Statistical mechanical lattice model of the dual-peak electrocaloric effect in ferroelectric relaxors and the role of pressure

International Nuclear Information System (INIS)

Dunne, Lawrence J; Axelsson, Anna-Karin; Alford, Neil McN; Valant, Matjaz; Manos, George

2011-01-01

Despite considerable effort, the microscopic origin of the electrocaloric (EC) effect in ferroelectric relaxors is still intensely discussed. Ferroelectric relaxors typically display a dual-peak EC effect, whose origin is uncertain. Here we present an exact statistical mechanical matrix treatment of a lattice model of polar nanoregions forming in a neutral background and use this approach to study the characteristics of the EC effect in ferroelectric relaxors under varying electric field and pressure. The dual peaks seen in the EC properties of ferroelectric relaxors are due to the formation and ordering of polar nanoregions. The model predicts significant enhancement of the EC temperature rise with pressure which may have some contribution to the giant EC effect.

Monte Carlo simulations for describing the ferroelectric-relaxor crossover in BaTiO3-based solid solutions

International Nuclear Information System (INIS)

Padurariu, Leontin; Enachescu, Cristian; Mitoseriu, Liliana

2011-01-01

The properties induced by the M 4+ addition (M = Zr, Sn, Hf) in BaM x Ti 1-x O 3 solid solutions have been described on the basis of a 2D Ising-like network and Monte Carlo calculations, in which BaMO 3 randomly distributed unit cells were considered as being non-ferroelectric. The polarization versus temperature dependences when increasing the M 4+ concentration (x) showed a continuous reduction of the remanent polarization and of the critical temperature corresponding to the ferroelectric-paraelectric transition and a modification from a first-order to a second-order phase transition with a broad temperature range for which the transition takes place, as commonly reported for relaxors. The model also describes the system's tendency to reduce the polar clusters' average size while increasing their stability in time at higher temperatures above the Curie range, when a ferroelectric-relaxor crossover is induced by increasing the substitution (x). The equilibrium micropolar states during the polarization reversal process while describing the P(E) loops were comparatively monitored for the ferroelectric (x = 0) and relaxor (x = 0.3) states. Polarization reversal in relaxor compositions proceeds by the growth of several nucleated domains (the 'labyrinthine domain pattern') instead of the large scale domain formation typical for the ferroelectric state. The spatial and temporal evolution of the polar clusters in BaM x Ti 1-x O 3 solid solutions at various x has also been described by the correlation length and correlation time. As expected for the ferroelectric-relaxor crossover characterized by a progressive increasing degree of disorder, local fluctuations cause a reducing correlation time when the substitution degree increases, at a given temperature. The correlation time around the Curie temperature increases, reflecting the increasing stability in time of some polar nanoregions in relaxors in comparison with ferroelectrics, which was experimentally proved in

Ferroelectric capped magnetization in multiferroic PZT/LSMO tunnel junctions

Energy Technology Data Exchange (ETDEWEB)

Kumar, Ashok, E-mail: ashok553@nplindia.org; Shukla, A. K. [National Physical Laboratory (CSIR), Dr. K. S. Krishnan Road, New Delhi-110012 (India); Barrionuevo, D.; Ortega, N.; Katiyar, Ram S. [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343 (United States); Shannigrahi, Santiranjan [Institute of Materials Research and Engineering - IMRE, Agency for Science Technology and Research (A-STAR), 3 Research Link, Singapore 117602 (Singapore); Scott, J. F. [Department of Chemistry and Department of Physics, University of St. Andrews, St. Andrews KY16 ST (United Kingdom)

2015-03-30

Self-poled ultra-thin ferroelectric PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PZT) (5 and 7 nm) films have been grown by pulsed laser deposition technique on ferromagnetic La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO) (30 nm) to check the effect of polar capping on magnetization for ferroelectric tunnel junction devices. PZT/LSMO heterostructures with thick polar PZT (7 nm) capping show nearly 100% enhancement in magnetization compared with thin polar PZT (5 nm) films, probably due to excess hole transfer from the ferroelectric to the ferromagnetic layers. Core-level x-ray photoelectron spectroscopy studies revealed the presence of larger Mn 3s exchange splitting and higher Mn{sup 3+}/Mn{sup 4+} ion ratio in the LSMO with 7 nm polar capping.

Development of “fragility” in relaxor ferroelectrics

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi-zhen, E-mail: wangyizhen80@gmail.com [College of Physics and Electronic Engineering, Hainan Normal University, Haikou 571158 (China); Bioengineering Program and Mechanical Engineering and Mechanics Department, Lehigh University, 19 Memorial Drive West, Bethlehem, Pennsylvania 18015 (United States); State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Chen, Lan; Xiong, Xiao-min; Zhang, Jin-xiu [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Wang, Hai-yan [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Guangzhou Institute of Measurement and Testing Technology, Guangzhou 510663 (China); Frank Zhang, X. [Bioengineering Program and Mechanical Engineering and Mechanics Department, Lehigh University, 19 Memorial Drive West, Bethlehem, Pennsylvania 18015 (United States); Fu, Jun [College of Physics and Electronic Engineering, Hainan Normal University, Haikou 571158 (China)

2014-02-07

Relaxor ferroelectrics (RFs), a special class of the disordered crystals or ceramics, exhibit a pronounced slowdown of their dynamics upon cooling as glass-forming liquids, called the “Super-Arrhenius (SA)” relaxation. Despite great progress in glass-forming liquids, the “fragility” property of the SA relaxation in RFs remains unclear so far. By measuring the temperature-dependent dielectric relaxation in the typical relaxor Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-x%PbTiO{sub 3} (PMN − x%PT) with 0 ≤ x ≤ 20.0, we in-depth study the “fragility” properties of the SA relaxation in PMN − x%PT. Such fascinating issues as the mechanism of the “fragility” at an atomic scale, the roles of the systematic configurational entropy change and interaction among relaxing units (RUs, including polar nanoregions and free dipoles) and the relation between “fragility” and ferroelectric order are investigated. Our results show that both the “fragility” of the temperature-dependent SA relaxation and ferroelectric order in the PMN − x%PT systems investigated arise thermodynamically from the configurational-entropy loss due to the attractive interaction among RUs, and develops as a power law, possibly diverging at the finite critical temperature T{sub c}. A reasonable physical scenario, based on our “configurational-entropy-loss” theory and Nowick's “stress-induced-ordering” theory, was proposed.

Development of “fragility” in relaxor ferroelectrics

International Nuclear Information System (INIS)

Wang, Yi-zhen; Chen, Lan; Xiong, Xiao-min; Zhang, Jin-xiu; Wang, Hai-yan; Frank Zhang, X.; Fu, Jun

2014-01-01

Relaxor ferroelectrics (RFs), a special class of the disordered crystals or ceramics, exhibit a pronounced slowdown of their dynamics upon cooling as glass-forming liquids, called the “Super-Arrhenius (SA)” relaxation. Despite great progress in glass-forming liquids, the “fragility” property of the SA relaxation in RFs remains unclear so far. By measuring the temperature-dependent dielectric relaxation in the typical relaxor Pb(Mg 1/3 Nb 2/3 )O 3 -x%PbTiO 3 (PMN − x%PT) with 0 ≤ x ≤ 20.0, we in-depth study the “fragility” properties of the SA relaxation in PMN − x%PT. Such fascinating issues as the mechanism of the “fragility” at an atomic scale, the roles of the systematic configurational entropy change and interaction among relaxing units (RUs, including polar nanoregions and free dipoles) and the relation between “fragility” and ferroelectric order are investigated. Our results show that both the “fragility” of the temperature-dependent SA relaxation and ferroelectric order in the PMN − x%PT systems investigated arise thermodynamically from the configurational-entropy loss due to the attractive interaction among RUs, and develops as a power law, possibly diverging at the finite critical temperature T c . A reasonable physical scenario, based on our “configurational-entropy-loss” theory and Nowick's “stress-induced-ordering” theory, was proposed

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.

Electric and ferroelectric properties of PZT/BLT multilayer films prepared by photochemical metal-organic deposition

Science.gov (United States)

Park, Hyeong-Ho; Lee, Hong-Sub; Park, Hyung-Ho; Hill, Ross H.; Hwang, Yun Taek

2009-01-01

The electric and ferroelectric properties of lead zirconate titanate (PZT) and lanthanum-substituted bismuth titanate (BLT) multilayer films prepared using photosensitive precursors were characterized. The electric and ferroelectric properties were investigated by studying the effect of the stacking order of four ferroelectric layers of PZT or BLT in 4-PZT, PZT/2-BLT/PZT, BLT/2-PZT/BLT, and 4-BLT multilayer films. The remnant polarization values of the 4-BLT and BLT/2-PZT/BLT multilayer films were 12 and 17 μC/cm 2, respectively. Improved ferroelectric properties of the PZT/BLT multilayer films were obtained by using a PZT intermediate layer. The films which contained a BLT layer on the Pt substrate had improved leakage currents of approximately two orders of magnitude and enhanced fatigue resistances compared to the films with a PZT layer on the Pt substrate. These improvements are due to the reduced number of defects and space charges near the Pt electrodes. The PZT/BLT multilayer films prepared by photochemical metal-organic deposition (PMOD) possessed enhanced electric and ferroelectric properties, and allow direct patterning to fabricate micro-patterned systems without dry etching.

Electric and ferroelectric properties of PZT/BLT multilayer films prepared by photochemical metal-organic deposition

International Nuclear Information System (INIS)

Park, Hyeong-Ho; Lee, Hong-Sub; Park, Hyung-Ho; Hill, Ross H.; Hwang, Yun Taek

2009-01-01

The electric and ferroelectric properties of lead zirconate titanate (PZT) and lanthanum-substituted bismuth titanate (BLT) multilayer films prepared using photosensitive precursors were characterized. The electric and ferroelectric properties were investigated by studying the effect of the stacking order of four ferroelectric layers of PZT or BLT in 4-PZT, PZT/2-BLT/PZT, BLT/2-PZT/BLT, and 4-BLT multilayer films. The remnant polarization values of the 4-BLT and BLT/2-PZT/BLT multilayer films were 12 and 17 μC/cm 2 , respectively. Improved ferroelectric properties of the PZT/BLT multilayer films were obtained by using a PZT intermediate layer. The films which contained a BLT layer on the Pt substrate had improved leakage currents of approximately two orders of magnitude and enhanced fatigue resistances compared to the films with a PZT layer on the Pt substrate. These improvements are due to the reduced number of defects and space charges near the Pt electrodes. The PZT/BLT multilayer films prepared by photochemical metal-organic deposition (PMOD) possessed enhanced electric and ferroelectric properties, and allow direct patterning to fabricate micro-patterned systems without dry etching.

Relaxor ferroelectrics: back to the single-soft-mode picture

Czech Academy of Sciences Publication Activity Database

Hehlen, B.; Al-Sabbagh, M.; Al-Zein, A.; Hlinka, Jiří

2016-01-01

Roč. 117, č. 15 (2016), 1-6, č. článku 155501. ISSN 0031-9007 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : relaxor * ferroelectrics * light-scattering * hyper-Raman * dielectric permittivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 8.462, year: 2016

Origin of the "Waterfall" Effect in Phonon Dispersion of Relaxor Perovskites

OpenAIRE

Hlinka, J.; Kamba, S.; Petzelt, J.; Kulda, J.; Randall, C. A.; Zhang, S. J.

2003-01-01

We have undertaken an inelastic neutron scattering study of the perovskite relaxor ferroelectric \\ud P\\ud b\\ud (\\ud Z\\ud n\\ud 1\\ud /\\ud 3\\ud N\\ud b\\ud 2\\ud /\\ud 3\\ud )\\ud O\\ud 3\\ud with 8% \\ud P\\ud b\\ud T\\ud i\\ud O\\ud 3\\ud (PZN-8%PT) in order to elucidate the origin of the previously reported unusual kink on the low frequency transverse phonon dispersion curve (known as the “waterfall effect”). We show that its position (\\ud q\\ud w\\ud f\\ud ) depends on the choice of the Brillouin zone and tha...

Kinetics of Domain Switching by Mechanical and Electrical Stimulation in Relaxor-Based Ferroelectrics

Science.gov (United States)

Chen, Zibin; Hong, Liang; Wang, Feifei; An, Xianghai; Wang, Xiaolin; Ringer, Simon; Chen, Long-Qing; Luo, Haosu; Liao, Xiaozhou

2017-12-01

Ferroelectric materials have been extensively explored for applications in high-density nonvolatile memory devices because of their ferroelectric-ferroelastic domain-switching behavior under electric loading or mechanical stress. However, the existence of ferroelectric and ferroelastic backswitching would cause significant data loss, which affects the reliability of data storage. Here, we apply in situ transmission electron microscopy and phase-field modeling to explore the unique ferroelastic domain-switching kinetics and the origin of this in relaxor-based Pb (Mg1 /3Nb2 /3)O3-33 % PbTiO3 single-crystal pillars under electrical and mechanical stimulations. Results showed that the electric-mechanical hysteresis loop shifted for relaxor-based single-crystal pillars because of the low energy levels of domains in the material and the constraint on the pillars, resulting in various mechanically reversible and irreversible domain-switching states. The phenomenon can potentially be used for advanced bit writing and reading in nonvolatile memories, which effectively overcomes the backswitching problem and broadens the types of ferroelectric materials for nonvolatile memory applications.

Origin of the "waterfall" effect in phonon dispersion of relaxor perovskites.

Science.gov (United States)

Hlinka, J; Kamba, S; Petzelt, J; Kulda, J; Randall, C A; Zhang, S J

2003-09-05

We have undertaken an inelastic neutron scattering study of the perovskite relaxor ferroelectric Pb(Zn(1/3)Nb(2/3))O3 with 8% PbTiO3 (PZN-8%PT) in order to elucidate the origin of the previously reported unusual kink on the low frequency transverse phonon dispersion curve (known as the "waterfall effect"). We show that its position (q(wf)) depends on the choice of the Brillouin zone and that the relation of q(wf) to the size of the polar nanoregions is highly improbable. The waterfall phenomenon is explained in the framework of a simple model of coupled damped harmonic oscillators representing the acoustic and optic phonon branches.

Synthesis and dielectric properties of ferroelectric-ferrimagnetic PZT-SFMO composites

Directory of Open Access Journals (Sweden)

Alexander V. Petrov

2017-03-01

Full Text Available Ferrimagnetic-ferroelectric composite materials on the base of Pb0.85Zr0.53Ti0.47O3– Sr2FeMoO6–δ (PZT-SFMO compounds have been prepared by a complex ceramic technology and a modified sol-gel synthesis. The dielectric properties of the PZT-SFMO composites with the PZT concentrations of 55 wt% and less, as well as of pure SFMO, are caused by the Maxwell-Wagner relaxation and a huge electrical conductivity. In contrast, in pure PZT the ferroelectric phase transition is clearly expressed in the static dielectric permittivity anomaly. Moreover, in all investigated composites, similarly to pure SFMO, the electrical conductivity anomaly is observed in the range from 560–540 K. This indicates that the composites with PZT concentrations of 55 wt% and higher are above the electrical and magnetic percolation threshold, in a good agreement with the excluded volume theory. In PZT-SFMO composites the DC electrical conductivity increases with SFMO concentration almost in a power law fashion, while the activation energy of the DC conductivity decreases under certain conditions.

Advantages and Challenges of Relaxor-PbTiO3 Ferroelectric Crystals for Electroacoustic Transducers- A Review

Science.gov (United States)

Zhang, Shujun; Li, Fei; Jiang, Xiaoning; Kim, Jinwook; Luo, Jun; Geng, Xuecang

2014-01-01

Relaxor-PbTiO3 (PT) based ferroelectric crystals with the perovskite structure have been investigated over the last few decades due to their ultrahigh piezoelectric coefficients (d33 > 1500 pC/N) and electromechanical coupling factors (k33 > 90%), far outperforming state-of-the-art ferroelectric polycrystalline Pb(Zr,Ti)O3 ceramics, and are at the forefront of advanced electroacoustic applications. In this review, the performance merits of relaxor-PT crystals in various electroacoustic devices are presented from a piezoelectric material viewpoint. Opportunities come from not only the ultrahigh properties, specifically coupling and piezoelectric coefficients, but through novel vibration modes and crystallographic/domain engineering. Figure of merits (FOMs) of crystals with various compositions and phases were established for various applications, including medical ultrasonic transducers, underwater transducers, acoustic sensors and tweezers. For each device application, recent developments in relaxor-PT ferroelectric crystals were surveyed and compared with state-of-the-art polycrystalline piezoelectrics, with an emphasis on their strong anisotropic features and crystallographic uniqueness, including engineered domain - property relationships. This review starts with an introduction on electroacoustic transducers and the history of piezoelectric materials. The development of the high performance relaxor-PT single crystals, with a focus on their uniqueness in transducer applications, is then discussed. In the third part, various FOMs of piezoelectric materials for a wide range of ultrasound applications, including diagnostic ultrasound, therapeutic ultrasound, underwater acoustic and passive sensors, tactile sensors and acoustic tweezers, are evaluated to provide a thorough understanding of the materials’ behavior under operational conditions. Structure-property-performance relationships are then established. Finally, the impacts and challenges of relaxor

Stacking effect on the ferroelectric properties of PZT/PLZT multilayer thin films formed by photochemical metal-organic deposition

International Nuclear Information System (INIS)

Park, Hyeong-Ho; Park, Hyung-Ho; Hill, Ross H.

2004-01-01

The ferroelectric properties of lead zirconate titanate (PZT) and lanthanum-doped lead zirconate titanate (PLZT) multilayer films formed by photochemical metal-organic deposition (PMOD) using photosensitive precursors have been characterized. The substitution of La for Pb was reported to induce improved ferroelectric properties, especially fatigue resistance, through the reduction of oxygen vacancies. The relation between La-substitution and the ferroelectric properties was investigated by characterization of the effect of the order of stacking four ferroelectric layers of PZT or PLZT in the multilayer films 4-PZT, PZT/2-PLZT/PZT, PLZT/2-PZT/PLZT, and 4-PLZT. The films with the PLZT layer at the top and bottom showed an improvement in the fatigue resistance. It was revealed that defect dipole such as O vacancy was reduced at the ferroelectric/Pt interface by doping with La. Also, the bottom layer, just on Pt substrate had a significant influence on the surface microstructure and growth orientation of ferroelectric film

Structural, dielectric and ferroelectric characterization of PZT thin films

Directory of Open Access Journals (Sweden)

Araújo E.B.

1999-01-01

Full Text Available In this work ferroelectric thin films of PZT were prepared by the oxide precursor method, deposited on Pt/Si substrate. Films of 0.5 mm average thickness were obtained. Electrical and ferroelectric characterization were carried out in these films. The measured value of the dielectric constant for films was 455. Ferroelectricity was confirmed by Capacitance-Voltage (C-V characteristics and P-E hysteresis loops. Remanent polarization for films presented value around 5.0 µC/cm2 and a coercive field of 88.8 kV/cm.

Thin PZT-Based Ferroelectric Capacitors on Flexible Silicon for Nonvolatile Memory Applications

KAUST Repository

Ghoneim, Mohamed T.; Zidan, Mohammed A.; Al-Nassar, Mohammed Y.; Hanna, Amir; Kosel, Jü rgen; Salama, Khaled N.; Hussain, Muhammad Mustafa

2015-01-01

A flexible version of traditional thin lead zirconium titanate ((Pb1.1Zr0.48Ti0.52O3)-(PZT)) based ferroelectric random access memory (FeRAM) on silicon shows record performance in flexible arena. The thin PZT layer requires lower operational

Visualization of dielectric constant-electric field-temperature phase maps for imprinted relaxor ferroelectric thin films

International Nuclear Information System (INIS)

Frederick, J. C.; Kim, T. H.; Maeng, W.; Brewer, A. A.; Podkaminer, J. P.; Saenrang, W.; Vaithyanathan, V.; Schlom, D. G.; Li, F.; Chen, L.-Q.; Trolier-McKinstry, S.; Rzchowski, M. S.; Eom, C. B.

2016-01-01

The dielectric phase transition behavior of imprinted lead magnesium niobate–lead titanate relaxor ferroelectric thin films was mapped as a function of temperature and dc bias. To compensate for the presence of internal fields, an external electric bias was applied while measuring dielectric responses. The constructed three-dimensional dielectric maps provide insight into the dielectric behaviors of relaxor ferroelectric films as well as the temperature stability of the imprint. The transition temperature and diffuseness of the dielectric response correlate with crystallographic disorder resulting from strain and defects in the films grown on strontium titanate and silicon substrates; the latter was shown to induce a greater degree of disorder in the film as well as a dielectric response lower in magnitude and more diffuse in nature over the same temperature region. Strong and stable imprint was exhibited in both films and can be utilized to enhance the operational stability of piezoelectric devices through domain self-poling.

High Performance Relaxor-Based Ferroelectric Single Crystals for Ultrasonic Transducer Applications

Directory of Open Access Journals (Sweden)

Yan Chen

2014-07-01

Full Text Available Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3O3-PbTiO3 (PMN-PT have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33~2000 pC/N, kt~60% near the morphotropic phase boundary (MPB. Ternary Pb(In1/2Nb1/2O3-Pb(Mg1/3Nb2/3O3-PbTiO3 (PIN-PMN-PT single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed.

Thin PZT-Based Ferroelectric Capacitors on Flexible Silicon for Nonvolatile Memory Applications

KAUST Repository

Ghoneim, Mohamed T.

2015-04-24

A flexible version of traditional thin lead zirconium titanate ((Pb1.1Zr0.48Ti0.52O3)-(PZT)) based ferroelectric random access memory (FeRAM) on silicon shows record performance in flexible arena. The thin PZT layer requires lower operational voltages to achieve coercive electric fields, reduces the sol-gel coating cycles required (i.e., more cost-effective), and, fabrication wise, is more suitable for further scaling of lateral dimensions to the nano-scale due to the larger feature size-to-depth aspect ratio (critical for ultra-high density non-volatile memory applications). Utilizing the inverse proportionality between substrate\\'s thickness and its flexibility, traditional PZT based FeRAM on silicon is transformed through a transfer-less manufacturable process into a flexible form that matches organic electronics\\' flexibility while preserving the superior performance of silicon CMOS electronics. Each memory cell in a FeRAM array consists of two main elements; a select/access transistor, and a storage ferroelectric capacitor. Flexible transistors on silicon have already been reported. In this work, we focus on the storage ferroelectric capacitors, and report, for the first time, its performance after transformation into a flexible version, and assess its key memory parameters while bent at 0.5 cm minimum bending radius.

The effects of PbZn1/3Nb2/3O3-doping on structural, thermal, optical, dielectric, and ferroelectric properties of BaTiO3 ceramics

Science.gov (United States)

Suchanicz, J.; Świerczek, K.; Sitko, D.; Czaja, P.; Marchet, P.; Czternastek, H.; Majda, D.

2017-09-01

Low-lead (1-x)BT-xPZN (x = 0, 0.025, 0.05, 0.075, 0.10, 0.125, and 0.15) ceramics were successfully synthesized by the spark-plasma-sintering method for the first time. Their phase transition behavior as well as structural, thermal, optical, and electrical properties was investigated. These materials exhibit the structure of perovskite-type solid solutions and undergo a sequence of phase transitions, typical of pure BaTiO3 (BT). The dielectric test results revealed that with the increase in the PbZn1/3Nb2/3O3 (PZN) content, the frequency dispersion of electric permittivity increases, whilst the dielectric/ferroelectric properties tend to deteriorate, which is characteristic of relaxor-type behavior. Therefore, it is reasonable to suppose that these ceramics progressively lack long-range ordering. These effects are due to the competition between lone-pair electrons' induced changes in the A-O band upon Pb2+ addition and ionic size differences. In general, the transition temperatures observed by dielectric analyses are in good agreement with those obtained from X-ray diffraction and differential scanning calorimetry measurements. The BT-PZN system may help to understand why relaxor behavior appears in perovskite-based materials. It appears that these materials can become a good starting point for the development of new low-lead electronic ceramics.

Aging and Barkhausen Noise in the Relaxor Ferroelectric SBN:La and PMN/PT

Science.gov (United States)

Chao, Lambert K.; Colla, Eugene V.; Weissman, M. B.

2003-03-01

Relaxor ferroelectrics form a diverse class of materials which exhibit frequency-dependent freezing into a disordered state. The relation to other cooperative glassy freezing, such as in spin glasses, remain uncertain. Previous aging investigations on several relaxors already indicate diverse behavior (E.V. Colla phet al., Phys. Rev. B 63, 134107 (2001)). We present results on aging behavior on PMN/PT (90/10) and SBN:La. SBN:La, believed to fit a random-field Ising model, exhibits complicated aging behavior with a low-temperature regime lacking the memory effects characteristic of spin-glass-like aging seen in the perovskites PMN and PMN/PT. Further information on the glassy freezing is provided via Barkhausen noise experiments using a balanced capacitance bridge technique capable of measuring random noise despite a large systematic background signal [E.V. Colla phet al., Phys. Rev. Lett. 88 017601 (2002).].

Structural Contribution to the Ferroelectric Fatigue in Lead Zirconate Titanate (PZT) Ceramics

OpenAIRE

Hinterstein , Manuel; Rouquette , Jerome; Haines , J; Papet , Ph; Glaum , Julia; Knapp , Michael; Eckert , J; Hoffman , M

2014-01-01

International audience; Many ferroelectric devices are based on doped lead zirconate titanate (PZT) ceramics with compositions near the morphotropic phase boundary (MPB), at which the relevant material's properties approach their maximum. Based on a synchrotron x-ray diffraction study of MPB PZT, bulk fatigue is unambiguously found to arise from a less effective field induced tetragonal-to-monoclinic transformation, at which the degradation of the polarization flipping is detected by a less i...

Stress effects in ferroelectric perovskite thin-films

Science.gov (United States)

Zednik, Ricardo Johann

The exciting class of ferroelectric materials presents the engineer with an array of unique properties that offer promise in a variety of applications; these applications include infra-red detectors ("night-vision imaging", pyroelectricity), micro-electro-mechanical-systems (MEMS, piezoelectricity), and non-volatile memory (NVM, ferroelectricity). Realizing these modern devices often requires perovskite-based ferroelectric films thinner than 100 nm. Two such technologically important material systems are (Ba,Sr)TiO3 (BST), for tunable dielectric devices employed in wireless communications, and Pb(Zr,Ti)O3 (PZT), for ferroelectric non-volatile memory (FeRAM). In general, the material behavior is strongly influenced by the mechanical boundary conditions imposed by the substrate and surrounding layers and may vary considerably from the known bulk behavior. A better mechanistic understanding of these effects is essential for harnessing the full potential of ferroelectric thin-films and further optimizing existing devices. Both materials share a common crystal structure and similar properties, but face unique challenges due to the design parameters of these different applications. Tunable devices often require very low dielectric loss as well as large dielectric tunability. Present results show that the dielectric response of BST thin-films can either resemble a dipole-relaxor or follow the accepted empirical Universal Relaxation Law (Curie-von Schweidler), depending on temperature. These behaviors in a single ferroelectric thin-film system are often thought to be mutually exclusive. In state-of-the-art high density FeRAM, the ferroelectric polarization is at least as important as the dielectric response. It was found that these properties are significantly affected by moderate biaxial tensile and compressive stresses which reversibly alter the ferroelastic domain populations of PZT at room temperature. The 90-degree domain wall motion observed by high resolution

Stable Ferroelectric Behavior of Nb-Modified Bi0.5K0.5TiO3-Bi(Mg0.5Ti0.5)O3 Lead-Free Relaxor Ferroelectric Ceramics

Science.gov (United States)

Zaman, Arif; Malik, Rizwan Ahmed; Maqbool, Adnan; Hussain, Ali; Ahmed, Tanveer; Song, Tae Kwon; Kim, Won-Jeong; Kim, Myong-Ho

2018-03-01

Crystal structure, dielectric, ferroelectric, piezoelectric, and electric field-induced strain properties of lead-free Nb-modified 0.96Bi0.5K0.5TiO3-0.04Bi(Mg0.5Ti0.5)O3 (BKT-BMT) piezoelectric ceramics were investigated. Crystal structure analysis showed a gradual phase transition from tetragonal to pseudocubic phase with increasing Nb content. The optimal piezoelectric property of small-signal d 33 was enhanced up to ˜ 68 pC/N with a lower coercive field ( E c) of ˜ 22 kV/cm and an improved remnant polarization ( P r) of ˜ 13 μC/cm2 for x = 0.020. A relaxor-like behavior with a frequency-dependent Curie temperature T m was observed, and a high T m around 320°C was obtained in the investigated system. This study suggests that the ferroelectric properties of BKT-BMT was significantly improved by means of Nb substitution. The possible shift of depolarization temperature T d toward high temperature T m may have triggered the spontaneous relaxor to ferroelectric phase transition with long-range ferroelectric order without any traces of a nonergodic relaxor state in contradiction with Bi0.5Na0.5TiO3-based systems. The possible enhancement in ferroelectric and piezoelectric properties near the critical composition x = 0.020 may be attributed to the increased anharmonicity of lattice vibrations which may facilitate the observed phase transition from a low-symmetry tetragonal to a high-symmetry cubic phase with a decrease in the lattice anisotropy of an undoped sample. This highly flexible (at a unit cell level) narrow compositional range triggers the enhancement of d 33 and P r values.

Multidimensional dynamic piezoresponse measurements. Unraveling local relaxation behavior in relaxor-ferroelectrics via big data

International Nuclear Information System (INIS)

Vasudevan, Rama K.; Zhang, Shujun; Okatan, Mahmut Baris; Jesse, Stephen; Kalinin, Sergei V.; Bassiri-Gharb, Nazanin

2015-01-01

Compositional and charge disorder in ferroelectric relaxors lies at the heart of the unusual properties of these systems, such as aging and non-ergodicity, polarization rotations, and a host of temperature and field-driven phase transitions. However, much information about the field-dynamics of the polarization in the prototypical ferroelectric relaxor (1-x)Pb(Mg 1/3 Nb 2/3 )O 3-x PbTiO 3 (PMN-xPT) remains unprobed at the mesoscopic level. We use a piezoresponse force microscopy-based dynamic multimodal relaxation spectroscopy technique, enabling the study of ferroelectric switching and polarization relaxation at mesoscopic length scales, and carry out measurements on a PMN-0.28PT sample with minimal polishing. Results indicate that beyond a threshold DC bias the average relaxation increases as the system attempts to relax to the previous state. Phenomenological fitting reveals the presence of mesoscale heterogeneity in relaxation amplitudes and clearly suggests the presence of two distinct amplitudes. Independent component analysis reveals the presence of a disorder component of the relaxation, which is found to be strongly anti-correlated with the maximum piezoresponse at that location, suggesting smaller disorder effects where the polarization reversal is large and vice versa. The disorder in the relaxation amplitudes is postulated to arise from rhombohedral and field-induced tetragonal phase in the crystal, with each phase associated with its own relaxation amplitude. As a result, these studies highlight the crucial importance of the mixture of ferroelectric phases in the compositions in proximity of the morphotropic phase boundary in governing the local response and further highlight the ability of PFM voltage and time spectroscopies, in conjunction with big-data multivariate analyses, to locally map disorder and correlate it with parameters governing the dynamic behavior

Polarization-dependent interfacial coupling modulation of ferroelectric photovoltaic effect in PZT-ZnO heterostructures.

Science.gov (United States)

Pan, Dan-Feng; Bi, Gui-Feng; Chen, Guang-Yi; Zhang, Hao; Liu, Jun-Ming; Wang, Guang-Hou; Wan, Jian-Guo

2016-03-08

Recently, ferroelectric perovskite oxides have drawn much attention due to potential applications in the field of solar energy conversion. However, the power conversion efficiency of ferroelectric photovoltaic effect currently reported is far below the expectable value. One of the crucial problems lies in the two back-to-back Schottky barriers, which are formed at the ferroelectric-electrode interfaces and blocking most of photo-generated carriers to reach the outside circuit. Herein, we develop a new approach to enhance the ferroelectric photovoltaic effect by introducing the polarization-dependent interfacial coupling effect. Through inserting a semiconductor ZnO layer with spontaneous polarization into the ferroelectric ITO/PZT/Au film, a p-n junction with strong polarization-dependent interfacial coupling effect is formed. The power conversion efficiency of the heterostructure is improved by nearly two orders of magnitude and the polarization modulation ratio is increased about four times. It is demonstrated that the polarization-dependent interfacial coupling effect can give rise to a great change in band structure of the heterostructure, not only producing an aligned internal electric field but also tuning both depletion layer width and potential barrier height at PZT-ZnO interface. This work provides an efficient way in developing highly efficient ferroelectric-based solar cells and novel optoelectronic memory devices.

Electrical and ferroelectric properties of RF sputtered PZT/SBN on silicon for non-volatile memory applications

Science.gov (United States)

Singh, Prashant; Jha, Rajesh Kumar; Singh, Rajat Kumar; Singh, B. R.

2018-02-01

We report the integration of multilayer ferroelectric film deposited by RF magnetron sputtering and explore the electrical characteristics for its application as the gate of ferroelectric field effect transistor for non-volatile memories. PZT (Pb[Zr0.35Ti0.65]O3) and SBN (SrBi2Nb2O9) ferroelectric materials were selected for the stack fabrication due to their large polarization and fatigue free properties respectively. Electrical characterization has been carried out to obtain memory window, leakage current density, PUND and endurance characteristics. Fabricated multilayer ferroelectric film capacitor structure shows large memory window of 17.73 V and leakage current density of the order 10-6 A cm-2 for the voltage sweep of -30 to +30 V. This multilayer gate stack of PZT/SBN shows promising endurance property with no degradation in the remnant polarization for the read/write iteration cycles upto 108.

Ferroelectric switching of band alignments in LSMO/PZT/Co multiferroic tunnel junctions: an ab initio study.

Science.gov (United States)

Imam, M; Stojić, N; Binggeli, N

2017-08-04

Band alignments in ferroelectric tunnel junctions (FTJs) are expected to play a critical role in determining the charge transport across the tunneling barrier. In general, however, the interface band discontinuities and their polarization dependence are not well known in these systems. Using a first-principles density-functional-theory approach, we explore the ferroelectric (FE) polarization dependence of the band alignments in [Formula: see text] (LSMO/PZT/Co) multiferroic tunnel junctions, for which recent experiments indicated an ON/OFF conductivity behavior upon switching the PZT FE polarization. Our results on the pseudomorphic defect-free LSMO/PZT/Co FTJs evidence a major FE switching effect on the band discontinuities at both interfaces. Based on the changes in the band alignments, we provide a possible explanation for the observed trends in the resistive switching.

Enhanced ferroelectric and piezoelectric properties in La-modified PZT ceramics

Science.gov (United States)

Kour, P.; Pradhan, S. K.; Kumar, Pawan; Sinha, S. K.; Kar, Manoranjan

2016-06-01

The effect of lanthanum (La) doping on ferroelectric and piezoelectric properties of lead zirconate titanate (PZT) sample has been investigated. Pb1- x La x Zr0.52Ti0.48O3 ceramics with x = 0.00, 0.02, 0.04, 0.06 and 0.10 were prepared by the sol-gel technique. Raman and Fourier transforms infrared spectroscopy have been employed to understand the structural modification due to ionic size mismatch. Raman spectra show the existence of both rhombohedral and tetragonal crystal symmetries. It also shows the dielectric relaxation with increase in La concentration in the sample. The increase in lattice strain due to La doping increases the remnant polarization and coercive field. The linear piezoelectric coefficient increases with the increase in La concentration. It reveals that La-substituted PZT is a better candidate for piezoelectric sensor applications as compared to that of PZT.

Pressure-induced ferroelectric to antiferroelectric phase transformation in porous PZT95/5 ceramics

International Nuclear Information System (INIS)

Zeng, T.; Dong, X.L.; Chen, X.F.; Yao, C.H.; He, H.L.

2007-01-01

The hydrostatic pressure-induced ferroelectric to antiferroelectric (FE-AFE) phase transformation of PZT95/5 ceramics was investigated as a function of porosity, pore shape and pore size. FE-AFE phase transformations were more diffuse and occurred at lower hydrostatic pressures with increasing porosity. The porous PZT95/5 ceramics with spherical pores exhibited higher transformation pressures than those with irregular pores. Moreover, FE-AFE phase transformations of porous PZT95/5 ceramics with polydisperse irregular pores were more diffuse than those of porous PZT95/5 ceramics with monodisperse irregular pores. The relation between pore structure and hydrostatic pressure-induced FE-AFE transformation was established according to stress concentration theory. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Boosting the Recoverable Energy Density of Lead-Free Ferroelectric Ceramic Thick Films through Artificially Induced Quasi-Relaxor Behavior.

Science.gov (United States)

Peddigari, Mahesh; Palneedi, Haribabu; Hwang, Geon-Tae; Lim, Kyung Won; Kim, Ga-Yeon; Jeong, Dae-Yong; Ryu, Jungho

2018-06-08

Dielectric ceramic film capacitors, which store energy in the form of electric polarization, are promising for miniature pulsed power electronic device applications. For a superior energy storage performance of the capacitors, large recoverable energy density, along with high efficiency, high power density, fast charge/discharge rate, and good thermal/fatigue stability, is desired. Herein, we present highly dense lead-free 0.942[Na 0.535 K 0.480 NbO 3 ]-0.058LiNbO 3 (KNNLN) ferroelectric ceramic thick films (∼5 μm) demonstrating remarkable energy storage performance. The nanocrystalline KNNLN thick film fabricated by aerosol deposition (AD) process and annealed at 600 °C displayed a quasi-relaxor ferroelectric behavior, which is in contrast to the typical ferroelectric nature of the KNNLN ceramic in its bulk form. The AD film exhibited a large recoverable energy density of 23.4 J/cm 3 , with an efficiency of over 70% under the electric field of 1400 kV/cm. Besides, an ultrahigh power density of 38.8 MW/cm 3 together with a fast discharge speed of 0.45 μs, good fatigue endurance (up to 10 6 cycles), and thermal stability in a wide temperature range of 20-160 °C was also observed. Using the AD process, we could make a highly dense microstructure of the film containing nano-sized grains, which gave rise to the quasi-relaxor ferroelectric characteristics and the remarkable energy storage properties.

Broadband dielectric response of Ba(Zr,Ti)O.sub.3./sub. ceramics: From incipient via relaxor and diffuse up to classical ferroelectric behavior

Czech Academy of Sciences Publication Activity Database

Nuzhnyy, Dmitry; Petzelt, Jan; Savinov, Maxim; Ostapchuk, Tetyana; Bovtun, Viktor; Kempa, Martin; Hlinka, Jiří; Buscaglia, V.; Buscaglia, M. T.; Nanni, P.

2012-01-01

Roč. 86, č. 1 (2012), "014106-1"-"014106-9" ISSN 1098-0121 R&D Projects: GA ČR GAP204/12/0232 Institutional research plan: CEZ:AV0Z10100520 Keywords : dielectric spectroscopy * soft mode * central mode * diffuse ferroelectric transition * relaxor ferroelectric transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.767, year: 2012

Effects of Mn doping on the ferroelectric properties of PZT thin films

International Nuclear Information System (INIS)

Zhang Qi

2004-01-01

The effects of Mn doping on the ferroelectric properties of Pb(Zr 0.3 Ti 0.7 )O 3 (PZT) thin films on Pt/Ti/SiO 2 /Si substrates have been investigated. The composition of the PZT and Mn doping level are Pb(Zr 0.3 Ti 0.7 ) 1-x Mn x O 3 (x = 0,0.2,0.5,1,2,4 mol%). The PZT thin films doped with a small amount of Mn 2+ (x ≤ 1) showed almost no hysteretic fatigue up to 10 10 switching bipolar pulse cycles, coupled with excellent retention properties. However, excessive additions of manganese made the fatigue behaviour worse. We propose that the addition of small amounts of Mn is able to reduce the oxygen vacancy concentration due to the combination of Mn 2+ and oxygen vacancies in PZT films, forming Mn 4+ ions. The interfacial layer between the Pt electrode and PZT films and Mn-doped PZT (x = 4) was detected by measuring the dielectric constant of thin films of different thickness. However, this interfacial layer was not detected in Mn-doped PZT (x = 1). These observations support the concept of the preferential electromigration of oxygen vacancies into sites in planes parallel to the electrodes, which is probably responsible for the hysteretic fatigue

Ferroelectric Dipole Electrets Prepared from Soft and Hard PZT Ceramics in Electrostatic Vibration Energy Harvesters

International Nuclear Information System (INIS)

Asanuma, H; Oguchi, H; Hara, M; Kuwano, H

2013-01-01

Aiming at longer stability of surface potential, we propose a ferroelectric dipole electret (FDE) prepared from hard ferroelectric material. We compared output power of electrostatic vibration energy harvester and surface potential stability between FDEs prepared from soft and hard PZT ceramics, as well as a CYTOP polymer electret. The hard FDE showed a seven-fold increase in output power over the soft FDE and nine-fold increase over the CYTOP polymer electret. The hard FDE also showed longer stability of surface potential than that of the soft FDE, whereas the stability of the hard FDE was not yet comparable to that of CYTOP polymer electret. A FDE prepared from harder PZT ceramic (with higher coercive electric field and Curie temperature) may provide more stability in surface potential

Magnetodielectric effect in relaxor/ferrimagnetic composites

Energy Technology Data Exchange (ETDEWEB)

Naveed Ul-Haq, M., E-mail: naveedulhaq07@gmail.com [Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Institute for Materials Sciences and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Essen 45141 (Germany); Yunus, Tayyaba; Mumtaz, Arif [Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Shvartsman, V.V.; Lupascu, Doru C. [Institute for Materials Sciences and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Essen 45141 (Germany)

2015-08-15

Highlights: • Single phase ferroelectric (relaxor)/ferrimagnetic composites are synthesized. • The composite shows magnetodielectric effect. • Effect of interface strain is discussed. • MD is explained via defining a local order parameter q(T). - Abstract: We report on the effect of an applied static magnetic field on the dielectric properties of ferroelectric relaxor/ferrimagnetic composites consisting of [Ba(Sn{sub 0.3}Ti{sub 0.7})O{sub 3}]{sub 0.8}–[CoFe{sub 2}O{sub 4}]{sub 0.2} (BST{sub 0.8}–CFO{sub 0.2}). The pure Ba(Sn{sub 0.3}Ti{sub 0.7})O{sub 3} (BST30) as well as the composites, were synthesized by solid state reaction method. The X-ray diffraction analysis confirmed that BST30 and CFO coexist in the composite without any secondary phase. The real and the imaginary part of the dielectric permittivity were studied as a function of temperature, with and without static magnetic field, respectively. Relaxor characteristics such as dielectric permittivity and its peak temperature are observed to vary with the magnetic field. This is explained in the context that the applied magnetic field creates magnetostriction in the ferrite phase which is transferred to the relaxor phase via the interface coupling. The strain in the relaxor phase results in the reorientation of local polarization entities, polar nano regions (PNRs), which alters the dielectric characteristics of the sample. This effect is explained in relation to local order parameter q(T) which is found to increase in a certain temperature range above the typical ferroelectric temperature regime with the application of magnetic field.

Enhancement of fatigue endurance in ferroelectric PZT ceramic by the addition of bismuth layered SBT

Science.gov (United States)

Namsar, O.; Pojprapai, S.; Watcharapasorn, A.; Jiansirisomboon, S.

2014-10-01

Electrical fatigue properties of (1-x)PZT-xSBT ceramics (x = 0-1.0 weight fraction) were characterized. It was found that pure PZT ceramic had severe polarization fatigue. This was mainly attributed to an occurrence of the macroscopic cracks at near-electrode regions. On the contrary, pure SBT ceramic exhibited excellent fatigue resistance, which was attributed primarily to weak domain wall pinning. As small amount of SBT (0.1 ≤ x ≤ 0.3) was added into PZT, a small reduction of remanent polarization after fatigue process was observed. This demonstrated that these ceramics had high stability during the repeated domain switching due to their low oxygen vacancy concentration. Therefore, these results suggested that this new ceramic PZT-SBT system seemed to be an alternative material for replacing pure PZT in ferroelectric memory applications.

