample-size resonance, ferromagnetic resonance and magneto-permittivity resonance in multiferroic nano-BiFeO3/paraffin composites at room temperature

    International Nuclear Information System (INIS)

    Wang, Lei; Li, Zhenyu; Jiang, Jia; An, Taiyu; Qin, Hongwei; Hu, Jifan

    2017-01-01

    In the present work, we demonstrate that ferromagnetic resonance and magneto-permittivity resonance can be observed in appropriate microwave frequencies at room temperature for multiferroic nano-BiFeO 3 /paraffin composite sample with an appropriate sample-thickness (such as 2 mm). Ferromagnetic resonance originates from the room-temperature weak ferromagnetism of nano-BiFeO 3 . The observed magneto-permittivity resonance in multiferroic nano-BiFeO 3 is connected with the dynamic magnetoelectric coupling through Dzyaloshinskii–Moriya (DM) magnetoelectric interaction or the combination of magnetostriction and piezoelectric effects. In addition, we experimentally observed the resonance of negative imaginary permeability for nano BiFeO 3 /paraffin toroidal samples with longer sample thicknesses D=3.7 and 4.9 mm. Such resonance of negative imaginary permeability belongs to sample-size resonance. - Highlights: • Nano-BiFeO 3 /paraffin composite shows a ferromagnetic resonance. • Nano-BiFeO 3 /paraffin composite shows a magneto-permittivity resonance. • Resonance of negative imaginary permeability in BiFeO 3 is a sample-size resonance. • Nano-BiFeO 3 /paraffin composite with large thickness shows a sample-size resonance.

  1. Nanoscale magnetic ratchets based on shape anisotropy

    Science.gov (United States)

    Cui, Jizhai; Keller, Scott M.; Liang, Cheng-Yen; Carman, Gregory P.; Lynch, Christopher S.

    2017-02-01

    Controlling magnetization using piezoelectric strain through the magnetoelectric effect offers several orders of magnitude reduction in energy consumption for spintronic applications. However strain is a uniaxial effect and, unlike directional magnetic field or spin-polarized current, cannot induce a full 180° reorientation of the magnetization vector when acting alone. We have engineered novel ‘peanut’ and ‘cat-eye’ shaped nanomagnets on piezoelectric substrates that undergo repeated deterministic 180° magnetization rotations in response to individual electric-field-induced strain pulses by breaking the uniaxial symmetry using shape anisotropy. This behavior can be likened to a magnetic ratchet, advancing magnetization clockwise with each piezostrain trigger. The results were validated using micromagnetics implemented in a multiphysics finite elements code to simulate the engineered spatial and temporal magnetic behavior. The engineering principles start from a target device function and proceed to the identification of shapes that produce the desired function. This approach opens a broad design space for next generation magnetoelectric spintronic devices.

  2. A concept for a magnetic field detector underpinned by the nonlinear dynamics of coupled multiferroic devices

    Science.gov (United States)

    Beninato, A.; Emery, T.; Baglio, S.; Andò, B.; Bulsara, A. R.; Jenkins, C.; Palkar, V.

    2013-12-01

    Multiferroic (MF) composites, in which magnetic and ferroelectric orders coexist, represent a very attractive class of materials with promising applications in areas, such as spintronics, memories, and sensors. One of the most important multiferroics is the perovskite phase of bismuth ferrite, which exhibits weak magnetoelectric properties at room temperature; its properties can be enhanced by doping with other elements such as dysprosium. A recent paper has demonstrated that a thin film of Bi0.7Dy0.3FeO3 shows good magnetoelectric coupling. In separate work it has been shown that a carefully crafted ring connection of N (N odd and N ≥ 3) ferroelectric capacitors yields, past a critical point, nonlinear oscillations that can be exploited for electric (E) field sensing. These two results represent the starting point of our work. In this paper the (electrical) hysteresis, experimentally measured in the MF material Bi0.7Dy0.3FeO3, is characterized with the applied magnetic field (B) taken as a control parameter. This yields a "blueprint" for a magnetic (B) field sensor: a ring-oscillator coupling of N = 3 Sawyer-Tower circuits each underpinned by a mutliferroic element. In this configuration, the changes induced in the ferroelectric behavior by the external or "target" B-field are quantified, thus providing a pathway for very low power and high sensitivity B-field sensing.

  3. Selective control of multiple ferroelectric switching pathways using a trailing flexoelectric field

    Science.gov (United States)

    Park, Sung Min; Wang, Bo; Das, Saikat; Chae, Seung Chul; Chung, Jin-Seok; Yoon, Jong-Gul; Chen, Long-Qing; Yang, Sang Mo; Noh, Tae Won

    2018-05-01

    Flexoelectricity is an electromechanical coupling between electrical polarization and a strain gradient1 that enables mechanical manipulation of polarization without applying an electrical bias2,3. Recently, flexoelectricity was directly demonstrated by mechanically switching the out-of-plane polarization of a uniaxial system with a scanning probe microscope tip3,4. However, the successful application of flexoelectricity in low-symmetry multiaxial ferroelectrics and therefore active manipulation of multiple domains via flexoelectricity have not yet been achieved. Here, we demonstrate that the symmetry-breaking flexoelectricity offers a powerful route for the selective control of multiple domain switching pathways in multiaxial ferroelectric materials. Specifically, we use a trailing flexoelectric field that is created by the motion of a mechanically loaded scanning probe microscope tip. By controlling the SPM scan direction, we can deterministically select either stable 71° ferroelastic switching or 180° ferroelectric switching in a multiferroic magnetoelectric BiFeO3 thin film. Phase-field simulations reveal that the amplified in-plane trailing flexoelectric field is essential for this domain engineering. Moreover, we show that mechanically switched domains have a good retention property. This work opens a new avenue for the deterministic selection of nanoscale ferroelectric domains in low-symmetry materials for non-volatile magnetoelectric devices and multilevel data storage.

  4. Cobalt-doped ZnO as dilute magnetic semiconductor; Cobalt dotiertes ZnO als verduennter magnetischer Halbleiter

    Energy Technology Data Exchange (ETDEWEB)

    Gacic, Milan

    2009-04-24

    Dilute magnetic semiconductors (DMS) are technologically promising materials that show ferromagnetic as well as semiconducting properties. These are one of the crucial compounds concerning the development of spintronic devices. The main problem so far ist that for applications the Curie temperature of most of the DMS compounds is much too low. However, DMS compounds based on ZnO as Zn{sub 1-x}Co{sub x}O seem to show ferromagnetism above room temperature, but the ferromagnetic exchange is not fully understood. Intensive experimental investigations need to be done. In the course of this theses Zn{sub 0.95}Co{sub 0.05}O thin films were fabricated by pulsed laser deposition and investigated concerning their magnetic, magnetoelectric and structural properties in order to understand the ferromagnetism in this material. Different experimental methods have been used, as magnetometry, X-ray diffraction (XRD), X-ray magnetic circular dichroism (XMCD), electron spin resonance (ESR) and magnetoelectric transport measurements. At special preparation conditions, where a high defect density is induced, the samples are clearly ferromagnetic above room temperature with a saturation magnetization of 2 {mu}{sub b}/Co and a remanence of 90%. Electrical transport measurements show a clear magnetoresistance as well as a anomalous Hall effect. The anomalous Hall effect rises with the magnetization indicating intrinsic ferromagnetism and a certain degree of spin polarization. As the ferromagnetism disappears with rising charge carrier density the ferromagnetic interaction cannot be mediated by the conduction electrons. A more precise evaluation of the magnetoelectric results shows that there is an additional conducting impurity band which could even be spinpolarized. So there are indications that the ferromagnetism is due to magnetic polarons. Some of the structural and magnetometric results as well as the electron spin resonance measurements suggest an additional extrinsic contribution

  5. An X-ray absorption spectroscopic study of the metal site preference in Al1−xGaxFeO3

    International Nuclear Information System (INIS)

    Walker, James D.S.; Grosvenor, Andrew P.

    2013-01-01

    Magnetoelectric materials have potential for being introduced into next generation technologies, especially memory devices. The AFeO 3 (Pna2 1 ; A=Al, Ga) system has received attention to better understand the origins of magnetoelectric coupling. The magnetoelectric properties this system exhibits depend on the amount of anti-site disorder present, which is affected by the composition and the method of synthesis. In this study, Al 1−x Ga x FeO 3 was synthesized by the ceramic method and studied by X-ray absorption spectroscopy. Al L 2,3 -, Ga K-, and Fe K-edge spectra were collected to examine how the average metal coordination number changes with composition. Examination of XANES spectra from Al 1−x Ga x FeO 3 indicate that with increasing Ga content, Al increasingly occupies octahedral sites while Ga displays a preference for occupying the tetrahedral site. The Fe K-edge spectra indicate that more Fe is present in the tetrahedral site in AlFeO 3 than in GaFeO 3 , implying more anti-site disorder is present in AlFeO 3 . - Graphical abstract: Al 1−x Ga x FeO 3 has been investigated by XANES. Through examination of Al L 2,3 -, Ga K-, and Fe K-edge XANES spectra, it was found that more anti-site disorder of the Fe atoms is present in AlFeO 3 compared to in GaFeO 3 . Highlights: ► Al 1−x Ga x FeO 3 was investigated by X-ray absorption spectroscopy. ► Ga prefers to occupy the tetrahedral site in Al 1−x Ga x FeO 3 . ► Fe prefers to occupy the octahedral sites in Al 1−x Ga x FeO 3 as x increases. ► More anti-site disorder is present in AlFeO 3 compared to in GaFeO 3.