Origin of dielectric relaxor behavior in PVDF-based copolymer and terpolymer films

Science.gov (United States)

Pramanick, Abhijit; Osti, Naresh C.; Jalarvo, Niina; Misture, Scott T.; Diallo, Souleymane Omar; Mamontov, Eugene; Luo, Y.; Keum, Jong-Kahk; Littrell, Ken

2018-04-01

Relaxor ferroelectrics exhibit frequency-dispersion of their dielectric permittivity peak as a function of temperature, the origin of which has been widely debated. Microscopic understanding of such behavior for polymeric ferroelectrics has presented new challenges since unlike traditional ceramic ferroelectrics, dielectric relaxation in polymers is a consequence of short-range molecular dynamics that are difficult to measure directly. Here, through careful analysis of atomic-level H-atom dynamics as determined by Quasi-elastic Neutron Scattering (QENS), we show that short-range molecular dynamics within crystalline domains cannot explain the macroscopic frequency-dispersion of dielectric properties observed in prototypical polyvinylidene-fluoride (PVDF)-based relaxor ferroelectrics. Instead, from multiscale quantitative microstructural characterization, a clear correlation between the amount of crystalline-amorphous interfaces and dielectric relaxation is observed, which indicates that such interfaces play a central role. These results provide critical insights into the role of atomic and microscopic structures towards relaxor behavior in ferroelectric polymers, which will be important for their future design.

Origin of dielectric relaxor behavior in PVDF-based copolymer and terpolymer films

Directory of Open Access Journals (Sweden)

Abhijit Pramanick

2018-04-01

Full Text Available Relaxor ferroelectrics exhibit frequency-dispersion of their dielectric permittivity peak as a function of temperature, the origin of which has been widely debated. Microscopic understanding of such behavior for polymeric ferroelectrics has presented new challenges since unlike traditional ceramic ferroelectrics, dielectric relaxation in polymers is a consequence of short-range molecular dynamics that are difficult to measure directly. Here, through careful analysis of atomic-level H-atom dynamics as determined by Quasi-elastic Neutron Scattering (QENS, we show that short-range molecular dynamics within crystalline domains cannot explain the macroscopic frequency-dispersion of dielectric properties observed in prototypical polyvinylidene-fluoride (PVDF-based relaxor ferroelectrics. Instead, from multiscale quantitative microstructural characterization, a clear correlation between the amount of crystalline-amorphous interfaces and dielectric relaxation is observed, which indicates that such interfaces play a central role. These results provide critical insights into the role of atomic and microscopic structures towards relaxor behavior in ferroelectric polymers, which will be important for their future design.

High-pressure structure of Pb-based relaxor ferroelectrics

Energy Technology Data Exchange (ETDEWEB)

Maier, Bernd J.; Mihailova, Boriana; Paulmann, Carsten; Welsch, Anna-Maria; Bismayer, Ulrich [Mineralogisch-Petrographisches Institut, Universitaet Hamburg (Germany); Angel, Ross J. [Crystallography Laboratory, Virgina Tech, Blacksburg (United States); Marshall, William G. [ISIS Neutron Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon (United Kingdom); Engel, Jens M. [Institut fuer Werkstoffwissenschaft, Technische Universitaet Dresden (Germany); Gospodinov, Marin [Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia (Bulgaria); Petrova, Dimitrina [Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia (Bulgaria); South-West University Neofit Rilski, Blagoevgrad (Bulgaria)

2010-07-01

The pressure-induced phase transitions that occur in the perovskite-type relaxor ferroelectric PbSc{sub 0.5}Ta{sub 0.5}O{sub 3} (PST) and Pb{sub 0.78}Ba{sub 0.22}Sc{sub 0.5}Ta{sub 0.5}O{sub 3} (PST-Ba) were studied with combined neutron powder diffraction and single-crystal X-ray diffraction. An increase in the intensities of h,k,l=all odd reflections is observed while the intensity of h,h,h peaks, h=2n+1, does not change with pressure, indicating a glide-plane pseudo-symmetry of the structural distortion along the left angle 111 right angle cubic directions. Rietveld refinement to the neutron powder data shows that the high-pressure phase has either R anti 3c or R anti 3 symmetry, depending on whether the presence of 1:1 octahedral cation ordering is neglected or taken into account, and comprises anti-phase octahedral tilts of type a{sup -}a{sup -}a{sup -} that continuously evolve with pressure.

Characterizing new compositions of [001]C relaxor ferroelectric single crystals using a work-energy model

Science.gov (United States)

Gallagher, John A.

2016-04-01

The desired operating range of ferroelectric materials with compositions near the morphotropic phase boundary is limited by field induced phase transformations. In [001]C cut and poled relaxor ferroelectric single crystals the mechanically driven ferroelectric rhombohedral to ferroelectric orthorhombic phase transformation is hindered by antagonistic electrical loading. Instability around the phase transformation makes the current experimental technique for characterization of the large field behavior very time consuming. Characterization requires specialized equipment and involves an extensive set of measurements under combined electrical, mechanical, and thermal loads. In this work a mechanism-based model is combined with a more limited set of experiments to obtain the same results. The model utilizes a work-energy criterion that calculates the mechanical work required to induce the transformation and the required electrical work that is removed to reverse the transformation. This is done by defining energy barriers to the transformation. The results of the combined experiment and modeling approach are compared to the fully experimental approach and error is discussed. The model shows excellent predictive capability and is used to substantially reduce the total number of experiments required for characterization. This decreases the time and resources required for characterization of new compositions.

Dielectric characteristics of PZT 95/5 ferroelectric ceramics at high pressures

International Nuclear Information System (INIS)

Spears, R.K.

1978-01-01

The room temperature dielectric properties of a ferroelectric ceramic having a nominal composition of 95 atomic percent lead zirconate and 5 atomic percent lead titanate (designated as PZT 95/5) with a niobium dopant were examined at high hydrostatic pressures using a tetrahedral anvil apparatus. This ceramic has practical applications as a power source in which large quantities of charge are released by dynamic (shock wave) depolarization. Numerous mathematical models of this process have been proposed; however, the use of models has been limited because of the lack of high pressure electrical properties. This study attempted to provide these data on PZT 95/5 by determining the small signal and high electric field dielectric properties at pressures over 4 GPa

BaZr.sub.0.5./sub.Ti.sub.0.5./sub.O.sub.3./sub.: Lead-free relaxor ferroelectric or dipolar glass

Czech Academy of Sciences Publication Activity Database

Filipič, C.; Kutnjak, Z.; Pirc, R.; Canu, G.; Petzelt, Jan

2016-01-01

Roč. 93, č. 22 (2016), 1-7, č. článku 224105. ISSN 2469-9950 Institutional support: RVO:68378271 Keywords : relaxor ferroelectric * dipolar glass * dielectric relaxation * Edwards-Anderson parameter Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

Ferroelectric relaxor behaviour and impedance spectroscopy of Bi2O3-doped barium zirconium titanate ceramics

Science.gov (United States)

Mahajan, Sandeep; Thakur, O P; Bhattacharya, D K; Sreenivas, K

2009-03-01

Bi2O3-doped barium zirconate titanate ceramics, Ba1-xBix(Zr0.05Ti0.95)O3, have been prepared by the conventional solid-state reaction method. The ferroelectric relaxor behaviour and dielectric properties have been investigated in detail. By XRD analysis, it is suggested that up to x = 0.04, Bi3+ substitutes A-site ion, and thereafter with higher Bi3+ content, it enters the B-site sub lattice. Substitution of Bi3+ ions induces ferroelectric relaxor behaviour and the degree of relaxation behaviour increases with bismuth concentration. The remanent polarization and strain behaviour show a slight increase with the substitution level. The degree of hysteresis (strain versus electric field) also reduces from 21.4% to 4.6% with bismuth substitution. Impedance measurements were made on the prepared sample over a wide range of temperatures (300-723 K) and frequencies (40 Hz-1 MHz), which show the presence of both bulk and grain boundary effects in the material. The bulk and grain boundary conductivities determined from impedance study indicate the Arrhenius-type thermally activated process. Impedance spectroscopy is shown to be an efficient method capable of detecting the contributions of the resistances of grains and grain boundaries to the complex impedance of a ceramic system, accurately estimating its electrical conductivity as well as its corresponding activation energies and drawing conclusions on its structural properties.

Ferroelectric relaxor behaviour and impedance spectroscopy of Bi2O3-doped barium zirconium titanate ceramics

International Nuclear Information System (INIS)

Mahajan, Sandeep; Thakur, O P; Bhattacharya, D K; Sreenivas, K

2009-01-01

Bi 2 O 3 -doped barium zirconate titanate ceramics, Ba 1-x Bi x (Zr 0.05 Ti 0.95 )O 3 , have been prepared by the conventional solid-state reaction method. The ferroelectric relaxor behaviour and dielectric properties have been investigated in detail. By XRD analysis, it is suggested that up to x = 0.04, Bi 3+ substitutes A-site ion, and thereafter with higher Bi 3+ content, it enters the B-site sub lattice. Substitution of Bi 3+ ions induces ferroelectric relaxor behaviour and the degree of relaxation behaviour increases with bismuth concentration. The remanent polarization and strain behaviour show a slight increase with the substitution level. The degree of hysteresis (strain versus electric field) also reduces from 21.4% to 4.6% with bismuth substitution. Impedance measurements were made on the prepared sample over a wide range of temperatures (300-723 K) and frequencies (40 Hz-1 MHz), which show the presence of both bulk and grain boundary effects in the material. The bulk and grain boundary conductivities determined from impedance study indicate the Arrhenius-type thermally activated process. Impedance spectroscopy is shown to be an efficient method capable of detecting the contributions of the resistances of grains and grain boundaries to the complex impedance of a ceramic system, accurately estimating its electrical conductivity as well as its corresponding activation energies and drawing conclusions on its structural properties.

Debye’s temperature and heat capacity for Sr0.15Ba0.85Bi2Nb2O9 relaxor ferroelectric ceramic

Directory of Open Access Journals (Sweden)

A. Peláiz-Barranco

2016-03-01

Full Text Available A lead-free relaxor ferroelectric, Sr0.15Ba0.85Bi2Nb2O9, was synthesized via solid-state reaction and the temperature-dependence of the heat capacity was measured in a wide temperature range. The dielectric permittivity was also measured between 500Hz and 5MHz in the same temperature range. No anomaly has been detected in the heat capacity curve for the whole temperature range covered in the present experiments, while broad peaks have been observed in the dielectric permittivity with high frequency dispersion. A typical relaxor behavior has been observed from the dielectric analysis. The Debye’s temperature has showed a minimum value near the freezing temperature. The results are discussed considering the spin-glass model and the high frequency dispersion, which has been observed for the studied relaxor system.

Improvement of the fatigue and the ferroelectric properties of PZT films through a LSCO seed layer

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Sofia A.S., E-mail: sofiarodrigues@fisica.uminho.pt; Silva, José P.B.; Khodorov, Anatoli; Martín-Sánchez, Javier; Pereira, M.; Gomes, M.J.M.

2013-11-01

Highlights: • Pulsed laser deposited PZT thin films. • Seed layer effect on the structural and ferroelectric properties of the PZT films. • The stability of P{sub r} was improved with the introduction of the LSCO layer. -- Abstract: The ability to optimizate the preparation of Lead Zirconate Titanate (PZT) films on platinized Si substrate by pulsed laser deposition was demonstrated. The effect of the modification of the interface film/electrode through the use of a (La,Sr)CoO{sub 3} (LSCO) seed layer on the remnant polarization, fatigue endurance and stress in PZT films was studied. An improvement on the ferroelectric properties was found with the using of the LSCO layer. A remnant polarization (P{sub r}) of 19.8 μC/cm{sup 2} and 4.4 μC/cm{sup 2} for films with and without the LSCO layer were found. In the same way the polarization fatigue decreases significantly after deposition of the LSCO layer between the film and substrate. Atomic force microscopy (AFM) images revealed a different growth process in the films. Current–voltage (I–V) measurements showed that the use of LSCO seed layer improves the leakage current and, on the other hand the conduction mechanisms in the film without LSCO, after the fatigue test, was found to be changed from Schottky to Poole–Frenkel. The trap activation energy (about 0.14 eV) determined from Poole–Frenkel mode agrees well with the energy level of oxygen vacancies. The films stresses were estimated by XRD in order to explain the improvement on the structure and consequentially ferroelectric properties of the films. The model proposed by Dawber and Scott was found to be in agreement with our experimental data, which seems to predict that the oxygen vacancies play an important role on fatigue.

Ferroelectricity, Piezoelectricity, and Dielectricity of 0.06PMnN-0.94PZT(45/55 Thin Film on Silicon Substrate

Directory of Open Access Journals (Sweden)

Tao Zhang

2015-01-01

Full Text Available The high piezoelectricity and high quality factor ferroelectric thin films are important for electromechanical applications especially the micro electromechanical system (MEMS. The ternary compound ferroelectric thin films 0.06Pb(Mn1/3, Nb2/3O3 + 0.94Pb(Zr0.45, Ti0.55O3 (0.06PMnN-0.94PZT(45/55 were deposited on silicon(100 substrates by RF magnetron sputtering method considering that Mn and Nb doping will improve PZT properties in this research. For comparison, nondoped PZT(45/55 films were also deposited. The results show that both of thin films show polycrystal structures with the main (111 and (101 orientations. The transverse piezoelectric coefficients are e31,eff=−4.03 C/m2 and e31,eff=-3.5 C/m2, respectively. These thin films exhibit classical ferroelectricity, in which the coercive electric field intensities are 2Ec=147.31 kV/cm and 2Ec=135.44 kV/cm, and the saturation polarization Ps=30.86 μC/cm2 and Ps=17.74 μC/cm2, and the remnant polarization Pr=20.44 μC/cm2 and Pr=9.87 μC/cm2, respectively. Moreover, the dielectric constants and loss are εr=681 and D=5% and εr=537 and D=4.3%, respectively. In conclusion, 0.06PMnN-0.94PZT(45/55 thin films act better than nondoped films, even though their dielectric constants are higher. Their excellent ferroelectricity, piezoelectricity, and high power and energy storage property, especially the easy fabrication, integration realizable, and potentially high quality factor, make this kind of thin films available for the realistic applications.

Far-infrared and THz spectroscopy of 0.4PMN-0.3PSN-0.3PZN relaxor ferroelectric ceramics

Czech Academy of Sciences Publication Activity Database

Macutkevic, J.; Kamba, Stanislav; Banys, J.; Pashkin, Alexej; Bormanis, K.; Sternberg, A.

2007-01-01

Roč. 27, - (2007), s. 3713-3717 ISSN 0955-2219 R&D Projects: GA ČR(CZ) GA202/06/0403; GA ČR GA202/04/0993 Institutional research plan: CEZ:AV0Z10100520 Keywords : sintering * spectroscopy * ferroelectric properties * petrovskites * traditional ceramics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.562, year: 2007

Anisotropic phonon coupling in the relaxor ferroelectric (Na1/2Bi1/2)TiO3 near its high-temperature phase transition

Science.gov (United States)

Cai, Ling; Toulouse, Jean; Luo, Haosu; Tian, Wei

2014-08-01

The lead free relaxor Na1/2Bi1/2TiO3 (NBT) undergoes a structural cubic-to-tetragonal transition near 800 K which is caused by the cooperative rotations of O6 octahedra. These rotations are also accompanied by the displacements of the cations and the formation of the polar nanodomains (PNDs) that are responsible for the characteristic dielectric dispersion of relaxor ferroelectrics. Because of their intrinsic properties, spontaneous polarization, and lack of inversion symmetry, these PNDs are also piezoelectric and can mediate an interaction between polarization and strain or couple the optic and acoustic phonons. Because PNDs introduce a local tetragonal symmetry, the phonon coupling they mediate is found to be anisotropic. In this paper we present inelastic neutron scattering results on coupled transverse acoustic (TA) and transverse optic (TO) phonons in the [110] and [001] directions and across the cubic-tetragonal phase transition at TC˜800 K. The phonon spectra are analyzed using a mode coupling model. In the [110] direction, as in other relaxors and some ferroelectric perovskites, a precipitous drop of the TO phonon into the TA branch or "waterfall" is observed at a certain qwf˜0.14 r.l.u. In the [001] direction, the highly overdamped line shape can be fitted with closely positioned bare mode energies which are largely overlapping along the dispersion curves. Two competing lattice coupling mechanism are proposed to explain these observations.

Ferroelectric relaxor behaviour and impedance spectroscopy of Bi{sub 2}O{sub 3}-doped barium zirconium titanate ceramics

Energy Technology Data Exchange (ETDEWEB)

Mahajan, Sandeep; Thakur, O P; Bhattacharya, D K [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi-110054 (India); Sreenivas, K, E-mail: omprakasht@hotmail.co [Department of Physics and Astrophysics, University of Delhi- 110007 (India)

2009-03-21

Bi{sub 2}O{sub 3}-doped barium zirconate titanate ceramics, Ba{sub 1-x}Bi{sub x}(Zr{sub 0.05}Ti{sub 0.95})O{sub 3}, have been prepared by the conventional solid-state reaction method. The ferroelectric relaxor behaviour and dielectric properties have been investigated in detail. By XRD analysis, it is suggested that up to x = 0.04, Bi{sup 3+} substitutes A-site ion, and thereafter with higher Bi{sup 3+} content, it enters the B-site sub lattice. Substitution of Bi{sup 3+} ions induces ferroelectric relaxor behaviour and the degree of relaxation behaviour increases with bismuth concentration. The remanent polarization and strain behaviour show a slight increase with the substitution level. The degree of hysteresis (strain versus electric field) also reduces from 21.4% to 4.6% with bismuth substitution. Impedance measurements were made on the prepared sample over a wide range of temperatures (300-723 K) and frequencies (40 Hz-1 MHz), which show the presence of both bulk and grain boundary effects in the material. The bulk and grain boundary conductivities determined from impedance study indicate the Arrhenius-type thermally activated process. Impedance spectroscopy is shown to be an efficient method capable of detecting the contributions of the resistances of grains and grain boundaries to the complex impedance of a ceramic system, accurately estimating its electrical conductivity as well as its corresponding activation energies and drawing conclusions on its structural properties.

Relaxor properties of barium titanate crystals grown by Remeika method

Science.gov (United States)

Roth, Michel; Tiagunov, Jenia; Dul'kin, Evgeniy; Mojaev, Evgeny

2017-06-01

Barium titanate (BaTiO3, BT) crystals have been grown by the Remeika method using both the regular KF and mixed KF-NaF (0.6-0.4) solvents. Typical acute angle "butterfly wing" BT crystals have been obtained, and they were characterized using x-ray diffraction, scanning electron microscopy (including energy dispersive spectroscopy), conventional dielectric and acoustic emission methods. A typical wing has a triangular plate shape which is up to 0.5 mm thick with a 10-15 mm2 area. The plate has a (001) habit and an atomically smooth outer surface. Both K+ and F- solvent ions are incorporated as dopants into the crystal lattice during growth substituting for Ba2+ and O2- ions respectively. The dopants' distribution is found to be inhomogeneous, their content being almost an order of magnitude higher (up to 2 mol%) at out surface of the plate relatively to the bulk. A few μm thick surface layer is formed where a multidomain ferroelectric net is confined between two≤1 μm thick dopant-rich surfaces. The layer as a whole possess relaxor ferroelectric properties, which is apparent from the appearance of additional broad maxima, Tm, in the temperature dependence of the dielectric permittivity around the ferroelectric phase transition. Intense acoustic emission responses detected at temperatures corresponding to the Tm values allow to observe the Tm shift to lower temperatures at higher frequencies, or dispersion, typical for relaxor ferroelectrics. The outer surface of the BT wing can thus serve as a relaxor thin film for various electronic application, such as capacitors, or as a substrate for BT-based multiferroic structure. Crystals grown from KF-NaF fluxes contain sodium atoms as an additional impurity, but the crystal yield is much smaller, and while the ferroelectric transition peak is diffuse it does not show any sign of dispersion typical for relaxor behavior.

Hyperfine interaction measurements on ceramics: PZT revisited

International Nuclear Information System (INIS)

Guarany, Cristiano A.; Araujo, Eudes B.; Silva, Paulo R.J.; Saitovitch, Henrique

2007-01-01

The solid solution of PbZr 1- x Ti x O 3 , known as lead-zirconate titanate (PZT), was probably one of the most studied ferroelectric materials, especially due to its excellent dielectric, ferroelectric and piezoelectric properties. The highest piezoelectric coefficients of the PZT are found near the morphotropic phase boundary (MPB) (0.46≤x≤0.49), between the tetragonal and rhombohedral regions of the composition-temperature phase diagram. Recently, a new monoclinic phase near the MPB was observed, which can be considered as a 'bridge' between PZT's tetragonal and rhombohedral phases. This work is concerned with the study of the structural properties of the ferroelectric PZT (Zr/Ti=52/48, 53/47) by hyperfine interaction (HI) measurements obtained from experiments performed by using the nuclear spectroscopy time differential perturbed angular correlation (TDPAC) in a wide temperature range

Influence of processing parameters on PZT thick films

International Nuclear Information System (INIS)

Huang, Oliver; Bandyopadhyay, Amit; Bose, Susmita

2005-01-01

We have studied influence of processing parameters on the microstructure and ferroelectric properties of lead zirconate titanate (PZT)-based thick films in the range of 5-25 μm. PZT and 2% La-doped PZT thick films were processed using a modified sol-gel process. In this process, PZT- and La-doped PZT powders were first prepared via sol-gel. These powders were calcined and then used with respective sols to form a slurry. Slurry composition was optimized to spin-coat thick films on platinized Si substrate (Si/SiO 2 /Ti/Pt). Spinning rate, acceleration and slurry deposition techniques were optimized to form thick films with uniform thickness and without any cracking. Increasing solids loading was found to enhance the surface smoothness of the film and decrease porosity. Films were tested for their electrical properties and ferroelectric fatigue response. The maximum polarization obtained was 40 μC/cm 2 at 250 kV/cm for PZT thick film and 30 μC/cm 2 at 450 kV/cm for La-doped PZT thick film. After 10 9 cycles of fatiguing at 35 kHz, La-doped PZT showed better resistance for ferroelectric fatigue compared with un-doped PZT films

Hyperfine interaction measurements on ceramics: PZT revisited

Energy Technology Data Exchange (ETDEWEB)

Guarany, Cristiano A. [Universidade Estadual Paulista (Unesp), Departmento de Fisica Quimica, Caixa Postal 31, 15.385-000 Ilha Solteira, SP (Brazil); Araujo, Eudes B. [Universidade Estadual Paulista (Unesp), Departmento de Fisica Quimica, Caixa Postal 31, 15.385-000 Ilha Solteira, SP (Brazil); Silva, Paulo R.J. [Centro Brasileiro de Pesquisas Fisicas-Rua Dr. Xavier Sigaud, 150, 22290-180 Rio de Janeiro, RJ (Brazil); Saitovitch, Henrique [Centro Brasileiro de Pesquisas Fisicas-Rua Dr. Xavier Sigaud, 150, 22290-180 Rio de Janeiro, RJ (Brazil)]. E-mail: henrique@cbpf.br

2007-02-01

The solid solution of PbZr{sub 1-} {sub x} Ti {sub x} O{sub 3}, known as lead-zirconate titanate (PZT), was probably one of the most studied ferroelectric materials, especially due to its excellent dielectric, ferroelectric and piezoelectric properties. The highest piezoelectric coefficients of the PZT are found near the morphotropic phase boundary (MPB) (0.46{<=}x{<=}0.49), between the tetragonal and rhombohedral regions of the composition-temperature phase diagram. Recently, a new monoclinic phase near the MPB was observed, which can be considered as a 'bridge' between PZT's tetragonal and rhombohedral phases. This work is concerned with the study of the structural properties of the ferroelectric PZT (Zr/Ti=52/48, 53/47) by hyperfine interaction (HI) measurements obtained from experiments performed by using the nuclear spectroscopy time differential perturbed angular correlation (TDPAC) in a wide temperature range.

Fabrication of relaxer-based piezoelectric energy harvesters using a sacrificial poly-Si seeding layer

KAUST Repository

Fuentes-Fernandez, E. M A

2014-08-07

The effect of a polycrystalline silicon (poly-Si) seeding layer on the properties of relaxor Pb(Zr0.53,Ti0.47)O3-Pb(Zn1/3,Nb2/3)O3 (PZT-PZN) thin films and energy-harvesting cantilevers was studied. We deposited thin films of the relaxor on two substrates, with and without a poly-Si seeding layer. The seeding layer, which also served as a sacrificial layer to facilitate cantilever release, was found to improve morphology, phase purity, crystal orientation, and electrical properties. We attributed these results to reduction of the number of nucleation sites and, therefore, to an increase in relaxor film grain size. The areal power density of the wet-based released harvester was measured. The power density output of the energy harvester with this relaxor composition and the poly-Si seeding layer was 325 μW/cm2.

Fabrication of relaxer-based piezoelectric energy harvesters using a sacrificial poly-Si seeding layer

KAUST Repository

Fuentes-Fernandez, E. M A; Salomon-Preciado, A. M.; Gnade, Bruce E.; Quevedo-Ló pez, Manuel Angel Quevedo; Shah, Pradeep; Alshareef, Husam N.

2014-01-01

The effect of a polycrystalline silicon (poly-Si) seeding layer on the properties of relaxor Pb(Zr0.53,Ti0.47)O3-Pb(Zn1/3,Nb2/3)O3 (PZT-PZN) thin films and energy-harvesting cantilevers was studied. We deposited thin films of the relaxor on two substrates, with and without a poly-Si seeding layer. The seeding layer, which also served as a sacrificial layer to facilitate cantilever release, was found to improve morphology, phase purity, crystal orientation, and electrical properties. We attributed these results to reduction of the number of nucleation sites and, therefore, to an increase in relaxor film grain size. The areal power density of the wet-based released harvester was measured. The power density output of the energy harvester with this relaxor composition and the poly-Si seeding layer was 325 μW/cm2.

Relaxor ferroelectricity, ferromagnetic and optical second harmonic properties in lanthanum lithium niobate (La0.05Li0.85NbO3) nanoparticles

Science.gov (United States)

Díaz-Moreno, Carlos A.; Ding, Yu; Li, Chunqiang; Portelles, Jorge; Heiras, J.; Hurtado-Macias, A.; Farias, J. R.; González-Hernández, J.; Yacamán, M. J.; López, Jorge

2017-07-01

Relaxor ferroelectricity, ferromagnetism and Second Harmonic Generation properties were founded and studied as a function of a reduction heat treatment at 650 °C in a Ar-5%H2 atmosphere in stoichiometric La0.05Li0.85NbO3 nanoparticles of 40 nm. A diffuse dielectric anomaly related with relaxor behavior from 25 °C to 800 °C in a frequency range from 100 Hz to 1 MHz was founded. It also shows ferromagnetic anhysterestic type and ferroelectric hysteresis loops at room temperature with a magnetic spin remnant of 2.5 × 10-3 emu/g and polarization saturation of 0.235 μC/cm2, remnant polarization of 0.141 μC/cm2, coercive field of 1.35 kV/cm, respectively. It shows very good second harmonic generation signal at 450 nm and 500 nm. High Resolution Transmission Electron Microscopy, X-ray Photoelectron Spectroscopy and Raman spectroscopy, indicate an ABO3 perovskite structure, new electronic binding energy structure for La (5s, 4d), Li (1s), Nb (4s, 3d, 4p) and oxygen (1s, 2s) and new vibrations modes on octahedron NbO6 related to multiferroic single phase nanoparticles, respectively.

Relaxor ferroelectricity, ferromagnetic and optical second harmonic properties in lanthanum lithium niobate (La0.05Li0.85NbO3) nanoparticles

International Nuclear Information System (INIS)

Díaz-Moreno, Carlos A.; Ding, Yu; Li, Chunqiang; Portelles, Jorge; Heiras, J.; Hurtado-Macias, A.; Farias, J.R.; González-Hernández, J.; Yacamán, M.J.

2017-01-01

Relaxor ferroelectricity, ferromagnetism and Second Harmonic Generation properties were founded and studied as a function of a reduction heat treatment at 650 °C in a Ar-5%H 2 atmosphere in stoichiometric La 0.05 Li 0.85 NbO 3 nanoparticles of 40 nm. A diffuse dielectric anomaly related with relaxor behavior from 25 °C to 800 °C in a frequency range from 100 Hz to 1 MHz was founded. It also shows ferromagnetic anhysterestic type and ferroelectric hysteresis loops at room temperature with a magnetic spin remnant of 2.5 × 10 −3 emu/g and polarization saturation of 0.235 μC/cm 2 , remnant polarization of 0.141 μC/cm 2 , coercive field of 1.35 kV/cm, respectively. It shows very good second harmonic generation signal at 450 nm and 500 nm. High Resolution Transmission Electron Microscopy, X-ray Photoelectron Spectroscopy and Raman spectroscopy, indicate an ABO 3 perovskite structure, new electronic binding energy structure for La (5s, 4d), Li (1s), Nb (4s, 3d, 4p) and oxygen (1s, 2s) and new vibrations modes on octahedron NbO 6 related to multiferroic single phase nanoparticles, respectively.

Infrared and dielectric spectroscopy of the relaxor ferroelectric Sr.sub.0.61./sub.Ba.sub.0.39./sub.Nb.sub.2./sub.O.sub.6./sub..

Czech Academy of Sciences Publication Activity Database

Buixaderas, Elena; Savinov, Maxim; Kempa, Martin; Veljko, Sergiy; Kamba, Stanislav; Petzelt, Jan; Pankrath, R.; Kapphan, S.

2005-01-01

Roč. 17, - (2005), s. 653-666 ISSN 0953-8984 R&D Projects: GA AV ČR(CZ) IAA1010213; GA ČR(CZ) GA202/04/0993 Institutional research plan: CEZ:AV0Z10100520 Keywords : relaxor ferroelectrics * dielectric relaxation * phonons Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.145, year: 2005

Lattice dynamics and dielectric spectroscopy of BZT and NBT lead-free perovskite relaxors - comparison with lead-based relaxors

Czech Academy of Sciences Publication Activity Database

Petzelt, Jan; Nuzhnyy, Dmitry; Bovtun, Viktor; Kempa, Martin; Savinov, Maxim; Kamba, Stanislav; Hlinka, Jiří

2015-01-01

Roč. 88, č. 3 (2015), 320-332 ISSN 0141-1594 R&D Projects: GA ČR GA13-15110S Institutional support: RVO:68378271 Keywords : relaxor ferroelectrics * polar phonons * polar nanoregions * dielectric spectroscopy * off-centred ions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.858, year: 2015

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.)

Superspin glass phase and hierarchy of interactions in multiferroic PbFe.sub.1/2./sub.Sb.sub.1/2./sub.O.sub.3./sub.: an analog of ferroelectric relaxors?

Czech Academy of Sciences Publication Activity Database

Laguta, Valentyn; Stephanovich, V. A.; Savinov, Maxim; Maryško, Miroslav; Kuzian, R. O.; Kondakova, I.V.; Olekhnovich, N.M.; Pushkarev, A.V.; Radyush, Yu.V.; Raevski, I. P.; Raevskaya, S. I.; Prosandeev, S. A.

2014-01-01

Roč. 16, Nov (2014), "113041-1"-"113041-19" ISSN 1367-2630 R&D Projects: GA ČR GA13-11473S Institutional support: RVO:68378271 Keywords : multiferroics * spin glass * superantiferromagnetism * ferroelectrics * relaxors Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.558, year: 2014

Gamma Radiation Damage Evaluation Studies on Ferroelectric La and Nb doped PZT Related Ceramics

International Nuclear Information System (INIS)

Cruz, Carlos M.; Pinnera, Ibrahin; Rodriguez, Arturo; Durruti, Ma. Dolores; Hernandez, Moises; Yannez-Limon, J. M.

2015-01-01

It is reported the research results of the gamma radiation damage evaluation on La (crystalline sites A) and / or Nb (crystalline sites B) doped ferroelectric PZT ceramics, which were irradiated with 60 Co gamma rays by applying two irradiation regimes: up to 125 lGy (irradiation steps of 25 kGy) and up to 700 kGy (irradiation steps of 100 kGy) exposition doses. The X Ray Diffraction pattern profiles of the irradiated sample were analyzed and the induced crystalline structure changes are reported and correlated with the observed irradiation induced changes on their ferroelectric properties on regard of the irradiation doses. Through the application of the MCCM atom displacements calculations algorithm and code, total dpa profiles were calculated for the studied samples, as well as, the dpa contributions of the different atomics species, where the atom displacements threshold energies were extrapolated from the values calculated by Molecular Dynamic methods for BaTiO 3 system. An evaluation of the reported dpa calculated values on regard of the observed crystal structure and radiation response of the ferroelectric properties is presented. (Author)

Novel optically active lead-free relaxor ferroelectric (Ba0.6Bi0.2Li0.2)TiO3

International Nuclear Information System (INIS)

Borkar, Hitesh; Rao, Vaibhav; Barvat, Arun; Pal, Prabir; Kumar, Ashok; Dutta, Soma; Tomar, M; Gupta, Vinay; Scott, J F

2016-01-01

We discovered a near-room-temperature lead-free relaxor-ferroelectric (Ba 0.6 Bi 0.2 Li 0.2 )TiO 3 (BBLT) having A-site compositionally disordered ABO 3 perovskite structure. Microstructure-property relations revealed that the chemical inhomogeneities and development of local polar nano-regions (PNRs) are responsible for dielectric dispersion as a function of probe frequencies and temperatures. Rietveld analysis indicates mixed crystal structure with 80% tetragonal structure (space group P4mm) and 20% orthorhombic structure (space group Amm2), which is confirmed by the high resolution transmission electron diffraction (HRTEM). Dielectric constant and tangent loss dispersion with and without illumination of light obey nonlinear Vogel–Fulcher (VF) relations. The material shows slim polarization–hysteresis (P – E) loops and excellent displacement coefficients (d 33 ∼ 233 pm V −1 ) near room temperature, which gradually diminish near the maximum dielectric dispersion temperature (T m ) . The underlying physics for light-sensitive dielectric dispersion was probed by x-ray photon spectroscopy (XPS), which strongly suggests that mixed valence of bismuth ions, especially Bi 5+ ions, comprise most of the optically active centers. Ultraviolet photoemission measurements showed most of the Ti ions are in 4 +  states and sit at the centers of the TiO 6 octahedra; along with asymmetric hybridization between O 2 p and Bi 6 s orbitals, this appears to be the main driving force for net polarization. This BBLT material may open a new path for environmental friendly lead-free relaxor-ferroelectric research. (paper)

The relative contribution of ferroelastic and ferroelectric texture to the character of a hard PZT ceramic

Science.gov (United States)

Key, Thomas Stallings

The development of ferroelastic (90°) texture in addition to ferroelectric (180°) texture is essential to maximizing the piezoelectric properties of many hard tetragonal PZTs, including Piezoetechnologies K270. Ferroelastic texture results from motion of domain walls that is dependent on an individual crystals orientation. Increases in ferroelastic texture raises the maximum net polarization that can be achieved by changes in ferroelectric texture. By studying a hard PZT poled under various temperature conditions, insight was gained into factors affecting the development of ferroelastic texture and how ferroelastic texture contributes to piezoelectric properties. Depinning proved to be the major barrier to preventing ferroelastic domain wall motion where strain based domain interactions and polar defect complexes on the domain level appear to be the dominant factors. Insight into the affect of increased domain texture on the relationship between the increasing magnitude of the remnant polarization (|Pr|) and the magnitude of the coercive field (|EC|) was gained by plotting |EC| vs. |Pr| as a function of poling time for a variety of poling temperatures. At low |Pr| values, |EC| increased rapidly as a function of increases in |Pr| regardless of the poling temperature. This relationship was characteristic of samples poled at 25 °C where increases in ferroelastic texture were largely suppressed. Because increases in polarization were still observable changes in ferroelectric texture most responsible for the polarization increase and like play a strong role in the initial |EC| vs. |Pr| relationship. As |Pr| increased beyond 5 to 8 iC/cm2, the slope of |EC| vs. |Pr| decreased where the reduction in slope increased with poling temperature. This only occurred in samples poled at elevated temperatures where ferroelastic texture was know to ultimately develop during the poling process, leading to the suggestion that the change in slope was due to increases in combined

Controlling dielectric and relaxor-ferroelectric properties for energy storage by tuning Pb0.92La0.08Zr0.52Ti0.48O3 film thickness.

Science.gov (United States)

Brown, Emery; Ma, Chunrui; Acharya, Jagaran; Ma, Beihai; Wu, Judy; Li, Jun

2014-12-24

The energy storage properties of Pb0.92La0.08Zr0.52Ti0.48O3 (PLZT) films grown via pulsed laser deposition were evaluated at variable film thickness of 125, 250, 500, and 1000 nm. These films show high dielectric permittivity up to ∼1200. Cyclic I-V measurements were used to evaluate the dielectric properties of these thin films, which not only provide the total electric displacement, but also separate contributions from each of the relevant components including electric conductivity (D1), dielectric capacitance (D2), and relaxor-ferroelectric domain switching polarization (P). The results show that, as the film thickness increases, the material transits from a linear dielectric to nonlinear relaxor-ferroelectric. While the energy storage per volume increases with the film thickness, the energy storage efficiency drops from ∼80% to ∼30%. The PLZT films can be optimized for different energy storage applications by tuning the film thickness to optimize between the linear and nonlinear dielectric properties and energy storage efficiency.

Dynamics of nanoscale polarization fluctuations in a uniaxial relaxor

Czech Academy of Sciences Publication Activity Database

Ondrejkovič, Petr; Kempa, Martin; Kulda, J.; Frick, B.; Appel, M.; Combet, J.; Dec, J.; Lukasiewicz, T.; Hlinka, Jiří

2014-01-01

Roč. 113, č. 16 (2014), "167601-1"-"167601-5" ISSN 0031-9007 Institutional support: RVO:68378271 Keywords : strontium barium niobate * relaxor ferroelectrics * dielectric relaxations * neutron backscattering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.512, year: 2014

Influence of plasma pressure on the growth characteristics and ferroelectric properties of sputter-deposited PZT thin films

International Nuclear Information System (INIS)

Bose, A.; Maity, T.; Bysakh, S.; Seal, A.; Sen, Suchitra

2010-01-01

PZT thin films of thickness (320-1040) nm were synthesized on Si/SiO 2 /Ti/Pt multilayered substrates by radio frequency magnetron sputtering. The influence of plasma pressure in the range of (0.24-4.9) Pa, during deposition, on the structural, electrical and ferroelectric properties of the PZT films was systematically studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and cross-sectional transmission electron microscopy (XTEM) were employed for structural study. Nano-probe Energy Dispersive (EDX) line scanning was employed to investigate the elemental distribution across the film-bottom electrode interface. I-V characteristics and polarization-electric field (P-E) hysteresis loop of the films were measured. The study reveals that the plasma pressure has a strong influence on the evolution and texture of the ferroelectric perovskite phase and microstructure of the films. At an optimum plasma pressure of 4.1 Pa, PZT films are grown with 93% perovskite phase with (1 1 1) preferred orientation and uniform granular microstructure. These films show a saturation polarization of 67 μC/cm 2 , remnant polarization of 30 μC/cm 2 and coercive field of 28 kV/cm which, according to the literature, seem to be suitable for device applications. Transmission electron microscopy (TEM) study shows that at a plasma pressure of 4.1 Pa, the PZT/bottom Pt interface is sharp and no amorphous interlayer is formed at the interface. At a higher plasma pressure of 4.9 Pa, poor I-V and P-E hysteresis loop are observed which are interpreted as due to an amorphous interlayer at the film-bottom electrode interface which is possibly enriched in Pb, Zr, O and Pt.

Improvement in ferroelectric properties of Pt/PZT/Pt capacitors etched as a function of Ar/O2 gas mixing ratio into Cl2/CF4 plasma

International Nuclear Information System (INIS)

Lim, Kyu-Tae; Koo, Seong-Mo; Kim, Kyoung-Tae; Kim, Dong-Pyo; Kim, Chang-Il

2004-01-01

In this work, to investigate improvement of the damage using oxygen containing plasma, we etched PZT films as a function of Ar (x%)/O 2 (y%) gas mixing ratio in Cl 2 (56%)/CF 4 (14%) plasma (where the sum of x and y is 30). The maximum etch rate of the PZT thin films was 146 nm/min for Ar (30%)/O 2 (0%) added into the Cl 2 /CF 4 plasma. After the etching, the plasma-induced damages were characterized in terms of hysteresis curves, leakage current, switching polarization and retention capacity as a function of the gas mixing ratio. When the ferroelectric properties of PZT films were etched as a function of O 2 and Ar and the gas mixing ratios were compared, the value of remnant polarization in O 2 (30%) added Cl 2 /CF 4 plasma is higher than that in Ar (30%). The results showed that after the etching the charges accumulated by oxygen vacancies prevented further domain switching at the top electrode-ferroelectric interface and created leakage current because of modification of the interfacial Schottky barrier during the etching process. The physical damage to the near surface and the crystal structure of the etched PZT thin films was evaluated by using X-ray diffraction (XRD). The remnant polarization, leakage current, retention and fatigue properties are improved with increasing O 2 content. From XRD results, the improvement in the ferroelectric properties of PZT capacitors etched in O 2 containing plasma was consistent with the increased intensities of the (100) and (200) peaks

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.

Chemical approach to neutral-ionic valence instability, quantum phase transition, and relaxor ferroelectricity in organic charge-transfer complexes

International Nuclear Information System (INIS)

Horiuchi, Sachio; Kumai, Reiji; Okimoto, Yoichi; Tokura, Yoshinori

2006-01-01

Neutral-ionic (NI) phase transition is a reversible switching of organic charge-transfer complexes between distinct valence states by external stimuli. This phase transformation in the low-dimensional system is demonstrated to provide a variety of novel dielectric, structural, and electronic properties. Importantly, ionization of the electron donor-acceptor pairs is usually accompanied by a ferroelectric or antiferroelectric order of the molecular lattice, leading to huge dielectric response near the transition point. Although these characteristics are potentially useful for future electronic and optical applications, the thermally accessible NI transition (TINIT) is still an extremely rare case. The TINIT compounds including some new materials are overviewed in order to provide convenient guides to their design and experimental identifications. The phase transition and dielectric properties can be closely controlled in various ways depending on chemical and physical modifications of the crystals. Among them, a quantum phase transition and relaxor ferroelectricity, both of which are currently attracting subjects from both scientific and practical perspectives, are highlighted as the first achievements in organic charge-transfer complexes

Relaxor ferroelectricity, ferromagnetic and optical second harmonic properties in lanthanum lithium niobate (La{sub 0.05}Li{sub 0.85}NbO{sub 3}) nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Díaz-Moreno, Carlos A., E-mail: cdiazmoreno@utep.edu [Department of Physics of University of Texas at El Paso, 500 W. University Ave, El Paso, TX 79968 (United States); Ding, Yu; Li, Chunqiang [Department of Physics of University of Texas at El Paso, 500 W. University Ave, El Paso, TX 79968 (United States); Portelles, Jorge [Facultad de Física, Universidad de La Habana, San lázaro y L, 10400 (Cuba); Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, km 107 Carretera Tijuana-Ensenada, Ensenada, B.C. 22860 (Mexico); Heiras, J. [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, km 107 Carretera Tijuana-Ensenada, Ensenada, B.C. 22860 (Mexico); Hurtado-Macias, A. [Centro de Investigación en Materiales Avanzados S.C., Miguel de Cervantes #120, Complejo Industrial Chihuahua, Chihuahua, C.P. 31109 (Mexico); Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 (United States); Farias, J.R. [Instituto de Ingeniería y Tecnología, UACJ, Avenida del Charro #450 N. Cd. Juárez, Chihuahua, C.P. 32310 (Mexico); González-Hernández, J. [Centro de Ingeniería y Desarrollo Industrial, Santiago de Querétaro 76130, Qro (Mexico); Yacamán, M.J. [Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 (United States); and others

2017-07-01

Relaxor ferroelectricity, ferromagnetism and Second Harmonic Generation properties were founded and studied as a function of a reduction heat treatment at 650 °C in a Ar-5%H{sub 2} atmosphere in stoichiometric La{sub 0.05}Li{sub 0.85}NbO{sub 3} nanoparticles of 40 nm. A diffuse dielectric anomaly related with relaxor behavior from 25 °C to 800 °C in a frequency range from 100 Hz to 1 MHz was founded. It also shows ferromagnetic anhysterestic type and ferroelectric hysteresis loops at room temperature with a magnetic spin remnant of 2.5 × 10{sup −3} emu/g and polarization saturation of 0.235 μC/cm{sup 2}, remnant polarization of 0.141 μC/cm{sup 2}, coercive field of 1.35 kV/cm, respectively. It shows very good second harmonic generation signal at 450 nm and 500 nm. High Resolution Transmission Electron Microscopy, X-ray Photoelectron Spectroscopy and Raman spectroscopy, indicate an ABO{sub 3} perovskite structure, new electronic binding energy structure for La (5s, 4d), Li (1s), Nb (4s, 3d, 4p) and oxygen (1s, 2s) and new vibrations modes on octahedron NbO{sub 6} related to multiferroic single phase nanoparticles, respectively.

A polarized Raman study of the relaxor and ferroelectric states of La-modified lead zirconate titanate ceramics

International Nuclear Information System (INIS)

El Marssi, M.; Farhi, R.; Viehland, D.

1997-01-01

Lanthanum modified lead zirconate titanate ceramics with La/Zr/Ti ratios of 6/40/60, 12/40/60, 5/65/35, and 9/65/35 have been studied by polarized Raman scattering. In the two former (tetragonal-type) compositions, selection rules were rather well defined and allowed an assignment of the Raman lines at lower temperature. These selection rules disappeared for 6/40/60 but remained for 12/40/60 even at higher temperatures. The behavior of the two latter (rhombohedral-type compositions) was quite different. No assignment of lines could be done. In addition, the spectra recorded in parallel and crossed polarizations were almost identical for 5/65/35 regardless of temperature. A very smeared paraelectric to ferroelectric transition was evidenced by Raman intensity measurements for this composition. On the contrary, selection rules were always present for the relaxor composition 9/65/35 which were similar to those for 12/40/60 and 6/40/60. This suggests that both tetragonal and rhombohedral-type local polar order is present for 9/65/35. The spectra of the field induced ferroelectric phase for 9/65/35 revealed no selection rules, similar to 5/65/35. This is attributed to the onset of only medium range ferroelectric order. Finally, Raman spectra recorded on powders of every composition did not reveal any selection rules, suggesting that intergranular effects might play a significant role in the behavior of these materials. copyright 1997 American Institute of Physics

Electrocaloric effect and freezing temperature in (Pb0.8Ba0.2[(Zn1∕3Nb2∕30.7Ti0.3]O3 relaxor ferroelectric ceramic

Directory of Open Access Journals (Sweden)

A. Peláiz-Barranco

2016-09-01

Full Text Available The electrocaloric effect (ECE is studied in (Pb0.8Ba0.2[(Zn1∕3Nb2∕30.7Ti0.3]O3 relaxor ferroelectric ceramic by using an “indirect method”. The electric dependence for the polarization (hysteresis loops has been obtained for several temperatures showing typical relaxor characteristics. The temperature change ΔT, which is associated with the ECE, is calculated by using the temperature dependence for the polarization. A maximum value for ΔT is observed for temperatures close above the freezing temperature, showing an indirect evidence of that critical temperature. The results are discussed considering the contribution of the polar nanoregions to the polarization.

Temperature dependent polarization reversal mechanism in 0.94(Bi1/2Na1/2)TiO3-0.06Ba(Zr0.02Ti0.98)O3 relaxor ceramics

Science.gov (United States)

Glaum, Julia; Simons, Hugh; Hudspeth, Jessica; Acosta, Matias; Daniels, John E.

2015-12-01

The temperature at which the electric field induced long-range ordered ferroelectric state undergoes transition into the short-range ordered relaxor state, TF-R, is commonly defined by the onset of strong dispersion of the dielectric permittivity. However, this combined macroscopic property and structural investigation of the polarization reversal process in the prototypical lead-free relaxor 0.94(Bi1/2Na1/2)TiO3-0.06Ba(Zr0.02Ti0.98)O3 reveals that an applied electric field can trigger depolarization and onset of relaxor-like behavior well below TF-R. The polarization reversal process can as such be described as a combination of (1) ferroelectric domain switching and (2) a reversible phase transition between two polar ferroelectric states mediated by a non-polar relaxor state. Furthermore, the threshold fields of the second, mediated polarization reversal mechanism depend strongly on temperature. These results are concomitant with a continuous ferroelectric to relaxor transition occurring over a broad temperature range, during which mixed behavior is observed. The nature of polarization reversal can be illustrated in electric-field-temperature (E-T) diagrams showing the electric field amplitudes associated with different polarization reversal processes. Such diagrams are useful tools for identifying the best operational temperature regimes for a given composition in actuator applications.

Structure and phase formation behavior and dielectric and magnetic properties of lead iron tantalate-lead zirconate titanate multiferroic ceramics

International Nuclear Information System (INIS)

Wongmaneerung, R.; Tipakontitikul, R.; Jantaratana, P.; Bootchanont, A.; Jutimoosik, J.; Yimnirun, R.; Ananta, S.

2016-01-01

Highlights: • The multiferroic ceramics consisted of PFT and PZT. • Crystal structure changed from cubic to mixedcubic and tetragonal with increasing PZT content. • Dielectric showed the samples underwent a typical relaxor ferroelectric behavior. • Magnetic properties showed very interesting behavior with square saturated magnetic hysteresis loops. - Abstract: Multiferroic (1 − x)Pb(Fe_0_._5Ta_0_._5)O_3–xPb(Zr_0_._5_3Ti_0_._4_7)O_3 (or PFT–PZT) ceramics were synthesized by solid-state reaction method. The crystal structure and phase formation of the ceramics were examined by X-ray diffraction (XRD). The local structure surrounding Fe and Ti absorbing atoms was investigated by synchrotron X-ray Absorption Near-Edge Structure (XANES) measurement. Dielectric properties were studied as a function of frequency and temperature using a LCR meter. A vibrating sample magnetometer (VSM) was used to determine the magnetic hysteresis loops. XRD study indicated that the crystal structure of the sample changed from pure cubic to mixed cubic and tetragonal with increasing PZT content. XANES measurements showed that the local structure surrounding Fe and Ti ions was similar. Dielectric study showed that the samples underwent a typical relaxor ferroelectric behavior while the magnetic properties showed very interesting behavior with square saturated magnetic hysteresis loops.

A modified barbell-shaped PNN-PZT-PIN piezoelectric ceramic energy harvester

Science.gov (United States)

Gao, Xiangyu; Wu, Jingen; Yu, Yang; Dong, Shuxiang

2017-11-01

The quaternary system of relaxor-ferroelectric based Pb(Ni1/3Nb2/3)O3-Pb(ZrxTi1-x)O3-Pb(In0.5Nb0.5)O3 (PNN-PZT-PIN) piezoelectric ceramic at the morphotropic phase boundary was investigated via the solid reaction method. The optimized ceramic with excellent electric properties of ɛr = 8084, d33 = 977 pC/N, kp = 0.61, and Ec = 3.0 kV/cm was fabricated into d33-mode discs with separated surface electrodes, which were arranged in a series connection and, then as a piezo-stack, assembled into a barbell-shaped energy harvester that could bear a strong mechanical vibration. It is found that under a vibration mass-induced bending moment, the energy harvester produces an open circuit voltage of 26.4 Vp-p at the acceleration of 2.5 g at a load of 1.56 MΩ, which is two times higher in comparison to one without surface electrode separation. Its power output is 30 μW at the acceleration of 1 g and 104 μW at 2.5 g, which are even six times higher than that of a previously reported barbell-shaped energy harvester at room-temperature with the same acceleration. The enhanced power output can be attributed to (i) the excellent piezoelectric response of PNN-PZT-PIN ceramic and (ii) harvesting positive and negative charges from the separated surface electrodes other than a full surface electrode on piezoelectric discs under bending moment. Furthermore, the practical test was performed within a car engine, which shows that the PNN-PZT-PIN piezoelectric ceramic is a promising candidate for vibration energy harvesting.

Characterization of PZT thin films on metal substrates; Charakterisierung von PZT-Duennschichten auf Metallsubstraten

Energy Technology Data Exchange (ETDEWEB)

Dutschke, A.

2008-02-02

Lead zirconate titanate (PbZr{sub x}Ti{sub 1-x}O{sub 3},PZT) is one of the most applied ceramic materials because of its distinctive piezo- and ferroelectric properties. Prepared as thin films on flexible, metallic substrates it can be used for various applications as strain gauges, key switches, vibration dampers, microactuators and ultrasonic transducers. The aim of this work is to analyze the microstructure and the phase-content of PZT-thin films deposited on temperature- und acid-resistant hastelloy-sheets, to correlate the results with the ferroelectric and dielectric properties. It is demonstrated, that the specific variation of the microstructure can be achieved by different thermal treatments and the selective addition of Neodymium as dopant. Nd-doping leads to a shift of the maximum nucleation rate towards reduced temperatures and a decrease in the rate of growth compared to undoped films. The PZT-films are prepared by a sol-gel-process in fourfold multilayers with a composition near the morphotropic phase boundary, where the tetragonal und rhombohedral perovskite-phases coexist. The crystallisation in Nd-doped and undoped films takes place heterogeneously, preferentially at the interfaces and on the surface of the multilayered films as well as on the inner surface of pores within the films. For the first time, the Zr:Ti fluctuation phenomena emerging in sol-gel derived PZT films is related to the microstructure and the local phase content on a nanometer scale. In this connection it is proved, that long-distance Zr:Ti gradients arise preferentially before and during the crystallisation of the pyrochlore phase. During the following crystallisation of the perovskite phase, the crystallites grow across these gradients without modifying them. It is pointed out that the fluctuation in the Zr:Ti ratio has only minor influence on the amount of the tetragonal or rhombohedral distortion of the crystallites after the transition from the para- to the ferroelectric

Characterization of Bi and Fe co-doped PZT capacitors for FeRAM.

Science.gov (United States)

Cross, Jeffrey S; Kim, Seung-Hyun; Wada, Satoshi; Chatterjee, Abhijit

2010-08-01

Ferroelectric random access memory (FeRAM) has been in mass production for over 15 years. Higher polarization ferroelectric materials are needed for future devices which can operate above about 100 °C. With this goal in mind, co-doping of thin Pb(Zr 40 ,Ti 60 )O 3 (PZT) films with 1 at.% Bi and 1 at.% Fe was examined in order to enhance the ferroelectric properties as well as characterize the doped material. The XRD patterns of PZT-5% BiFeO 3 (BF) and PZT 140-nm thick films showed (111) orientation on (111) platinized Si wafers and a 30 °C increase in the tetragonal to cubic phase transition temperature, often called the Curie temperature, from 350 to 380 °C with co-doping, indicating that Bi and Fe are substituting into the PZT lattice. Raman spectra revealed decreased band intensity with Bi and Fe co-doping of PZT compared to PZT. Polarization hysteresis loops show similar values of remanent polarization, but square-shaped voltage pulse-measured net polarization values of PZT-BF were higher and showed higher endurance to repeated cycling up to 10 10 cycles. It is proposed that Bi and Fe are both in the +3 oxidation state and substituting into the perovskite A and B sites, respectively. Substitution of Bi and Fe into the PZT lattice likely creates defect dipoles, which increase the net polarization when measured by the short voltage pulse positive-up-negative-down (PUND) method.

In-situ structural investigations of ferroelasticity in soft and hard rhombohedral and tetragonal PZT

Energy Technology Data Exchange (ETDEWEB)

Morozov, Maxim I., E-mail: maximm@alumni.ntnu.no; Einarsrud, Mari-Ann; Tolchard, Julian R.; Grande, Tor [Department of Materials Science and Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Geiger, Philipp T.; Webber, Kyle G. [Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen (Germany); Damjanovic, Dragan [Ceramics Laboratory, Swiss Federal Institute of Technology in Lausanne-EPFL, 1015 Lausanne (Switzerland)

2015-10-28

Despite the technological importance of hard and soft PZT, Pb(Zr,Ti)O{sub 3}, ceramics, the mechanisms of ferroelectric hardening and softening remain widely discussed in the literature. The hardening and softening phenomena have traditionally been investigated in relation with dielectric manifestations such as aging of the dielectric susceptibility and constriction of the polarization-electric field hysteresis loop. Here, we present a systematic investigation of the ferroelectric and ferroelastic properties of soft and hard PZT in both the tetragonal and rhombohedral phases. A particular focus has been devoted to ferroelastic domain switching by characterizing the macroscopic mechanical constitutive behavior and in-situ synchrotron X-ray diffraction during compression. It is demonstrated that variation of the ordering state of point defects in PZT ceramics affects the switching behavior of both ferroelectric and ferroelastic domains under mechanical or electrical fields. Softening of the mechanical and electrical properties of originally hard PZT ceramics was conferred by quenching the materials from above the Curie temperature. The present findings are discussed with respect to the current understanding of hardening-softening transitions in ferroelectric materials.

Far-infrared and dielectric spectroscopy of relaxor ferroelectric (Pb.sub.1-x./sub.La.sub.x./sub.)(Zr.sub.0,4./sub.Ti.sub.0,6./sub.)O.sub.3./sub..

Czech Academy of Sciences Publication Activity Database

Buixaderas, Elena; Nuzhnyy, Dmitry; Veljko, Sergiy; Kamba, Stanislav; Savinov, Maxim; Petzelt, Jan; Kosec, M.

2007-01-01

Roč. 101, č. 7 (2007), 074106/1-074106/8 ISSN 0021-8979 R&D Projects: GA AV ČR IAA100100701; GA ČR(CZ) GA202/06/0403; GA ČR GA202/04/0993 Institutional research plan: CEZ:AV0Z10100520 Keywords : relaxor ferroelectrics * phase transitions * soft mode Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.171, year: 2007

Three-mode coupling interference patterns in the dynamic structure factor of a relaxor ferroelectric

Science.gov (United States)

Manley, M. E.; Abernathy, D. L.; Sahul, R.; Stonaha, P. J.; Budai, J. D.

2016-09-01

A longstanding controversy for relaxor ferroelectrics has been the origin of the "waterfall" effect in the phonon dispersion curves, in which low-energy transverse phonons cascade into vertical columns. Originally interpreted as phonons interacting with polar nanoregions (PNRs), it was later explained as an interference effect of coupling damped optic and acoustic phonons. In light of a recently discovered PNR vibrational mode near the "waterfall" wave vector [M. E. Manley, J. W. Lynn, D. L. Abernathy, E. D. Specht, O. Delaire, A. R. Bishop, R. Sahul, and J. D. Budai, Nat. Commun. 5, 3683 (2014), 10.1038/ncomms4683], we have reexamined this feature using neutron scattering on [100]-poled PMN-30%PT [0.6 Pb (M g1 /3N b2 /3 ) O3-0.3 PbTi O3] . We find that the PNR mode couples to both optic and acoustic phonons and that this results in complex patterns in the dynamic structure factor, including intensity pockets and peaks localized in momentum-energy space. These features are fully explained by extending the mode-coupling model to include three coupled damped harmonic oscillators representing the transverse optic, acoustic, and PNR modes.

Ferroelectric properties of Pb(Zr,Ti)O3 films under ion-beam induced strain

Science.gov (United States)

Lee, Jung-Kun; Nastasi, Michael

2012-11-01

The influence of an ion-beam induced biaxial stress on the ferroelectric and dielectric properties of Pb(Zr,Ti)O3 (PZT) films is investigated using the ion beam process as a novel approach to control external stress. Tensile stress is observed to decrease the polarization, permittivity, and ferroelectric fatigue resistance of the PZT films whose structure is monoclinic. However, a compressive stress increases all of them in monoclinic PZT films. The dependence of the permittivity on stress is found not to follow the phenomenological theory relating external forces to intrinsic properties of ferroelectric materials. Changes in the ferroelectric and dielectric properties indicate that the application of a biaxial stress modulates both extrinsic and intrinsic properties of PZT films. Different degrees of dielectric non-linearity suggests the density and mobility of non-180o domain walls, and the domain switching can be controlled by an applied biaxial stress and thereby influence the ferroelectric and dielectric properties.

Pyroelectricity versus conductivity in soft lead zirconate titanate (PZT) ceramics

NARCIS (Netherlands)

Kamel, T.M.; With, de G.

2007-01-01

The electrical behavior of modified soft lead zirconate titanate (PZT) ceramics has been studied as a function of temperature at different direct current (dc) electric fields and grain sizes. As ferroelectrics, such as PZT, are highly polarizable materials, poling, depolarization, and electric

Highly polarized single-c-domain single-crystal Pb(Mn,Nb)O(3)-PZT thin films.

Science.gov (United States)

Wasa, Kiyotaka; Adachi, Hideaki; Nishida, Ken; Yamamoto, Takashi; Matsushima, Tomoaki; Kanno, Isaku; Kotera, Hidetoshi

2012-01-01

In-plane unstrained single-c-domain/single-crystal thin films of PZT-based ternary ferroelectric perovskite, ξPb(Mn,Nb)O3-(1 - ξ)PZT, were grown on SrRuO(3)/Pt/MgO substrates using magnetron sputtering followed by quenching. The sputtered unstrained thin films exhibit unique ferroelectric properties: high coercive field, Ec > 180 kV/cm, large remanent polarization, P(r) = 100 μC/cm(2), small relative dielectric constants, ε* = 100 to 150, high Curie temperature, Tc = ~600 °C, and bulk-like large transverse piezoelectric constants, e31,f = -12.0 C/m(2) for PZT(48/52) at ξ = 0.06. The unstrained thin films are an ideal structure to extract the bulk ferroelectric properties. Their micro-structures and ferroelectric properties are discussed in relation to the potential applications for piezoelectric MEMS. © 2012 IEEE

Novel Photovoltaic Devices Using Ferroelectric Material and Colloidal Quantum Dots

Science.gov (United States)

Paik, Young Hun

As the global concern for the financial and environmental costs of traditional energy resources increases, research on renewable energy, most notably solar energy, has taken center stage. Many alternative photovoltaic (PV) technologies for 'the next generation solar cell' have been extensively studied to overcome the Shockley-Queisser 31% efficiency limit as well as tackle the efficiency vs. cost issues. This dissertation focuses on the novel photovoltaic mechanism for the next generation solar cells using two inorganic nanomaterials, nanocrystal quantum dots and ferroelectric nanoparticles. Lead zirconate titanate (PZT) materials are widely studied and easy to synthesize using solution based chemistry. One of the fascinating properties of the PZT material is a Bulk Photovoltaic effect (BPVE). This property has been spotlighted because it can produce very high open circuit voltage regardless of the electrical bandgap of the materials. However, the poor optical absorption of the PZT materials and the required high temperature to form the ferroelectric crystalline structure have been obstacles to fabricate efficient photovoltaic devices. Colloidal quantum dots also have fascinating optical and electrical properties such as tailored absorption spectrum, capability of the bandgap engineering due to the wide range of material selection and quantum confinement, and very efficient carrier dynamics called multiple exciton generations. In order to utilize these properties, many researchers have put numerous efforts in colloidal quantum dot photovoltaic research and there has been remarkable progress in the past decade. However, several drawbacks are still remaining to achieve highly efficient photovoltaic device. Traps created on the large surface area, low carrier mobility, and lower open circuit voltage while increasing the absorption of the solar spectrum is main issues of the nanocrystal based photovoltaic effect. To address these issues and to take the advantages of

Effect of La and W dopants on dielectric and ferroelectric properties of PZT thin films prepared by sol-gel process

International Nuclear Information System (INIS)

Xiao, Mi; Zhang, Zebin; Zhang, Weikang; Zhang, Ping

2018-01-01

La or W-doped lead zirconate titanate thin films (PLZT or PZTW) were prepared on platinized silicon substrates by sol-gel process. The effects of La or W dopant on the phase development, microstructure, dielectric and ferroelectric characteristics of films were studied. For PLZT films, the optimum doping concentration was found to be 2 mol%. While for PZTW films, the dielectric and ferroelectric properties were found to be improved as the doping concentration increased. The fatigue properties of PLZT and PZTW thin films were also investigated, the results showed that A- or B-site donor doping could improve the fatigue properties of PZT thin films. The theory of oxygen vacancy was used to explain the performance improvement caused by donor doping. (orig.)

Effect of La and W dopants on dielectric and ferroelectric properties of PZT thin films prepared by sol-gel process

Science.gov (United States)

Xiao, Mi; Zhang, Zebin; Zhang, Weikang; Zhang, Ping

2018-01-01

La or W-doped lead zirconate titanate thin films (PLZT or PZTW) were prepared on platinized silicon substrates by sol-gel process. The effects of La or W dopant on the phase development, microstructure, dielectric and ferroelectric characteristics of films were studied. For PLZT films, the optimum doping concentration was found to be 2 mol%. While for PZTW films, the dielectric and ferroelectric properties were found to be improved as the doping concentration increased. The fatigue properties of PLZT and PZTW thin films were also investigated, the results showed that A- or B-site donor doping could improve the fatigue properties of PZT thin films. The theory of oxygen vacancy was used to explain the performance improvement caused by donor doping.

Structure and phase formation behavior and dielectric and magnetic properties of lead iron tantalate-lead zirconate titanate multiferroic ceramics

Energy Technology Data Exchange (ETDEWEB)

Wongmaneerung, R., E-mail: re_nok@yahoo.com [Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Tipakontitikul, R. [Department of Physics, Ubonratchathani University, Ubonratchathani 31490 (Thailand); Jantaratana, P. [Department of Physics, Kasetsart University, Bangkok 10900 (Thailand); Bootchanont, A.; Jutimoosik, J.; Yimnirun, R. [School of Physics, Institute of Science, and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Ananta, S. [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2016-03-15

Highlights: • The multiferroic ceramics consisted of PFT and PZT. • Crystal structure changed from cubic to mixedcubic and tetragonal with increasing PZT content. • Dielectric showed the samples underwent a typical relaxor ferroelectric behavior. • Magnetic properties showed very interesting behavior with square saturated magnetic hysteresis loops. - Abstract: Multiferroic (1 − x)Pb(Fe{sub 0.5}Ta{sub 0.5})O{sub 3}–xPb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3} (or PFT–PZT) ceramics were synthesized by solid-state reaction method. The crystal structure and phase formation of the ceramics were examined by X-ray diffraction (XRD). The local structure surrounding Fe and Ti absorbing atoms was investigated by synchrotron X-ray Absorption Near-Edge Structure (XANES) measurement. Dielectric properties were studied as a function of frequency and temperature using a LCR meter. A vibrating sample magnetometer (VSM) was used to determine the magnetic hysteresis loops. XRD study indicated that the crystal structure of the sample changed from pure cubic to mixed cubic and tetragonal with increasing PZT content. XANES measurements showed that the local structure surrounding Fe and Ti ions was similar. Dielectric study showed that the samples underwent a typical relaxor ferroelectric behavior while the magnetic properties showed very interesting behavior with square saturated magnetic hysteresis loops.

A flexible tactile-feedback touch screen using transparent ferroelectric polymer film vibrators

International Nuclear Information System (INIS)

Ju, Woo-Eon; Moon, Yong-Ju; Park, Cheon-Ho; Choi, Seung Tae

2014-01-01

To provide tactile feedback on flexible touch screens, transparent relaxor ferroelectric polymer film vibrators were designed and fabricated in this study. The film vibrator can be integrated underneath a transparent cover film or glass, and can also produce acoustic waves that cause a tactile sensation on human fingertips. Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] polymer was used as the relaxor ferroelectric polymer because it produces a large strain under applied electric fields, shows a fast response, and has excellent optical transparency. The natural frequency of this tactile-feedback touch screen was designed to be around 200–240 Hz, at which the haptic perception of human fingertips is the most sensitive; therefore, the resonance of the touch screen at its natural frequency provides maximum haptic sensation. A multilayered relaxor ferroelectric polymer film vibrator was also demonstrated to provide the same vibration power at reduced voltage. The flexible P(VDF-TrFE-CTFE) film vibrators developed in this study are expected to provide tactile sensation not only in large-area flat panel displays, but also in flexible displays and touch screens. (papers)

Temperature dependent polarization reversal mechanism in 0.94(Bi1/2Na1/2) TiO3-0.06Ba(Zr0.02Ti0.98)O3 relaxor ceramics

DEFF Research Database (Denmark)

Glaum, Julia; Simons, Hugh; Hudspeth, Jessica

2015-01-01

and structural investigation of the polarization reversal process in the prototypical lead-free relaxor 0.94(Bi1/2Na1/2)TiO3-0.06Ba(Zr0.02Ti0.98)O3 reveals that an applied electric field can trigger depolarization and onset of relaxor-like behavior well below TF-R. The polarization reversal process can...... as such be described as a combination of (1) ferroelectric domain switching and (2) a reversible phase transition between two polar ferroelectric states mediated by a non-polar relaxor state. Furthermore, the threshold fields of the second, mediated polarization reversal mechanism depend strongly on temperature....... These results are concomitant with a continuous ferroelectric to relaxortransition occurring over a broad temperature range, during which mixed behavior is observed. The nature of polarization reversal can be illustrated in electric-field-temperature (E-T) diagrams showing the electric field amplitudes...

Fabrication and characterization of Pb(Zr 0.53,Ti 0.47)O 3-Pb(Nb 1/3,Zn 2/3)O 3 thin films on cantilever stacks

KAUST Repository

Fuentes-Fernandez, E. M A

2010-11-18

0.9Pb(Zr 0.53,Ti 0.47)O 3-0.1Pb(Zn 1/3,Nb 2/3)O 3 (PZT-PZN) thin films and integrated cantilevers have been fabricated. The PZT-PZN films were deposited on SiO 2/Si or SiO 2/Si 3N 4/SiO 2/poly-Si/Si membranes capped with a sol-gel-derived ZrO 2 buffer layer. It is found that the membrane layer stack, lead content, existence of a template layer of PbTiO 3 (PT), and ramp rate during film crystallization are critical for obtaining large-grained, single-phase PZT-PZN films on the ZrO 2 surface. By controlling these parameters, the electrical properties of the PZT-PZN films, their microstructure, and phase purity were significantly improved. PZT-PZN films with a dielectric constant of 700 to 920 were obtained, depending on the underlying stack structure. © 2010 TMS.

Unveiling the Role of CNTs on the Phase Formation of 1D Ferroelectrics

KAUST Repository

Mahajan, Amit

2015-05-21

Carbon nanotubes (CNTs) have the potential to act as templates or bottom electrodes for three dimension (3D) capacitor arrays, which utilise one dimension (1D) ferroelectric nanostructures to increase memory size and density. However, growing a ferroelectric on the surface of CNTs is non-trivial. Here, we demonstrate that multi-walled (MW) CNTs decrease the time and temperature for formation of lead zirconium titanate Pb(Zr1-xTix)O3 (PZT) by ~100 ºC commensurate with a decrease in activation energy from 68±15 kJ/mol to 27±2 kJ/mol. As a consequence, monophasic PZT was obtained at 575 ºC for MWCNTs/PZT whereas for pure PZT traces of pyrochlore were still present at 650 ºC, where PZT phase formed due to homogeneous nucleation. The piezoelectric nature of MWCNT/PZT synthesised at 500 ºC for 1 h was proved. Although further work is required to prove the concept of 3D capacitor arrays, our result suggests that it is feasible to utilise MWCNTs as templates/electrodes for the formation of 1D PZT nano ferroelectrics.

Thick-film processing of Pb5Ge3O11-based ferroelectric glass-ceramics

International Nuclear Information System (INIS)

Cornejo, I.A.; Haun, M.J.

1996-01-01

Processing techniques were investigated to produce c-axis orientation, or texture, of ferroelectric Pb 5 Ge 3 O 11 -based glass-ceramic compositions during crystallization of amorphous thick-film printed samples from the Pb 5 Ge 3 O 11 -PbTiO 3 (PG-PT) and Pb 5 Ge 3 O 11 -Pb(Zr 1/2 Ti 1/2 )O 3 (PG-PZT) systems. In these systems the PG crystallized into a ferroelectric phase, producing a multiple ferroelectric phase composite at low temperatures, PG-PT or PG-PZT. In this way the non-ferroelectric component of traditional ferroelectric glass-ceramics was eliminated

Cross-sectional analysis of ferroelectric domains in PZT capacitors via piezoresponse force microscopy

Energy Technology Data Exchange (ETDEWEB)

Liu, J S [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang City (China); Zeng, H Z [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Kholkin, A L [Department of Ceramic and Glass Engineering and CICECO, University of Aveiro, Aveiro 3810-193 (Portugal)

2007-11-21

Ferroelectric domains have been investigated on the cross-section of Pb(Zr{sub 0.55}Ti{sub 0.45})O{sub 3} (PZT) thin film capacitors by scanning probe microscopy. The static domain images on the cross-section were obtained by the lateral piezoresponse force microscopy (LPFM) method, in which the ac voltage used to induce the converse piezoelectric effect was applied between the conductive tip and the bottom electrode. The polarization component normal to the substrate could be characterized via both d{sub 33} and d{sub 15} piezoelectric coefficients, which resulted in a high resolution of LPFM images. After a variable dc bias was applied between the top and the bottom electrodes, the variations of domain image on the cross-section were recorded by the LPFM immediately. Upon the application of low bias, new domain sites appeared near the PZT/Pt interface opposite to the initial polarization. Forward stretch of new domains was facilitated under the dc field approaching the coercive field E{sub c}. Under a very high field (about three times of the E{sub c}), the sidewise expansion of columnar domains was observed. However, the domains were only partially switched even though a very high field was applied. The observed domain growth process indicated a lower energy barrier for nucleation compared with that of domain wall motion. Possible reasons for the incomplete switching are the substantial influences of the interface and depolarization in thin film capacitors.

Application of the FITSC method for characterization of PZT-type ceramics with the diffuse phase transition

International Nuclear Information System (INIS)

Adamczyk, M.; Kozielski, L.; Lisinska-Czekaj, A.; Czekaj, D.

2011-01-01

Highlights: → Profound electrical properties examination of interesting PBZT composition, with the superposition of piezoelectric and relaxor properties. → Explanation of unusual behavior of dielectric characteristics, especially of a low frequency dispersion that appears in paraelectric phase → We can assume that the response will be a combination of three key factors: relaxor (changing polar regions), piezoelectric (reducing the remanent polarization) and technology (processing). → Findings presented on the paper give a starting point for developing material to prevent or slow the progression of relaxor properties, what could be implementing in actuator and MEMS applications. - Abstract: In the present work the (Pb 0.84 Ba 0.16 )(Zr 0.54 Ti 0.46 )O 3 (PBZT 16/54/46) ceramics has been studied from the point of view of its electrical properties. Dielectric properties of PBZT were measured within the temperature range of the ferroelectric-paraelectric (FE-PE) phase transition region. The method of field-induced thermally stimulated currents (FITSC) was applied and thus the thermal relaxation effects were studied. The observed field dependence of thermally stimulated depolarization currents has revealed the existence of different frequency-dependent relaxation processes in the temperature range between 200 and 400 deg. C. Our experiment demonstrates that modification of ferroelectric materials with isovalent ions, but bigger radii than the origin atom, significantly affect its properties, particularly the PBZT real part of electrical permittivity shows the phase transition character change from ferroelectric to relaxor and finally, that electrical examination can be effectively used for drawing decisive applications conclusions considering polarization parameters distribution.

Determination of the Steady State Leakage Current in Structures with Ferroelectric Ceramic Films

Science.gov (United States)

Podgornyi, Yu. V.; Vorotilov, K. A.; Sigov, A. S.

2018-03-01

Steady state leakage currents have been investigated in capacitor structures with ferroelectric solgel films of lead zirconate titanate (PZT) formed on silicon substrates with a lower Pt electrode. It is established that Pt/PZT/Hg structures, regardless of the PZT film thickness, are characterized by the presence of a rectifying contact similar to p-n junction. The steady state leakage current in the forward direction increases with a decrease in the film thickness and is determined by the ferroelectric bulk conductivity.

PZT-5A4/PA and PZT-5A4/PDMS piezoelectric composite bimorphs

International Nuclear Information System (INIS)

Babu, I; Hendrix, M M R M; De With, G

2014-01-01

Disc type reinforced piezoelectric composite bimorphs with series connection were designed and the performance was investigated. The composite bimorphs (PZT/PA and PZT/PDMS (40/60 vol%)) were successfully fabricated by a compression molding and solution casting technique. The charge developed at an applied force of 150 N is 18150 pC (PZT/PA) and 2310 pC (PZT/PDMS), respectively. Electric force microscopy (EFM) is used to study the structural characterization and piezoelectric properties of the materials realized. A clear inverse piezoelectric effect was observed when the bimorphs were subjected to an electric field stepped up through 2, 6 and 10 V, indicating the net polarization direction of the different ferroelectric domains. The as-developed bimorphs have the basic structure of a sensor and actuator, and, since they do not use any bonding agent for bonding, they can provide a valuable alternative to the present bimorphs where bonding processes are required for their realization that can limit their application at high temperature. (paper)

Structure and properties of PZT thin films on strontium ruthenate and calcium ruthenate electrodes

International Nuclear Information System (INIS)

Wu, T.-J.; Tsai, D.-S.

2004-01-01

PZT thin films have been prepared via metalorganic CVD (MOCVD) on four substrates of conducting oxides of ruthenates, SrRuO 3 /Pt/Ti/SiO 2 /Si(1 0 0), SrRuO 3 /SiO 2 /Si(1 0 0), CaRuO 3 /Pt/Ti/SiO 2 /Si(1 0 0), CaRuO 3 /SiO 2 /Si(1 0 0). The conducting ruthenate layers were also grown using MOCVD. Ferroelectric properties of polarization fatigue and leakage current density are measured. The internal strain of PZT thin crystal which is mainly constrained by the bottom electrode seems to be the decisive factor in ferroelectric properties. The internal strain of PZT is represented by its tetragonality ratio. The PZT thin film in the capacitor Au/PZT/SrRuO 3 /Pt/Ti/SiO 2 /Si, with the largest tetragonality ratio 1.026, exhibits an optimum combination of large polarization, less fatigue, and low leakage current density. Both SrRuO 3 and CaRuO 3 are good diffusion barriers to prevent interdiffusion of cations between the ferroelectric and the electrode. The slightly higher intermixing at the CaRuO 3 -to-Pt/Ti interface is owing to the high annealing temperature needed in CaRuO 3 synthesis

The thickness effect of Bi3.25La0.75Ti3O12 buffer layer in PbZr0.58Ti0.42O3/Bi3.25La0.75Ti3O12 (PZT/BLT) multilayered ferroelectric thin films

International Nuclear Information System (INIS)

Li Jianjun; Li Ping; Zhang Guojun; Yu Jun; Wu Yunyi; Wen Xinyi

2011-01-01

A series of PbZr 0.58 Ti 0.42 O 3 (PZT) thin films with various Bi 3.25 La 0.75 Ti 3 O 12 (BLT) buffer layer thicknesses were deposited on Pt/TiO 2 /SiO 2 /p-Si(100) substrates by RF magnetron sputtering. The X-ray diffraction measurements of PZT film and PZT/BLT multilayered films illustrate that the pure PZT film shows (111) preferential orientation, and the PZT/BLT films show (110) preferential orientation with increasing thickness of the BLT layer. There are no obvious diffraction peaks for the BLT buffer layer in the multilayered films, for interaction effect between the bottom BLT and top PZT films during annealing at the same time. From the surface images of field-emission scanning electron microscope, there are the maximum number of largest-size grains in PZT/BLT(30 nm) film among all the samples. The growth direction and grain size have significant effects on ferroelectric properties of the multilayered films. The fatigue characteristics of PZT and PZT/BLT films suggest that 30-nm-thick BLT is just an effective buffer layer enough to alleviate the accumulation of oxygen vacancies near the PZT/BLT interface. The comparison of these results with that of PZT/Pt/TiO 2 /SiO 2 /p-Si(100) basic structured film suggests that the buffer layer with an appropriate thickness can improve the ferroelectric properties of multilayered films greatly.

Interaction between depolarization effects, interface layer, and fatigue behavior in PZT thin film capacitors

Science.gov (United States)

Böttger, U.; Waser, R.

2017-07-01

The existence of non-ferroelectric regions in ferroelectric thin films evokes depolarization effects leading to a tilt of the P(E) hysteresis loop. The analysis of measured hysteresis of lead zirconate titanate (PZT) thin films is used to determine a depolarization factor which contains quantitative information about interfacial layers as well as ferroelectrically passive zones in the bulk. The derived interfacial capacitance is smaller than that estimated from conventional extrapolation techniques. In addition, the concept of depolarization is used for the investigation of fatigue behavior of PZT thin films indicating that the mechanism of seed inhibition, which is responsible for the effect, occurs in the entire film.

Pyroelectric Charge Release in Rhombohedral PZT

NARCIS (Netherlands)

Noheda, Beatriz; Duan, Ning; Cereceda, Noé; Gonzalo, Julio A.

1998-01-01

A new experimental set-up controlled by computer has been made to measure the pyroelectric charge of ferroelectric materials with a relatively high conductivity at slow rates of temperature variation. It allowed us to obtain the polarisation vs. temperature behaviour of PZT with various compositions

Elastic and anelastic relaxation behaviour of perovskite multiferroics II: PbZr0.53Ti0.47O3 (PZT)-PbFe0.5Ta0.5O3 (PFT).

Science.gov (United States)

Schiemer, J A; Lascu, I; Harrison, R J; Kumar, A; Katiyar, R S; Sanchez, D A; Ortega, N; Mejia, C Salazar; Schnelle, W; Shinohara, H; Heap, A J F; Nagaratnam, R; Dutton, S E; Scott, J F; Nair, B; Mathur, N D; Carpenter, M A

2017-01-01

Elastic and anelastic properties of ceramic samples of multiferroic perovskites with nominal compositions across the binary join PbZr 0.53 Ti 0.47 O 3 -PbFe 0.5 Ta 0.5 O 3 (PZT-PFT) have been assembled to create a binary phase diagram and to address the role of strain relaxation associated with their phase transitions. Structural relationships are similar to those observed previously for PbZr 0.53 Ti 0.47 O 3 -PbFe 0.5 Nb 0.5 O 3 (PZT-PFN), but the magnitude of the tetragonal shear strain associated with the ferroelectric order parameter appears to be much smaller. This leads to relaxor character for the development of ferroelectric properties in the end member PbFe 0.5 Ta 0.5 O 3 . As for PZT-PFN, there appear to be two discrete instabilities rather than simply a reorientation of the electric dipole in the transition sequence cubic-tetragonal-monoclinic, and the second transition has characteristics typical of an improper ferroelastic. At intermediate compositions, the ferroelastic microstructure has strain heterogeneities on a mesoscopic length scale and, probably, also on a microscopic scale. This results in a wide anelastic freezing interval for strain-related defects rather than the freezing of discrete twin walls that would occur in a conventional ferroelastic material. In PFT, however, the acoustic loss behaviour more nearly resembles that due to freezing of conventional ferroelastic twin walls. Precursor softening of the shear modulus in both PFT and PFN does not fit with a Vogel-Fulcher description, but in PFT there is a temperature interval where the softening conforms to a power law suggestive of the role of fluctuations of the order parameter with dispersion along one branch of the Brillouin zone. Magnetic ordering appears to be coupled only weakly with a volume strain and not with shear strain but, as with multiferroic PZT-PFN perovskites, takes place within crystals which have significant strain heterogeneities on different length scales.

Characterization of PZT thin films on metal substrates

International Nuclear Information System (INIS)

Dutschke, A.

2008-01-01

Lead zirconate titanate (PbZr x Ti 1-x O 3 ,PZT) is one of the most applied ceramic materials because of its distinctive piezo- and ferroelectric properties. Prepared as thin films on flexible, metallic substrates it can be used for various applications as strain gauges, key switches, vibration dampers, microactuators and ultrasonic transducers. The aim of this work is to analyze the microstructure and the phase-content of PZT-thin films deposited on temperature- und acid-resistant hastelloy-sheets, to correlate the results with the ferroelectric and dielectric properties. It is demonstrated, that the specific variation of the microstructure can be achieved by different thermal treatments and the selective addition of Neodymium as dopant. Nd-doping leads to a shift of the maximum nucleation rate towards reduced temperatures and a decrease in the rate of growth compared to undoped films. The PZT-films are prepared by a sol-gel-process in fourfold multilayers with a composition near the morphotropic phase boundary, where the tetragonal und rhombohedral perovskite-phases coexist. The crystallisation in Nd-doped and undoped films takes place heterogeneously, preferentially at the interfaces and on the surface of the multilayered films as well as on the inner surface of pores within the films. For the first time, the Zr:Ti fluctuation phenomena emerging in sol-gel derived PZT films is related to the microstructure and the local phase content on a nanometer scale. In this connection it is proved, that long-distance Zr:Ti gradients arise preferentially before and during the crystallisation of the pyrochlore phase. During the following crystallisation of the perovskite phase, the crystallites grow across these gradients without modifying them. It is pointed out that the fluctuation in the Zr:Ti ratio has only minor influence on the amount of the tetragonal or rhombohedral distortion of the crystallites after the transition from the para- to the ferroelectric state due to

Domain switching of fatigued ferroelectric thin films

Science.gov (United States)

Tak Lim, Yun; Yeog Son, Jong; Shin, Young-Han

2014-05-01

We investigate the domain wall speed of a ferroelectric PbZr0.48Ti0.52O3 (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue.

Domain switching of fatigued ferroelectric thin films

International Nuclear Information System (INIS)

Tak Lim, Yun; Yeog Son, Jong; Shin, Young-Han

2014-01-01

We investigate the domain wall speed of a ferroelectric PbZr 0.48 Ti 0.52 O 3 (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue

Ferroelectric BaPbO3/PbZr0.53Ti0.47/BaPbO3 heterostructures

International Nuclear Information System (INIS)

Liang Chunsheng; Wu Jennming; Chang Mingchu

2002-01-01

BaPbO 3 (BPO)/PbZr 0.53 Ti 0.47 (PZT)/BPO heterostructures were fabricated by combining the sol-gel and rf-magnetron sputtering techniques. Experimental results indicate that the BPO bottom electrodes effectively prevent the formation of the rosette structure of PZT, producing smooth surfaces. Additionally, ferroelectric, fatigue, and leakage current properties were markedly improved when both the top and the bottom electrodes were changed from Pt to BPO. These improvements are due to a superior electrode/ferroelectric interface. BPO is better than Pt and other oxide electrodes for use in PZT ferroelectric capacitors due to its remarkably improved properties and quite low growth temperature

Relaxor-like behavior of BaTiO.sub.3./sub. crystals from acoustic emission study

Czech Academy of Sciences Publication Activity Database

Dul´kin, E.; Petzelt, Jan; Kamba, Stanislav; Mojaev, E.; Roth, M.