  6. One-Dimensional Chirality: Strong Optical Activity in Epsilon-Near-Zero Metamaterials.

    Science.gov (United States)

    Rizza, Carlo; Di Falco, Andrea; Scalora, Michael; Ciattoni, Alessandro

    2015-07-31

    We suggest that electromagnetic chirality, generally displayed by 3D or 2D complex chiral structures, can occur in 1D patterned composites whose components are achiral. This feature is highly unexpected in a 1D system which is geometrically achiral since its mirror image can always be superposed onto it by a 180 deg rotation. We analytically evaluate from first principles the bianisotropic response of multilayered metamaterials and we show that the chiral tensor is not vanishing if the system is geometrically one-dimensional chiral; i.e., its mirror image cannot be superposed onto it by using translations without resorting to rotations. As a signature of 1D chirality, we show that 1D chiral metamaterials support optical activity and we prove that this phenomenon undergoes a dramatic nonresonant enhancement in the epsilon-near-zero regime where the magnetoelectric coupling can become dominant in the constitutive relations.

  7. Novel topological effects in dense QCD in a magnetic field

    Science.gov (United States)

    Ferrer, E. J.; de la Incera, V.

    2018-06-01

    We study the electromagnetic properties of dense QCD in the so-called Magnetic Dual Chiral Density Wave phase. This inhomogeneous phase exhibits a nontrivial topology that comes from the fermion sector due to the asymmetry of the lowest Landau level modes. The nontrivial topology manifests in the electromagnetic effective action via a chiral anomaly term θFμνF˜μν, with a dynamic axion field θ given by the phase of the Dual Chiral Density Wave condensate. The coupling of the axion with the electromagnetic field leads to several macroscopic effects that include, among others, an anomalous, nondissipative Hall current, an anomalous electric charge, magnetoelectricity, and the formation of a hybridized propagating mode known as an axion polariton. Connection to topological insulators and Weyls semimetals, as well as possible implications for heavy-ion collisions and neutron stars are all highlighted.

  8. Semiclassical magnetotransport in strongly spin-orbit coupled Rashba two-dimensional electron systems

    Science.gov (United States)

    Xiao, Cong; Li, Dingping

    2016-06-01

    Semiclassical magnetoelectric and magnetothermoelectric transport in strongly spin-orbit coupled Rashba two-dimensional electron systems is investigated. In the presence of a perpendicular classically weak magnetic field and short-range impurity scattering, we solve the linearized Boltzmann equation self-consistently. Using the solution, it is found that when Fermi energy E F locates below the band crossing point (BCP), the Hall coefficient is a nonmonotonic function of electron density n e and not inversely proportional to n e. While the magnetoresistance (MR) and Nernst coefficient vanish when E F locates above the BCP, non-zero MR and enhanced Nernst coefficient emerge when E F decreases below the BCP. Both of them are nonmonotonic functions of E F below the BCP. The different semiclassical magnetotransport behaviors between the two sides of the BCP can be helpful to experimental identifications of the band valley regime and topological change of Fermi surface in considered systems.