2010-01-01

Roč. 97, č. 3 (2010), 032903/1-032903/3 ISSN 0003-6951 R&D Projects: GA ČR GAP204/10/0616; GA ČR(CZ) GA202/09/0682 Institutional research plan: CEZ:AV0Z10100520 Keywords : relaxor ferroelectrics * acoustic emission * phase transitions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.820, year: 2010

A hybrid ferroelectric-flash memory cells

Science.gov (United States)

Park, Jae Hyo; Byun, Chang Woo; Seok, Ki Hwan; Kim, Hyung Yoon; Chae, Hee Jae; Lee, Sol Kyu; Son, Se Wan; Ahn, Donghwan; Joo, Seung Ki

2014-09-01

A ferroelectric-flash (F-flash) memory cells having a metal-ferroelectric-nitride-oxynitride-silicon structure are demonstrated, and the ferroelectric materials were perovskite-dominated Pb(Zr,Ti)O3 (PZT) crystallized by Pt gate electrode. The PZT thin-film as a blocking layer improves electrical and memorial performance where programming and erasing mechanism are different from the metal-ferroelectric-insulator-semiconductor device or the conventional silicon-oxide-nitride-oxide-silicon device. F-flash cells exhibit not only the excellent electrical transistor performance, having 442.7 cm2 V-1 s-1 of field-effect mobility, 190 mV dec-1 of substhreshold slope, and 8 × 105 on/off drain current ratio, but also a high reliable memory characteristics, having a large memory window (6.5 V), low-operating voltage (0 to -5 V), faster P/E switching speed (50/500 μs), long retention time (>10 years), and excellent fatigue P/E cycle (>105) due to the boosting effect, amplification effect, and energy band distortion of nitride from the large polarization. All these characteristics correspond to the best performances among conventional flash cells reported so far.

Giant electrocaloric response in the prototypical Pb(Mg,Nb)O3 relaxor ferroelectric from atomistic simulations

Science.gov (United States)

Jiang, Zhijun; Nahas, Y.; Prokhorenko, S.; Prosandeev, S.; Wang, D.; Íñiguez, Jorge; Bellaiche, L.

2018-03-01

An atomistic effective Hamiltonian is used to investigate electrocaloric (EC) effects of Pb (Mg1 /3Nb2 /3) O3 relaxor ferroelectrics in its ergodic regime, and subject to electric fields applied along the pseudocubic [111] direction. Such a Hamiltonian qualitatively reproduces (i) the electric field-versus-temperature phase diagram, including the existence of a critical point where first-order and second-order transitions meet each other; and (ii) a giant EC response near such a critical point. It also reveals that such giant response around this critical point is microscopically induced by field-induced percolation of polar nanoregions. Moreover, it is also found that, for any temperature above the critical point, the EC coefficient-versus-electric-field curve adopts a maximum (and thus larger electrocaloric response too), that can be well described by the general Landau-like model proposed by Jiang et al., [Phys. Rev. B 96, 014114 (2017)], 10.1103/PhysRevB.96.014114, and that is further correlated with specific microscopic features related to dipoles lying along different rhombohedral directions. Furthermore, for temperatures being at least 40 K higher than the critical temperature, the (electric field, temperature) line associated with this maximal EC coefficient is below both the Widom line and the line representing percolation of polar nanoregions.

Effect of solid content variations on PZT slip for tape casting

Directory of Open Access Journals (Sweden)

Gang Jian

2012-12-01

Full Text Available Lead zirconate titanate (PZT particles with pure tetragonal structure were synthesized by solid-state reaction method and used for preparation of slurries with different solid contents (34–80 wt.%. Then, PZT thick films were fabricated by the nonaqueous tape casting method. It was shown that the slurry prepared from ball-milled particles exhibited better rheology properties than slurry from particles which were not ball-milled. Measurement of sedimentation volumes and zeta potentials indicated particle aggregation, resulting in weak stability of the slurries with high solid contents. The microstructure, piezoelectric and ferroelectric properties of PZT sintered films were investigated in terms of solid contents. Ceramic films prepared from the slurry with solid contents of 73 wt.% had the optimal structure and properties. After poling at 200 °C with an applied field of 1.2 kV/cm, a d33 of 294 pC/N was achieved; typical ferroelectric properties were also observed with a Ps of 38 μC/cm2.

Morphology-dependent photo-induced polarization recovery in ferroelectric thin films

Science.gov (United States)

Wang, J. Y.; Liu, G.; Sando, D.; Nagarajan, V.; Seidel, J.

2017-08-01

We investigate photo-induced ferroelectric domain switching in a series of Pb(Zr0.2Ti0.8)O3/La0.7Sr0.3MnO3 (PZT/LSMO) bilayer thin films with varying surface morphologies by piezoresponse force microscopy under light illumination. We demonstrate that reverse poled ferroelectric regions can be almost fully recovered under laser irradiation of the PZT layer and that the recovery process is dependent on the surface morphology on the nanometer scale. The recovery process is well described by the Kolmogorov-Avrami-Ishibashi model, and the evolution speed is controlled by light intensity, sample thickness, and initial write voltage. Our findings shed light on optical control of the domain structure in ferroelectric thin films with different surface morphologies.

A study of radiation vulnerability of ferroelectric material and devices

International Nuclear Information System (INIS)

Coiec, Y.M.; Musseau, O.; Leray, J.L.

1994-01-01

The radiation effects on ferroelectric material and devices are presented, based on commercially available samples. After recalling the background, effects in ferroelectric PZT capacitors are presented, concerning dose, neutrons and fatigue associated with dose effects. Physical implications and interpretations are sketched. In a second stage, effects are studied at the complete non-volatile RAM device level. Vulnerability in dose, dose rate and neutron fluence of commercial 4 kbit ferroelectric RAM is addressed. 64 kbit results are mentioned in dose rate. These results are compared to previously published data from other manufacturers or laboratories and supplement them. In the appendix, equivalence between rad(Si) and rad (PZT) is discussed in the case of low energy ''10 keV Aracor'' x-rays and 60 Co gamma rays

An Ultrathin Single Crystalline Relaxor Ferroelectric Integrated on a High Mobility Semiconductor

Energy Technology Data Exchange (ETDEWEB)

Moghadam, Reza M. [Department; Xiao, Zhiyong [Department; Ahmadi-Majlan, Kamyar [Department; Grimley, Everett D. [Department; Bowden, Mark [Environmental; amp, Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Ong, Phuong-Vu [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Chambers, Scott A. [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Lebeau, James M. [Department; Hong, Xia [Department; Sushko, Peter V. [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Ngai, Joseph H. [Department

2017-09-13

The epitaxial growth of multifunctional oxides on semiconductors has opened a pathway to introduce new functionalities to semiconductor device technologies. In particular, ferroelectric materials integrated on semiconductors could lead to low-power field-effect devices that can be used for logic or memory. Essential to realizing such field-effect devices is the development of ferroelectric metal-oxide-semiconductor (MOS) capacitors, in which the polarization of a ferroelectric gate is coupled to the surface potential of a semiconducting channel. Here we demonstrate that ferroelectric MOS capacitors can be realized using single crystalline SrZrxTi1-xO3 (x= 0.7) that has been epitaxially grown on Ge. We find that the ferroelectric properties of SrZrxTi1-xO3 are exceptionally robust, as gate layers as thin as 5 nm give rise to hysteretic capacitance-voltage characteristics that are 2 V in width. The development of ferroelectric MOS capacitors with gate thicknesses that are technologically relevant opens a pathway to realize scalable ferroelectric field-effect devices.

Ferroelectric properties of bilayer structured Pb(Zr0.52Ti0.48)O3/SrBi2Ta2O9 (PZT/SBT) thin films on Pt/TiO2/SiO2/Si substrates

International Nuclear Information System (INIS)

Zhang Wenqi; Li Aidong; Shao Qiyue; Xia Yidong; Wu Di; Liu Zhiguo; Ming Naiben

2008-01-01

Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films with large remanent polarization and SrBi 2 Ta 2 O 9 (SBT) thin films with excellent fatigue-resisting characteristic have been widely studied for non-volatile random access memories, respectively. To combine these two advantages , bilayered Pb(Zr 0.52 Ti 0.48 )O 3 /SrBi 2 Ta 2 O 9 (PZT/SBT) thin films were fabricated on Pt/TiO 2 /SiO 2 /Si substrates by chemical solution deposition method. X-ray diffraction patterns revealed that the diffraction peaks of PZT/SBT thin films were completely composed of PZT and SBT, and no other secondary phase was observed. The electrical properties of the bilayered structure PZT/SBT films have been investigated in comparison with pure PZT and SBT films. PZT/SBT bilayered thin films showed larger remanent polarization (2P r ) of 18.37 μC/cm 2 than pure SBT and less polarization fatigue up to 1 x 10 9 switching cycles than pure PZT. These results indicated that this bilayered structure of PZT/SBT is a promising material combination for ferroelectric memory applications

Transmission electron microscope studies of phase transitions in single crystals and ceramics of ferroelectric Pb(Sc1/2Ta1/2)O3

International Nuclear Information System (INIS)

Baba-Kishi, K.Z.; Barber, D.J.

1990-01-01

An account is given of transmission electron microscope investigations of the phase transitions in single crystals and ceramics of the complex perovskite-structured ferroelectric 'relaxor' compound Pb(Sc 1/2 Ta 1/2 )O 3 . The crystal symmetries pertaining to both the non-polar paraelectric (PE) and polar ferroelectric (FE) states have been studied by the technique of convergent-beam electron diffraction. A new phase transition has been discovered in the temperature range for which the FE and PE states coexist. The new phase transition is interpreted as the creation of a modulated antiferroelectric state, and this is viewed as marking a departure from relaxor behaviour towards more 'normal' ferroelectric behaviour. (orig.)

Flexoelectricity: strain gradient effects in ferroelectrics

Energy Technology Data Exchange (ETDEWEB)

Ma Wenhui [Department of Physics, Shantou Unversity, Shantou, Guangdong 515063 (China)

2007-12-15

Mechanical strain gradient induced polarization effect or flexoelectricity in perovskite-type ferroelectric and relaxor ferroelectric ceramics was investigated. The flexoelectric coefficients measured at room temperature ranged from about 1 {mu} C m{sup -1} for lead zirconate titanate to 100 {mu} C m{sup -1} for barium strontium titanate. Flexoelectric effects were discovered to be sensitive to chemical makeup, phase symmetry, and domain structures. Based on phenomenological discussion and experimental data on flexoelectricity, the present study proposed that mechanical strain gradient field could influence polarization responses in a way analogous to electric field. Flexoelectric coefficients were found to be nonlinearly enhanced by dielectric permittivity and strain gradient. Interfacial mismatch in epitaxial thin films can give rise to high strain gradients, enabling flexoelectric effects to make a significant impact in properly engineered ferroelectric heterostructure systems.

Frontiers of ferroelectricity a special issue of the journal of materials science

CERN Document Server

Lang, Sidney B

2007-01-01

The book presents theory, fundamentals and some applications of ferroelectricy. The 24 chapters comprise reviews and research reports covering the spectrum of ferroelectricity. It is intended to describe the current levels of understanding of various aspects of ferroelectricity as presented by authorities in the field. Topics include relaxors, piezoelectrics, microscale and nanoscale studies, polymers and composites, unusual properties, and techniques and devices. The information in this book is intended for physicists, engineers and materials scientists working with ferroelectric materials including ceramics, single crystals, polymers, composites and even some biological materials.

Synthesis and Characterization of Pb(Zr𝟎.𝟓𝟑, Ti𝟎.𝟒𝟕)O𝟑-Pb(Nb𝟏/𝟑, Zn𝟐/𝟑)O𝟑 Thin Film Cantilevers for Energy Harvesting Applications

KAUST Repository

Fuentes-Fernandez, E. M. A.; Debray-Mechtaly, W.; Quevedo-Lopez, M. A.; Gnade, B.; Leon-Salguero, E.; Shah, P.; Alshareef, Husam N.

2012-01-01

A complete analysis of the morphology, crystallographic orientation, and resulting electrical properties of Pb(Zr0.53,Ti0.47) Pb(Nb1/3, Zn2/3)O3 (PZT-PZN) thin films, as well as the electrical behavior when integrated in a cantilever for energy harvesting applications, is presented. The PZT-PZN films were deposited using sol-gel methods. We report that using 20% excess Pb, a nucleation layer of PbTiO3 (PT), and a fast ramp rate provides large grains, as well as denser films. The PZT-PZN is deposited on a stack of TiO2/PECVD SiO2/Si3N4/thermal SiO2/Poly-Si/Si. This stack is designed to allow wet-etching the poly-Si layer to release the cantilever structures. It was also found that the introduction of the poly-Si layer results in larger grains in the PZT-PZN film. PZT-PZN films with a dielectric constant of 3200 and maximum polarization of 30 μC/cm2 were obtained. The fabricated cantilever devices produced ~300–400 mV peak-to-peak depending on the cantilever design. Experimental results are compared with simulations.

Synthesis and Characterization of Pb(Zr., Ti.)O-Pb(Nb/, Zn/)O Thin Film Cantilevers for Energy Harvesting Applications

KAUST Repository

Fuentes-Fernandez, E. M. A.

2012-01-18

A complete analysis of the morphology, crystallographic orientation, and resulting electrical properties of Pb(Zr0.53,Ti0.47) Pb(Nb1/3, Zn2/3)O3 (PZT-PZN) thin films, as well as the electrical behavior when integrated in a cantilever for energy harvesting applications, is presented. The PZT-PZN films were deposited using sol-gel methods. We report that using 20% excess Pb, a nucleation layer of PbTiO3 (PT), and a fast ramp rate provides large grains, as well as denser films. The PZT-PZN is deposited on a stack of TiO2/PECVD SiO2/Si3N4/thermal SiO2/Poly-Si/Si. This stack is designed to allow wet-etching the poly-Si layer to release the cantilever structures. It was also found that the introduction of the poly-Si layer results in larger grains in the PZT-PZN film. PZT-PZN films with a dielectric constant of 3200 and maximum polarization of 30 μC/cm2 were obtained. The fabricated cantilever devices produced ~300–400 mV peak-to-peak depending on the cantilever design. Experimental results are compared with simulations.

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.

Misfit strain dependence of ferroelectric and piezoelectric properties of clamped (001) epitaxial Pb(Zr0.52,Ti0.48)O3 thin films

Science.gov (United States)

Nguyen, Minh D.; Dekkers, Matthijn; Houwman, Evert; Steenwelle, Ruud; Wan, Xin; Roelofs, Andreas; Schmitz-Kempen, Thorsten; Rijnders, Guus

2011-12-01

A study on the effects of the residual strain in Pb(Zr0.52Ti0.48)O3 (PZT) thin films on the ferroelectric and piezoelectric properties is presented. Epitaxial (001)-oriented PZT thin film capacitors are sandwiched between SrRuO3 electrodes. The thin film stacks are grown on different substrate-buffer-layer combinations by pulsed laser deposition. Compressive or tensile strain caused by the difference in thermal expansion of the PZT film and substrate influences the ferroelectric and piezoelectric properties. All the PZT stacks show ferroelectric and piezoelectric behavior that is consistent with the theoretical model for strained thin films in the ferroelectric r-phase. We conclude that clamped (001) oriented Pb(Zr0.52Ti0.48)O3 thin films strained by the substrate always show rotation of the polarization vector.

Quantum mechanical studies of complex ferroelectric perovskites

Science.gov (United States)

Ramer, Nicholas John

In many electronic device applications, there is a need to interconvert electrical energy and other types of energy. Ferroelectric materials, which possess a voltage-dependent polarization, can enable this energy conversion process. Because of the broad interest in ferroelectric materials for these devices, there is a critical research effort, both experimental and theoretical, to understand these materials and aid in the development of materials with improved properties. This thesis presents detailed quantum mechanical investigations of the behavior of a complex ferroelectric perovskite under applied stress. In particular, we have chosen to study the solid solution PbZr1-xTix O3 (PZT). Since the study of ferroelectricity involves understanding both its structural and electronic signatures in materials, it has necessitated the development of a novel theoretical technique which improves the accuracy of the pseudopotentials used in our density functional theory calculations as well as a new method for constructing three-dimensional atomistic responses to small amounts of external stress. To examine the material's behavior under larger amounts of stress, we have studied the behavior of a composition of PZT lying near a structural phase boundary. On either side of the phase boundary, the material is characterized by a different polarization direction and may easily be switched between phases by applying external stress. In addition to stress-induced phase transitions, most ferroelectric materials also have composition dependent phase boundaries. Since different compositions of PZT would require increased computational effort, we have formulated an improved virtual crystal approach that makes tractable the study of the entire composition range. Using this method, we have been able to show for the first time via first-principles calculations, a composition dependent phase transition in a ferroelectric material. This thesis has accomplished three important goals: new

Energy band alignment at ferroelectric/electrode interface determined by photoelectron spectroscopy

International Nuclear Information System (INIS)

Chen Feng; Wu Wen-Bin; Li Shun-Yi; Klein Andreas

2014-01-01

The most important interface-related quantities determined by band alignment are the barrier heights for charge transport, given by the Fermi level position at the interface. Taking Pb(Zr,Ti)O 3 (PZT) as a typical ferroelectric material and applying X-ray photoelectron spectroscopy (XPS), we briefly review the interface formation and barrier heights at the interfaces between PZT and electrodes made of various metals or conductive oxides. Polarization dependence of the Schottky barrier height at a ferroelectric/electrode interface is also directly observed using XPS. (topical review - magnetism, magnetic materials, and interdisciplinary research)

Electric-field-induced local structural phenomena in relaxor ferroelectric PbSc0.5Nb0.5O3 near the intermediate temperature T* studied by Raman spectroscopy

International Nuclear Information System (INIS)

Steilmann, T; Maier, B J; Bismayer, U; Mihailova, B; Gospodinov, M

2014-01-01

Raman spectroscopy at different temperatures and under an external electric field E was applied to PbSc 0.5 Nb 0.5 O 3 single crystals in order to gain further insights into the mesoscopic-scale coupling processes in perovskite-type (ABO 3 ) relaxor ferroelectrics. Parallel and cross-polarized Raman spectra were collected between 800–80 K with E applied along the cubic [1 0 0], [1 1 0] or [1 1 1] crystallographic directions. The analysis was focused on the field-induced changes in the temperature evolution of three low-energy phonon modes: the Pb-localized mode near 50 cm −1 , the Pb-BO 3 translation mode near 150 cm −1 , and the B-cation-localized mode near 250 cm −1 . The results show that competitive ferroelectric (FE) and antiferroelectric (AFE) coupling exists within the system of off-centred Pb 2+ cations, within the system of off-centred B-site cations as well as between off-centred Pb 2+ and B-site cations. The strong AFE-type coupling between Pb 2+ cations along the cubic body diagonal significantly influences the coupling between the B-site cations via the Pb-BO 3 mode and results in AFE-type behaviour of the ‘microscopic’ T* determined from the B-cation-localized mode near 250 cm −1 , which explains the previously reported non-trivial field dependence of the ‘macroscopic’ characteristic temperatures: the temperature of the dielectric-permittivity maximum T m , T*, and the Burns temperature T B . The comparative analysis between PbSc 0.5 Nb 0.5 O 3 and PbSc 0.5 Ta 0.5 O 3 indicates that two major displacive order parameters couple to form a relaxor state in B-site complex perovskites: the FE order associated with polar shifts of B-site cations and the AFE order associated with polar shifts of A-site cations. The latter penetrates through both polar and non-polar regions, but it is highly frustrated due to the high density of translation-symmetry faults in the chemical NaCl-type B-site order. The frustrated AFE order

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.

Properties of PZT-Based Piezoelectric Ceramics Between -150 and 250 C

Science.gov (United States)

Hooker, Matthew W.

1998-01-01

The properties of three PZT-based piezoelectric ceramics and one PLZT electrostrictive ceramic were measured as a function of temperature. In this work, the dielectric, ferroelectric polarization versus electric field, and piezoelectric properties of PZT-4, PZT-5A, PZT-5H, and PLZT-9/65/35 were measured over a temperature range of -150 to 250 C. In addition to these measurements, the relative thermal expansion of each composition was measured from 25 to 600 C and the modulus of rupture of each material was measured at room temperature. This report describes the experimental results and compares and contrasts the properties of these materials with respect to their applicability to intelligent aerospace systems.

A study of radiation vulnerability of ferroelectric material and devices

Energy Technology Data Exchange (ETDEWEB)

Coic, Y M; Musseau, O; Leray, J L [CEA Centre d` Etudes de Bruyeres-le-Chatel, 91 (France)

1994-12-31

The radiation effects on ferroelectric material and devices are presented, based on commercially available samples. After recalling the background, effects in ferroelectric PZT capacitors are presented, concerning dose, neutrons and fatigue associated with dose effects. Physical implications and interpretations are sketched. In a second stage, effects are studied at the complete non-volatile RAM device level. Vulnerability in dose, dose rate and neutron fluence of commercial 4 kbit ferroelectric RAM is addressed. 64 kbit results are mentioned in dose rate. These results are compared to previously published data from other manufacturers or laboratories and supplement them. In the appendix, equivalence between rad (Si) and rad (PZT) is discussed in the case of low energy ``10 keV Aracor`` s-rays and {sup 60}Co gamma rays. (author). 24 refs., 11 figs., 7 tabs.

A study of radiation vulnerability of ferroelectric material and devices

International Nuclear Information System (INIS)

Coic, Y.M.; Musseau, O.; Leray, J.L.

1994-01-01

The radiation effects on ferroelectric material and devices are presented, based on commercially available samples. After recalling the background, effects in ferroelectric PZT capacitors are presented, concerning dose, neutrons and fatigue associated with dose effects. Physical implications and interpretations are sketched. In a second stage, effects are studied at the complete non-volatile RAM device level. Vulnerability in dose, dose rate and neutron fluence of commercial 4 kbit ferroelectric RAM is addressed. 64 kbit results are mentioned in dose rate. These results are compared to previously published data from other manufacturers or laboratories and supplement them. In the appendix, equivalence between rad (Si) and rad (PZT) is discussed in the case of low energy ''10 keV Aracor'' s-rays and 60 Co gamma rays. (author). 24 refs., 11 figs., 7 tabs

Neutron Diffraction Study of the Irreversible R-MA-MC Phase Transition in Single Crystal Pb[(Zn1/3Nb2/3)1-xTix]O3

NARCIS (Netherlands)

Ohwada, Kenji; Hirota, Kazuma; Rehrig, Paul W.; Gehring, Peter M.; Noheda, Beatriz; Fujii, Yasuhiko; Park, Seung-Eek Eagle; Shirane, Gen

2001-01-01

Single crystals of the relaxor PZN-xPT display an enormously strong piezoelectric character. Recent x-ray scattering studies have revealed novel electric-field induced phase transitions in PZN-8%PT. As-grown crystals exhibit a rhombohedral structure that, under application of an electric field

Total scattering and pair distribution function analysis in modelling disorder in PZN (PbZn1/3Nb2/3O3

Directory of Open Access Journals (Sweden)

Ross E. Whitfield

2016-01-01

Full Text Available The ability of the pair distribution function (PDF analysis of total scattering (TS from a powder to determine the local ordering in ferroelectric PZN (PbZn1/3Nb2/3O3 has been explored by comparison with a model established using single-crystal diffuse scattering (SCDS. While X-ray PDF analysis is discussed, the focus is on neutron diffraction results because of the greater extent of the data and the sensitivity of the neutron to oxygen atoms, the behaviour of which is important in PZN. The PDF was shown to be sensitive to many effects not apparent in the average crystal structure, including variations in the B-site—O separation distances and the fact that 〈110〉 Pb2+ displacements are most likely. A qualitative comparison between SCDS and the PDF shows that some features apparent in SCDS were not apparent in the PDF. These tended to pertain to short-range correlations in the structure, rather than to interatomic separations. For example, in SCDS the short-range alternation of the B-site cations was quite apparent in diffuse scattering at (½ ½ ½, whereas it was not apparent in the PDF.

Total scattering and pair distribution function analysis in modelling disorder in PZN (PbZn1/3Nb2/3O3)

Science.gov (United States)

Whitfield, Ross E.; Goossens, Darren J.; Welberry, T. Richard

2016-01-01

The ability of the pair distribution function (PDF) analysis of total scattering (TS) from a powder to determine the local ordering in ferroelectric PZN (PbZn1/3Nb2/3O3) has been explored by comparison with a model established using single-crystal diffuse scattering (SCDS). While X-ray PDF analysis is discussed, the focus is on neutron diffraction results because of the greater extent of the data and the sensitivity of the neutron to oxygen atoms, the behaviour of which is important in PZN. The PDF was shown to be sensitive to many effects not apparent in the average crystal structure, including variations in the B-site—O separation distances and the fact that 〈110〉 Pb2+ displacements are most likely. A qualitative comparison between SCDS and the PDF shows that some features apparent in SCDS were not apparent in the PDF. These tended to pertain to short-range correlations in the structure, rather than to interatomic separations. For example, in SCDS the short-range alternation of the B-site cations was quite apparent in diffuse scattering at (½ ½ ½), whereas it was not apparent in the PDF. PMID:26870378

High-resolution 2-D Bragg diffraction reveal heterogeneous domain transformation behavior in a bulk relaxor ferroelectric

Energy Technology Data Exchange (ETDEWEB)

Pramanick, Abhijit, E-mail: apramani@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Stoica, Alexandru D.; An, Ke [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2016-08-29

In-situ measurement of fine-structure of neutron Bragg diffraction peaks from a relaxor single-crystal using a time-of-flight instrument reveals highly heterogeneous mesoscale domain transformation behavior under applied electric fields. It is observed that only ∼25% of domains undergo reorientation or phase transition contributing to large average strains, while at least 40% remain invariant and exhibit microstrains. Such insights could be central for designing new relaxor materials with better performance and longevity. The current experimental technique can also be applied to resolve complex mesoscale phenomena in other functional materials.

Dynamic Observation of Brain-Like Learning in a Ferroelectric Synapse Device

Science.gov (United States)

Nishitani, Yu; Kaneko, Yukihiro; Ueda, Michihito; Fujii, Eiji; Tsujimura, Ayumu

2013-04-01

A brain-like learning function was implemented in an electronic synapse device using a ferroelectric-gate field effect transistor (FeFET). The FeFET was a bottom-gate type FET with a ZnO channel and a ferroelectric Pb(Zr,Ti)O3 (PZT) gate insulator. The synaptic weight, which is represented by the channel conductance of the FeFET, is updated by applying a gate voltage through a change in the ferroelectric polarization in the PZT. A learning function based on the symmetric spike-timing dependent synaptic plasticity was implemented in the synapse device using the multilevel weight update by applying a pulse gate voltage. The dynamic weighting and learning behavior in the synapse device was observed as a change in the membrane potential in a spiking neuron circuit.

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.

Preparation of PZT/YBCO/YAlO heterostructure thin films by KrF excimer laser ablation

International Nuclear Information System (INIS)

Ebihara, Kenji; Kurogi, Hiromitsu; Yamagata, Yukihiko; Ikegami, Tomoaki; Grishin, A.M.

1998-01-01

The perovskite oxide YBa 2 Cu 3 O 7-x (YBCO) and Pb(Zr x Ti 1-x )O 3 (PZT) thin films have been deposited for superconducting-ferroelectric devices. KrF excimer laser ablation technique was used at the deposition conditions of 200--600 mTorr O 2 , 2-3J/cm 2 and 5--10 Hz operation frequency. Heterostructures of PZT-YBCO-YAlO 3 :Nd show the zero resistivity critical temperature of 82 K and excellent ferroelectric properties of remnant polarization 32 microC/cm 2 , coercive force of 80 kV/cm and dielectric constant 800. Cycling fatigue characteristics and leakage current are also discussed

Reconstruction of the domain orientation distribution function of polycrystalline PZT ceramics using vector piezoresponse force microscopy.

Science.gov (United States)

Kratzer, Markus; Lasnik, Michael; Röhrig, Sören; Teichert, Christian; Deluca, Marco

2018-01-11

Lead zirconate titanate (PZT) is one of the prominent materials used in polycrystalline piezoelectric devices. Since the ferroelectric domain orientation is the most important parameter affecting the electromechanical performance, analyzing the domain orientation distribution is of great importance for the development and understanding of improved piezoceramic devices. Here, vector piezoresponse force microscopy (vector-PFM) has been applied in order to reconstruct the ferroelectric domain orientation distribution function of polished sections of device-ready polycrystalline lead zirconate titanate (PZT) material. A measurement procedure and a computer program based on the software Mathematica have been developed to automatically evaluate the vector-PFM data for reconstructing the domain orientation function. The method is tested on differently in-plane and out-of-plane poled PZT samples, and the results reveal the expected domain patterns and allow determination of the polarization orientation distribution function at high accuracy.

Phase and electrical properties of PZT thin films embedded with CuO nano-particles by a hybrid sol-gel route

Science.gov (United States)

Sreesattabud, Tharathip; Gibbons, Brady J.; Watcharapasorn, Anucha; Jiansirisomboon, Sukanda

2013-07-01

Pb(Zr0.52Ti0.48)O3 or PZT thin films embedded with CuO nano-particles were successfully prepared by a hybrid sol-gel process. In this process, CuO (0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1 wt. %) nanopowder was suspended in an organometallic solution of PZT, and then coated on platinised silicon substrate using a spin-coating technique. The influence of CuO nano-particles' dispersion on the phase of PZT thin films was investigated. XRD results showed a perovskite phase in all films. At the CuO concentration of 0.4-1 wt. %, a second phase was observed. The addition of CuO nano-particles affected the orientation of PZT thin films. The addition was also found to reduce the ferroelectric properties of PZT thin films. However, at 0.2 wt. % CuO concentration, the film exhibited good ferroelectric properties similar to those of PZT films. In addition, the fatigue retention properties of the PZT/CuO system was observed, and it showed 14% fatigue at 108 switching bipolar pulse cycles while the fatigue in PZT thin films was found to be 17% at the same switching bipolar pulse cycles.

PMN-PT-PZT composite films for high frequency ultrasonic transducer applications.

Science.gov (United States)

Hsu, Hsiu-Sheng; Benjauthrit, Vatcharee; Zheng, Fan; Chen, Rumin; Huang, Yuhong; Zhou, Qifa; Shung, K Kirk

2012-06-01

We have successfully fabricated x (0.65PMN-0.35PT)-(1 - x )PZT ( x PMN-PT-(1 - x )PZT), where x is 0.1, 0.3, 0.5, 0.7 and 0.9, thick films with a thickness of approximately 9 µm on platinized silicon substrate by employing a composite sol-gel technique. X-ray diffraction analysis and scanning electron microscopy revealed that these films are dense and creak-free with well-crystallized perovskite phase in the whole composition range. The dielectric constant can be controllably adjusted by using different compositions. Higher PZT content of x PMN-PT-(1 - x )PZT films show better ferroelectric properties. A representative 0.9PMN-PT-0.1PZT thick film transducer is built. It has 200 MHz center frequency with a -6 dB bandwidth of 38% (76 MHz). The measured two-way insertion loss is 65 dB.

Directly patternable high refractive index ferroelectric sol–gel resist

Energy Technology Data Exchange (ETDEWEB)

Garoli, D., E-mail: denis.garoli@iit.it [Istituto Italiano di Tecnologia, Via Morego 16, 16136 Genova (Italy); Della Giustina, G. [Industrial Engineering Department, University of Padova and INSTM, Via Marzolo 9, 35131 Padova (Italy)

2015-08-15

The development of a ferroelectric negative tone sol–gel resist for Ultraviolet (UV) and Electron Beam (EB) lithography is presented. A new system based on Lead Zirconate Titanate (PZT, with formula PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}) was synthesized by sol–gel method. The lithographic performances were investigated and several structures spanning from the micron range down to less than 50 nm have been achieved by UV and EB lithography. The system interaction with UV light and Electron beam was thoroughly characterized by FT-IT spectroscopy. The exposed PZT was annealed at high temperatures in order to study the crystalline phase evolution, the optical constants values and stability of patterned structures. After exposure and annealing, the refractive index of the material can vary from 1.68 up to 2.33 (@400 nm), while the ferroelectric behaviour seems to be maintained after high temperature annealing. These results suggest a possible application of PZT resist not only as ferroelectric but also as nanopatternable high refractive index material. Moreover, direct nanopatterning by means of Focused Ion Beam (FIB) lithography was verified and the potentiality for the preparation of high aspect ratio hollow nanostructures will be presented. - Highlights: • A new formula directly patternable PZT high refractive index resist is presented. • The gel is sensitive to both UV and electron beam exposure. • The refractive index can vary from 1.68 up to 2.33 (@400 nm). • Direct nanopatterning by means of Focused Ion Beam (FIB) lithography was verified. • High aspect ratio hollow nanostructures will be presented.

Polarization fatigue in ferroelectric Pb(Zr0.52Ti0.48)O3-SrBi2Nb2O9 ceramics

Science.gov (United States)

Namsar, Orapim; Pojprapai, Soodkhet; Watcharapasorn, Anucha; Jiansirisomboon, Sukanda

2015-09-01

Ferroelectric fatigue induced by cyclic electric loading of the (1- x)PZT- xSBN ceramics (0.1 ≤ x ≤ 0.3) have been investigated in comparison with pure PZT and SBN ceramics. The results showed that pure PZT ceramic possessed severe polarization fatigue after long bipolar switching pulses. This was mainly attributed to the appearance of microstructural damage at the near-electrode regions. Whereas, pure SBN ceramic exhibited no fatigue at least up to 1 × 106 switching cycles. The fatigue-free behavior of SBN ceramics was due primarily to weak domain wall pinning. PZT-SBN ceramics showed less polarization fatigue up to 1 × 106 switching cycles than pure PZT. This could be attributed to their low oxygen vacancy concentration. Therefore, this new ceramic PZT-SBN system seems to be an alternative material for replacing PZT in ferroelectric memory applications. [Figure not available: see fulltext.

Manipulation of charge transfer and transport in plasmonic-ferroelectric hybrids for photoelectrochemical applications

Science.gov (United States)

Wang, Zhijie; Cao, Dawei; Wen, Liaoyong; Xu, Rui; Obergfell, Manuel; Mi, Yan; Zhan, Zhibing; Nasori, Nasori; Demsar, Jure; Lei, Yong

2016-01-01

Utilizing plasmonic nanostructures for efficient and flexible conversion of solar energy into electricity or fuel presents a new paradigm in photovoltaics and photoelectrochemistry research. In a conventional photoelectrochemical cell, consisting of a plasmonic structure in contact with a semiconductor, the type of photoelectrochemical reaction is determined by the band bending at the semiconductor/electrolyte interface. The nature of the reaction is thus hard to tune. Here instead of using a semiconductor, we employed a ferroelectric material, Pb(Zr,Ti)O3 (PZT). By depositing gold nanoparticle arrays and PZT films on ITO substrates, and studying the photocurrent as well as the femtosecond transient absorbance in different configurations, we demonstrate an effective charge transfer between the nanoparticle array and PZT. Most importantly, we show that the photocurrent can be tuned by nearly an order of magnitude when changing the ferroelectric polarization in PZT, demonstrating a versatile and tunable system for energy harvesting. PMID:26753764

Structural contribution to the ferroelectric fatigue in lead zirconate titanate ceramics

Science.gov (United States)

Hinterstein, M.; Rouquette, J.; Haines, J.; Papet, Ph.; Glaum, J.; Knapp, M.; Eckert, J.; Hoffman, M.

2014-09-01

Many ferroelectric devices are based on doped lead zirconate titanate (PZT) ceramics with compositions near the morphotropic phase boundary (MPB), at which the relevant material's properties approach their maximum. Based on a synchrotron x-ray diffraction study of MPB PZT, bulk fatigue is unambiguously found to arise from a less effective field induced tetragonal-to-monoclinic transformation, at which the degradation of the polarization flipping is detected by a less intense and more diffuse anomaly in the atomic displacement parameter of lead. The time dependence of the ferroelectric response on a structural level down to 250 μs confirms this interpretation in the time scale of the piezolectric strain response.

Temperature dependent optical dispersion and electronic transitions of highly a-axis oriented 0.8Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-0.2PbTiO{sub 3} films on SrTiO{sub 3} crystals: An ellipsometric evidence

Energy Technology Data Exchange (ETDEWEB)

Li, C.Q.; Zhang, J.Z.; Xu, L.P.; Zhu, J.J.; Duan, Z.H.; Hu, Z.G., E-mail: zghu@ee.ecnu.edu.cn; Chu, J.H.

2016-03-31

The relaxor ferroelectric 0.8Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-0.2PbTiO{sub 3} (0.8PZN-0.2PT) films have been fabricated on (100) SrTiO{sub 3} substrates by the sol–gel method. The structure, optical properties and electronic transitions have been investigated using X-ray diffraction (XRD), atomic force microscopy, scanning electron microscopy and ellipsometric spectra. The pure perovskite phase with highly a-axis (100)-preferential orientation as well as low screw dislocation are extracted based on high resolution XRD. Moreover, the red-shift trend of the electronic transitions at about 3.01 eV as a function of temperature follows the Bose-Einstein law induced by the electron–phonon interactions and lattice thermal expansion. Interestingly, the different optical behavior and structure variation can be observed at about 500 K, which reveal tetragonal to cubic structural transformations for the 0.8PZN-0.2PT films. It indicates that the potential application of ellipsometric spectra in judging the phase transitions and symmetries of ferroelectric material. - Highlights: • The highly a-axis oriented as well as low screw dislocated films were fabricated. • The temperature-dependent evolution of band gap was investigated. • The tetragonal to cubic structural transformations were observed at about 500 K. • The electronic transition mechanism was discussed mainly by first-principles calculations.

Influence of Fe{sup 3+} substitution on the dielectric and ferroelectric characteristics of Lead Indium Niobate

Energy Technology Data Exchange (ETDEWEB)

Divya, A.S.; Kumar, V., E-mail: vkumar10@yahoo.com

2015-07-15

Highlights: • Prepared phase-pure Fe{sup 3+}-substituted Lead Indium Niobate, Pb[(In{sub 0.50−x}Fe{sub x})Nb{sub 0.50}]O{sub 3} by sol–gel method. • Spontaneous Relaxor (R) → Ferroelectric (FE) transition observed for the composition with x = 0.20. • Local structural rearrangement responsible for R → FE transition has been confirmed by Raman spectroscopy. - Abstract: Lead Indium Niobate, Pb(In{sub 0.50}Nb{sub 0.50})O{sub 3} (PIN) is a complex perovskite that exhibits Relaxor (R) characteristics. In this study, we report the synthesis of phase-pure compositions in the system Pb[(In{sub 0.50−x}Fe{sub x})Nb{sub 0.50}]O{sub 3} by sol–gel method and discuss the influence of isovalent substitution of Indium by Iron on the dielectric and ferroelectric characteristics. Spontaneous transition to the Ferroelectric (FE) phase has been observed for the composition having x = 0.20. Local structural rearrangements responsible for R → FE transition have also been studied by Raman spectroscopy and are discussed in detail.

Phase transitions in PZT ceramics prepared by different techniques

Czech Academy of Sciences Publication Activity Database

Deineka, Alexander; Suchaneck, G.; Jastrabík, Lubomír; Gerlach, G.

2002-01-01

Roč. 41, 11B (2002), s. 6966-6968 ISSN 0021-4922 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010914 Keywords : PZT * phase transitions * band gap * ferroelectrics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.280, year: 2002

Single crystal magnetic, dielectric and thermal studies of the relaxor ferroelectric Pb(Fe2/3W1/3)O3

International Nuclear Information System (INIS)

Ye, Z.G.; Sato, M.; Kita, E.; Bursill, L.A.; Schmid, H.

1998-01-01

The magnetic, dielectric and thermal properties of the complex perovskite Pb(Fe 2/3 W 1/3 )O 3 [PFW] have been studied on single crystals by means of a SQUID magnetometer, dielectric measurements and thermal analysis. Anomalies in the temperature dependence of the magnetization have revealed magnetic phase transitions at T N1 =350 K and T N2 =20 K. These two steps of antiferromagnetic ordering are attributed to the microstructural feature of the complex perovskite, characterized by ordered and disordered arrangements on the B-site, giving rise to a strong superexchange interaction of - Fe 3 + - O - Fe 3+ - type with a higher ordering temperature, and to a weak superexchange interaction of the B-site ordered elpasolite type - Fe 3+ + - O - W - O - Fe 3+ - with a lower Neel temperature. The low temperature antiferromagnetic phase exhibits a weak ferromagnetism. The dielectric properties of PFW show a relaxor ferroelectric behaviour with a dispersive maximum of permittivity at Tm (170 -190 K). The magnetic phase transition at T N2 =20 K results in anomalies both of the real part of permittivity and the dissipation factor, suggesting a magneto-electric coupling via magneto-structural interactions

Homogenized electromechanical properties of crystalline and ceramic relaxor ferroelectric 0.58Pb(Mg1/3Nb2/3)O3 0.42PbTiO3

Science.gov (United States)

Jayachandran, K. P.; Guedes, J. M.; Rodrigues, H. C.

2007-10-01

A modelling framework that incorporates the peculiarities of microstructural features, such as the spatial correlation of crystallographic orientations and morphological texture in piezoelectrics, is established. The mathematical homogenization theory of a piezoelectric medium is implemented using the finite element method by solving the coupled equilibrium electrical and mechanical fields. The dependence of the domain orientation on the macroscopic electromechanical properties of crystalline as well as polycrystalline ceramic relaxor ferroelectric 0.58Pb(Mg1/3Nb2/3)O3-0.42PbTiO3 (PMN-42% PT) is studied based on this model. The material shows large anisotropy in the piezoelectric coefficient ejK in its crystalline form. The homogenized electromechanical moduli of polycrystalline ceramic also exhibit significantly anisotropic behaviours. An optimum texture at which the piezoceramic exhibits its maximum longitudinal piezoelectric response is identified.

PMN-PT–PZT composite films for high frequency ultrasonic transducer applications

Science.gov (United States)

Hsu, Hsiu-Sheng; Benjauthrit, Vatcharee; Zheng, Fan; Chen, Rumin; Huang, Yuhong; Zhou, Qifa; Shung, K. Kirk

2013-01-01

We have successfully fabricated x(0.65PMN-0.35PT)–(1 − x)PZT (xPMN-PT–(1 − x)PZT), where x is 0.1, 0.3, 0.5, 0.7 and 0.9, thick films with a thickness of approximately 9 µm on platinized silicon substrate by employing a composite sol–gel technique. X-ray diffraction analysis and scanning electron microscopy revealed that these films are dense and creak-free with well-crystallized perovskite phase in the whole composition range. The dielectric constant can be controllably adjusted by using different compositions. Higher PZT content of xPMN-PT–(1 − x)PZT films show better ferroelectric properties. A representative 0.9PMN-PT–0.1PZT thick film transducer is built. It has 200 MHz center frequency with a −6 dB bandwidth of 38% (76 MHz). The measured two-way insertion loss is 65 dB. PMID:23750072

Microscopic local fatigue in PZT thin films

International Nuclear Information System (INIS)

Li, B S; Wu, A; Vilarinho, P M

2007-01-01

The reduction in switchable polarization during fatigue largely limits the application of PZT thin films in ferroelectric nonvolatile memories. So, it is very important to understand the fatigue mechanism in PZT films, especially at a nanoscale level. In this paper, nanoscale fatigue properties in PZT thin films have been studied by piezoresponse force microscopy and local piezoloops. It has been found that a piezoloop obtained on a fatigued point exhibits a much more pinched shape and a local imprint phenomenon is observed after severe fatigue. Furthermore, the domain structure evolves from a simple single-peak profile to a complex fluctuant one. However, there is only some shift of the piezoloop when a unipolar field with the same amplitude is applied on the film. The available experimental data show that there exist obvious domain wall pinning and injection of electrons into the film during fatigue. Finally, a schematic illustration is suggested to explain the possible fatigue mechanism

Nonlinear current-voltage behavior in PZT thin films

Energy Technology Data Exchange (ETDEWEB)

Xiao, Mi; Zhang, Weikang; Zhang, Zebin; Li, Shida; Zhang, Ping; Lan, Kuibo [Tianjin University, School of Electrical and Information Engineering, Tianjin (China)

2017-05-15

In this paper, Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) thin films were prepared by sol-gel synthesis and characterized by X-ray diffraction, field emission scanning electron microscopy and current-voltage measurements. Here, we demonstrate that in addition to the outstanding ferroelectric and dielectric properties, the PZT films also have remarkably nonlinear current-voltage characteristics. Considering the contact of semi-conductive grains in the PZT films, a double Schottky barrier (DSB) model may be responsible for such phenomena. The test results show that with the decrease of annealing temperature and the increase of the film thickness, the threshold voltages (V{sub th}) increase obviously. The maximum V{sub th} value of 60.95 V and the minimum value of 6.9 V in our experiments were obtained from the five-layered samples annealed at 600 C and the two-layered samples annealed at 700 C, respectively. As a result, PZT thin film may lead to efficient switching and sensing devices. (orig.)

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.

Giant flexoelectric polarization in a micromachined ferroelectric diaphragm

KAUST Repository

Wang, Zhihong

2012-08-14

The coupling between dielectric polarization and strain gradient, known as flexoelectricity, becomes significantly large on the micro- and nanoscale. Here, it is shown that giant flexoelectric polarization can reverse remnant ferroelectric polarization in a bent Pb(Zr0.52Ti0.48) O3 (PZT) diaphragm fabricated by micromachining. The polarization induced by the strain gradient and the switching behaviors of the polarization in response to an external electric field are investigated by observing the electromechanical coupling of the diaphragm. The method allows determination of the absolute zero polarization state in a PZT film, which is impossible using other existing methods. Based on the observation of the absolute zero polarization state and the assumption that bending of the diaphragm is the only source of the self-polarization, the upper bound of flexoelectric coefficient of PZT film is calculated to be as large as 2.0 × 10-4 C m -1. The strain gradient induced by bending the diaphragm is measured to be on the order of 102 m-1, three orders of magnitude larger than that obtained in the bulk material. Because of this large strain gradient, the estimated giant flexoelectric polarization in the bent diaphragm is on the same order of magnitude as the normal remnant ferroelectric polarization of PZT film. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced electrical properties in bilayered ferroelectric thin films

Science.gov (United States)

Zhang, Hao; Long, WeiJie; Chen, YaQing; Guo, DongJie

2013-03-01

Sr2Bi4Ti5O18 (SBTi) single layered and Sr2Bi4Ti5O18/Pb(Zr0.53Ti0.47)O3 (SBTi/PZT) bilayered thin films have been prepared on Pt/TiO2/SiO2/Si substrates by pulsed-laser deposition (PLD). The related structural characterizations and electrical properties have been comparatively investigated. X-ray diffraction reveals that both films have crystallized into perovskite phases and scanning electron microscopy shows the sharp interfaces. Both films show well-saturated ferroelectric hysteresis loops, however, compared with the single layered SBTi films, the SBTi/PZT bilayered films have significantly increased remnant polarization ( P r) and decreased coercive field ( E c), with the applied field of 260 kV/cm. The measured P r and E c of SBTi and SBTi/PZT films were 7.9 μC/cm2, 88.1 kV/cm and 13.0 μC/cm2, 51.2 kV/cm, respectively. In addition, both films showed good fatigue-free characteristics, the switchable polarization decreased by 9% and 11% of the initial values after 2.2×109 switching cycles for the SBTi single layered films and the SBTi/PZT bilayered films, respectively. Our results may provide some guidelines for further optimization of multilayered ferroelectric thin films.

Total-dose radiation-induced degradation of thin film ferroelectric capacitors

International Nuclear Information System (INIS)

Schwank, J.R.; Nasby, R.D.; Miller, S.L.; Rodgers, M.S.; Dressendorfer, P.V.

1990-01-01

Thin film PbZr y Ti 1-y O 3 (PZT) ferroelectric memories offer the potential for radiation-hardened, high-speed nonvolatile memories with good retention and fatigue properties. In this paper we explore in detail the radiation hardness of PZT ferroelectric capacitors. Ferroelectric capacitors were irradiated using x-ray and Co-60 sources to dose levels up to 16 Mrad(Si). The capacitors were characterized for their memory properties both before and after irradiation. The radiation hardness was process dependent. Three out of four processes resulted in capacitors that showed less than 30% radiation-induced degradation in retained polarization charge and remanent polarization after irradiating to 16 Mrad(Si). On the other hand, one of the processes showed significant radiation-induced degradation in retained polarization charge and remanent polarization at dose levels above 1 Mrad(Si). The decrease in retained polarization charge appears to be due to an alteration of the switching characteristics of the ferroelectric due to changes in the internal fields. The radiation-induced degradation is recoverable by a postirradiation biased anneal and can be prevented entirely if devices are cycled during irradiation. The authors have developed a model to simulate the observed degradation

Investigation of the switching characteristics in ferroelectrics by first-order reversal curve diagrams

International Nuclear Information System (INIS)

Stancu, Alexandru; Mitoseriu, Liliana; Stoleriu, Laurentiu; Piazza, Daniele; Galassi, Carmen; Ricinschi, Dan; Okuyama, Masanori

2006-01-01

First-order reversal curves (FORC) diagrams are proposed for describing the switching properties in ferroelectric materials. The method is applied for Pb(Zr,Ti)O 3 (PZT) ferroelectric ceramics and films with different P(E) hysteresis and microstructural characteristics. The separation of the reversible and irreversible contributions to the ferroelectric polarization is explained in terms of microstructural characteristics of the investigated samples. The influence of parameters as field frequency, crystallite orientation, ferroelectric fatigue and porosity degree on the FORC diagrams is discussed

Local Fatigue Evaluation in PZT Thin Films with Nanoparticles by Piezoresponse Force Microscopy

OpenAIRE

B. S. Li

2012-01-01

Lead zirconate titanate (PZT) thin films with the morphotropic phase boundary composition (Zr/Ti = 52/48) have been prepared using a modified diol-based sol-gel route by introducing 1–5 mol% barium titanate (BT) nanoseeds into the precursor solution on platinized silicon substrates (Pt/Ti/SiO2/Si). Macroscopic electric properties of PZT film with nanoparticle showed a significant improvement of ferroelectric properties. This work aims at the systematic study of the local switching polarizatio...

Research Update: Enhanced energy storage density and energy efficiency of epitaxial Pb0.9La0.1(Zr0.52Ti0.48O3 relaxor-ferroelectric thin-films deposited on silicon by pulsed laser deposition

Directory of Open Access Journals (Sweden)

Minh D. Nguyen

2016-08-01

Full Text Available Pb0.9La0.1(Zr0.52Ti0.48O3 (PLZT relaxor-ferroelectric thin films were grown on SrRuO3/SrTiO3/Si substrates by pulsed laser deposition. A large recoverable storage density (Ureco of 13.7 J/cm3 together with a high energy efficiency (η of 88.2% under an applied electric field of 1000 kV/cm and at 1 kHz frequency was obtained in 300-nm-thick epitaxial PLZT thin films. These high values are due to the slim and asymmetric hysteresis loop when compared to the values in the reference undoped epitaxial lead zirconate titanate Pb(Zr0.52Ti0.48O3 ferroelectric thin films (Ureco = 9.2 J/cm3 and η = 56.4% which have a high remanent polarization and a small shift in the hysteresis loop, under the same electric field.

Characteristics of Au/PZT/TiO2/Nitride/Si structure capacitors with ICP nitride treatments

International Nuclear Information System (INIS)

Min, Hyung Seob; Kim, Tae Ho; Jeon, Chang Bae; Lee, Jae Gab; Kim, Ji Young

2002-01-01

In this study, the characteristics of PZT/TiO 2 ferroelectric gate stack capacitors with Inductively Coupled Plasma (ICP) nitridation were investigated for field effect transistor (FET)-type Ferroelectric Random Access Memory (FeRAM) applications. If a high accumulation capacitance is to be had, the ICP nitridation time needs to be optimized. While a short ICP treatment time results in thermal oxide growth due to lack of nitrogen, a long nitridation time causes a nitride layer which is too thick. Au/PZT(200 nm)/TiO 2 (40 nm)/Nitride/Si (MeFINS) structure capacitors show a memory window (ΔV) of 1.6 V under ±3-V operation while Au/PZT(200 nm)/TiO 2 (40 nm)/Si (MeFIS) capacitors without nitride treatment exhibit a small memory window of 0.6 V. At the same time, the capacitance of the MeFINS device is almost twice that of the MeFIS capacitor. This result implies that the ICP nitride treatment suppresses the formation of a low dielectric constant interfacial SiO x layer and alleviates the series capacitance problem

High temperature phases in PZT ferroelectric films

Czech Academy of Sciences Publication Activity Database

Deineka, Alexander; Suchaneck, G.; Jastrabík, Lubomír; Gerlach, G.

2003-01-01

Roč. 293, - (2003), s. 111-118 ISSN 0015-0193 R&D Projects: GA ČR GP202/02/D078; GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferroelectric film * phase transition * film profile Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.406, year: 2003

Multiscale numerical study on ferroelectric nonlinear response of PZT thin films (Conference Presentation)

Science.gov (United States)

Wakabayashi, Hiroki; Uetsuji, Yasutomo; Tsuchiya, Kazuyoshi

2017-06-01

PZT thin films have excellent performance in deformation precision and response speed, so it is used widely for actuators and sensors of Micro Electro Mechanical System (MEMS). Although PZT thin films outputs large piezoelectricity at morphotropic phase bounfary (MPB), it shows a complicated hysteresis behavior caused by domain switching and structural phase transition between tetragonal and rhombohedral. In general, PZT thin films have some characteristic crystal morphologies. Additionally mechanical strains occur by lattice mismatch with substrate. Therefore it is important for fabrication and performance improvement of PZT thin films to understand the relation between macroscopic hysteresis response and microstructural changes. In this study, a multiscale nonlinear finite element simulation was proposed for PZT thin films at morphotropic phase boundary (MPB) on the substrate. The homogenization theory was employed for scale-bridging between macrostructure and microstructure. Figure 1 shows the proposed multiscale nonlinear simulation [1-3] based on the homogenization theory. Macrostructure is a homogeneous structure to catch the whole behaviors of actuators and sensors. And microstructure is a periodic inhomogeneous structure consisting of domains and grains. Macrostructure and microstructure are connected perfectly by homogenization theory and are analyzed by finite element method. We utilized an incremental form of fundamental constitutive law in consideration with physical property change caused by domain switching and structural phase transition. The developed multiscale finite element method was applied to PZT thin films with lattice mismatch strain on the substrate, and the relation between the macroscopic hysteresis response and microscopic domain switching and structural phase transition were investigated. Especially, we discuss about the effect of crystal morphologies and lattice mismatch strain on hysteresis response.

Ferroelectric properties of PZT/BFO multilayer thin films prepared using the sol-gel method.

Science.gov (United States)

Jo, Seo-Hyeon; Lee, Sung-Gap; Lee, Young-Hie

2012-01-05

In this study, Pb(Zr0.52Ti0.48)O3/BiFeO3 [PZT/BFO] multilayer thin films were fabricated using the spin-coating method on a Pt(200 nm)/Ti(10 nm)/SiO2(100 nm)/p-Si(100) substrate alternately using BFO and PZT metal alkoxide solutions. The coating-and-heating procedure was repeated several times to form the multilayer thin films. All PZT/BFO multilayer thin films show a void-free, uniform grain structure without the presence of rosette structures. The relative dielectric constant and dielectric loss of the six-coated PZT/BFO [PZT/BFO-6] thin film were approximately 405 and 0.03%, respectively. As the number of coatings increased, the remanent polarization and coercive field increased. The values for the BFO-6 multilayer thin film were 41.3 C/cm2 and 15.1 MV/cm, respectively. The leakage current density of the BFO-6 multilayer thin film at 5 V was 2.52 × 10-7 A/cm2.

Broadband Electromagnetic Emission from PZT Ferroelectric Ceramics after Shock Loading

Directory of Open Access Journals (Sweden)

Fiodoras ANISIMOVAS

2013-12-01

Full Text Available It was experimentally registered pulsed electromagnetic (EM radiation in frequency range higher than television one using wideband horns with coaxial and waveguide outputs. The EM radiation was received during shock loading of lead zirconate titanate (PZT ceramics cylinders in conventional piezoelectric ignition mechanisms. Digital oscilloscope allows registering whole series of EM pulses and each pulse from the series transmitted from horn antenna of (1 – 18 GHz operating band frequencies. There is (1 – 4 ms delay between the shock and the first pulse of the series. Duration of the series is about (3 – 4 ms. The PZT cylinders were cleaved along their axes and the surfaces formed in the process were investigated by scanning electron microscope. It was concluded that from electrical point of view PZT ceramics contain interacting subsystems. It was found that EM radiation spectrum of pulse detected by waveguide detector heads has harmonics reaching 80 GHz. Presence of harmonics higher than 20 GHz indicates on radiation due to deceleration of electrons emitted during the switching. The EM pulses in the series appear randomly and have different amplitudes which partly confirmed thesis on independent switching dynamics of small volumes governed by a local electric field.DOI: http://dx.doi.org/10.5755/j01.ms.19.4.3137

Observation of domain patterns on a ferroelectric ceramic

International Nuclear Information System (INIS)

Ibrahim, R.C.; Zavaglia, C.A.C.

1992-01-01

In this work ferroelectric domain patterns are observed on a PZT-like ceramic material produced in Brazil. This material has tetragonal unit cell composing a perovskite type structure. The samples, after grinding and polishing, were chemically etched and observed on optical microscope and scanning electron microscope. (author)

Why is the electrocaloric effect so small in ferroelectrics?

Directory of Open Access Journals (Sweden)

G. G. Guzmán-Verri

2016-06-01

Full Text Available Ferroelectrics are attractive candidate materials for environmentally friendly solid state refrigeration free of greenhouse gases. Their thermal response upon variations of external electric fields is largest in the vicinity of their phase transitions, which may occur near room temperature. The magnitude of the effect, however, is too small for useful cooling applications even when they are driven close to dielectric breakdown. Insight from microscopic theory is therefore needed to characterize materials and provide guiding principles to search for new ones with enhanced electrocaloric performance. Here, we derive from well-known microscopic models of ferroelectricity meaningful figures of merit for a wide class of ferroelectric materials. Such figures of merit provide insight into the relation between the strength of the effect and the characteristic interactions of ferroelectrics such as dipolar forces. We find that the long range nature of these interactions results in a small effect. A strategy is proposed to make it larger by shortening the correlation lengths of fluctuations of polarization. In addition, we bring into question other widely used but empirical figures of merit and facilitate understanding of the recently observed secondary broad peak in the electrocalorics of relaxor ferroelectrics.

Dynamics of space and polarization charges of ferroelectric thin films measured by atomic force microscopy

International Nuclear Information System (INIS)

Oh, Y.J.; Lee, J.H.; Jo, W.

2006-01-01

Retention behavior and local hysteresis characteristics in Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films on Pt electrodes have been investigated by electrostatic force microscopy (EFM). A sol-gel method is used to synthesize PZT thin films and drying conditions are carefully explored over a wide range of temperature. Decay and retention mechanisms of single-poled and reverse-poled regions of the ferroelectric thin films are explained by space charge redistribution. Trapping behavior of space charges is dependent on the nature of interface between ferroelectric thin films and bottom electrodes. Local measurement of polarization-electric field curves by EFM shows inhomogeneous space charge entrapment

High Frequency Magneto Dielectric Effects In Self Assembled Ferrite Ferroelectric Core Shell Nanoparticles

Science.gov (United States)

2014-09-10

ferrimagnetic metals, alloys or oxides and ferroelectrics such as barium titanate (BTO), lead zirconate titanate ( PZT ), and lead magnesium niobate-lead...estimate the magneto-capacitance effect in BTO or PZT films on substrates of ferromagnetic alloys.25 This work is on the observation and theory of MDE...transmission and reflection coefficients were done to estimate the complex permittivity. During the measurements a bias static magnetic field was

Ferroelectricity-induced resistive switching in Pb(Zr0.52Ti0.48)O3/Pr0.7Ca0.3MnO3/Nb-doped SrTiO3 epitaxial heterostructure

Science.gov (United States)

Md. Sadaf, Sharif; Mostafa Bourim, El; Liu, Xinjun; Hasan Choudhury, Sakeb; Kim, Dong-Wook; Hwang, Hyunsang

2012-03-01

We investigated the effect of a ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) thin film on the generation of resistive switching in a stacked Pr0.7Ca0.3MnO3 (PCMO)/Nb-doped SrTiO3 (Nb:STO) heterostructure forming a p-n junction. To promote the ferroelectric effect, the thin PZT active layer was deposited on an epitaxially grown p-type PCMO film on a lattice-matched n-type Nb:STO single crystal. It was concluded that the observed resistive switching behavior in the all-perovskite Pt/PZT/PCMO/Nb:STO heterostructure was related to the modulation of PCMO/Nb:STO p-n junction's depletion width, which was caused either by the PZT ferroelectric polarization field effect, the electrochemical drift of oxygen ions under an electric field, or both simultaneously.

Dielectric response of capacitor structures based on PZT annealed at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Kamenshchikov, Mikhail V., E-mail: Mikhailkamenshchikov@yandex.ru [Tver State University, 170002, Tver (Russian Federation); Solnyshkin, Alexander V. [Tver State University, 170002, Tver (Russian Federation); Pronin, Igor P. [Ioffe Institute, 194021, St. Petersburg (Russian Federation)

2016-12-09

Highlights: • Correlation of the microstructure of PZT films and dielectric response was found. • Difference of dielectric responses under low and high bias is caused by domains. • Internal fields is discussed on the basis of the space charges. • Dependences of PZT films characteristics on synthesis temperature are extremal. - Abstract: Dielectric response of thin-film capacitor structures of Pt/PZT/Pt deposited by the RF magnetron sputtering method and annealed at temperatures of 540–570 °C was investigated. It was found that dielectric properties of these structures depend on the synthesis temperature. Stability of a polarized state is considered on the basis of the analysis of hysteresis loops and capacitance–voltage (C–V) characteristics. The contribution of the domain mechanism in the dielectric response of the capacitor structure comprising a ferroelectric is discussed. Extreme dependences of electrophysical characteristics of PZT films on their synthesis temperature were observed. Correlation of dielectric properties with microstructure of these films is found out.

Optical and electro-optic anisotropy of epitaxial PZT thin films

Science.gov (United States)

Zhu, Minmin; Du, Zehui; Jing, Lin; Yoong Tok, Alfred Iing; Tong Teo, Edwin Hang

2015-07-01

Strong optical and electro-optic (EO) anisotropy has been investigated in ferroelectric Pb(Zr0.48Ti0.52)O3 thin films epitaxially grown on Nb-SrTiO3 (001), (011), and (111) substrates using magnetron sputtering. The refractive index, electro-optic, and ferroelectric properties of the samples demonstrate the significant dependence on the growth orientation. The linear electro-optic coefficients of the (001), (011), and (111)-oriented PZT thin films were 270.8, 198.8, and 125.7 pm/V, respectively. Such remarkable anisotropic EO behaviors have been explained according to the structure correlation between the orientation dependent distribution, spontaneous polarization, epitaxial strain, and domain pattern.

Modelling of dielectric hysteresis loops in ferroelectric semiconductors with charged defects

International Nuclear Information System (INIS)

Morozovska, Anna N; Eliseev, Eugene A

2004-01-01

We have proposed the phenomenological description of dielectric hysteresis loops in ferroelectric semiconductors with charged defects and prevailing extrinsic conductivity. We have modified the Landau-Ginsburg approach and shown that the macroscopic state of the aforementioned inhomogeneous system can be described by three coupled equations for three order parameters. Both the experimentally observed coercive field values well below the thermodynamic values and the various hysteresis-loop deformations (constricted and double loops) have been obtained in the framework of our model. The obtained results quantitatively explain the ferroelectric switching in such ferroelectric materials as thick PZT films

Controlling the properties of ferroelectric-nickelate interfaces

Science.gov (United States)

Marshall, Matthew S. J.; Malashevich, Andrei; Disa, Ankit; Han, Myung-Geun; Zhu, Yimei; Ismail-Beigi, Sohrab; Walker, Frederick; Ahn, Charles

2015-03-01

Ferroelectrics are a class of materials that exhibit a stable, reversible polarization making them useful for non-volatile electronic devices. In devices consisting of thin film ferroelectric PZT acting as a gate and a thin film of the conductive oxide LaNiO3 grown on LaAlO3(001) acting as a channel, we have realized a large change in room temperature channel resistance by switching the ferroelectric polarization. The effect of switching the polarization of the ferroelectric is to modify the electronic structure of the interface between the gate and channel, resulting in conduction in the otherwise insulating ferroelectric. Here, we discuss how changing the epitaxial strain and interface termination of LaNiO3 can result in larger changes in resistivity. The epitaxial strain is varied by growing the devices on LaAlO3 for tensile strain and SrTiO3 for compressive strain. An interface termination of either an atomic layer of NiO2 or LaO is achieved via atomic layering using oxygen plasma assisted molecular beam epitaxy (MBE).

Characterization of the effective electrostriction coefficients in ferroelectric thin films

Science.gov (United States)

Kholkin, A. L.; Akdogan, E. K.; Safari, A.; Chauvy, P.-F.; Setter, N.

2001-06-01

Electromechanical properties of a number of ferroelectric films including PbZrxTi1-xO3(PZT), 0.9PbMg1/3Nb2/3O3-0.1PbTiO3(PMN-PT), and SrBi2Ta2O9(SBT) are investigated using laser interferometry combined with conventional dielectric measurements. Effective electrostriction coefficients of the films, Qeff, are determined using a linearized electrostriction equation that couples longitudinal piezoelectric coefficient, d33, with the polarization and dielectric constant. It is shown that, in PZT films, electrostriction coefficients slightly increase with applied electric field, reflecting the weak contribution of non-180° domains to piezoelectric properties. In contrast, in PMN-PT and SBT films electrostriction coefficients are field independent, indicating the intrinsic nature of the piezoelectric response. The experimental values of Qeff are significantly smaller than those of corresponding bulk materials due to substrate clamping and possible size effects. Electrostriction coefficients of PZT layers are shown to depend strongly on the composition and preferred orientation of the grains. In particular, Qeff of (100) textured rhombohedral films (x=0.7) is significantly greater than that of (111) layers. Thus large anisotropy of the electrostrictive coefficients is responsible for recently observed large piezoelectric coefficients of (100) textured PZT films. Effective electrostriction coefficients obtained by laser interferometry allow evaluation of the electromechanical properties of ferroelectric films based solely on the dielectric parameters and thus are very useful in the design and fabrication of microsensors and microactuators.

Relaxor-ferroelectric BaLnZT (Ln = La, Nd, Sm, Eu, and Sc) ceramics for actuator and energy storage application

Science.gov (United States)

Ghosh, Sarit K.; Mallick, Kaushik; Tiwari, B.; Sinha, E.; Rout, S. K.

2018-01-01

Lead free ceramics Ba1-x Ln2x/3Zr0.3Ti0.7O3 (Ln = La, Nd, Sm, Eu and Sc), x = 0.02-0.10 are investigated for electrostrictive effect and energy storage properties in the proximity of relaxor-paraelectric phase boundary. Relaxor phase evidence from slim hysteresis loop and low remnant polarization are the key parameters responsible for improve the electrostrictive effect and energy storage properties simultaneously. With increase in rare earth content negative strain disappeared and almost hysteresis free strain is achieved. Strain-hysteresis profile in term of S-E, S-E 2 and S-P 2 is used to analyze the electrostrictive behavior of these ceramics. An average strain (S%) ˜ 0.03%, is accomplished at initial concentrations of x = 0.02-0.04 and electrostrictive coefficients (Q 11, and M 11) as well as the energy storage density is improved by a factor of 1.2 and 2.6 respectively when compare with pure (x = 0.0) ceramic. Above x ≥ 0.06, all compositions show a stable behavior which suggested the possibilities of these relaxor ceramics towards high precision actuators and energy storage application.

Note: High-power piezoelectric transformer fabricated with ternary relaxor ferroelectric Pb(Mg(1/3)Nb(2/3))O3-Pb(In(1/2)Nb(1/2))O3-PbTiO3 single crystal.

Science.gov (United States)

Wang, Qing; Ma, Chuanguo; Wang, Feifei; Liu, Bao; Chen, Jianwei; Luo, Haosu; Wang, Tao; Shi, Wangzhou

2016-03-01

A plate-shaped piezoelectric transformer was designed and fabricated using ternary relaxor ferroelectric single crystal Pb(Mg(1/3)Nb(2/3))O3-Pb(In(1/2)Nb(1/2))O3-PbTiO3. Both the input and output sections utilized the transverse-extensional vibration mode. The frequency and load dependences of the electrical properties for the proposed transformer were systematically studied. Results indicated that under a matching load resistance of 14.9 kΩ, a maximum output power of 2.56 W was obtained with the temperature rise less than 5 °C. The corresponding power density reached up to 50 W/cm(3). This ternary single-crystal transformer had potential applications in compact-size converters requiring high power density.

Effect of polarization fatigue on the Rayleigh coefficients of ferroelectric lead zirconate titanate thin films: Experimental evidence and implications

Science.gov (United States)

Lou, X. J.; Zhang, H. J.; Luo, Z. D.; Zhang, F. P.; Liu, Y.; Liu, Q. D.; Fang, A. P.; Dkhil, B.; Zhang, M.; Ren, X. B.; He, H. L.

2014-09-01

The effect of polarization fatigue on the Rayleigh coefficients of ferroelectric lead zirconate titanate (PZT) thin film was systematically investigated. It was found that electrical fatigue strongly affects the Rayleigh behaviour of the PZT film. Both the reversible and irreversible Rayleigh coefficients decrease with increasing the number of switching cycles. This phenomenon is attributed to the growth of an interfacial degraded layer between the electrode and the film during electrical cycling. The methodology used in this work could serve as an alternative way for evaluating the fatigue endurance and degradation in dielectric properties of ferroelectric thin-film devices during applications.

Properties of epitaxial ferroelectric PbZr0.56Ti0.44O3 heterostructures with La0.5Sr0.5CoO3 metallic oxide electrodes

International Nuclear Information System (INIS)

Wang, F.; Leppaevuori, S.

1997-01-01

PbZr 0.56 Ti 0.44 O 3 (PZT) epitaxial ferroelectric thin films on a LaAlO 3 (100) substrate, covered by a metallic oxide electrode La 0.5 Sr 0.5 CoO 3 (LSCO) are demonstrated in this work. The films are fabricated by the sol endash gel method and effort was focused on thermal processing to obtain the desired epitaxial heterostructure. The dielectric and ferroelectric properties of PZT thin films were measured and it was found that they are as good as in the films deposited by other thin-film methods. The dielectric constant and the dissipation factor of the PZT films are, respectively, about 500 and 0.06 below 20 kHz. The remanent polarization P r is about 27 μC/cm 2 and the coercive field E c is about 50 kV/cm. It was found that the ferroelectric properties were significantly influenced by the microstructure of the PZT layers. The present study also showed that the fatigue characteristics of the epitaxial heterostructure with LSCO electrodes under a reversed electrical field are far superior to those obtained with a polycrystalline ferroelectric layer on Pt bottom electrodes. A low leakage current, about 3 μA/cm 2 at 0.5 MV/cm, was obtained for these epitaxial films. In addition, the optical transmittance spectrum of PZT thin films was also measured and the conduction mechanism is discussed.copyright 1997 American Institute of Physics

Transparent Ferroelectric Capacitors on Glass

Directory of Open Access Journals (Sweden)

Daniele Sette

2017-10-01

Full Text Available We deposited transparent ferroelectric lead zirconate titanate thin films on fused silica and contacted them via Al-doped zinc oxide (AZO transparent electrodes with an interdigitated electrode (IDE design. These layers, together with a TiO2 buffer layer on the fused silica substrate, are highly transparent (>60% in the visible optical range. Fully crystallized Pb(Zr0.52Ti0.48O3 (PZT films are dielectrically functional and exhibit a typical ferroelectric polarization loop with a remanent polarization of 15 μC/cm2. The permittivity value of 650, obtained with IDE AZO electrodes is equivalent to the one measured with Pt electrodes patterned with the same design, which proves the high quality of the developed transparent structures.

Optical properties of self-polarized PZT ferroelectric films

Czech Academy of Sciences Publication Activity Database

Deineka, Alexander; Jastrabík, Lubomír; Suchaneck, G.; Gerlach, G.

2002-01-01

Roč. 273, - (2002), s. 155-160 ISSN 0015-0193 R&D Projects: GA MŠk LN00A015; GA ČR GA202/00/1425 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferroelectric film * phase transition * band gap Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.408, year: 2002

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.

Losses in Ferroelectric Materials

Science.gov (United States)

Liu, Gang; Zhang, Shujun; Jiang, Wenhua; Cao, Wenwu

2015-01-01

Ferroelectric materials are the best dielectric and piezoelectric materials known today. Since the discovery of barium titanate in the 1940s, lead zirconate titanate ceramics in the 1950s and relaxor-PT single crystals (such as lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate) in the 1980s and 1990s, perovskite ferroelectric materials have been the dominating piezoelectric materials for electromechanical devices, and are widely used in sensors, actuators and ultrasonic transducers. Energy losses (or energy dissipation) in ferroelectrics are one of the most critical issues for high power devices, such as therapeutic ultrasonic transducers, large displacement actuators, SONAR projectors, and high frequency medical imaging transducers. The losses of ferroelectric materials have three distinct types, i.e., elastic, piezoelectric and dielectric losses. People have been investigating the mechanisms of these losses and are trying hard to control and minimize them so as to reduce performance degradation in electromechanical devices. There are impressive progresses made in the past several decades on this topic, but some confusions still exist. Therefore, a systematic review to define related concepts and clear up confusions is urgently in need. With this objective in mind, we provide here a comprehensive review on the energy losses in ferroelectrics, including related mechanisms, characterization techniques and collections of published data on many ferroelectric materials to provide a useful resource for interested scientists and engineers to design electromechanical devices and to gain a global perspective on the complex physical phenomena involved. More importantly, based on the analysis of available information, we proposed a general theoretical model to describe the inherent relationships among elastic, dielectric, piezoelectric and mechanical losses. For multi-domain ferroelectric single crystals and ceramics, intrinsic and extrinsic energy

Losses in Ferroelectric Materials.

Science.gov (United States)

Liu, Gang; Zhang, Shujun; Jiang, Wenhua; Cao, Wenwu

2015-03-01

Ferroelectric materials are the best dielectric and piezoelectric materials known today. Since the discovery of barium titanate in the 1940s, lead zirconate titanate ceramics in the 1950s and relaxor-PT single crystals (such as lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate) in the 1980s and 1990s, perovskite ferroelectric materials have been the dominating piezoelectric materials for electromechanical devices, and are widely used in sensors, actuators and ultrasonic transducers. Energy losses (or energy dissipation) in ferroelectrics are one of the most critical issues for high power devices, such as therapeutic ultrasonic transducers, large displacement actuators, SONAR projectors, and high frequency medical imaging transducers. The losses of ferroelectric materials have three distinct types, i.e., elastic, piezoelectric and dielectric losses. People have been investigating the mechanisms of these losses and are trying hard to control and minimize them so as to reduce performance degradation in electromechanical devices. There are impressive progresses made in the past several decades on this topic, but some confusions still exist. Therefore, a systematic review to define related concepts and clear up confusions is urgently in need. With this objective in mind, we provide here a comprehensive review on the energy losses in ferroelectrics, including related mechanisms, characterization techniques and collections of published data on many ferroelectric materials to provide a useful resource for interested scientists and engineers to design electromechanical devices and to gain a global perspective on the complex physical phenomena involved. More importantly, based on the analysis of available information, we proposed a general theoretical model to describe the inherent relationships among elastic, dielectric, piezoelectric and mechanical losses. For multi-domain ferroelectric single crystals and ceramics, intrinsic and extrinsic energy

Ferroelectric glass of spheroidal dipoles with impurities: polar nanoregions, response to applied electric field, and ergodicity breakdown

International Nuclear Information System (INIS)

Takae, Kyohei; Onuki, Akira

2017-01-01

Using molecular dynamics simulation, we study dipolar glass in crystals composed of slightly spheroidal, polar particles and spherical, apolar impurities between metal walls. We present physical pictures of ferroelectric glass, which have been observed in relaxors, mixed crystals (such as KCN x KBr 1−x ), and polymers. Our systems undergo a diffuse transition in a wide temperature range, where we visualize polar nanoregions (PNRs) surrounded by impurities. In our simulation, the impurities form clusters and their space distribution is heterogeneous. The polarization fluctuations are enhanced at relatively high T depending on the size of the dipole moment. They then form frozen PNRs as T is further lowered into the nonergodic regime. As a result, the dielectric permittivity exhibits the characteristic features of relaxor ferroelectrics. We also examine nonlinear response to cyclic applied electric field and nonergodic response to cyclic temperature changes (ZFC/FC), where the polarization and the strain change collectively and heterogeneously. We also study antiferroelectric glass arising from molecular shape asymmetry. We use an Ewald scheme of calculating the dipolar interaction in applied electric field. (paper)

Bending-Induced Giant Polarization in Ferroelectric MEMS Diaphragm

KAUST Repository

Wang, Zhihong

2016-09-09

The polarization induced by the strain gradient, i.e. the flexoelectric effect, has been observed in a micromachined Pb(Zr0.52Ti0.48)O3 (PZT) diaphragms. Applying air pressure to bend a flat diaphragm which initially does not exhibit any electromechanical coupling can induce a resonance peak in its impedance spectrum. This result supposes that bending, thus the strain gradient in the diaphragm causes polarization in PZT film. We also investigated the switching behaviors of the polarization in response to an external electric field in a bent diaphragm and further quantified the polarization induced by the strain gradient. The effective flexoelectric coefficient of the PZT film has been calculated as large as 2.0 × 10−4 C/m. A giant flexoelectric polarization of the order of 1 μC/cm2 was characterized which is of the same order of magnitude as the normal remnant ferroelectric polarization of PZT film. The suggested explanation for the giant polarization is the large strain gradient in the diaphragm and the strain gradient induced reorientation of the polar nanodomains.

Structural Transition and Electrical Properties of (1 - x)(Na0.4K0.1Bi0.5)TiO3- xSrTiO3 Lead-Free Piezoceramics

Science.gov (United States)

Liu, Xing; Zhai, Jiwei; Shen, Bo; Li, Feng; Li, Peng

2017-10-01

(1 - x)(Na0.4K0.1Bi0.5)TiO3- xSrTiO3 (NKBT- xST) ceramics with x = 0 mol.%, 3 mol.%, and 5 mol.% (0ST, 3ST, and 5ST) have been prepared by a conventional solid-state reaction method and their ferroelectric, electrostrictive, and pyroelectric properties investigated. Addition of ST considerably disrupted the long-range ferroelectric order of NKBT- xST ceramics, and the 5ST ceramic exhibited ergodic relaxor phase structure. T FR shifted to near or below room temperature for 5ST ceramic, accompanied by a significant decline of ferroelectricity and enhanced strain. As the temperature approached T FR, the NKBT- xST ceramics exhibited predominantly electrostrictive effect, and the 5ST ceramic presented relatively high electrostrictive coefficient Q 33 of 0.0193 m4/C2. High pyroelectric response was observed for 0ST, 3ST, and 5ST ceramics in the vicinity of T FR due to the large polarization release during the ferroelectric-relaxor structural transition. The 5ST ceramic exhibited high and frequency-insensitive (100 Hz to 10 kHz) room-temperature pyroelectric properties with pyroelectric coefficient p of 656 μC m-2 K-1 and figures of merit F i, F v, and F d reaching 233 pm/V, 0.013 m2/C, and 7.61 μPa-1/2, respectively, indicating that 5ST ceramic is a promising candidate to replace PZT-based ceramics.

Upconversion photoluminescence of epitaxial Yb{sup 3+}/Er{sup 3+} codoped ferroelectric Pb(Zr,Ti)O{sub 3} films on silicon substrates

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yang, E-mail: zhangy_acd@hotmail.com [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Kämpfe, Thomas [Institut für Angewandte Physik, TU Dresden, 01062 Dresden (Germany); Bai, Gongxun [Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong (China); Mietschke, Michael; Yuan, Feifei; Zopf, Michael [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Abel, Stefan [IBM Research GmbH, Saümerstrasse 4, 8803 Rüschlikon (Switzerland); Eng, Lukas M. [Institut für Angewandte Physik, TU Dresden, 01062 Dresden (Germany); Hühne, Ruben [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Fompeyrine, Jean [IBM Research GmbH, Saümerstrasse 4, 8803 Rüschlikon (Switzerland); Ding, Fei, E-mail: f.ding@ifw-dresden.de [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Schmidt, Oliver G. [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer strasse 70, 09107 Chemnitz (Germany)

2016-05-31

Thin films of Yb{sup 3+}/Er{sup 3+} codoped Pb(Zr,Ti)O{sub 3} (PZT:Yb/Er) have been epitaxially grown on the SrTiO{sub 3} buffered Si wafer by pulsed laser deposition. Strong upconversion photoluminescence was observed in the PZT:Yb/Er thin film. Using piezoresponse force microscopy, polar domains in the PZT:Yb/Er film can be reversibly switched with a phase change of 180°. Ferroelectric hysteresis loop shape with a well-saturated response was observed. The epitaxially grown lanthanide-doped PZT on silicon opens up a promising route to the integration of luminescent functional oxides on the silicon platform. - Highlights: • Epitaxial growth of Yb{sup 3+}/Er{sup 3+} codoped Pb(Zr,Ti)O{sub 3} films on SrTiO{sub 3} buffered silicon • Upconversion emissions were obtained from the lanthanide ion doped thin films. • Saturated ferroelectric hysteresis loops were observed. • Polar domains were switched by PFM with a phase change of 180°.

Optimization of the low-temperature MOCVD process for PZT thin films

CERN Document Server

Wang, C H; Choi, D J

2000-01-01

Pb(Zr sub X Ti sub 1 sub - sub X)O sub 3 (PZT) thin films of about 0.34 nm were successfully grown at a low temperature of 500 .deg. C by metalorganic chemical vapor deposition with a beta-diketonate complex of Pb(tmhd) sub 2 , zirconium t-butoxide, and titanium isopropoxide as source precursors. Ferroelectric capacitors of a Pt/PZT/Pt configuration were fabricated, and their structural and electrical properties were investigated as a function of the input Pb/(Zr+Ti) and Zr/(Zr+Ti) source ratios. The structure of the as-grown films at 500 .deg. C changed from tetragonal to pseudocubic with increasing the Zr/(Zr+Ti) ratio above an input Pb/(Zr+Ti) source ratio of 5.0 while a 2nd phase of ZrO sub 2 was only observed below Pb/(Zr+Ti) ratio of 5.0, regardless of the Zr/(Zr+Ti) ratio. The dielectric constant and loss of the PZT films were 150-1200 and 0.01-0.04 at 100 kHz, respectively, Leakage current densities decreased with increasing the Zr/(Zr+Ti) ratio. The process window for growing a single phase PZT is ve...

Relaxor-PT Single Crystal Piezoelectric Sensors

Directory of Open Access Journals (Sweden)

Xiaoning Jiang

2014-07-01

Full Text Available Relaxor-PbTiO3 piezoelectric single crystals have been widely used in a broad range of electromechanical devices, including piezoelectric sensors, actuators, and transducers. This paper reviews the unique properties of these single crystals for piezoelectric sensors. Design, fabrication and characterization of various relaxor-PT single crystal piezoelectric sensors and their applications are presented and compared with their piezoelectric ceramic counterparts. Newly applicable fields and future trends of relaxor-PT sensors are also suggested in this review paper.

A quaternary lead based perovskite structured materials with diffuse phase transition behavior

Energy Technology Data Exchange (ETDEWEB)

Puli, Venkata Sreenivas, E-mail: pvsri123@gmail.com [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States); Martinez, R.; Kumar, Ashok [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States); Scott, J.F. [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States); Cavendish Laboratory, Dept. Physics, University of Cambridge, Cambridge CB0 3HE (United Kingdom); Katiyar, Ram S., E-mail: rkatiyar@uprrp.edu [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States)

2011-12-15

Graphical abstract: (a) Curie-Weiss plot for the inverse of the relative dielectric permittivity and (b) log (1/{epsilon} - 1/{epsilon}{sub m}) as function of log (T - T{sub m}) for ceramics at 1 kHz. Highlights: Black-Right-Pointing-Pointer Retaining phase pure structure with quaternary complex stoichiometric compositions. Black-Right-Pointing-Pointer P-E loops with good saturation polarization (P{sub s} {approx} 30.7 {mu}C/cm{sup 2}). Black-Right-Pointing-Pointer Diffused relaxor phase transition behavior with {gamma} estimated is {approx}1.65. -- Abstract: A lead based quaternary compound composed of 0.25(PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}) + 0.25(PbFe{sub 0.5}Ta{sub 0.5}O{sub 3}) + 0.25 (PbF{sub 0.67}W{sub 0.33}O{sub 3}) + 0.25(PbFe{sub 0.5}Nb{sub 0.5}O{sub 3}) - (PZT-PFT-PFW-PFN) was synthesized by conventional solid-state reaction techniques. It showed moderate high dielectric constant, low dielectric loss, and two diffuse phase transitions, one below the room temperature {approx}261 K and other above {approx}410 K. X-ray diffraction (XRD) patterns revealed a tetragonal crystal structure at room temperature where as scanning electron micrograph (SEM) indicates inhomogeneous surface with an average grain size of 500 nm-3 {mu}m. Well saturated ferroelectric hysteresis loops with good saturation polarization (spontaneous polarization, P{sub s} {approx} 30.68 {mu}C/cm{sup 2}) were observed. Temperature-dependent ac conductivity displayed low conductivity with kink in spectra near the phase transition. In continuing search for developing new ferroelectric materials, in the present study we report stoichiometric compositions of complex perovskite ceramic materials: (PZT-PFT-PFW-PFN) with diffuse phase transition behavior. The crystal structure, dielectric properties, and ferroelectric properties were characterized by XRD, SEM, dielectric spectroscopy, and polarization. 1/{epsilon} versus (T) plots revealed diffuse relaxor phase transition (DPT) behavior. The

Structural evolution in three and four-layer Aurivillius solid solutions: A comparative study versus relaxor properties

Science.gov (United States)

Tellier, Jenny; Boullay, Philippe; Ben Jennet, Dorra; Mercurio, Daniele

2008-02-01

Two solid solutions of three-layer Ba xBi 4- xNb xTi 3- xO 12 (0 ≤ x ≤ 1.2) and four-layer Aurivillius compounds (Na 0.5Bi 0.5) 1- xBa xBi 4Ti 4O 15 (0 ≤ x ≤ 1), which both present a ferroelectric to relaxor-like transition with increasing x, were synthesized by solid state reaction. The evolution of their crystal structures, as a function of x, was performed using Rietveld refinements from X-ray powder diffraction data. As x increases, the average crystal structures become less distorted with respect to the archetypal high temperature tetragonal one and the coordination number of Bi 3+ in M 2O 2 layers continuously changes from {4 + 2} to {4}. The relaxor behaviour which appears in samples for a tolerance factor t > 0.96 is associated with a general static disorder in A and M sites together with the presence of some Ba 2+ cations in M 2O 2 layers (less than 10%).