  9. Semiclassical magnetotransport in strongly spin–orbit coupled Rashba two-dimensional electron systems

    International Nuclear Information System (INIS)

    Xiao, Cong; Li, Dingping

    2016-01-01

    Semiclassical magnetoelectric and magnetothermoelectric transport in strongly spin–orbit coupled Rashba two-dimensional electron systems is investigated. In the presence of a perpendicular classically weak magnetic field and short-range impurity scattering, we solve the linearized Boltzmann equation self-consistently. Using the solution, it is found that when Fermi energy E F locates below the band crossing point (BCP), the Hall coefficient is a nonmonotonic function of electron density n e and not inversely proportional to n e . While the magnetoresistance (MR) and Nernst coefficient vanish when E F locates above the BCP, non-zero MR and enhanced Nernst coefficient emerge when E F decreases below the BCP. Both of them are nonmonotonic functions of E F below the BCP. The different semiclassical magnetotransport behaviors between the two sides of the BCP can be helpful to experimental identifications of the band valley regime and topological change of Fermi surface in considered systems. (paper)

  10. Theory and experiment research for ultra-low frequency maglev vibration sensor

    International Nuclear Information System (INIS)

    Zheng, Dezhi; Liu, Yixuan; Guo, Zhanshe; Fan, Shangchun; Zhao, Xiaomeng

    2015-01-01

    A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that the lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements

  11. Magnetic response to applied electrostatic field in external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Adorno, T.C. [Universidade de Sao Paulo, Instituto de Fisica, Caixa Postal 66318, Sao Paulo, SP (Brazil); University of Florida, Department of Physics, Gainesville, FL (United States); Gitman, D.M. [Universidade de Sao Paulo, Instituto de Fisica, Caixa Postal 66318, Sao Paulo, SP (Brazil); Tomsk State University, Department of Physics, Tomsk (Russian Federation); Shabad, A.E. [P. N. Lebedev Physics Institute, Moscow (Russian Federation)

    2014-04-15

    We show, within QED and other possible nonlinear theories, that a static charge localized in a finite domain of space becomes a magnetic dipole, if it is placed in an external (constant and homogeneous) magnetic field in the vacuum. The magnetic moment is quadratic in the charge, depends on its size and is parallel to the external field, provided the charge distribution is at least cylindrically symmetric. This magneto-electric effect is a nonlinear response of the magnetized vacuum to an applied electrostatic field. Referring to the simple example of a spherically symmetric applied field, the nonlinearly induced current and its magnetic field are found explicitly throughout the space; the pattern of the lines of force is depicted, both inside and outside the charge, which resembles that of a standard solenoid of classical magnetostatics. (orig.)

  12. Multiferroic oxide thin films and heterostructures

    KAUST Repository

    Lu, Chengliang

    2015-05-26

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  13. Acoustic phonons mediated non-equilibrium spin current in the presence of Rashba and Dresselhaus spin–orbit couplings

    International Nuclear Information System (INIS)

    Hasanirokh, K.; Phirouznia, A.

    2013-01-01

    Influence of electrons interaction with longitudinal acoustic phonons on magnetoelectric and spin-related transport effects are investigated. The considered system is a two-dimensional electron gas system with both Rashba and Dresselhaus spin–orbit couplings. The works which have previously been performed in this field, have revealed that the Rashba and Dresselhaus couplings cannot be responsible for spin current in the non-equilibrium regime. In the current Letter, a semiclassical method was employed using the Boltzmann approach and it was shown that the spin current of the system, in general, does not go all the way to zero when the electron–phonon coupling is taken into account. It was also shown that spin accumulation of the system could be influenced by electron–phonon coupling.

  14. Interpreting Stone's model of Berry phases

    International Nuclear Information System (INIS)

    Carra, Paolo

    2004-01-01

    We show that a simple quantum-mechanical model, put forward by Stone some time ago, affords a description of site magnetoelectricity, a phenomenon which takes place in crystals (and molecular systems) when space inversion is locally broken and coexistence of electric and magnetic moments is permitted by the site point group. We demonstrate this by identifying a local order parameter, which is odd under both space inversion and time reversal. This order parameter (a magnetic quadrupole) characterizes Stone's ground state. Our results indicate that the model, extended to a lattice of sites, could be relevant to the study of electronic properties of transition-metal oxides. A generalization of Stone's Hamiltonian to cover cases of different symmetry is also discussed. (letter to the editor)

  15. Electrical percolation threshold of magnetostrictive inclusions in a piezoelectric matrix under simulated sintering conditions

    Science.gov (United States)

    Bedard, Antoine Joseph; Barbero, Ever J.

    2018-03-01

    Magnetoelectric (ME) composites can be produced by embedding magnetostrictive H particles in a piezoelectric E matrix derived from a piezoelectric powder precursor. Previously, using a bi-disperse hard-shell model (Barbero and Bedard in Comput Part Mech, 2018. https://doi.org/10.1007/s40571-017-0165-4), it has been shown that the electrical percolation threshold of the conductive H phase can be increased by decreasing the piezoelectric E particle size, relative to the H phase particle size, and by increasing short-range affinity between the E and H particles. This study builds on our previous study by exploring what happens during sintering of the ME composite when either the H or E particles undergo deformation. It was found that deformation of the H particles reduces the percolation threshold, and that deformation of E particles increases inter-phase H-E mechanical coupling, thus contributing to enhancing of ME coupling.