Elasticity Imaging of Ferroelectric Domain Structure in PZT by Ultrasonic Atomic Force Microscopy

International Nuclear Information System (INIS)

Tsuji, T.; Ogiso, H.; Fukuda, K.; Yamanaka, K.

2004-01-01

UAFM was applied to the observation of the domain structure in lead zirconate titanate (PZT). It imaged the change of elasticity due to grain and domain boundary (DB). For the quantitative evaluation of the contact stiffness, the lateral contact stiffness was taken into account. The stiffness of DB was 10% lower than that within the domain and the width of the DB was about 30 nm. The implication of this work is the understanding of the fatigue mechanism in a PZT memory and the high resolution imaging for a high-density memory

Remarkable Strontium B-Site Occupancy in FerroelectricPb(Zr1-xTix)O3 Solid Solutions Doped with Cryolite-Type StrontiumNiobate

Energy Technology Data Exchange (ETDEWEB)

Feltz, A.; Schmidt-Winkel, P.; Schossman, M.; Booth, C.H.; Albering, J.

2007-04-26

New high-performance ferroelectric materials based on Pb(Zr{sub 1-x}Ti{sub x})O{sub 3} (PZT) that are doped with cryolite-type strontium niobate (SNO, Sr{sub 4}(Sr{sub 2-2y/3}Nb{sub 2+2y/3})O{sub 11+y}V{sub 0,1-y} with 0 {le} y {le} 1), hence denoted PZT:SNO, and their microscopic structure are described. The combination of exceptional piezoelectric properties, i.e. a piezoelectric strain constant of d{sub 33} {approx} 760 pm/V, with excellent stability and degradation resistance makes ferroelectric PZT:SNO solid solutions very attractive for use in novel and innovative piezoelectric actuator and transducer applications. Extended X-ray absorption fine-structure (EXAFS) analyses of PZT:SNO samples revealed that {approx}10 % of the Sr cations occupy the nominal B-sites of the perovskite-type PZT host lattice. This result was supported by EXAFS analyses of both a canonical SrTiO{sub 3} perovskite and two SNO model and reference compounds. Fit models that do not account for Sr cations on B-sites were ruled out. A clear Sr-Pb peak in Fourier transformed EXAFS data visually confirmed this structural model. The generation of temporary oxygen vacancies and the intricate defect chemistry induced by SNO-doping of PZT are crucial for the exceptional materials properties exhibited by PZT:SNO materials.

Electrodynamic properties of porous PZT-Pt films at terahertz frequency range

Energy Technology Data Exchange (ETDEWEB)

Komandin, Gennady A.; Porodinkov, Oleg E.; Spektor, Igor E.; Volkov, Alexander A. [Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Vorotilov, Konstantin A.; Seregin, Dmitry S.; Sigov, Alexander S. [Moscow Technological University (MIREA), Moscow (Russian Federation)

2017-01-15

Electrodynamics of Si-SiO{sub 2}-TiO{sub 2}-Pt-PZT heterostructures is studied in the frequency range from 5 to 5000 cm{sup -1} by monochromatic BWO (backward wave oscillator) and infrared Fourier-transform spectroscopy techniques to derive the dielectric characteristics of the sol-gel porous ferroelectric PbZr{sub 0.48}Ti{sub 0.52}O{sub 3} films. Broad frequency band dielectric response of PZT films with different density is constructed using the oscillator dispersion models. The main contribution to the film permittivity is found to form at frequencies below 100 cm{sup -1} depending strongly and non-linearly on the film medium density. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Preparation of PZT thin films on YBCO electrodes by KrF excimer laser ablation technique

International Nuclear Information System (INIS)

Kurogi, H.; Yamagata, Y.; Ebihara, K.

1998-01-01

Pb(Zr X Ti 1-X )O 3 (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, λ=248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 Jcm -2 on YBCO/MgO(100) substrate at a wide temperature range of 550-680 C have a perovskite (001) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (001) structure only at 650 C. The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be P r =15 μC cm -2 , 30 μC cm -2 and E c =200 kV cm -1 , 100 kV cm -1 for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 10 8 cycles of switching. (orig.)

A Diagram of the Structure Evolution of Pb(Zn1/3Nb2/3 O3-9%PbTiO3 Relaxor Ferroelectric Crystals with Excellent Piezoelectric Properties

Directory of Open Access Journals (Sweden)

Hua Zhou

2017-05-01

Full Text Available Piezoelectric properties are of significant importance to medical ultrasound, actuators, sensors, and countless other device applications. The mechanism of piezoelectric properties can be deeply understood in light of structure evolutions. In this paper, we report a diagram of the structure evolutions of Pb(Zn1/3Nb2/30.91Ti0.09O3 (PZN-9PT crystals with excellent piezoelectric properties among orthorhombic, tetragonal, and cubic phases, with a temperature increasing from room temperature to 220 °C. Through fitting the temperature-dependent XRD curves with Gauss and Lorenz functions, we obtained the evolutions of the content ratio of three kinds of phases (orthorhombic, tetragonal and cubic and the lattice parameters of the PZN-9PT system with the changes of temperature. The XRD fitting results together with Raman and dielectric spectra show that the phase transitions of PZN-9PT are a typical continuous evolution process. Additionally, resonance and anti-resonance spectra show the excellent piezoelectric properties of these crystals, which probably originate from the nano twin domains, as demonstrated by TEM images. Of particular attention is that the thickness electromechanical coupling factor kt is up to 72%.

Structural and dielectric characteristics of donor dopants in A and B places of perovskite ceramic PZT 54/46

International Nuclear Information System (INIS)

Durruthy-Rodriguez, M.D.; Perez-Fernandez, L.D.; Pelaiz-Barranco, A.; Calderon-Pinar, F.

2009-01-01

The microstructural (XRD and SEM) and dielectric behavior of Pb(Zr 0.54 Ti 0.46 )O 3 (PZT 54/46) ceramic system with donor (La, Nb and La+Nb) doping was studied. For all Nb-doped PZT samples, only one (tetragonal) phase was found, which confirms the compositional shifts near the morphotropic phase boundary. For La- and La+Nb-doped samples, there are two (rhombohedral and tetragonal) phases. Dielectric characteristic behavior (1/ε) for La- and La+Nb-doped PZT was associated with two-phase transitions: Ferro-Ferro at low temperature and Ferro-Para at Curie temperature. For Nb-doped samples, only one phase transition is observed, which indicates the presence of a single ferroelectric phase. (orig.)

Broadband dielectric spectroscopy of Ba(Zr,Ti)O.sub.3./sub.: dynamics of relaxors and diffuse ferroelectrics

Czech Academy of Sciences Publication Activity Database

Petzelt, Jan; Nuzhnyy, Dmitry; Savinov, Maxim; Bovtun, Viktor; Kempa, Martin; Ostapchuk, Tetyana; Hlinka, Jiří; Canu, G.; Buscaglia, V.

2014-01-01

Roč. 469, č. 1 (2014), s. 14-25 ISSN 0015-0193 R&D Projects: GA ČR GAP204/12/0232; GA ČR GA13-15110S Institutional support: RVO:68378271 Keywords : relaxor * diffuse phase transition * dielectric dispersion * polar phonons * local ion hopping Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.469, year: 2014

Mechanisms of aging and fatigue in ferroelectrics

Energy Technology Data Exchange (ETDEWEB)

Genenko, Yuri A. [Sonderforschungsbereich 595, Institut für Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Str. 2, 64287 Darmstadt (Germany); Glaum, Julia [Department of Materials Science and Engineering, University of New South Wales, Sydney (Australia); Hoffmann, Michael J. [Institut für keramische Werkstoffe, Haid-und-Neu Str. 7, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Albe, Karsten, E-mail: albe@mm.tu-darmstadt.de [Sonderforschungsbereich 595, Institut für Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Str. 2, 64287 Darmstadt (Germany)

2015-02-15

Highlights: • Experiments on aging and fatigue of bulk ferroelectrics are thoroughly reviewed. • Lead-based PZT and lead-free BNT–BT and KNN materials are covered. • Various fatigue regimes and factors are classified. • Defect associate formation and alignment are analyzed by density functional theory. • Emerging of internal bias field is studied within drift-diffusion approach. - Abstract: A comprehensive review of aging and fatigue phenomena in bulk polycrystalline ferroelectrics is presented. Three material classes are covered, namely the most widely used Pb[Zr{sub 1−x}Ti{sub x}]O{sub 3} (PZT) ceramics and lead-free materials, including those based on bismuth sodium titanate Bi{sub 1/2}Na{sub 1/2}TiO{sub 3} (BNT) and alkali niobate [K{sub x}Na{sub 1−x}]NbO{sub 3} (KNN). Aging is studied in poled and unpoled states both experimentally and theoretically. The variety of different loading regimes for fatigue includes DC electric field, unipolar, sesquipolar and bipolar cycling and all these differently combined with mechanical loading at different frequencies and temperatures. The role of device geometries and electrode materials is addressed and models describing charge migration and defect dipole re-orientation are discussed in the context of recent experimental studies.

Mechanisms of aging and fatigue in ferroelectrics

International Nuclear Information System (INIS)

Genenko, Yuri A.; Glaum, Julia; Hoffmann, Michael J.; Albe, Karsten

2015-01-01

Highlights: • Experiments on aging and fatigue of bulk ferroelectrics are thoroughly reviewed. • Lead-based PZT and lead-free BNT–BT and KNN materials are covered. • Various fatigue regimes and factors are classified. • Defect associate formation and alignment are analyzed by density functional theory. • Emerging of internal bias field is studied within drift-diffusion approach. - Abstract: A comprehensive review of aging and fatigue phenomena in bulk polycrystalline ferroelectrics is presented. Three material classes are covered, namely the most widely used Pb[Zr 1−x Ti x ]O 3 (PZT) ceramics and lead-free materials, including those based on bismuth sodium titanate Bi 1/2 Na 1/2 TiO 3 (BNT) and alkali niobate [K x Na 1−x ]NbO 3 (KNN). Aging is studied in poled and unpoled states both experimentally and theoretically. The variety of different loading regimes for fatigue includes DC electric field, unipolar, sesquipolar and bipolar cycling and all these differently combined with mechanical loading at different frequencies and temperatures. The role of device geometries and electrode materials is addressed and models describing charge migration and defect dipole re-orientation are discussed in the context of recent experimental studies

Effects of Bi(Zn2/3Nb1/3)O3 Modification on the Relaxor Behavior and Piezoelectricity of Pb(Mg1/3Nb2/3)O3-PbTiO3 Ceramics.

Science.gov (United States)

Liu, Zenghui; Wu, Hua; Paterson, Alisa; Ren, Wei; Ye, Zuo-Guang

2017-10-01

Relaxor lead magnesium niobate (PMN)-based materials exhibit complex structures and unusual properties that have been puzzling researchers for decades. In this paper, a new ternary solid solution of Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 -Bi(Zn 2/3 Nb 1/3 )O 3 (PMN-PT-BZN) is prepared in the form of ceramics, and the effects of the incorporation of BZN into the PMN-PT binary system are investigated. The crystal structure favors a pseudocubic symmetry and the relaxor properties are enhanced as the concentration of BZN increases. The relaxor behavior and the related phase transformations are studied by dielectric spectroscopy. A phase diagram mapping out the characteristic temperatures and various states is established. Interestingly, the piezoelectricity of the PMN-PT ceramics is significantly enhanced by the BZN substitution, with an optimal value of d 33 reaching 826 pC/N for 0.96[0.7Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 ]-0.04Bi(Zn 2/3 Nb 1/3 )O 3 . This paper provides a better understanding of the relaxor ferroelectric behavior, and unveils a new relaxor-based ternary system as piezoelectric materials potentially useful for electromechanical transducer applications.

The Homogenized Energy Model (HEM) for Characterizing Polarization and Strains in Hysteretic Ferroelectric Materials: Material Properties and Uniaxial Model Development

Science.gov (United States)

2012-01-01

Sebastian, Spain, 2006. [68] N.O. Pérez-Arancibia, K.Y. Ma, K.C. Galloway , J.D. Greenberg and R.J. Wood, “First con- trolled vertical flight of a...temperature on the large field electromechanical response of relaxor ferroelectric 8/65/35 PLZT,” Acta Materialia, 2011, to appear. [70] J.F. Scott

Microwave hydrothermal synthesis and characterization of PZT 52/48 powders

International Nuclear Information System (INIS)

Teixeira, G.F.; Gasparotto, G.; Santos, N.A.; Zaghete, M.A.; Varela, J.A.; Longo, E.

2009-01-01

Full text: Lead Zirconate Titanate (PZT) is a ceramic witch has great interest because of their ferroelectric, piezoelectric, and other electrical properties. In this work Pb(ZrxTi1-x)O3 powders were synthesized by microwave hydrothermal synthesis (M-H) at 180°C without excess lead content. This method allows obtaining particles whit nanometer size, good stoichiometric controls, high purity and crystalline degree at low temperatures and short times of synthesis. Powders were synthesized with molar concentration of 0.15 mol.L -1 during different times: 30 min, 2, 4, 6 and 8 h. After that the powders were characterized by X-ray diffraction (XRD), Field Emission Gun (FEG) and photoluminescence (PL). Through analysis it is observed that the crystalline phase of PZT is obtained from 2 hours of synthesis and this same time also presents more intense PL emission. (author)

Preparation of PZT thin films on YBCO electrodes by KrF excimer laser ablation technique

Energy Technology Data Exchange (ETDEWEB)

Kurogi, H; Yamagata, Y; Ebihara, K [Kumamoto Univ. (Japan). Dept. of Electr. Eng. and Comput. Sci.; Inoue, N [Kyushu Electric Power Co., Inc., Suizenji, 1-6-36, Kumamoto 862 (Japan)

1998-03-01

Pb(Zr{sub X}Ti{sub 1-X})O{sub 3} (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, {lambda}=248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 Jcm{sup -2} on YBCO/MgO(100) substrate at a wide temperature range of 550-680 C have a perovskite (001) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (001) structure only at 650 C. The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be P{sub r}=15 {mu}C cm{sup -2}, 30 {mu}C cm{sup -2} and E{sub c}=200 kV cm{sup -1}, 100 kV cm{sup -1} for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 10{sup 8} cycles of switching. (orig.) 7 refs.

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.

Proceedings of the 8th International Symposium on Applications of Ferroelectrics

Science.gov (United States)

Liu, M.; Safari, A.; Kingon, A.; Haertling, G.

1993-02-01

The eighth International Symposium on the Applications of Ferroelectrics was held in Greenville, SC, on August 30 to Sept 2, 1992. It was attended by approximately 260 scientists and engineers who presented nearly 200 oral and poster papers. The three plenary presentations covered ferroelectric materials which are currently moving into commercial exploitation or have strong potential to do so. These were (1) pyroelectric imaging, (2) ferroelectric materials integrated with silicon for use as micromotors and microsensors and (3) research activity in Japan on high permittivity materials for DRAM's. Invited papers covered such subjects as pyroelectric and electrooptic properties of thin films, photorefractive effects, ferroelectric polymers, piezoelectric transducers, processing of ferroelectrics, domain switching in ferroelectrics, thin film memories, thin film vacuum deposition techniques and the fabrication of chemically prepared PZT and PLZT thin films. The papers continued to reflect the large interest in ferroelectric thin films. It was encouraging that there have been substantial strides made in both the processing and understanding of the films in the last two years. It was equally clear, however, that much still remains to be done before reliable thin film devices will be available in the marketplace.

Large Stroke High Fidelity PZN-PT Single-Crystal "Stake" Actuator.

Science.gov (United States)

Huang, Yu; Xia, Yuexue; Lin, Dian Hua; Yao, Kui; Lim, Leong Chew

2017-10-01

A new piezoelectric actuator design, called "Stake" actuator, is proposed and demonstrated in this paper. As an example, the stake actuator is made of four d 32 -mode PZN-5.5%PT single crystals (SCs), each of 25 mm ( L ) ×8 mm ( W ) ×0.4 mm (T) in dimensions, bonded with the aid of polycarbonate edge guide-cum-stiffeners into a square-pipe configuration for improved bending and twisting strengths and capped with top and bottom pedestals made of 1.5-mm-thick anodized aluminum. The resultant stake actuator measured 9 mm ×9 mm ×28 mm. The hollow structure is a key design feature, which optimizes SC usage efficiency and lowers the overall cost of the actuator. The displacement-voltage responses, blocking forces, resonance characteristics of the fabricated stake actuator, as well as the load and temperature effects, are measured and discussed. Since d 32 is negative for [011]-poled SC, the "Stake" actuator contracts in the axial direction when a positive-polarity field is applied to the crystals. Biased drive is thus recommended when extensional displacement is desired. The SC stake actuator has negligible (0.13% when driven up to +300 V (i.e., 0.75 kV/mm), which is close to the rhombohedral-to-orthorhombic transformation field ( E RO ) of 0.85 kV/mm of the SC used. The stake actuator displays a stroke of [Formula: see text] (at +300 V) despite its small overall dimensions, and has a blocking force of 114 N. The SC d 32 stake actuator fabricated displays more than 30% larger axial strain than the state-of-the-art PZT stack actuators of comparable length as well as moderate blocking forces. Said actuators are thus ideal for applications when large displacements with simple open-loop control are preferred.

Dielectric, piezoelectric, and ferroelectric properties of grain-orientated Bi3.25La0.75Ti3O12 ceramics

International Nuclear Information System (INIS)

Liu Jing; Shen Zhijian; Yan Haixue; Reece, Michael J.; Kan Yanmei; Wang Peiling

2007-01-01

By dynamic forging during Spark Plasma Sintering (SPS), grain-orientated ferroelectric Bi 3.25 La 0.75 Ti 3 O 12 (BLT) ceramics were prepared. Their ferroelectric, piezoelectric, and dielectric properties are anisotropic. The textured ceramics parallel and perpendicular to the shear flow directions have similar thermal depoling behaviors. The d 33 piezoelectric coefficient of BLT ceramics gradually reduces up to 350 deg. C; it then drops rapidly. The broadness of the dielectric constant and loss peaks and the existence of d 33 above the permittivity peak, T m , show that the BLT ceramic has relaxor-like behavior

The effects of strain relaxation on the dielectric properties of epitaxial ferroelectric Pb(Zr0.2Ti0.8)TiO3 thin films

Science.gov (United States)

Khan, Asif Islam; Yu, Pu; Trassin, Morgan; Lee, Michelle J.; You, Long; Salahuddin, Sayeef

2014-07-01

We study the effects of strain relaxation on the dielectric properties of epitaxial 40 nm Pb(Zr0.2Ti0.8)TiO3 (PZT) films. A significant increase in the defect and dislocation density due to strain relaxation is observed in PZT films with tetragonality c/a fatigue in ferroelectric materials.

ELABORATION AND DIELECTRIC CHARACTERIZATION OF A DOPED FERROELECTRIC MATERIAL TYPE PZT

Directory of Open Access Journals (Sweden)

M. Abba

2013-12-01

Full Text Available The main objective of this work is based on the synthesis and dielectric characterization of a new material in ceramic PZT with a perovskite structure ABO3. We are interested to study the Quaternary system (doping in site A and site B of general formula: Pb0.96Ba0.02Ca0.02[(Zr0.52Ti0.480.94(Zn1/3Ta2/30.03(In1/3Sb2/30.03]O3 short PZT-PBC-ZTIS. The sample selected for this study was prepared by the method of synthesis with solid way. Heat treatment was applied to these compositions at different temperatures: 1100, 1150,1180 and 1200 °C successively to optimize the sintering temperature optimal where the density of the sample is maximum (near theoretical density and therefore the product has better physical quality. The study of dielectric properties of all samples showed a high permittivity dielectric εr = 18018, low dielectric loss: tgδ = 7.62%, for the composition sintered to 1180 ° C included in the phase morphotropique zone (FMP.

ELABORATION AND DIELECTRIC CHARACTERIZATION OF A DOPED FERROELECTRIC MATERIAL TYPE PZT

Directory of Open Access Journals (Sweden)

M. Abba

2015-07-01

Full Text Available The main objective of this work is based on the synthesis and dielectric characterization of a new material in ceramic PZT with a perovskite structure ABO3. We are interested to study the Quaternary system (doping in site A and site B of general formula: Pb0.96Ba0.02Ca0.02[(Zr0.52Ti0.480.94(Zn1/3Ta2/30.03(In1/3Sb2/30.03]O3 short PZT-PBC-ZTIS. The sample selected for this study was prepared by the method of synthesis with solid way. Heat treatment was applied to these compositions at different temperatures: 1100, 1150,1180 and 1200 °C successively to optimize the sintering temperature optimal where the density of the sample is maximum (near theoretical density and therefore the product has better physical quality. The study of dielectric properties of all samples showed a high permittivity dielectric εr = 18018, low dielectric loss: tgδ = 7.62%, for the composition sintered to 1180 ° C included in the phase morphotropique zone (FMP.

Improvement in fatigue property for a PZT ferroelectric film device with SRO electrode film prepared by chemical solution deposition

International Nuclear Information System (INIS)

Miyazaki, H.; Miwa, Y.; Suzuki, H.

2007-01-01

PZT films with (1 0 0) and (1 1 0) orientation were prepared by spin coating using the chemical solution deposition (CSD) method on an SRO/Si or a Pt/Ti/SiO 2 /Si substrate. The remnant polarization and the saturation polarization of the PZT/SRO/Si film were 21 and 35 μC/cm 2 , and those of the PZT/Pt/Ti/SiO 2 /Si film were 20 and 31 μC/cm 2 . The remnant polarization of the PZT/SRO/Si film maintained more than 10 8 switching cycles, and the fatigue property was observed for the PZT film fabricated on the Pt/Ti/SiO 2 /Si electrode

Characterization of PZT Capacitor Structures with Various Electrode Materials Processed In-Situ Using AN Automated, Rotating Elemental Target, Ion Beam Deposition System

Science.gov (United States)

Gifford, Kenneth Douglas

Ferroelectric thin film capacitor structures containing lead zirconate titanate (PZT) as the dielectric, with the chemical formula Pb(rm Zr_{x }Ti_{1-x})O_3, were synthesized in-situ with an automated ion beam sputter deposition system. Platinum (Pt), conductive ruthenium oxide (RuO_2), and two types of Pt-RuO_2 hybrid electrodes were used as the electrode materials. The capacitor structures are characterized in terms of microstructure and electrical characteristics. Reduction or elimination of non-ferroelectric phases, that nucleate during PZT processing on Pt/TiO _2/MgO and RuO_2/MgO substrates, is achieved by reducing the thickness of the individually deposited layers and by interposing a buffer layer (~100-200A) of PbTiO _3 (PT) between the bottom electrode and the PZT film. Capacitor structures containing a Pt electrode exhibit poor fatigue resistance, irregardless of the PZT microstructure or the use of a PT buffer layer. From these results, and results from similar capacitors synthesized with sol-gel and laser ablation, PZT-based capacitor structures containing Pt electrodes are considered to be unsuitable for use in memory devices. Using a PT buffer layer, in capacitor structures containing RuO_2 top and bottom electrodes and polycrystalline, highly (101) oriented PZT, reduces or eliminates the nucleation of zirconium-titanium oxide, non-ferroelectric species at the bottom electrode interface during processing. This results in good fatigue resistance up to ~2times10^ {10} switching cycles. DC leakage current density vs. time measurements follow the Curie-von Schweidler law, J(t) ~ t^ {rm -n}. Identification of the high electric field current conduction mechanism is inconclusive. The good fatigue resistance, low dc leakage current, and excellent retention, qualifies the use of these capacitor structures in non-volatile random access (NVRAM) and dynamic random access (DRAM) memory devices. Excellent fatigue resistance (10% loss in remanent polarization up to

Cation vacancies in ferroelectric PbTiO3 and Pb(Zr,Ti)O3 : A positron annihilation lifetime spectroscopy study

Science.gov (United States)

Keeble, D. J.; Singh, S.; Mackie, R. A.; Morozov, M.; McGuire, S.; Damjanovic, D.

2007-10-01

Positron annihilation lifetime spectroscopy measurements identify A - and B -site cation vacancies in ferroelectric perovskite oxides (ABO3) . Crystal PbTiO3 and ceramic lead zirconium titanate (PZT) were studied and gave consistent values for the lifetime resulting from positron localization at lead vacancies VPb . Positron trapping to B -site vacancies was inferred in PZT. Temperature dependent studies showed that the defect specific trapping rate was higher for VB compared to VPb , consistent with the larger negative charge. Doping PZT with Fe increased the fraction positron trapping to VB compared to VPb -type defects.

Relaxor-like behavior of lead-free Sr.sub.2./sub.LaTi.sub.2./sub.Nb.sub.3./sub.O.sub.15./sub. ceramics with tetragonal tungsten bronze structure

Czech Academy of Sciences Publication Activity Database

Bovtun, Viktor; Kamba, Stanislav; Veljko, Sergiy; Nuzhnyy, Dmitry; Knížek, Karel; Savinov, Maxim; Petzelt, Jan

2007-01-01

Roč. 101, č. 5 (2007), 054115/1-054115/6 ISSN 0021-8979 R&D Projects: GA ČR(CZ) GA202/06/0403; GA ČR GA202/04/0993; GA MŠk OC 101 Institutional research plan: CEZ:AV0Z10100520 Keywords : relaxor ferroelectrics * dielectric spectroscopy * dipolar glass * infrared spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.171, year: 2007

Ferroelectric and piezoelectric properties of epitaxial PZT films and devices on silicon

NARCIS (Netherlands)

Nguyen, Duc Minh

2010-01-01

In this thesis, the integration of lead zirconate titanate Pb(Zr,Ti)O3 (PZT) thin films into piezoelectric microelectromechanical systems (MEMS) based on silicon is studied. In these structures, all epitaxial oxide layers (thin film/electrode/buffer-layer(s)) were deposited by pulsed laser

Enhanced pyroelectric and piezoelectric properties of PZT with aligned porosity for energy harvesting applications.

Science.gov (United States)

Zhang, Yan; Xie, Mengying; Roscow, James; Bao, Yinxiang; Zhou, Kechao; Zhang, Dou; Bowen, Chris R

2017-04-14

This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction. As a result of the introduction of porosity into the ceramic microstructure, high piezoelectric and pyroelectric harvesting figures of merits were achieved for porous freeze-cast PZT compared to dense PZT due to the reduced permittivity and volume specific heat capacity. Experimental results were compared to parallel and series analytical models with good agreement and the PZT with porosity aligned parallel to the freezing direction exhibited the highest piezoelectric and pyroelectric harvesting response; this was a result of the enhanced interconnectivity of the ferroelectric material along the poling direction and reduced fraction of unpoled material that leads to a higher polarization. A complete thermal energy harvesting system, composed of a parallel-aligned PZT harvester element and an AC/DC converter, was successfully demonstrated by charging a storage capacitor. The maximum energy density generated by the 60 vol% porous parallel-connected PZT when subjected to thermal oscillations was 1653 μJ cm -3 , which was 374% higher than that of the dense PZT with an energy density of 446 μJ cm -3 . The results are beneficial for the design and manufacture of high performance porous pyroelectric and piezoelectric materials in devices for energy harvesting and sensor applications.

Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites

Directory of Open Access Journals (Sweden)

Gollapudi Sreenivasulu

2016-02-01

Full Text Available Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i a bimorph of oppositely-poled lead zirconate titanate (PZT platelets and (ii a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data.

Sensitivity Enhancement in Magnetic Sensors Based on Ferroelectric-Bimorphs and Multiferroic Composites.

Science.gov (United States)

Sreenivasulu, Gollapudi; Qu, Peng; Petrov, Vladimir; Qu, Hongwei; Srinivasan, Gopalan

2016-02-20

Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity. Novel magnetic sensors with a permanent magnet proof mass, either on a ferroelectric bimorph or a ferromagnetic-ferroelectric composite, are discussed. In both types, the interaction between the applied AC magnetic field and remnant magnetization of the magnet results in a mechanical strain and a voltage response in the ferroelectric. Our studies have been performed on sensors with a Nd-Fe-B permanent magnet proof mass on (i) a bimorph of oppositely-poled lead zirconate titanate (PZT) platelets and (ii) a layered multiferroic composite of PZT-Metglas-Ni. The sensors have been characterized in terms of sensitivity and equivalent magnetic noise N. Noise N in both type of sensors is on the order of 200 pT/√Hz at 1 Hz, a factor of 10 improvement compared to multiferroic sensors without a proof mass. When the AC magnetic field is applied at the bending resonance for the bimorph, the measured N ≈ 700 pT/√Hz. We discuss models based on magneto-electro-mechanical coupling at low frequency and bending resonance in the sensors and theoretical estimates of ME voltage coefficients are in very good agreement with the data.

Nano-embossing technology on ferroelectric thin film Pb(Zr0.3,Ti0.7O3 for multi-bit storage application

Directory of Open Access Journals (Sweden)

Lu Qian

2011-01-01

Full Text Available Abstract In this work, we apply nano-embossing technique to form a stagger structure in ferroelectric lead zirconate titanate [Pb(Zr0.3, Ti0.7O3 (PZT] films and investigate the ferroelectric and electrical characterizations of the embossed and un-embossed regions, respectively, of the same films by using piezoresponse force microscopy (PFM and Radiant Technologies Precision Material Analyzer. Attributed to the different layer thickness of the patterned ferroelectric thin film, two distinctive coercive voltages have been obtained, thereby, allowing for a single ferroelectric memory cell to contain more than one bit of data.

Role of oxygen disorder in the ferroelectric phase transitions for various materials

International Nuclear Information System (INIS)

Pasciak, Marek; Goossens, Darren J.; Welberry, Richard T.

2009-01-01

Full text: The nature of ferroelectric phase transitions in many materials have been questioned for many years. Whereas some methods provide definitive evidence of mode softening, other methods, such as local structure probes, indicate the existence of disorder in the paraelectric phase [1]. It is now widely accepted, that the ferroelectric phase transition usually has two components - soft-mode displacive and order-disorder. The latter leads inevitably to some form of pretransitional clusters in the paraelectric phase [2]. In relaxor ferroelectrics, in which disorder drives the transformation, such polar clusters can exist over a wide range of temperatures. Diffuse scattering is a powerful tool for studying such disorder and also for studying short-range order correlations in atomic displacements [3]. In this work we concentrate on the role of oxygens in various materials. By different means of molecular simulations we build models in which the oxygens constitute a framework for short range order correlations. This leads to a discussion of the differences between x-ray and neutron diffuse scattering patterns that may arise due to the disorder of oxygens.

Impact of process parameters on the structural and electrical properties of metal/PZT/Al2O3/silicon gate stack for non-volatile memory applications

Science.gov (United States)

Singh, Prashant; Jha, Rajesh Kumar; Singh, Rajat Kumar; Singh, B. R.

2018-02-01

In this paper, we present the structural and electrical properties of the Al2O3 buffer layer on non-volatile memory behavior using Metal/PZT/Al2O3/Silicon structures. Metal/PZT/Silicon and Metal/Al2O3/Silicon structures were also fabricated and characterized to obtain capacitance and leakage current parameters. Lead zirconate titanate (PZT::35:65) and Al2O3 films were deposited by sputtering on the silicon substrate. Memory window, PUND, endurance, breakdown voltage, effective charges, flat-band voltage and leakage current density parameters were measured and the effects of process parameters on the structural and electrical characteristics were investigated. X-ray data show dominant (110) tetragonal phase of the PZT film, which crystallizes at 500 °C. The sputtered Al2O3 film annealed at different temperatures show dominant (312) orientation and amorphous nature at 425 °C. Multiple angle laser ellipsometric analysis reveals the temperature dependence of PZT film refractive index and extinction coefficient. Electrical characterization shows the maximum memory window of 3.9 V and breakdown voltage of 25 V for the Metal/Ferroelectric/Silicon (MFeS) structures annealed at 500 °C. With 10 nm Al2O3 layer in the Metal/Ferroelectric/Insulator/Silicon (MFeIS) structure, the memory window and breakdown voltage was improved to 7.21 and 35 V, respectively. Such structures show high endurance with no significant reduction polarization charge for upto 2.2 × 109 iteration cycles.

In situ transmission electron microscopy study of the microstructural origins for the electric field-induced phenomena in ferroelectric perovskites

Energy Technology Data Exchange (ETDEWEB)

Guo, Hanzheng [Iowa State Univ., Ames, IA (United States)

2014-12-15

Ferroelectrics are important materials due to their extensive technological applications, such as non-volatile memories, field-effect transistors, ferroelectric tunneling junctions, dielectric capacitors, piezoelectric transducers, sensors and actuators. As is well known, the outstanding dielectric, piezoelectric, and ferroelectric properties of these functional oxides originate from their ferroelectric domain arrangements and the corresponding evolution under external stimuli (e.g. electric field, stress, and temperature). Electric field has been known as the most efficient stimulus to manipulate the ferroelectric domains through polarization switching and alignment. Therefore, direct observation of the dynamic process of electric field-induced domain evolution and crystal structure transformation is of significant importance to understand the microstructural mechanisms for the functional properties of ferroelectrics. In this dissertation, electric field in situ transmission electron microscopy (TEM) technique was employed to monitor the real-time evolution of the domain morphology and crystal structure during various electrical processes: (1) the initial poling process, (2) the electric field reversal process, and (3) the electrical cycling process. Two types of perovskite-structured ceramics, normal ferroelectrics and relaxor ferroelectrics, were used for this investigation. In addition to providing the microscopic insight for some wellaccepted phase transformation rules, discoveries of some new or even unexpected physical phenomena were also demonstrated.

Relaxor behavior in lead-free Ba(Ti1−xScx/2Nbx/2O3 ceramics

Directory of Open Access Journals (Sweden)

N. Bensemma

2014-06-01

Full Text Available Solid solutions of (1−xBaTiO3-xBaSc1/2Nb1/2O3 (BT-BSN with x = 0.025, 0.05, 0.075, 0.1 and 0.125 were prepared by a high temperature solid-state reaction technique. The effects of the Ba(Sc1/2Nb1/2O3 addition on the phase composition, dielectric properties, as well as polarization-electric field (P-E loops of the BT-BSN solid solution were investigated. The room-temperature X-ray diffraction analyses of all the ceramics revealed a perovskite phase after sintering at 1350 °C with a composition-dependent symmetry. Temperature and frequency dependence of the dielectric permittivity and losses have been explored: ceramics of compositions x ≤ 0.075 showed normal ferroelectric behavior, while ceramics with x ≥ 0.1 were of relaxor type. The degree of diffuseness and the relaxor effect increase while the transition temperature (TC or Tm decreases when both scandium and niobium are introduced in the BaTiO3 lattice. Ceramics of composition x = 0.125 exhibited interesting relaxor characteristics at 10 kHz: ΔTm = 20 K, ɛr = 12,000, and Tm = 140 K. In addition, modeled using Vogel–Fülcher relation, this same composition showed the fitting parameters: Ea = 0.0503 eV, f0 = 1.129 × 1014 Hz and TVF = 166.85 K.

Nondestructive investigatons of the depth profile of PZT ferroelectric films

Czech Academy of Sciences Publication Activity Database

Deineka, Alexander; Glinchuk, M. D.; Jastrabík, Lubomír; Suchaneck, G.; Gerlach, G.

2001-01-01

Roč. 264, - (2001), s. 151-156 ISSN 0015-0193 R&D Projects: GA MŠk LN00A015; GA ČR GA202/00/1425 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferroelectric film * depth profile * interface Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.471, year: 2001

Octahedral tilt transitions in the relaxor ferroelectric Na1/2Bi1/2TiO3

International Nuclear Information System (INIS)

Meyer, Kai-Christian; Gröting, Melanie; Albe, Karsten

2015-01-01

The kinetics of octahedral tilt transitions in the lead-free relaxor material sodium bismuth titanate Na 1/2 Bi 1/2 TiO 3 (NBT) is investigated by electronic structure calculations within density functional theory. Energy barriers for transitions between tetragonal, rhombohedral and orthorhombic tilts in cation configurations with [001]- and [111]-order on the A-sites are determined by nudged elastic band calculations. By tilting entire layers of octahedra simultaneously we find that the activation energy is lower for structures with 001-order compared to such with 111-order. The energetic coupling between differently tilted layers is, however, negligibly small. By introducing a single octahedral defect we create local tilt disorder and find that the deformation energy of the neighboring octahedra is less in a rhombohedral than in a tetragonal structure. By successively increasing the size of clusters of orthorhombic defects in a rhombohedral matrix with 001-order, we determine a critical cluster size of about 40 Å . Thus groups of about ten octahedra can be considered as nuclei for polar nanoregions, which are the cause of the experimentally observed relaxor behavior of NBT. - Graphical abstract: Nine orthorhombic oxygen octahedral tilt defects in a rhombohedral tilt configuration. - Highlights: • Chemical order influences energy barriers of octahedral tilt transitions. • The octahedral deformation energy is lower in rhombohedral phases. • Tilt defect clusters are more likely in rhombohedral structures. • Tilt defect clusters can act as nuclei for polar nanoregions

Structural and electrical properties of Sm{sup 3+} substituted PZT ceramics

Energy Technology Data Exchange (ETDEWEB)

Pandey, S.K. [Solid State Physics Laboratory, Timarpur, Delhi 110 054 (India)], E-mail: 628@ssplnet.org; Thakur, O.P.; Bhattacharya, D.K. [Solid State Physics Laboratory, Timarpur, Delhi 110 054 (India); Prakash, Chandra [DRDO Bhawan, DHQ, New Delhi 110 011 (India); Chatterjee, Ratnamala [Department of Physics, Indian Institute of Technology, New Delhi 110 016 (India)

2009-01-22

Samarium modified lead zirconate titanate (PSZT: Pb{sub 1-x}Sm{sub x}(Zr{sub 0.65}Ti{sub 0.35})O{sub 3}: x = 0, 0.02, 0.04, 0.06) ceramics were synthesized by solid state ceramic route. XRD shows single-phase formation with rhombohedral structure up to x = 0.04. With Sm-substitution, the grain size first increases up to x = 0.02 and then decreases. A metal/ferroelectric/metal (MFM) structure was made by depositing gold electrode on the flat surfaces for electrical measurements. All samples show normal ferroelectric behaviour, however, a squareness of P-E loop (polarization vs. electric field) was observed to increase with Sm content. Higher electromechanical coupling coefficients (K{sub p} and K{sub t}) have been achieved for the PZT with 6 mol% Sm substitution and having fine grain size.

Ferroelectric materials for FeRAMs; FeRAM yo kyoyudentai zairyo

Energy Technology Data Exchange (ETDEWEB)

Miyasaka, Y [NEC Corp., Tokyo (Japan)

1998-10-01

Studies to utilize bistable spontaneous polarization of ferroelectric materials for non-volatile memory have already been started in the 1950`s. Recently, a possibility was indicated on a high-speed non-volatile RAM (FeRAM) with memory cell configuration combined with switching transistors as in DRAMs. This situation has led to performing very active studies on ferroelectric materials and electrode materials used in ferroelectric film cell capacitors. This paper summarizes the above research and development circumstances, as well as their future problems. On the other hand of having shown excellent fatigue resistance in the SrBi2Ta209(SBT) system, improvement has progressed steadily on the Pb(ZR, Ti)03 (abbreviated to PZT) system, which retains the mainstream position as the ferroelectric material for FeRAMs. Aiming at realizing a high integration FeRAM in the future will require discussions on property changes due to use of lower temperature and micronization in film formation, further improvement in relation with degradation such as in imprint, and elucidation of the mechanism. 31 refs., 3 figs.

Preparation and electromagnetic properties of low-temperature sintered ferroelectric-ferrite composite ceramics

International Nuclear Information System (INIS)

Yue Zhenxing; Chen Shaofeng; Qi Xiwei; Gui Zhilun; Li Longtu

2004-01-01

For the purpose of multilayer chip EMI filters, the new ferroelectric-ferrite composite ceramics were prepared by mixing PMZNT relaxor ferroelectric powder with composition of 0.85Pb(Mg 1/3 Nb 2/3 )O 3 -0.1Pb(Ni 1/3 Nb 2/3 )O 3 -0.05PbTiO 3 and NiCuZn ferrite powder with composition of (Ni 0.20 Cu 0.20 Zn 0.60 )O(Fe 2 O 3 ) 0.97 at low sintering temperatures. A small amount of Bi 2 O 3 was added to low sintering temperature. Consequently, the dense composite ceramics were obtained at relative low sintering temperatures, which were lower than 940 deg. C. The X-ray diffractometer (XRD) identifications showed that the sintered ceramics retained the presence of distinct ferroelectric and ferrite phases. The sintering studies and scanning electron microscope (SEM) observations revealed that the co-existed two phases affect the sintering behavior and grain growth of components. The electromagnetic properties, such as dielectric constant and initial permeability, change continuously between those of two components. Thus, the low-temperature sintered ferroelectric-ferrite composite ceramics with tunable electromagnetic properties were prepared by adjusting the relative content of two components. These materials can be used for multilayer chip EMI filters with various properties

Evaluation of Data Retention Characteristics for Ferroelectric Random Access Memories (FRAMs)

Science.gov (United States)

Sharma, Ashok K.; Teverovsky, Alexander

2001-01-01

Data retention and fatigue characteristics of 64 Kb lead zirconate titanate (PZT)-based Ferroelectric Random Access Memories (FRAMs) microcircuits manufactured by Ramtron were examined over temperature range from -85 C to +310 C for ceramic packaged parts and from -85 C to +175 C for plastic parts, during retention periods up to several thousand hours. Intrinsic failures, which were caused by a thermal degradation of the ferroelectric cells, occurred in ceramic parts after tens or hundreds hours of aging at temperatures above 200 C. The activation energy of the retention test failures was 1.05 eV and the extrapolated mean-time-to-failure (MTTF) at room temperature was estimated to be more than 280 years. Multiple write-read cycling (up to 3x10(exp 7)) during the fatigue testing of plastic and ceramic parts did not result in any parametric or functional failures. However, operational currents linearly decreased with the logarithm of number of cycles thus indicating fatigue process in PZT films. Plastic parts, that had more recent date code as compared to ceramic parts, appeared to be using die with improved process technology and showed significantly smaller changes in operational currents and data access times.

Electric field cycling behavior of ferroelectric hafnium oxide.

Science.gov (United States)

Schenk, Tony; Schroeder, Uwe; Pešić, Milan; Popovici, Mihaela; Pershin, Yuriy V; Mikolajick, Thomas

2014-11-26

HfO2 based ferroelectrics are lead-free, simple binary oxides with nonperovskite structure and low permittivity. They just recently started attracting attention of theoretical groups in the fields of ferroelectric memories and electrostatic supercapacitors. A modified approach of harmonic analysis is introduced for temperature-dependent studies of the field cycling behavior and the underlying defect mechanisms. Activation energies for wake-up and fatigue are extracted. Notably, all values are about 100 meV, which is 1 order of magnitude lower than for conventional ferroelectrics like lead zirconate titanate (PZT). This difference is mainly atttributed to the one to two orders of magnitude higher electric fields used for cycling and to the different surface to volume ratios between the 10 nm thin films in this study and the bulk samples of former measurements or simulations. Moreover, a new, analog-like split-up effect of switching peaks by field cycling is discovered and is explained by a network model based on memcapacitive behavior as a result of defect redistribution.

Electro-optic study of PZT ferroelectric ceramics using modulation of reflected light

Science.gov (United States)

Kniazkov, A. V.

2016-04-01

Electro-optic coefficients of variations in the refractive index of PZT and PLZT ceramic materials induced by ac electric field are estimated using modulation of reflected light. The electro-optic coefficients of PLZT ceramics measured with the aid of conventional birefringence using the phase shift of transmitted radiation and the proposed method of birefringence using the modulation of reflected light are compared.

Cofiring behavior and interfacial structure of NiCuZn ferrite/PMN ferroelectrics composites for multilayer LC filters

International Nuclear Information System (INIS)

Miao Chunlin; Zhou Ji; Cui Xuemin; Wang Xiaohui; Yue Zhenxing; Li Longtu

2006-01-01

The cofiring behavior, interfacial structure and cofiring migration between NiCuZn ferrite and lead magnesium niobate (PMN)-based relaxor ferroelectric materials were investigated via thermomechanical analyzer (TMA), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Mismatched sintering shrinkage between NiCuZn ferrite and PMN was modified by adding an appropriate amount of sintering aids, Bi 2 O 3 , into NiCuZn ferrite. Pyrochlore phase appeared in the mixture of NiCuZn ferrite and PMN, which is detrimental to the final electric properties of LC filters. EDS results indicated that the interdiffusion at the heterogeneous interfaces in the composites, such as Fe, Pb, Zn, existed which can strengthen combinations between ferrite layers and ferroelectrics layers

Study of mechanically stimulated ferroelectric domain formation using scanning probe microscope

Energy Technology Data Exchange (ETDEWEB)

Kim, J H; Baek, J; Khim, Z G [School of Physics and Nano-Systems Institute, Seoul National University, Seoul 151-747 (Korea, Republic of)

2007-03-15

The stress-related ferroelectric properties have been studied on the Triglycine sulfate (TGS) by scanning probe microscope (SPM). Together with normal stress of the tip, the lateral stress is applied to the sample with piezoelectric transducers. With this study, we characterized the way the ferroelectricity of TGS responds to the axis-specific stress. Specially, the b-directional stress applicable to the surface can amount to several GPa such that the polarization switching by mechanical stress is observable. Although the lateral stress is not strong enough to view such phenomena, a-axis(c-axis) stress still affects the polarization value so as to fortify (lessen) the electric field inside, respectively. These contrasting results can be explained by the sign relation of piezo-coefficients about the individual axis. This work can be a touchstone of future researches in characterizing the electromechanical properties of more popular ferroelectrics such as PZT or BTO.

Characterization of Phase Transitions in PZT Ferroelectric films with spectral Ellipsometry

Czech Academy of Sciences Publication Activity Database

Deineka, Alexander; Suchaneck, G.; Jastrabík, Lubomír; Gerlach, G.

11-12, - (2002), s. 377-380 ISSN 0447-6441 R&D Projects: GA MŠk LN00A015; GA ČR GA202/00/1425 Institutional research plan: CEZ:AV0Z1010921 Keywords : ferroelectric film * phase transition * film profile Subject RIV: BH - Optics, Masers, Lasers

Ferroelectric and piezoelectric responses of (110) and (001)-oriented epitaxial Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} thin films on all-oxide layers buffered silicon

Energy Technology Data Exchange (ETDEWEB)

Vu, Hien Thu [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No.1 Dai Co Viet Road, Hanoi 10000 (Viet Nam); Nguyen, Minh Duc, E-mail: minh.nguyen@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No.1 Dai Co Viet Road, Hanoi 10000 (Viet Nam); Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); SolMateS B.V., Drienerlolaan 5, Building 6, 7522 NB Enschede (Netherlands); Houwman, Evert; Boota, Muhammad [Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Dekkers, Matthijn [SolMateS B.V., Drienerlolaan 5, Building 6, 7522 NB Enschede (Netherlands); Vu, Hung Ngoc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No.1 Dai Co Viet Road, Hanoi 10000 (Viet Nam); Rijnders, Guus [Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

2015-12-15

Graphical abstract: The cross sections show a very dense structure in the (001)-oriented films (c,d), while an open columnar growth structure is observed in the case of the (110)-oriented films (a,b). The (110)-oriented PZT films show a significantly larger longitudinal piezoelectric coefficient (d33{sub ,f}), but smaller transverse piezoelectric coefficient (d31{sub ,f}) than the (001) oriented films. - Highlights: • We fabricate all-oxide, epitaxial piezoelectric PZT thin films on Si. • The orientation of the films can be controlled by changing the buffer layer stack. • The coherence of the in-plane orientation of the grains and grain boundaries affects the ferroelectric properties. • Good cycling stability of the ferroelectric properties of (001)-oriented PZT thin films. The (110)-oriented PZT thin films show a larger d33{sub ,f} but smaller d31{sub ,f} than the (001)-oriented films. - Abstract: Epitaxial ferroelectric Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) thin films were fabricated on silicon substrates using pulsed laser deposition. Depending on the buffer layers and perovskite oxide electrodes, epitaxial films with different orientations were grown. (110)-oriented PZT/SrRuO{sub 3} (and PZT/LaNiO{sub 3}) films were obtained on YSZ-buffered Si substrates, while (001)-oriented PZT/SrRuO{sub 3} (and PZT/LaNiO{sub 3}) were fabricated with an extra CeO{sub 2} buffer layer (CeO{sub 2}/YSZ/Si). There is no effect of the electrode material on the properties of the films. The initial remnant polarizations in the (001)-oriented films are higher than those of (110)-oriented films, but it increases to the value of the (001) films upon cycling. The longitudinal piezoelectric d33{sub ,f} coefficients of the (110) films are larger than those of the (001) films, whereas the transverse piezoelectric d31{sub ,f} coefficients in the (110)-films are less than those in the (001)-oriented films. The difference is ascribed to the lower density (connectivity between

Raman and IR phonons in ferroelectric Sr.sub.0.35./sub.Ba.sub.0.69./sub.Nb.sub.2./sub.O.sub.6.04./sub. single crystals

Czech Academy of Sciences Publication Activity Database

Buixaderas, Elena; Gregora, Ivan; Hlinka, Jiří; Dec, J.; Lukasiewicz, T.

2013-01-01

Roč. 86, 2-3 (2013), s. 217-229 ISSN 0141-1594 R&D Projects: GA ČR GAP204/10/0616 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectrics * Raman spectroscopy * IR spectroscopy * phonons * relaxors * tungsten-bronze materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.044, year: 2013

Low frequency modelling of hysteresis behaviour and dielectric permittivity in ferroelectric ceramics under electric field

International Nuclear Information System (INIS)

Ducharne, B; Guyomar, D; Sebald, G

2007-01-01

The properties of ferroelectric ceramics strongly depend on the electromechanical loading and their measurement conditions. In this paper, a nonlinear phenomenological one-dimensional model based on the dry friction concept is presented to describe the hysteretic polarization behaviour. Dielectric permittivities versus dc electric field (or capacitance C versus voltage V) loops are determined for the characterization of ferroelectric material. The ε 33 coefficient is used for the ceramic characterization because it is strongly correlated with the ceramic quality. The purpose of this paper is to develop a model of reversal polarization behaviour close to physical realities, able to provide good performances on the simulation of dielectric permittivity loop ε 33 (E dc ). Simulated behaviours are finally compared with experimental results on a typically soft PZT ferroelectric ceramic

Ultra-fast microwave sintering of PZT/FCO particulate composites prepared by ultrasonic mixing; Sinterizacao ultrarrapida por micro-ondas de compositos particulados PZT/FCO preparados por mistura em ultrassom

Energy Technology Data Exchange (ETDEWEB)

Fernandez, C.P.; Zabotto, F.L.; Garcia, D.; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

2017-07-15

Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3} (PZT) and Fe{sub 2}CoO{sub 4} (FCO) powders were synthesized separately by the Pechini method and then ultrasonically mixed in molar proportions of 80/20 and 50/50 of PZT/FCO. The resulting composites were pressed and subjected to conventional and ultrafast microwave-assisted sintering. The structure and microstructure of the sintered samples were analyzed, respectively, by X-ray diffraction and scanning electron microscopy. The dielectric constant as a function of temperature, electrical resistivity and magnetoelectric coupling coefficient were measured. The results indicated that the ultrasonic mixing method applied to PZT and FCO was fast and efficient, and that sintering resulted in globally connected (0-3) particulate composites and uniform distribution of the ferromagnetic phase (FCO) grains in the ferroelectric matrix (PZT). The structural analysis indicated that microwave sintering changed the arrangement (1-3) of the material's local connectivity, which was attributed to the intensification of diffusion processes that occur in this type of sintering, particularly in nanometric systems. The high values of resistivity indicated that although both sintering methods preserved the integrity of the two phases, microwave sintering was more efficient, ensuring the magnetoelectric behavior of all the composites under study. The values of H{sub max} field were dependent on the ferrite phase concentration and sintering; 80/20 1.4 and 1.9 kOe, and 50/50 3.5 and 3.0 kOe in the samples sintered by microwave and conventionally, consistent with the literature, which confirmed the integrity of the constituent phases PZT and FCO. (author)

Electrode contacts on ferroelectric Pb(Zr x Ti1−x )O3 and SrBi2Ta2O9 thin films and their influence on fatigue properties

OpenAIRE

Lee, J. J.; Thio, C. L.; Desu, Seshu B.

1995-01-01

The degradation (fatigue) of dielectric properties of ferroelectric Pb(ZrxTi1-x)O-3 (PZT) and SrBi2Ta2O9 thin films during cycling was investigated. PZT and SrBi2Ta2O9 thin films were fabricated by metalorganic decomposition and pulsed laser deposition, respectively. Samples with electrodes of platinum (Pt) and ruthenium oxide (RuO2) were studied. The interfacial capacitance (if any) at the Pt/PZT, RuO2/PZT, and Pt/SrBi2Ta2O9 interfaces was determined from the thickness dependence of low-fiel...

Non-Volatile Ferroelectric Switching of Ferromagnetic Resonance in NiFe/PLZT Multiferroic Thin Film Heterostructures (Postprint)

Science.gov (United States)

2016-09-01

deformation potentially leads to fatigue and fracture over time. Moreover, we show that by simply applying voltage pulses, a robust, non-volatile...polarization such as PZT , BiFeO3, or doped HfO2. Our results thus provide a pathway towards ferroelectric switching of magnetism that could be useful for

The influence of the coexistence of ferroelectric and antiferroelectric states on the lead lanthanum zirconate titanate crystal structure

International Nuclear Information System (INIS)

Ishchuk, V M; Baumer, V N; Sobolev, V L

2005-01-01

We present results of detailed investigation of the crystal structure of Pb 1-3x/2 La x (Zr 1-y Ti y )O 3 solid solutions. In this letter our attention is concentrated on the series of solid solutions with x = 6% usually referred to as relaxor ferroelectrics. We have established the reasons for the non-cubic crystal structure of these solid solutions at the temperatures below T C . It is demonstrated that the peculiarities of the properties of Pb 1-3x/2 La x (Zr 1-y Ti y )O 3 depend on the position of a particular solid solution with respect to the hysteresis ferroelectric-antiferroelectric region in the 'Ti-content-temperature' phase diagram. (letter to the editor)

Optical evidences for an intermediate phase in relaxor ferroelectric Pb(In1/2Nb1/2O3-Pb(Mg1/3Nb2/3O3-PbTiO3 single crystals

Directory of Open Access Journals (Sweden)

Xiaolong Zhang

2016-02-01

Full Text Available The mechanism of low-temperature structural transformation and evolution of polar nano-structures in relaxor ferroelectric Pb(In1/2Nb1/2O3-Pb(Mg1/3Nb2/3O3-xPbTiO3 (x = 0.33, 0.35, and 0.42 single crystals have been investigated with the aid of temperature dependent low-wavenumber Raman scattering (LWRS and photoluminescence (PL spectra. The E(TO1 phonon mode reveals the characteristic relaxational polarization fluctuations associated with the reorientation of either polar nano-regions or polar nano-domains. It was found that these mechanisms are not independent and they can be ascribed to the phonon localization. In addition, a short-range monoclinic phase (Mc can be found below 250 K in the tetragonal phase region by LWRS, which is always associated with the morphotropic phase boundary (MPB and excellent electromechanical properties. It is interesting that PL spectra confirm these results. The present work indicates that external field modulation and change of composition can result in the monoclinic phase and co-existence of multi-phase.

Electric-field influence on the neutron diffuse scattering near the ferroelectric transition of Sr.sub.0.61./sub.Ba.sub.0.39./sub.Nb.sub.2./sub.O.sub.6./sub.

Czech Academy of Sciences Publication Activity Database

Ondrejkovič, Petr; Kempa, Martin; Savinov, Maxim; Bednyakov, Petr; Kulda, J.; Bourges, P.; Dec, J.; Hlinka, Jiří

2016-01-01

Roč. 89, 7-8 (2016), s. 808-815 ISSN 0141-1594 R&D Projects: GA ČR GA16-09142S Institutional support: RVO:68378271 Keywords : relaxor ferroelectrics * lead-free * strontium barium niobate * neutron scattering * dielectric spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.060, year: 2016

Relationship between ferroelectric properties and local structure of Pb{sub 1−x}Ba{sub x}Zr{sub 0.40}Ti{sub 0.60}O{sub 3} ceramic materials studied by X-ray absorption and Raman spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Mesquita, Alexandre, E-mail: mesquita@rc.unesp.br [Instituto de Geociências e Ciências Exatas, UNESP – Univ Estadual Paulista, Departamento de Física, Av. 24-a, 1515, Rio Claro, SP 13506-900 (Brazil); Institut de Chimie et des Materiaux Paris Est, CNRS and Université Paris Est Créteil, 2 Rue Henri Dunant, 94320 Thiais (France); Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense, 400, São Carlos, SP (Brazil); Michalowicz, Alain, E-mail: michalov@u-pec.fr [Institut de Chimie et des Materiaux Paris Est, CNRS and Université Paris Est Créteil, 2 Rue Henri Dunant, 94320 Thiais (France); Moscovici, Jacques, E-mail: moscovic@u-pec.fr [Institut de Chimie et des Materiaux Paris Est, CNRS and Université Paris Est Créteil, 2 Rue Henri Dunant, 94320 Thiais (France); Pizani, Paulo Sergio, E-mail: pizani@df.ufscar.br [Departamento de Física, Universidade Federal de São Carlos, Rodovia Washington Luís, s/n, São Carlos, SP, 13565-905 (Brazil); Mastelaro, Valmor Roberto, E-mail: valmor@ifsc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense, 400, São Carlos, SP (Brazil)

2016-08-15

This paper reports on the structural characterization of Pb{sub 1−x}Ba{sub x}Zr{sub 0.40}Ti{sub 0.60}O{sub 3} (PBZT) ferroelectric ceramic compositions prepared by the conventional solid state reaction method. X-ray absorption spectroscopy (XAS) and Raman spectroscopy were used in the probing of the local structure of PBZT samples that exhibit a normal or relaxor ferroelectric behavior. They showed a considerable local disorder around Zr and Pb atoms in the samples of tetragonal or cubic long-range order symmetry. The intensity of the E(TO{sub 3}) mode in the Raman spectra of PBZT relaxor samples remains constant at temperatures lower than T{sub m}, which has proven the stabilization of the correlation process between nanodomains. - Graphical abstract: X-ray absorption measurements showed considerable local disorder around Zr and Pb atoms in the samples of tetragonal or cubic long-range order symmetry. The intensity of the E(TO{sub 3}) mode in the Raman spectra of PBZT relaxor samples remains constant at temperatures lower than T{sub m}, which has proven the stabilization of the correlation process between nanodomains. Display Omitted - Highlights: • Structural characterization of Pb{sub 1−x}Ba{sub x}Zr{sub 0.40}Ti{sub 0.60}O{sub 3} (PBZT) ferroelectric ceramic. • X-ray absorption and Raman spectroscopies were used to probe the structure of PBZT. • Dissymmetry of Zr and Pb sites was observed in samples long-range cubic symmetry. • Local disorder in all PBZT samples through the observation of Raman active modes.

TEMPLATE-ASSISTED FABRICATION AND DIELECTROPHORETIC MANIPULATION OF PZT MICROTUBES

Directory of Open Access Journals (Sweden)

VLADIMÍR KOVAĽ

2012-09-01

Full Text Available Mesoscopic high aspect ratio ferroelectric tube structures of a diverse range of compositions with tailored physical properties can be used as key components in miniaturized flexible electronics, nano- and micro-electro-mechanical systems, nonvolatile FeRAM memories, and tunable photonic applications. They are usually produced through advanced “bottom-up” or “topdown” fabrication techniques. In this study, a template wetting approach is employed for fabrication of Pb(Zr0.52Ti0.48O3 (PZT microtubes. The method is based on repeated infiltration of precursor solution into macroporous silicon (Si templates at a sub-atmospheric pressure. Prior to crystallization at 750°C, free-standing tubes of a 2-μm outer diameter, extending to over 30 μm in length were released from the Si template using a selective isotropic-pulsed XeF2 reactive ion etching. To facilitate rapid electrical characterization and enable future integration process, directed positioning and aligning of the PZT tubes was performed by dielectrophoresis. The electric field-assisted technique involves an alternating electric voltage that is applied through pre-patterned microelectrodes to a colloidal suspension of PZT tubes dispersed in isopropyl alcohol. The most efficient biasing for the assembly of tubes across the electrode gap of 12 μm was a square wave signal of 5 Vrms and 10 Hz. By varying the applied frequency in between 1 and 10 Hz, an enhancement in tube alignment was obtained.

Effect of dilute magnetic ions on the optical, dielectric and ferroelectric properties of PZT at morphotopic phase boundary

Science.gov (United States)

Rao, T. Lakshmana; Pradhan, M. K.; Ramakrishna, P. V.; Dash, S.

2018-05-01

Modified-PZT ceramics with a formula Pb0.9Ni0.1[(Zr0.52Ti0.48)]1-xSnxO3 located near the morphotropic phase boundary (MPB) were prepared by conventional solid state process to investigate effects of dilute doping of Ni and Sn in different sites of PZT. The single phase structure of the series of samples has been identified by x-ray diffraction technique. The optical band gap has been obtained from the UV-Vis spectra and found to be shrinkage with doping. The detail dielectric and impedance studies are being carried out to investigate the conduction mechanism of the samples. A significant enhancement in the electric polarization is observed for the maximum Sn doping in a modified PZT.

Electric field-controlled magnetization in exchange biased IrMn/Co/PZT multilayers

International Nuclear Information System (INIS)

Huong Giang, D T; Duc, N H; Agnus, G; Maroutian, T; Lecoeur, P

2013-01-01

Electric-field modulating exchange bias and near 180° deterministic magnetization switching at room temperature are demonstrated in simple antiferromagnetic/ferromagnetic/ferroelectric (AFM/FM/FE) exchange-coupled multiferroic multilayers of IrMn/Co/PZT. A rather large exchange bias field shift up to ΔH ex /H ex = 500% was obtained. This change governs mainly the electric-field strength rather than the applied current. It is explained as being realized through the competition between the electric-field induced uniaxial and unidirectional anisotropies. These results show good prospects for low-power spintronic devices. (paper)

Effects of electrodes on the properties of sol-gel PZT based capacitors in FeRAM

Science.gov (United States)

Zhang, Ming-Ming; Jia, Ze; Ren, Tian-Ling

2009-05-01

The effects of electrodes on the properties of capacitors applied in ferroelectric random access memories (FeRAM) are investigated in this work. Pt and Ir are used as bottom and top electrodes (BE and TE), respectively, in sol-gel Pb(Zr xTi 1-x)O 3 (PZT) based capacitors. Bottom electrodes are found to play a dominant role in the properties of PZT films and capacitors. Capacitors using Pt as bottom electrode have larger remnant polarization (2Pr) than those using Ir which may result from the different orientations of PZT films. The higher Schottky barrier, more dense film and smaller roughness are believed to be the reasons for the better leakage performance of capacitors using Pt as bottom electrodes. Different vacancies types and interface conditions are believed to be the main reasons for the better fatigue (less than 10% initial 2Pr loss after 10 11 fatigue cycles) and better imprint properties of TE/PZT/Ir capacitors. Top electrodes are found to have smaller impact on the properties of capacitors compared with bottom electrodes. A decrease in 2Pr is found when Ir is used as top electrode instead of Pt for PZT/Pt, which is believed to be caused by the stress resulting from lattice mismatch. The different thermal processes that top and bottom electrodes suffered are believed to be the reason for the different impacts they have on capacitors.

The Effect of Shock Stress and Field Strength on Shock-Induced Depoling of Normally Poled PZT 95/5

International Nuclear Information System (INIS)

CHHABILDAS, LALIT C.; FURNISH, MICHAEL D.; MONTGOMERY, STEPHEN T.; SETCHELL, ROBERT E.

1999-01-01

Shock-induced depoling of the ferroelectric ceramic PZT 95/5 is utilized in a number of pulsed power devices. Several experimental and theoretical efforts are in progress in order to improve numerical simulations of these devices. In this study we have examined the shock response of normally poled PZT 95/5 under uniaxial strain conditions. On each experiment the current produced in an external circuit and the transmitted waveform at a window interface were recorded. The peak electrical field generated within the PZT sample was varied through the choice of external circuit resistance. Shock pressures were varied from 0.6 to 4.6 GPa, and peak electrical fields were varied from 0.2 to 37 kV/cm. For a 2.4 GPa shock and the lowest peak field, a nearly constant current governed simply by the remanent polarization and the shock velocity was recorded. Both decreasing the shock pressure and increasing the electrical field resulted in reduced current generation, indicating a retardation of the depoling kinetics

Fabrication and characterization of metal-ferroelectric (PbZr0.6Ti0.4O3)-insulator (La2O3)-semiconductor capacitors for nonvolatile memory applications

Science.gov (United States)

Juan, Trevor Pi-Chun; Lin, Cheng-Li; Shih, Wen-Chieh; Yang, Chin-Chieh; Lee, Joseph Ya-Min; Shye, Der-Chi; Lu, Jong-Hong

2009-03-01

Metal-ferroelectric-insulator-semiconductor thin-film capacitors with Pb(Zr0.6,Ti0.4)O3 (PZT) ferroelectric layer and high-k lanthanum oxide (La2O3) insulator layer were fabricated. The outdiffusion of atoms between La2O3 and silicon was examined by the secondary-ion-mass spectroscopy. The size of memory window as a function of PZT annealing temperature was discussed. The maximum memory window saturated to 0.7 V, which is close to the theoretical memory window ΔW ≈2dfEc≈0.8 V with higher annealing temperatures above 700 °C. The memory window starts to decrease due to charge injection when the sweep voltage is higher than 5 V at 600 °C-annealed samples. The C-V flatband voltage shift (ΔVFB) as a function of charge injection was characterized in this work. An energy band diagram of the Al/PZT//La2O3/p-Si system was proposed to explain the memory window and the flatband voltage shift.

Mems-based pzt/pzt bimorph thick film vibration energy harvester

DEFF Research Database (Denmark)

Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

2011-01-01

We describe fabrication and characterization of a significantly improved version of a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical...... support materials since only PZT is strained, and thus it has a potential for significantly higher output power. An improved process scheme for the energy harvester resulted in a robust fabrication process with a record high fabrication yield of 98.6%. Moreover, the robust fabrication process allowed...... a high pressure treatment of the screen printed PZT thick films prior to sintering, improving the PZT thick film performance and harvester power output reaches 37.1 μW at 1 g....

Ab-initio and atomistic study of the ferroelectric properties of Cu doped potassium niobate

Energy Technology Data Exchange (ETDEWEB)

Koerbel, Sabine; Elsaesser, Christian [Fraunhofer-Institut fuer Werkstoffmechanik IWM, Woehlerstrasse 11, 79108 Freiburg (Germany)

2011-07-01

KNbO{sub 3} is one end member of the solid solution (K,Na)NbO{sub 3} (KNN), which has promising ferroelectric properties to become a future lead-free substitute for lead zirconate titanate Pb(Zr,Ti)O{sub 3} (PZT) in piezoelectric actors and sensors. Both KNN and PZT exhibit a phase transition with composition and a morphotropic phase boundary, at which enhanced piezoelectric coefficients are obtained. The material properties of PZT and KNN are commonly optimized by doping. E.g., CuO can be added when fabricating KNN as a sintering aid. Ab initio density functional theory and atomistic simulation using a classical shell model potential have been combined to investigate low Cu concentrations in the KNbO{sub 3}-CuNbO{sub 3} system. The atomistic model predicts a morphotropic phase boundary at a few percent Cu, analogous to the one found in the LiNbO{sub 3}-KNbO{sub 3} system.

Local strain heterogeneity and elastic relaxation dynamics associated with relaxor behavior in the single-crystal perovskite Pb (I n1 /2N b1 /2 ) O3-PbZr O3-Pb (M g1 /3N b2 /3 ) O3-PbTi O3

Science.gov (United States)

He, Wenhui; Carpenter, Michael A.; Lampronti, Giulio I.; Li, Qiang; Yan, Qingfeng

2017-10-01

Recently, Pb (In1/2Nb1/2 ) O3-PbZr O3-Pb (Mg1/3Nb2/3 ) O3-PbTiO3 (PIN-PZ-PMN-PT) relaxor single crystals were demonstrated to possess improved temperature-insensitive properties, which would be desirable for high-power device applications. The relaxor character associated with the development of local random fields (RFs) and a high rhombohedral-tetragonal (R-T) ferroelectric transition temperature (TR-T>120°C) would be critical for the excellent properties. A significant effect of the chemical substitution of In3+ and Zr4+ in PMN-PT to give PIN-PZ-PMN-PT is the development of local strain heterogeneity, which acts to suppress the development of macroscopic shear strains without suppressing the development of local ferroelectric moments and contribute substantially to the RFs in PIN-PZ-PMN-PT. Measurements of elastic and anelastic properties by resonant ultrasound spectroscopy show that PIN-PZ-PMN-PT crystal has a quite different form of elastic anomaly due to Vogel-Fulcher freezing, rather than the a discrete cubic-T transition seen in a single crystal of PMN-28PT. It also has high acoustic loss of the relaxor phase down to TR-T. Analysis of piezoresponse force microscopy phase images at different temperatures provides a quantitative insight into the extent to which the RFs influence the microdomain structure and the short-range order correlation length 〈ξ 〉 .

Enhanced Piezoelectric Response in HybridPerovskite via Interfacing with Ferroelectric Pb(Zr,Ti)O3

Science.gov (United States)

Song, Jingfeng; Xiao, Zhiyong; Chen, Bo; Prockish, Spencer; Chen, Xuegang; Wang, Dong; Huang, Jinsong; Hong, Xia

In this work, we have carried out a comprehensive study of the piezoelectric properties of polycrystalline hybrid perovskite CH3NH3PbI3 (MAPbI3) thin films on two types of substrates. We spin coated 20-100 nm MAPbI3 thin films on gold and ferroelectric Pb(Zr,Ti)O3 (PZT), and characterized their piezoelectric coefficient d33 using piezoresponse force microscopy (PFM). The MAPbI3 thin films on gold showed a d33 of 0.4 pm/V. The epitaxial PZT films ( 50 nm) were deposited on (La,Sr)MnO3/SrTiO3 substrates, with polarization uniformly oriented in the up direction. For MAPbI3 films on PZT, there are regions showing clear PFM phase response, suggesting that MAPbI3 is polar with out-of-plane polarization. The PFM amplitude image of MAPbI3 indicated the existence of both constructive and destructive piezoresponse with that of PZT. The extracted d33is4 pm/V, 10-fold higher than that on gold. The enhanced piezoresponse is attributed to the dipole-dipole interaction between MAPbI3 and PZT. Our study points to an effective route to engineer the piezoelectric properties MAPbI3 for applications such as mechanical actuators and energy harvesting.

Control of analog ferroelectric states by small dc-bias in conjunction with fluctuating waveforms

International Nuclear Information System (INIS)

Ricinschi, Dan; Okuyama, Masanori

2009-01-01

In this paper we demonstrate several possibilities to create and control partially switched analog states of ferroelectric materials, from measurements on PZT capacitors. By employing various types of fluctuating waveforms and controlling the domain dynamics with dc bias of small intensities, we have shown that it is possible to generate sequences of analog ferroelectric states that may appear identical from macroscopic measurements, yet they are unique at the local level. The experimental results have been analyzed theoretically by a simple microscopic model of switching. According to the model simulations, each analog state can be associated with a domain structure that captures subtle variations of the previously applied electric field as well as structural information about the inhomogeneities at the local level. The generation and control of such partially switched analog states may be important for new applications of ferroelectric materials to multi-value memories or in the field of artificial intelligence.

Sputtered highly oriented PZT thin films for MEMS applications

Science.gov (United States)

Kalpat, Sriram S.

Recently there has been an explosion of interest in the field of micro-electro-mechanical systems (MEMS). MEMS device technology has become critical in the growth of various fields like medical, automotive, chemical, and space technology. Among the many applications of ferroelectric thin films in MEMS devices, microfluidics is a field that has drawn considerable amount of research from bio-technology industries as well as chemical and semiconductor manufacturing industries. PZT thin films have been identified as best suited materials for micro-actuators and micro-sensors used in MEMS devices. A promising application for piezoelectric thin film based MEMS devices is disposable drug delivery systems that are capable of sensing biological parameters, mixing and delivering minute and precise amounts of drugs using micro-pumps or micro mixers. These devices call for low driving voltages, so that they can be battery operated. Improving the performance of the actuator material is critical in achieving battery operated disposal drug delivery systems. The device geometry and power consumption in MEMS devices largely depends upon the piezoelectric constant of the films, since they are most commonly used to convert electrical energy into a mechanical response of a membrane or cantilever and vice versa. Phenomenological calculation on the crystal orientation dependence of piezoelectric coefficients for PZT single crystal have reported a significant enhancement of the piezoelectric d33 constant by more than 3 times along [001] in the rhombohedral phase as compared to the conventionally used orientation PZT(111) since [111] is the along the spontaneous polarization direction. This could mean considerable improvement in the MEMS device performance and help drive the operating voltages lower. The motivation of this study is to investigate the crystal orientation dependence of both dielectric and piezoelectric coefficients of PZT thin films in order to select the appropriate

A composite approach boosts transduction coefficients of piezoceramics for energy harvesting

Science.gov (United States)

Yu, Xiaole; Hou, Yudong; Zheng, Mupeng; Zhao, Haiyan; Zhu, Mankang

2018-03-01

Piezoelectric energy harvesting is a hotspot in the field of new energy, the core goal of which is to prepare piezoceramics with a high transduction coefficient (d33×g33). The traditional solid-solution design strategy usually causes the same variation trend of d33 and ɛr, resulting in a low d33×g33 value. In this work, a composite design strategy was proposed that uses PZN-PZT/ZnAl2O4 as an example. By introducing ZnAl2O4, which is nonferroelectric with low ɛr, to the PZN-PZT piezoelectric matrix, ɛr decreased rapidly while d33 remained relatively stable. This behavior was ascribed to the increase of Q33 caused by an interfacial effect facilitating the formation of micro-domain structure.

Electric and magnetic properties of a CoFe2O4/PZT bilayer grown on (100)SrTiO3 by using PLD

International Nuclear Information System (INIS)

Zhang, X. D.; Dho, J. H.

2010-01-01

We have investigated the electric and the magnetic properties of a ferrimagnetic and ferroelectric bilayer CoFe 2 O 4 (CFO)/PbZr 0.2 Ti 0.8 O 3 (PZT) grown on a (100)SrTiO 3 (STO) substrate by using pulsed laser deposition. PZT (100 nm) and CFO (70 nm) layers were sequentially deposited on the (100)STO substrate with a bottom electrode LaNiO 3 (50 nm) layer at 600 - 650 .deg. C. X-ray diffraction for the PZT layer exhibited both (200) and (002) peaks, which are due to the c- and the a-domains, and a decrease of tetragonality after CFO deposition. The electric properties of the CFO/PZT bilayer were characterized by using P-V loop, C-f, and C-V measurements. The remnant polarization and coercivity were slightly decreased after the top-layer CFO deposition while fatigue behavior was distinctively improved. The M-H loop measurement confirmed that the CFO layer possessed a typical ferrimagnetic property at room temperature.

Physical properties of inorganic PMW-PNN-PZT ceramics

Science.gov (United States)

Sin, Sang-Hoon; Yoo, Ju-hyun; Kim, Yong-Jin; Baek, Sam-ki; Ha, Jun-Soo; No, Chung-Han; Song, Hyun-Seon; Shin, Dong-Chan

2015-07-01

In this work, inorganic Pb(Mg1/2W1/2)0.03(Ni1/3Nb2/3)x(Zr0.5Ti0.5)0.97-xO3 (x = 0.02 ∼ 0.12) composition ceramics were fabricated by the conventional solid state reaction method. And then their micro structure and ferroelectric properties were investigated according to the amount of PNN substitution. Small amounts of Li2CO3 and CaCO3 were used in order to decrease the sintering temperature of the ceramics. The 0.10 mol PNN-substituted PMW-PNN- PZT ceramics sintered at 920°C showed the excellent physical properties of piezoelectric constant (d33), electromechanical coupling factor (kp), mechanical quality coefficient (Qm), and dielectric constant of 566 pC/N, 0.61, 73, and 2183, respectively.

Modified PZT ceramics as a material that can be used in micromechatronics

Science.gov (United States)

Zachariasz, Radosław; Bochenek, Dariusz

2015-11-01

Results on investigations of the PZT type ceramics with the following chemical composition: Pb0.94Sr0.06(Zr0.50 Ti0.50)0.99 Cr0.01O3 (PSZTC) which belongs to a group of multicomponent ceramic materials obtained on basis of the PZT type solid solution, are presented in this work. Ceramics PSZTC was obtained by a free sintering method under the following conditions: Tsint = 1250 °C and tsint = 2 h. Ceramic compacts of specimens for the sintering process were made from the ceramic mass consisting of a mixture of the synthesized PSZTC powder and 3% polyvinyl alcohol while wet. The PSZTC ceramic specimens were subjected to poling by two methods: low temperature and high temperature. On the basis of the examinations made it has been found that the ceramics obtained belongs to ferroelectric-hard materials and that is why it may be used to build resonators, filters and ultrasonic transducers. Contribution to the Topical Issue "Materials for Dielectric Applications" edited by Maciej Jaroszewski and Sabu Thomas.

First-principles studies of the local structure and relaxor behavior of Pb(Mg 1 /3Nb2 /3) O3-PbTiO3 -derived ferroelectric perovskite solid solutions

Science.gov (United States)

Tan, Hengxin; Takenaka, Hiroyuki; Xu, Changsong; Duan, Wenhui; Grinberg, Ilya; Rappe, Andrew M.

2018-05-01

We have investigated the effect of transition-metal dopants on the local structure of the prototypical 0.75 Pb (Mg1 /3Nb2 /3) O3-0.25 PbTiO3 relaxor ferroelectric. We find that these dopants give rise to very different local structure and other physical properties. For example, when Mg is partially substituted by Cu or Zn, the displacement of Cu or Zn is much larger than that of Mg and is even comparable to that of Nb. The polarization of these systems is also increased, especially for the Cu-doped solution, due to the large polarizability of Cu and Zn. As a result, the predicted maximum dielectric constant temperatures Tm are increased. On the other hand, the replacement of a Ti atom with a Mo or Tc atom dramatically decreases the displacements of the cations and the polarization, and thus, the Tm values are also substantially decreased. The higher Tm cannot be explained by the conventional argument based on the ionic radii of the cations. Furthermore, we find that Cu, Mo, or Tc doping increases the cation displacement disorder. The effect of the dopants on the temperature dispersion Δ Tm , which is the change in Tm for different frequencies, is also discussed. Our findings lay the foundation for further investigations of unexplored dopants.

Effects of criticality and disorder on piezoelectric properties of ferroelectrics

International Nuclear Information System (INIS)

Porta, Marcel; Lookman, Turab; Saxena, Avadh

2010-01-01

The piezoelectric response of BaTiO 3 is studied in the vicinity of the cubic to tetragonal phase transition, as a function of temperature and the applied electric field in the polar direction. We also investigate the influence of disorder. In the clean limit we obtain the divergence of the piezoelectric tensor at the critical point. The effect of a small amount of disorder is to translate the critical point in the temperature-electric field phase diagram. For large values of the disorder, the paraelectric to ferroelectric phase transition becomes diffuse but a maximum of the piezoelectric tensor is still obtained even though the divergence of the piezoelectric response is lost. These results are in agreement with experimental observations for the relaxor ferroelectric Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 . We use a Ginzburg-Landau model which explicitly includes the coupling of the polarization to the strain, the electrostatic interaction between polarizations, and a quenched random compressional stress field generated by point defects. The strain field and its associated elastic energy are written in terms of the stress field and the electric polarization by energy minimization subject to elastic compatibility.

Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting

DEFF Research Database (Denmark)

Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

2012-01-01

We present a microelectromechanical system (MEMS) based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. Most piezoelectric energy harvesting devices use a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric...... elements. We show experimental results from two types PZT/PZT harvesting devices, one where the Pb(ZrxTi1−x)O3 (PZT) thick films are high pressure treated during the fabrication and the other where the treatment is omitted. We find that with the high pressure treatment prior to PZT sintering, the films...

Characteristics of ferroelectric Pb(Zr,Ti)O3 thin films having Pt/PtOx electrode barriers

International Nuclear Information System (INIS)

Lee, Kwangbae; Rhee, Byung Roh; Lee, Chanku

2001-01-01

We have investigated the feasibility of the Pt/PtO x multilayer as an electrode barrier for Pb(Zr,Ti)O 3 (PZT)-based ferroelectric random access memories. PtO x and Pt layers were prepared on polycrystalline-Si/SiO 2 /Si substrates by means of the sputtering method in Ar and O 2 ambience, and the Pb(Zr 0.53 Ti 0.47 )O 3 layer was prepared by the sol-gel method. A capacitor consisting of Pt/PtO x /PZT/PtO x /Pt/PtO x /poly-Si had a remanent polarization of 18 μC/cm 2 and a low coercive field of 32 kV/cm. The polarization fatigue behavior of test capacitors was improved as compared with that of Pt/PZT/Pt, which showed negligible fatigue loss of 15% after 10 11 switching repetitions with a frequency of 1 MHz. Copyright 2001 American Institute of Physics

History and the future perspective of the ferroelectric memory; Kyoyudentai memory no rekishiteki haikei to tenbo

Energy Technology Data Exchange (ETDEWEB)

Tarui, Y [Waseda University, Tokyo (Japan)

1998-10-01

Development work is in progress on ferroelectric memory. The memory is a most suitable non-volatile memory which can be incorporated into IC cards, with its higher speed, lower voltage operation, smaller power consumption, and greater number of rewriting times than EEPROM, DRAM and SRAM. Taking as an opportunity the announcement on an experiment as performed by the authors to control semiconductor charge by using electric depolarization of ferroelectric materials, reports have been made one after another on experiments on thin metal films on TGS or BaTiO3, and experiments on semiconductor films formed on ferroelectric crystals or ceramics substrates by using vacuum deposition. In order to solve problems in ferroelectric materials, thin films of PZT and PLZT have emerged, whose good hysteresis characteristics have also been reported. Thereafter, an announcement was made on a material with bismuth layer like perovskite structure. The material is characterized with having very little film fatigue degradation after rewriting of about 10 {sup 12} times. In scaling a ferroelectric memory, if voltage is decreased in proportion with the size, the operation can be reduced proportionately according to the voltage reduction. This paper introduces a method to constitute a ferroelectric memory. 22 refs., 11 figs., 2 tabs.

Novel ferroelectric capacitor for non-volatile memory storage and biomedical tactile sensor applications

International Nuclear Information System (INIS)

Liu, Shi Yang; Chua, Lynn; Tan, Kian Chuan; Valavan, S.E.

2010-01-01

We report on novel ferroelectric thin film compositions for use in non-volatile memory storage and biomedical tactile sensor applications. The lead zirconate titanate (PZT) composition was modified by lanthanum (La 3+ ) (PLZT) and vanadium (V 5+ ) (PZTV, PLZTV) doping. Hybrid films with PZTV and PLZTV as top layers are also made using seed layers of differing compositions using sol-gel and spin coating methods. La 3+ doping decreased the coercive field, polarization and leakage current, while increasing the relative permittivity. V 5+ doping, while having similar effects, results in an enhanced polarization, with comparable dielectric loss characteristics. Complex doping of both La 3+ and V 5+ in PLZTV, while reducing the polarization relative to PZTV, significantly decreases the coercive field. Hybrid films have a greater uniformity of grain formation than non-hybrid films, thus decreasing the coercive field, leakage current and polarization fatigue while increasing the relative permittivity. Analysis using X-ray diffraction (XRD) verified the retention of the PZT perovskite structure in the novel films. PLZT/PZTV has been identified as an optimal ferroelectric film composition due to its desirable ferroelectric, fatigue and dielectric properties, including the highest observed remnant polarization (P r ) of ∼ 25 μC/cm 2 , saturation polarization (P sat ) of ∼ 58 μC/cm 2 and low coercive field (E c ) of ∼ 60 kV/cm at an applied field of ∼ 1000 kV/cm, as well as a low leakage current density of ∼ 10 -5 A/cm 2 at 500 kV/cm and fatigue resistance of up to ∼ 10 10 switching cycles.

Electric Field-Induced Large Strain in Ni/Sb-co Doped (Bi0.5Na0.5) TiO3-Based Lead-Free Ceramics

Science.gov (United States)

Li, Liangliang; Hao, Jigong; Xu, Zhijun; Li, Wei; Chu, Ruiqing

2018-02-01

Lead-free piezoelectric ceramics (Bi0.5Na0.5)0.935Ba0.065Ti1- x (Ni0.5Sb0.5) x O3 (BNBT6.5- xNS) have been fabricated using conventional solid sintering technique. The effect of (Ni, Sb) doping on the phase structure and electrical properties of BNBT6.5 ceramics were systematically investigated. Results show that the addition of (Ni, Sb) destroyed the ferroelectric long-range order of BNBT6.5 and shifted the ferroelectric-relaxor transition temperature ( T F-R) down to room temperature. Thus, this process induced an ergodic relaxor phase at zero field in samples with x = 0.005. Under the electric field, the ergodic relaxor phase could reversibly transform to ferroelectric phase, which promotes the strain response with peak value of 0.38% (at 80 kV/cm, corresponding to d 33 * = 479 pm/V) at x = 0.005. Temperature-dependent measurements of both polarization and strain confirmed that the large strain originated from a reversible field-induced ergodic relaxor to ferroelectric phase transformation. The proposed material exhibits potential for nonlinear actuators.

Sol-gel reaction stability studied: Influence in the formation temperature and properties of ferroelectric thin films

International Nuclear Information System (INIS)

Perez, J.; Vilarinho, P.M.; Kholkin, A.L.; Almeida, A.