  16. Electric field modulated conduction mechanism in Al/BaTiO3/La0.67Sr0.33MnO3 heterostructures

    KAUST Repository

    Zheng, Dongxing

    2017-08-08

    Mediating a metastable state is a promising way to achieve a giant modulation of physical properties in artificial heterostructures. A metastable state La0.67Sr0.33MnO3 (LSMO) layer suffering tensile strain was grown on MgO substrates. Incorporating with the ferroelectric BaTiO3 (BTO) layer, an accumulation or depletion state controlled by electric fields can be formed at the BTO/LSMO interface, which drives a switching of the conduction mechanism between space charge limited conduction and Poole-Frenkel emission, corresponding to the low and high resistance states. Our results lighten an effective way for electric-field modulated resistance states in multiferroic magnetoelectric devices.

  17. Effect of lithographically-induced strain relaxation on the magnetic domain configuration in microfabricated epitaxially grown Fe81Ga19

    Science.gov (United States)

    Beardsley, R. P.; Parkes, D. E.; Zemen, J.; Bowe, S.; Edmonds, K. W.; Reardon, C.; Maccherozzi, F.; Isakov, I.; Warburton, P. A.; Campion, R. P.; Gallagher, B. L.; Cavill, S. A.; Rushforth, A. W.

    2017-02-01

    We investigate the role of lithographically-induced strain relaxation in a micron-scaled device fabricated from epitaxial thin films of the magnetostrictive alloy Fe81Ga19. The strain relaxation due to lithographic patterning induces a magnetic anisotropy that competes with the magnetocrystalline and shape induced anisotropies to play a crucial role in stabilising a flux-closing domain pattern. We use magnetic imaging, micromagnetic calculations and linear elastic modelling to investigate a region close to the edges of an etched structure. This highly-strained edge region has a significant influence on the magnetic domain configuration due to an induced magnetic anisotropy resulting from the inverse magnetostriction effect. We investigate the competition between the strain-induced and shape-induced anisotropy energies, and the resultant stable domain configurations, as the width of the bar is reduced to the nanoscale range. Understanding this behaviour will be important when designing hybrid magneto-electric spintronic devices based on highly magnetostrictive materials.

  18. Theory and experiment research for ultra-low frequency maglev vibration sensor

    Science.gov (United States)

    Zheng, Dezhi; Liu, Yixuan; Guo, Zhanshe; Zhao, Xiaomeng; Fan, Shangchun

    2015-10-01

    A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that the lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements.

  19. Field-induced magnetic phases and electric polarization in LiNiPO4

    DEFF Research Database (Denmark)

    Jensen, Thomas Bagger Stibius; Christensen, Niels Bech; Kenzelmann, M.

    2009-01-01

    Neutron diffraction is used to probe the (H,T) phase diagram of magnetoelectric (ME) LiNiPO4 for magnetic fields along the c axis. At zero field the Ni spins order in two antiferromagnetic phases. One has commensurate (C) structures and general ordering vectors k(C)=(0,0,0); the other one...... is incommensurate (IC) with k(IC)=(0,q,0). At low temperatures the C order collapses above mu H-0=12 T and adopts an IC structure with modulation vector parallel to k(IC). We show that C order is required for the ME effect and establish how electric polarization results from a field-induced reduction in the total...

  20. Instrument for x-ray absorption spectroscopy with in situ electrical control characterizations

    International Nuclear Information System (INIS)

    Huang, Chun-Chao; Chang, Shu-Jui; Yang, Chao-Yao; Tseng, Yuan-Chieh; Chou, Hsiung

    2013-01-01

    We report a synchrotron-based setup capable of performing x-ray absorption spectroscopy and x-ray magnetic circular dichroism with simultaneous electrical control characterizations. The setup can enable research concerning electrical transport, element- and orbital-selective magnetization with an in situ fashion. It is a unique approach to the real-time change of spin-polarized electronic state of a material/device exhibiting magneto-electric responses. The performance of the setup was tested by probing the spin-polarized states of cobalt and oxygen of Zn 1-x Co x O dilute magnetic semiconductor under applied voltages, both at low (∼20 K) and room temperatures, and signal variations upon the change of applied voltage were clearly detected