2009-01-01

Lead zirconium titanate (PZT) sol-gel solutions were prepared based on distilled lead acetate precursor solutions. A detailed analysis of the distillation effect on the lead precursor and the final PZT solution were carried out by Infrared and Raman techniques. It was found that the increase in the number of distillation steps experienced by the lead precursor solutions removes the constitutional water and increases the lead acetate-2-methoxyethanol interconnectivity; thus improving stability and avoiding the aging effect of the resulting PZT solutions. The thermal decomposition process of the PZT solutions was analyzed based on the thermogravimetric (TG) and differential thermogravimetric analysis (DTA) measurements. It was found that as the number of distillation steps in the lead precursor solutions increases, the decomposition rate increases and the formation temperature of pure perovskite PZT films decreases. X-ray diffraction (XRD) technique was used to study the film phase formation. A pure perovskite phase at 500 deg. C was found by the XRD analysis after the second distillation step. Scanning electron microscope technique was used to carry out the microstructural analysis. Dense microstructure was found in all analyzed films and an incipient columnar grain growth was revealed in PZT films prepared based on lead precursor solution with more than three distillation steps. The dependence of the dielectric, ferroelectric and piezoelectric properties on the number of distillation steps was revealed and a correlation between the distillation process, film microstructure properties and electrical performance was established

Thermal properties of PZT95/5(1.8Nb) and PSZT ceramics

International Nuclear Information System (INIS)

DiAntonio, Christopher Brian; Rae, David F.; Corelis, David J.; Yang, Pin; Burns, George Robert

2006-01-01

Thermal properties of niobium-modified PZT95/5(1.8Nb) and PSZT ceramics used for the ferroelectric power supply have been studied from -100 C to 375 C. Within this temperature range, these materials exhibit ferroelectric-ferroelectric and ferroelectric-paraelectric phase transformations. The thermal expansion coefficient, heat capacity, and thermal diffusivity of different phases were measured. Thermal conductivity and Grueneisen constant were calculated at several selected temperatures between -60 C and 100 C. Results show that thermal properties of these two solid solutions are very similar. Phase transformations in these ceramics possess first order transformation characteristics including thermal hysteresis, transformational strain, and enthalpy change. The thermal strain in the high temperature rhombohedral phase region is extremely anisotropic. The heat capacity for both materials approaches to 3R (or 5.938 cal/(g-mole*K)) near room temperature. The thermal diffusivity and the thermal conductivity are quite low in comparison to common oxide ceramics, and are comparable to amorphous silicate glass. Furthermore, the thermal conductivity of these materials between -60 C and 100 C becomes independent of temperature and is sensitive to the structural phase transformation. These phenomena suggest that the phonon mean free path governing the thermal conductivity in this temperature range is limited by the lattice dimensions, which is in good agreement with calculated values. Effects of small compositional changes and density/porosity variations in these ceramics on their thermal properties are also discussed. The implications of these transformation characteristics and unusual thermal properties are important in guiding processing and handling procedures for these materials

Electromechanical Anisotropy at the Ferroelectric to Relaxor Transition of (Bi0.5Na0.50.94Ba0.06TiO3 Ceramics from the Thermal Evolution of Resonance Curves

Directory of Open Access Journals (Sweden)

Nicolás Pérez

2018-01-01

Full Text Available (Bi0.5Na0.50.94Ba0.06TiO3 dense ceramics were obtained from autocombustion sol-gel synthesized nanopowders and sintered at 1050 °C for 1–2 h for the study of the electromechanical anisotropy. Measurement of the complex impedance spectrum was carried out on thin ceramic disks, thickness-poled, as a function of the temperature from 16 °C up to the vanishing of the electromechanical resonances at the ferroelectric to relaxor transition near 100 °C. The spectrum comprises the fundamental radial extensional mode and three overtones of this, together with the fundamental thickness extensional mode, coupled with other complex modes. Thermal evolution of the spectrum shows anisotropic behavior. Piezoelectric, elastic, and dielectric material coefficients, including all losses, were determined from iterative analysis of the complex impedance curves at the planar, thickness, and shear virtually monomodal resonances of disks and shear plates, thickness-poled. d33 was measured quasi-statically at 100 Hz. This set of data was used as the initial condition for the optimization of the numerical calculation by finite elements of the full spectrum of the disk, from 100 kHz to 1.9 MHz, to determine the thermal evolution of the material coefficients. An appropriate measurement strategy to study electromechanical anisotropy of piezoelectric ceramics has been developed.

Effects on Ferroelectric Thin-Film Stacks and Devices for Piezoelectric MEMS Applications at Varied Total Ionizing Dose (TID)

Science.gov (United States)

2017-03-01

non -linearly mobile internal interfaces, e.g. domain walls and eventual phase boundaries. Radiation exposure is expected...zirconate titanate; PZT; actuator; radiation ; gamma; total ionization dose; TID; top electrode; Pt; IrO2; polarization; PE; hysteresis; permittivity...Hayashigawa, et. al., “A 2 Mbit Radiation Hardened Stackable Ferroelectric Memory” Non - Volatile Memory Technology Symposium, NVMTS 07, Nov 10-13, 2007 Albuquerque, NM, USA

Predicting the effective response of bulk polycrystalline ferroelectric ceramics via improved spectral phase field methods

Science.gov (United States)

Vidyasagar, A.; Tan, W. L.; Kochmann, D. M.

2017-09-01

Understanding the electromechanical response of bulk polycrystalline ferroelectric ceramics requires scale-bridging approaches. Recent advances in fast numerical methods to compute the homogenized mechanical response of materials with heterogeneous microstructure have enabled the solution of hitherto intractable systems. In particular, the use of a Fourier-based spectral method as opposed to the traditional finite element method has gained significant interest in the homogenization of periodic microstructures. Here, we solve the periodic, electro-mechanically-coupled boundary value problem at the mesoscale of polycrystalline ferroelectrics in order to extract the effective response of barium titanate (BaTiO3) and lead zirconate titanate (PZT) under applied electric fields. Results include the effective electric hysteresis and the associated butterfly curve of strain vs. electric field for mean stress-free electric loading. Computational predictions of the 3D polycrystalline response show convincing agreement with our experimental electric cycling and strain hysteresis data for PZT-5A. In addition to microstructure-dependent effective physics, we also show how finite-difference-based approximations in the spectral solution scheme significantly reduce instability and ringing phenomena associated with spectral techniques and lead to spatial convergence with h-refinement, which have been major challenges when modeling high-contrast systems such as polycrystals.

Effect of atmosphere on the formation of perovskite phase in 0.90Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-0.10PbTiO{sub 3} (PZN-10PT) powders

Energy Technology Data Exchange (ETDEWEB)

Raigoza, C.F.V., E-mail: claudiafercha@gmail.com [Universidad del Cauca, Dpto. de Física, Grupo de Ciencia y Tecnología de Materiales Cerámicos, Popayán (Colombia); Kiminami, R.H.G.A. [Federal University of São Carlos, Department of Materials Engineering, São Carlos, SP, 13565-905 (Brazil); Eiras, J.A.; Garcia, D. [Federal University of São Carlos, Department of Physics, São Carlos, SP, 13565-905 (Brazil)

2017-04-01

Lead zinc niobate (PZN) and lead titanate (PT) solid solutions close to the morphotropic phase boundary (MPB) exhibit unusually large dielectric and piezoelectric constants. PZN-PT ceramics with a composition close to the MPB processed by the conventional route yield ceramics with a pyrochlore structure. In the last few decades, attempts to synthesize PZN-PT powders with perovskite structure via traditional ceramic methods and novel chemical processing routes have failed. In the present research, an analysis was made of the effect of the calcination atmosphere on the formation of perovskite phase in PZN-10PT powders. To this end, thermal analyses were carried out in four different atmospheres: oxygen, air, argon and nitrogen. The powders were calcined at the temperatures at which the DTA curves presented peaks, and the resulting phases were identified by X-ray diffraction. - Highlights: • PZN-PT ceramics powders. • Air, oxygen, argon and nitrogen as synthesis atmospheres. • Zinc as essential element in the formation and stabilization of the perovskite phase. • Nitrogen as inhibitor of the decomposition the zinc oxide.

Lattice dynamics and central-mode phenomena in the dielectric response of ferroelectrics and related materials

Czech Academy of Sciences Publication Activity Database

Buixaderas, Elena; Kamba, Stanislav; Petzelt, Jan

2004-01-01

Roč. 308, - (2004), s. 131-192 ISSN 0015-0193 R&D Projects: GA ČR GA202/01/0612; GA AV ČR IAA1010213; GA MŠk OC 525.20 Institutional research plan: CEZ:AV0Z1010914 Keywords : phonons in crystal lattice * commensurate-incommensurate transitions * dielectric properties of solids and liquids * ferroelectricity and antiferroelectricity * niobates * tantantalates * PZT ceramics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.517, year: 2004

Study of the structure, dielectric and ferroelectric behavior of BaBi4+δTi4O15 ceramics

Science.gov (United States)

Khokhar, Anita; Goyal, Parveen K.; Thakur, O. P.; Sreenivas, K.

2016-05-01

The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi4+δTi4O15 (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (Tm) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (Pr ~ 12.5 µC/cm2), low coercive fields (Ec ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d33 ~ 29 pC/N) is achieved in poled BaBi4Ti4O15 ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi4Ti4O15 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

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.

Oxygen tracer studies of ferroelectric fatigue in Pb(Zr,Ti)O3 thin films

International Nuclear Information System (INIS)

Schloss, Lawrence F.; McIntyre, Paul C.; Hendrix, Bryan C.; Bilodeau, Steven M.; Roeder, Jeffrey F.; Gilbert, Stephen R.

2002-01-01

Long-range oxygen motion has been observed in Pt/Pb(Zr,Ti)O 3 /Ir thin-film structures after electrical fatigue cycling at room temperature. Through an exchange anneal, isotopic 18 O was incorporated as a tracer into bare Pb(Zr,Ti)O 3 (PZT) films, allowing secondary ion mass spectrometry measurements of the tracer profile evolution as a function of the number of polarization reversals. Observation of 18 O tracer redistribution during voltage cycling, which is presumably mediated by oxygen vacancy motion, was found to be strongly dependent upon the thermal history of the film. However, there was no strong correlation between the extent of 18 O tracer redistribution and the extent of polarization suppression induced by voltage cycling. Our results suggest that oxygen vacancy motion plays, at most, a secondary role in ferroelectric fatigue of PZT thin films

Photoinduced effects of ferroelectric domains in PbZr1-xTixO3 thin films as obtained by using piezoresponse force microscopy

International Nuclear Information System (INIS)

Jang, Y. H.; Kim, C. H.; Hwang, H. J.; Cho, J. H.; Moon, H. B.; Bhang, S. H.

2011-01-01

Piezoresponse force microscopy (PFM) has been used to investigate the photoinduced effect of ferroelectric domains in PbZr 1-x Ti x O 3 (PZT) thin films. In order to perform nondestructive visualization of the high-resolution domain structure, we optimized the imaging condition, such as applying a lower voltage than 1.0 Vpp (peak-to-peak voltage). In this study, domain changes were measured before and after illumination on the surface of PZT films by using an UV light emitting diode (LED) source (λ = 310 nm) with a focusing lens to investigate the influence of the photoinduced carriers on the ferroelectric polarization. In addition, to investigate the photoinduced effects on the domain distribution, we performed histogram of positive and negative domains before and after UV-light illumination. The illumination with UV light resulted in an increase of the positive domain of the out-of-plane mode. Also, a change in the out-of-plane domain distribution was observed before and after UV illumination. The relaxation of photoinduced changes was monitored by repeated scans within a time range of 20 ∼ 60 minutes.

Structural and ferroelectric properties of Sr1−xBaxBi2Nb2O9 thin films obtained by dip-coating

Directory of Open Access Journals (Sweden)

Y. González-Abreu

2017-10-01

Full Text Available The paper presents the structural and ferroelectric results for Sr1−xBaxBi2Nb2O9(x=0.30; 0.85 thin films, which were obtained by using dip-coating. The solutions containing the desirable ions were prepared from the powders of the previous studied ceramic samples. The films were deposited at room temperature on Fluorine-doped Tin Oxide (FTO substrates and submitted to a heat treatment for crystallization. The films were characterized by using scanning microscopy electronic, energy dispersive spectroscopy and ellipsometry. Hysteresis ferroelectric loops were obtained, at room temperature, by using a Sawyer-Tower circuit at several frequencies. A well-defined grain structure was observed for both compositions. The energy dispersive spectroscopy (EDS measurements revealed the presence of the corresponding elements from the chemical composition of the ceramic systems. The band-gap energy was around 3.3eV for both samples. Typical hysteresis loops for normal and relaxor ferroelectrics were obtained for x=0.30 and 0.85, respectively.

Kramers-Kronig method for determination of optical properties of PZT nanotubes fabricated by sol-gel method and porous anodic alumina with high aspect ratio

Science.gov (United States)

Pakizeh, Esmaeil; Moradi, Mahmood

2018-03-01

Ferroelectric Pb(ZrTi)O3 (PZT) nanotubes were prepared by sol-gel method and porous anodic alumina (PAA) membrane using spin-coating technique. This method is based on filling-pyrolysis-filling process and the use of one-stage alumina membranes. One of the advantages of this method is its rapidity, which takes only 1 h time before the calcination step. The effect of repeated pores filling was investigated to get the required size of nanotubes. The field emission scanning electron microscope (FE-SEM) images were shown that the PZT nanotubes have inner diameters in the range of 65-90 nm and length of about 50-60 μm. This means that the samples have a significant aspect ratio (700-800). Also the FE-SEM image confirmed that the highly ordered, hexagonally distributed PAA membranes with the pore diameter about 140-150 nm were formed. The X-ray diffraction (XRD) results showed that the PZT nanotubes have a tetragonal structure. The metal oxide bands like ZrO6 and TiO6 of the final PZT nanotubes were detected by Fourier transform infrared (FT-IR) analysis and confirmed the formation of perovskite structure. By using FT-IR spectroscopy and Kramers-Kronig transformation method, the optical constants like real 𝜀1(ω) and imaginary 𝜀2(ω) parts of dielectric function, extinction coefficient k(ω) and refractive index n(ω) were determined. It was shown that the optical constants of PZT nanotubes are different from PZT nanoparticles.

Fabrication and characterization of MEMS-based PZT/PZT bimorph thick film vibration energy harvesters

DEFF Research Database (Denmark)

Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

2012-01-01

We describe the fabrication and characterization of a significantly improved version of a microelectromechanical system-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass; the harvester is fabricated in a fully monolithic process. The main advantage...... yield of 98%. The robust fabrication process allowed a high pressure treatment of the screen printed PZT thick films prior to sintering. The high pressure treatment improved the PZT thick film performance and increased the harvester power output to 37.1 μW at 1 g root mean square acceleration. We also...... characterize the harvester performance when only one of the PZT layers is used while the other is left open or short circuit....

In situ transmission electron microscopy study of the microstructural origins for the electric field-induced phenomena in ferroelectric perovskites

Science.gov (United States)

Guo, Hanzheng

Ferroelectrics are important materials due to their extensive technological applications, such as non-volatile memories, field-effect transistors, ferroelectric tunneling junctions, dielectric capacitors, piezoelectric transducers, sensors and actuators. As is well known, the outstanding dielectric, piezoelectric, and ferroelectric properties of these functional oxides originate from their ferroelectric domain arrangements and the corresponding evolution under external stimuli (e.g. electric field, stress, and temperature). Electric field has been known as the most efficient stimulus to manipulate the ferroelectric domains through polarization switching and alignment. Therefore, direct observation of the dynamic process of electric field-induced domain evolution and crystal structure transformation is of significant importance to understand the microstructural mechanisms for the functional properties of ferroelectrics. In this dissertation, electric field in situ transmission electron microscopy (TEM) technique was employed to monitor the real-time evolution of the domain morphology and crystal structure during various electrical processes: (1) the initial poling process, (2) the electric field reversal process, and (3) the electrical cycling process. Two types of perovskite-structured ceramics, normal ferroelectrics and relaxor ferroelectrics, were used for this investigation. In addition to providing the microscopic insight for some well-accepted phase transformation rules, discoveries of some new or even unexpected physical phenomena were also demonstrated. For the initial poling process, microstructural origins for the piezoelectricity development in the three most promising lead-free piezoceramic systems were investigated. For the non-ergodic relaxor ferroelectric compositions ( x = 6% - 9%) in the (1-x)(Bi1/2Na 1/2)TiO3-xBaTiO3 system, well-developed piezoelectricity was realized at poling fields far below the coercive field and phase transition field. Such

Study of the structure, dielectric and ferroelectric behavior of BaBi_4_+_δTi_4O_1_5 ceramics

International Nuclear Information System (INIS)

Khokhar, Anita; Goyal, Parveen K.; Sreenivas, K.; Thakur, O. P.

2016-01-01

The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi_4_+_δTi_4O_1_5 (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (T_m) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (P_r ~ 12.5  µC/cm"2), low coercive fields (E_c ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d_3_3 ~ 29 pC/N) is achieved in poled BaBi_4Ti_4O_1_5 ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi_4Ti_4O_1_5 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

Characterization of oxygen vacancies and their migration in Ba-doped Pb(Zr0.52Ti0.48)O3 ferroelectrics

Science.gov (United States)

Zhang, M. F.; Wang, Y.; Wang, K. F.; Zhu, J. S.; Liu, J.-M.

2009-03-01

We investigate in detail the migration kinetics of oxygen vacancies (OVs) in Ba-doped Pb(Zr0.52Ti0.48)O3 (PZT) ferroelectrics by complex impedance spectroscopy. The temperature dependent dc-electrical conductivity σdc suggests that Ba doping into PZT can lower significantly the density of OVs, leading to the distinctly decreased σdc and slightly enhanced activation energy U for the migration of OVs, thus benefiting the polarization fatigue resistance. Furthermore, the polarization fluctuation induced by the relaxation of OVs is reduced by the Ba doping. The Cole-Cole fitting to the dielectric loss manifests strong correlation among OVs, and the migration of OVs appears to be a collective behavior.

Atomic resolution imaging of ferroelectric domains

International Nuclear Information System (INIS)

Bursill, L.A.

1997-01-01

Electron optical principles involved in obtaining atomic resolution images of ferroelectric domains are reviewed, including the methods available to obtain meaningful interpretation and analysis of the image detail in terms of the atomic structures. Recent work is concerned with establishing the relationship between the essentially static chemical nanodomains and the spatial and temporal fluctuations of the nanoscale polar domains present in the relaxor class of materials, including lead scandium tantalate (PST) and lead magnesium niobate (PMN). Correct interpretation of the images required use of Next Nearest Neighbour Ising model simulations for the chemical domain textures upon which we must superimpose the polar domain textures; an introduction to this work is presented. A thorough analysis of the atomic scale chemical inhomogeneities, based upon the HRTEM results, has lead to an improved formulation of the theory of the dielectric response of PMN and PST, which is capable to predict the observed temperature and frequency dependence. HRTEM may be combined with solid state and statistical physics principles to provide a deeper understanding of structure/property relationships. 15 refs., 6 figs

Structural and Electrical Characteristics of Metal-Ferroelectric Pb1.1(Zr0.40Ti0.60O3-Insulator (ZnO-Silicon Capacitors for Nonvolatile Applications

Directory of Open Access Journals (Sweden)

S. R. Krishnamoorthi

2013-01-01

Full Text Available In this work metal-ferroelectric-insulator-semiconductor (MFIS thin-film structures using Pb1.1Zr0.40Ti0.60O3 (PZT as the ferroelectric layer and zinc oxide (ZnO as the insulator layer were fabricated on n-type (100 Si substrate. Pb1.1Zr0.40Ti0.60O3 and ZnO thin films were prepared on Si by the sol-gel route and thermal deposition method, respectively. On the optimized PZT (140 nm and ZnO (40 nm films were examined by scanning electron microscope (SEM. From AFM data the root mean square (r.m.s. roughness of the film surface is 13.11 nm. The leakage current density of ZnO/n-Si (MIS structure was as low as 1.8 × 10−8 A/cm2 at 2.5 V. The capacitance versus voltage (C-V characteristics of the annealed ZnO/Si (MIS diode indicated the good interface properties and no hysteresis was observed. Au/PZT (140 nm/ZnO (40 nm/Si (100 leakage-current density was about 5.7 × 10−8 A/cm2 at positive bias voltage of 3 V. The large memory window width in C-V (capacitance-voltage curve of Au/PZT/ZnO/Si capacitor was about 2.9 V under ±12 V which thus possibly enables nonvolatile applications. The memory window as a function of temperature was also discussed.

Ferroelectric properties of bismuth-doped PMT-PT ceramics

International Nuclear Information System (INIS)

Hyun, June Won; Kim, Yeon Jung; Kim, Gang Bae

2010-01-01

This study examined the ferroelectric properties of Bi-doped 0.66(Pb (1-3x/2) Bi x )(Mg 1/3 Ta 2/3 )O 3 - 0.34PbTiO 3 ceramics for use as a piezoelectric transformer. The optimum conditions for obtaining samples with high density and improved electrical properties were a sintering temperature of 1200 .deg. C/4 h and the addition of 3 mol% Bi. The temperature dependent dielectric constant of the ceramics was examined at frequencies ranging from 1 kHz to 100 kHz. The broad dielectric constant anomaly coupled with a shift in the dielectric maximum towards higher temperature with increasing frequency indicates a relaxor-type behavior in the ceramics. The piezoelectric coefficient (d 33 ) and the planar coupling factor (K p ) increase with the addition of 3 mol% Bi, and then decrease with further addition of Bi. The dielectric constant and the dissipation factor at room temperature could be improved by the addition of 3 mol% Bi.

Analyzing the defect structure of CuO-doped PZT and KNN piezoelectrics from electron paramagnetic resonance.

Science.gov (United States)

Jakes, Peter; Kungl, Hans; Schierholz, Roland; Eichel, Rüdiger-A

2014-09-01

The defect structure for copper-doped sodium potassium niobate (KNN) ferroelectrics has been analyzed with respect to its defect structure. In particular, the interplay between the mutually compensating dimeric (Cu(Nb)'''-V(O)··) and trimeric (V(O)··-Cu(Nb)'''-V(O)··)· defect complexes with 180° and non-180° domain walls has been analyzed and compared to the effects from (Cu'' - V(O)··)(x)× dipoles in CuO-doped lead zirconate titanate (PZT). Attempts are made to relate the rearrangement of defect complexes to macroscopic electromechanical properties.

Electromechanical properties of Na0.5Bi0.5TiO3-SrTiO3-PbTiO3 solid solutions

Science.gov (United States)

Svirskas, Šarūnas; Dunce, Marija; Birks, Eriks; Sternberg, Andris; Banys, Jūras

2018-03-01

Thorough studies of electric field-induced strain are presented in 0.4Na1/2Bi1/2TiO3-(0.6-x)SrTiO3-xPbTiO3 (NBT-ST-PT) ternary solid solutions. The increase of concentration of lead x induces crossover from relaxor to ferroelectric. Strain in a relaxor state can be described by electrostrictive behavior. The electrostrictive coefficients correspond to other well-known relaxor ferroelectrics. The concentration region with a stable ferroelectric phase revealed that the polarization dependence of strain does not exhibit nonlinearity, although they are inherent to the electric field dependence of strain. In this case, electric field dependence of strain is described in terms of the Rayleigh law and the role of domain wall contribution is extracted. Finally, the character of strain at the electric field-induced phase transition between the nonpolar and the ferroelectric states is studied. The data shows that in the vicinity of the electric field induced phase transition the strain vs. electric field displays electrostrictive character.

Anomalous atomic displacement parameters and local dynamics in the Curie range of a Pb-free relaxor ferroelectric system (Bi1-xBax)(Fe1-xTix)O3(0.36 ≤ x ≤ 0.50)

Science.gov (United States)

Singh, Anar; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Pandey, Dhananjai

2018-04-01

We report here the relaxor ferroelectric (RFE) behaviour in a multiferroic solid solution system, (Bi1-xBax)(Fe1-xTix)O3, at a critical disorder level of xC ˜ 0.35 in BiFeO3 and 0.65 (i.e., 1-xC = 0.35) in BaTiO3 similar to the 1:2 ratio of Mg2+ and Nb5+ in the canonical RFE Pb(Mg1/3Nb2/3)O3. This Pb-free system, like canonical Pb-based RFEs, does not exhibit macroscopic symmetry breaking and shows only the signatures of ergodicity breaking at Vogel-Fulcher freezing temperature (TVF). The atomic displacement parameters (ADPs) of Fe3+/Ti4+ and O2-, obtained using high wave vector (Q) and high-resolution synchrotron x-ray diffraction data as a function of temperature, show anomalous diffuse peaks in the Curie range. It is shown that the diffuse peak in ADPs is due to softening of the vibrational frequencies of the B-O chain (B = Fe3+/Ti4+ and O = O2-) below the Burns temperature (TB) followed by hardening below the characteristic temperature (T'm), which corresponds to a peak in the dielectric permittivity (ɛ').

High-power piezoelectric characteristics of textured bismuth layer structured ferroelectric ceramics.

Science.gov (United States)

Ogawa, Hirozumi; Kawada, Shinichiro; Kimura, Masahiko; Shiratsuyu, Kousuke; Sakabe, Yukio

2007-12-01

Abstract-The high-power piezoelectric characteristics in h001i oriented ceramics of bismuth layer structured ferroelectrics (BLSF), SrBi(2)Nb(2)O(9) (SBN), (Bi,La)(4)Ti(3)O(12) (BLT), and CaBi(4)Ti(4)O(15) (CBT), were studied by a constant voltage driving method. These textured ceramics were fabricated by a templated grain growth (TGG) method, and their Lotgering factors were 95%, 97%, and 99%, respectively. The vibration velocities of the longitudinal mode (33-mode) increased proportionally to an applied electric field up to 2.5 m/s in these textured BLSF ceramics, although, the vibration velocity of the 33-mode was saturated at more than 1.0 m/s in the Pb(Mn,Nb)O(3)-PZT ceramics. The resonant frequencies were constant up to the vibration velocity of 2.5 m/s in the SBN and CBT textured ceramics; however, the resonant frequency decreased with increasing over the vibration velocity of 1.5 m/s in the BLT textured ceramics. The dissipation power density of the BLT was almost the same as that of the Pb(Mn,Nb)O(3)-PZT ceramics. However, the dissipation power densities of the SBN and CBT were lower than those of the BLT and Pb(Mn,Nb)O(3)-PZT ceramics. The textured SBN and CBT ceramics are good candidates for high-power piezoelectric applications.

Nonlinear dielectric thin films for high-power electric storage with energy density comparable with electrochemical supercapacitors.

Science.gov (United States)

Yao, Kui; Chen, Shuting; Rahimabady, Mojtaba; Mirshekarloo, Meysam Sharifzadeh; Yu, Shuhui; Tay, Francis Eng Hock; Sritharan, Thirumany; Lu, Li

2011-09-01

Although batteries possess high energy storage density, their output power is limited by the slow movement of charge carriers, and thus capacitors are often required to deliver high power output. Dielectric capacitors have high power density with fast discharge rate, but their energy density is typically much lower than electrochemical supercapacitors. Increasing the energy density of dielectric materials is highly desired to extend their applications in many emerging power system applications. In this paper, we review the mechanisms and major characteristics of electric energy storage with electrochemical supercapacitors and dielectric capacitors. Three types of in-house-produced ferroic nonlinear dielectric thin film materials with high energy density are described, including (Pb(0.97)La(0.02))(Zr(0.90)Sn(0.05)Ti(0.05))O(3) (PLZST) antiferroelectric ceramic thin films, Pb(Zn(1/3)Nb(2/3))O(3-)Pb(Mg(1/3)Nb(2/3))O(3-)PbTiO(3) (PZN-PMN-PT) relaxor ferroelectric ceramic thin films, and poly(vinylidene fluoride) (PVDF)-based polymer blend thin films. The results showed that these thin film materials are promising for electric storage with outstandingly high power density and fairly high energy density, comparable with electrochemical supercapacitors.

Ferroelectric properties of sandwich structured (Bi, La)4T3O12/Pb(Zr, Ti)O3/ (Bi, La)4Ti3O12 thin films on Pt/Ti/SiO2/Si substrates

International Nuclear Information System (INIS)

Bao Dinghua; Wakiya, Naoki; Shinozaki, Kazuo; Mizutani, Nobuyasu

2002-01-01

Sandwich structured (Bi, La) 4 Ti 3 O 12 /Pb(Zr, Ti)O 3 /(Bi, La) 4 Ti 3 O 12 thin films were fabricated on Pt/Ti/SiO 2 /Si substrates, with the intention of simultaneously utilizing the advantages of both (Bi, La) 4 Ti 3 O 12 (BLT) and Pb(Zr, Ti)O 3 (PZT) thin films such as non-fatigue behaviours of BLT and good ferroelectric properties of PZT. Both BLT and PZT layers were prepared by a chemical solution deposition technique. The experiments demonstrated that the sandwich structure showed fatigue-free characteristics at least up to 10 10 switching bipolar pulse cycles under 8 V and excellent retention properties. The sandwich structured thin films also exhibited well-defined hysteresis loops with a remanent polarization (2P r ) of 8.8 μC cm -2 and a coercive field (E c ) of 47 kV cm -1 . The room-temperature dielectric constant and dissipation factor were 210 and 0.031, respectively, at a frequency of 100 kHz. These results suggest that this sandwich structure is a promising material combination for ferroelectric memory applications. (author)

Giant Electrocaloric Effect in Ferroelectrics with Tailored Polaw-Nanostructures

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qiming [Pennsylvania State Univ., University Park, PA (United States)

2015-06-24

Electrocaloric effect (ECE) is the temperature and/or entropy change in a dielectric material caused by an electric field induced polarization change. Although ECE has been studied since 1930s, the very small ECE observed in earlier studies in bulk materials before 2007 makes it not attractive for practical cooling applications. The objectives of this DOE program are to carry out a systematical scientific research on the entropy change and ECE in polar-dielectrics, especially ferroelectrics based on several fundamental hypotheses and to search for answers on a few scientific questions. Especially, this research program developed a series of polar-dielectric materials with controlled nano- and meso-structures and carried out studies on how these structures affect the polar-ordering, correlations, energy landscapes, and consequently the entropy states at different phases and ECE. The key hypotheses of the program include: (i) Whether a large ECE can be obtained near the ferroelectric-paraelectric (FE-PE) transition in properly designed ferroelectrics which possess large polarization P and large ß (the coefficient in the thermodynamic Landau theory where the Gibbs free energy G = G = G₀+ ½ a P² +1/4 b P⁴ + 1/6 c P⁶ – EP, and a = ß (T-T_c), where b,c,ß and Tc are constants)? (ii) What determines/determine ß? Whether a ferroelectric material with built-in disorders, which disrupt the polar-correlations and enabling a large number of local polar-states, such as a properly designed ferroelectric relaxor, can achieve a large ECE? (iii) How to design a ferroelectric material which has flat energy landscape so that the energy barriers for switching among different phases are vanishingly small? What are the necessary conditions to maximize the number of coexisting phases? (iv) How to design ferroelectric materials with a large tunable dielectric response? That is, at zero electric field, the material possesses very

Temperature Dependent Electrical Properties of PZT Wafer

Science.gov (United States)

Basu, T.; Sen, S.; Seal, A.; Sen, A.

2016-04-01

The electrical and electromechanical properties of lead zirconate titanate (PZT) wafers were investigated and compared with PZT bulk. PZT wafers were prepared by tape casting technique. The transition temperature of both the PZT forms remained the same. The transition from an asymmetric to a symmetric shape was observed for PZT wafers at higher temperature. The piezoelectric coefficient (d 33) values obtained were 560 pc/N and 234 pc/N, and the electromechanical coupling coefficient (k p) values were 0.68 and 0.49 for bulk and wafer, respectively. The reduction in polarization after fatigue was only ~3% in case of PZT bulk and ~7% for PZT wafer.

Fabrication of Pb (Zr, Ti) O3 Thin Film for Non-Volatile Memory Device Application

International Nuclear Information System (INIS)

Mar Lar Win

2011-12-01

Ferroelectric lead zirconate titanate powder was composed of mainly the oxides of titanium, zirconium and lead. PZT powder was firstly prepared by thermal synthesis at different Zr/Ti ratios with various sintering temperatures. PZT thin film was fabricated on SiO2/Si substrate by using thermal evaporation method. Physical and elemental analysis were carried out by using SEM, EDX and XRD The ferroelectric properties and the switching behaviour of the PZT thin films were investigated. The ferroelectric properties and switching properties of the PZT thin film (near morphotropic phase boundary sintered at 800 C) could function as a nonvolatile memory.

Polarization characterization of PZT disks and of embedded PZT plates by thermal wave methods

International Nuclear Information System (INIS)

Eydam, Agnes; Suchaneck, Gunnar; Gerlach, Gerald; Esslinger, Sophia; Schönecker, Andreas; Neumeister, Peter

2014-01-01

In this work, the thermal wave method was applied to characterize PZT disks and embedded PZT plates with regard to the polarization magnitude and spatial homogeneity. The samples were exposed to periodic heating by means of a laser beam and the pyroelectric response was determined. Thermal relaxation times (single time constants or distributions of time constants) describe the heat losses of the PZT samples to the environment. The resulting pyroelectric current spectrum was fitted to the superposition of thermal relaxation processes. The pyroelectric coefficient gives insight in the polarization distribution. For PZT disks, the polarization distribution in the surface region showed a characteristic decrease towards the electrodes

Biotemplated synthesis of PZT nanowires.

Science.gov (United States)

Cung, Kellye; Han, Booyeon J; Nguyen, Thanh D; Mao, Sheng; Yeh, Yao-Wen; Xu, Shiyou; Naik, Rajesh R; Poirier, Gerald; Yao, Nan; Purohit, Prashant K; McAlpine, Michael C

2013-01-01

Piezoelectric nanowires are an important class of smart materials for next-generation applications including energy harvesting, robotic actuation, and bioMEMS. Lead zirconate titanate (PZT), in particular, has attracted significant attention, owing to its superior electromechanical conversion performance. Yet, the ability to synthesize crystalline PZT nanowires with well-controlled properties remains a challenge. Applications of common nanosynthesis methods to PZT are hampered by issues such as slow kinetics, lack of suitable catalysts, and harsh reaction conditions. Here we report a versatile biomimetic method, in which biotemplates are used to define PZT nanostructures, allowing for rational control over composition and crystallinity. Specifically, stoichiometric PZT nanowires were synthesized using both polysaccharide (alginate) and bacteriophage templates. The wires possessed measured piezoelectric constants of up to 132 pm/V after poling, among the highest reported for PZT nanomaterials. Further, integrated devices can generate up to 0.820 μW/cm(2) of power. These results suggest that biotemplated piezoelectric nanowires are attractive candidates for stimuli-responsive nanosensors, adaptive nanoactuators, and nanoscale energy harvesters.

Ferroelectric Polarization-Modulated Interfacial Fine Structures Involving Two-Dimensional Electron Gases in Pb(Zr,Ti)O3/LaAlO3/SrTiO3 Heterostructures.

Science.gov (United States)

Wang, Shuangbao; Bai, Yuhang; Xie, Lin; Li, Chen; Key, Julian D; Wu, Di; Wang, Peng; Pan, Xiaoqing

2018-01-10

Interfacial fine structures of bare LaAlO 3 /SrTiO 3 (LAO/STO) heterostructures are compared with those of LAO/STO heterostructures capped with upward-polarized Pb(Zr 0.1 ,Ti 0.9 )O 3 (PZT up ) or downward-polarized Pb(Zr 0.5 ,Ti 0.5 )O 3 (PZT down ) overlayers by aberration-corrected scanning transmission electron microscopy experiments. By combining the acquired electron energy-loss spectroscopy mapping, we are able to directly observe electron transfer from Ti 4+ to Ti 3+ and ionic displacements at the interface of bare LAO/STO and PZT down /LAO/STO heterostructure unit cell by unit cell. No evidence of Ti 3+ is observed at the interface of the PZT up /LAO/STO samples. Furthermore, the confinement of the two-dimensional electron gas (2DEG) at the interface is determined by atomic-column spatial resolution. Compared with the bare LAO/STO interface, the 2DEG density at the LAO/STO interface is enhanced or depressed by the PZT down or PZT up overlayer, respectively. Our microscopy studies shed light on the mechanism of ferroelectric modulation of interfacial transport at polar/nonpolar oxide heterointerfaces, which may facilitate applications of these materials as nonvolatile memory.

Investigation of the epitaxial growth of Pb(Zr{sub 0,52}Ti{sub 0,48})O{sub 3} thin films and their application in ferroelectric superconducting field effect transistors; Untersuchung des epitaktischen Wachstums duenner Pb(Zr{sub 0,52}Ti{sub 0,48})O{sub 3}-Schichten und ihre Anwendung in ferroelektrischen supraleitenden Feldeffektransistoren

Energy Technology Data Exchange (ETDEWEB)

Aidam, R

1999-02-01

The influences of the polarization of ferroelectric Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) films on the properties of YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) films were investigated in ferroelectric superconducting field effect transistors (FSuFETs). First the epitaxial growth of PZT films deposited by reactive sputtering in an argon/oxygen atmosphere was investigated. SrTiO{sub 3} single crystals and YBCO thin films proved as suitable substrates. The lead content of the PZT films depended sensitively on the deposition temperature T{sub s} and the gas pressure. By using a high pressure of 0.26 mbar the correct stoichiometry could be achieved up to an maximum T{sub s} of 580 C. Above a minimum T{sub s} of 540 C the ferroelectric perovskite structure grew. In the optimum temperature range between 560 C and 580 C the films grew with a minimum mosaic spread of {delta}{omega} < 0.3 and a small amount of less than 1% of paraelectric phase. The best ferroelectric properties could be obtained for films with the highest degree of epitaxy and the correct stoichiometry. The maximum remanent polarization amounted P{sub r} = 61 {mu}C/cm{sup 2} and the coercive field E{sub C} was 150 kV/cm at 77 K. The breakdown field was four to five times larger than E{sub C}. Fatigue studies revealed a loss of switchable polarization of 30% after 10{sup 8} cycles at 77 K, whereas loss of retention and the effect of ageing were negligible. During the process of oxidation of the heterostructure at 400 C and an oxygen pressure of 800 mbar a reaction at the PZT/YBCO interface was observed, which lead to a degradation of the transport properties of the superconductor. This reaction could be avoided by a thin SrTiO{sub 3} buffer layer without disturbing the ferroelectric hysteresis essentially.

The effect of K and Na excess on the ferroelectric and piezoelectric properties of K0.5Na0.5NbO3 thin films

Science.gov (United States)

Ahn, C. W.; Y Lee, S.; Lee, H. J.; Ullah, A.; Bae, J. S.; Jeong, E. D.; Choi, J. S.; Park, B. H.; Kim, I. W.

2009-11-01

We have fabricated K0.5Na0.5NbO3 (KNN) thin films on Pt substrates by a chemical solution deposition method and investigated the effect of K and Na excess (0-30 mol%) on ferroelectric and piezoelectric properties of KNN thin film. It was found that with increasing K and Na excess in a precursor solution from 0 to 30 mol%, the leakage current and ferroelectric properties were strongly affected. KNN thin film synthesized by using 20 mol% K and Na excess precursor solution exhibited a low leakage current density and well saturated ferroelectric P-E hysteresis loops. Moreover, the optimized KNN thin film had good fatigue resistance and a piezoelectric constant of 40 pm V-1, which is comparable to that of polycrystalline PZT thin films.

The effect of K and Na excess on the ferroelectric and piezoelectric properties of K0.5Na0.5NbO3 thin films

International Nuclear Information System (INIS)

Ahn, C W; Bae, J S; Jeong, E D; Lee, S Y; Lee, H J; Ullah, A; Kim, I W; Choi, J S; Park, B H

2009-01-01

We have fabricated K 0.5 Na 0.5 NbO 3 (KNN) thin films on Pt substrates by a chemical solution deposition method and investigated the effect of K and Na excess (0-30 mol%) on ferroelectric and piezoelectric properties of KNN thin film. It was found that with increasing K and Na excess in a precursor solution from 0 to 30 mol%, the leakage current and ferroelectric properties were strongly affected. KNN thin film synthesized by using 20 mol% K and Na excess precursor solution exhibited a low leakage current density and well saturated ferroelectric P-E hysteresis loops. Moreover, the optimized KNN thin film had good fatigue resistance and a piezoelectric constant of 40 pm V -1 , which is comparable to that of polycrystalline PZT thin films.

Biotemplated Synthesis of PZT Nanowires

Science.gov (United States)

2013-11-25

electromechanical coupling coefficient , Y is the Young’s modulus, and Ri is intrinsic resistance. The PZT nanowire- based film is taken to have negligible...robotic actuation, and bioMEMS. Lead zirconate titanate ( PZT ), in particular, has attracted significant attention, owing to its superior...electromechanical conversion performance. Yet, the ability to synthesize crystalline PZT nanowires with reproducible and well-controlled properties remains a

Effects of Thickness, Pulse Duration, and Size of Strip Electrode on Ferroelectric Electron Emission of Lead Zirconate Titanate Films

Science.gov (United States)

Yaseen, Muhammad; Ren, Wei; Chen, Xiaofeng; Feng, Yujun; Shi, Peng; Wu, Xiaoqing

2018-02-01

Sol-gel-derived lead zirconate titanate (PZT) thin-film emitters with thickness up to 9.8 μm have been prepared on Pt/TiO2/SiO2/Si wafer via chemical solution deposition with/without polyvinylpyrrolidone (PVP) modification, and the relationship between the film thickness and electron emission investigated. Notable electron emission was observed on application of a trigger voltage of 120 V for PZT film with thickness of 1.1 μm. Increasing the film thickness decreased the threshold field to initiate electron emission for non-PVP-modified films. In contrast, the electron emission behavior of PVP-modified films did not show significant dependence on film thickness, probably due to their porous structure. The emission current increased with decreasing strip width and space between strips. Furthermore, it was observed that increasing the duration of the applied pulse increased the magnitude of the emission current. The stray field on the PZT film thickness was also calculated and found to increase with increasing ferroelectric sample thickness. The PZT emitters were found to be fatigue free up to 105 emission cycles. Saturated emission current of around 25 mA to 30 mA was achieved for the electrode pattern used in this work.

Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain.

Science.gov (United States)

Suzuki, Norihiro; Osada, Minoru; Billah, Motasim; Bando, Yoshio; Yamauchi, Yusuke; Hossain, Shahriar A

2018-03-27

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its well-balanced ferroelectricity, piezoelectricity, and dielectric constant. In addition, BT does not contain any toxic elements. Therefore, it is considered to be an eco-friendly material, which has attracted considerable interest as a replacement for lead zirconate titanate (PZT). However, bulk BT loses its ferroelectricity at approximately 130 °C, thus, it cannot be used at high temperatures. Because of the growing demand for high-temperature ferroelectric materials, it is important to enhance the thermal stability of ferroelectricity in BT. In previous studies, strain originating from the lattice mismatch at hetero-interfaces has been used. However, the sample preparation in this approach requires complicated and expensive physical processes, which are undesirable for practical applications. In this study, we propose a chemical synthesis of a porous material as an alternative means of introducing strain. We synthesized a porous BT thin film using a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles were used as an organic template. Through a series of studies, we clarified that the introduction of pores had a similar effect on distorting the BT crystal lattice, to that of a hetero-interface, leading to the enhancement and stabilization of ferroelectricity. Owing to its simplicity and cost effectiveness, this fabrication process has considerable advantages over conventional methods.

Fatigue-free PZT-based nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Hwang, H J; Sando, M [Nat. Ind. Res. Inst., Nagoya (Japan); Tajima, K [Synergy Ceramics Lab., Fine Ceramics Research Association, Nagoya (Japan); Niihara, K [ISIR, Osaka Univ., Mihogaoka, Ibaraki (Japan)

1999-03-01

The goal of this study is to fabricate fatigue-free piezoelectrics-based nanocomposites. Lead zirconate titanate (PZT) and metallic platinum (Pt) were selected as a matrix and secondary phase dispersoid. Fine Pt particles were homogeneously dispersed in the PZT matrix. Fatigue properties of the unpoled PZT-based nanocomposite under electrical cyclic loading were investigated. The electrical-field-induced crack growth was monitored by an optical microscope, and it depended on the number of cycles the sample was subjected to. Resistance to fatigue was significantly enhanced in the nanocomposite. The excellent fatigue behavior of the PZT/Pt nanocomposites may result from the grain boundary strenghtening due to the interaction between the matrix and Pt particles. (orig.) 8 refs.

Combined effect of preferential orientation and Zr/Ti atomic ratio on electrical properties of Pb(ZrxTi1-x)O3 thin films

International Nuclear Information System (INIS)

Gong Wen; Li Jingfeng; Chu Xiangcheng; Gui Zhilun; Li Longtu

2004-01-01

Lead zirconate titanate [Pb(Zr x Ti 1-x )O 3 , PZT] thin films with various compositions, whose Zr/Ti ratio were varied as 40/60, 48/52, 47/53, and 60/40, were deposited on Pt(111)/Ti/SiO 2 /Si substrates by sol-gel method. A seeding layer was introduced between the PZT layer and the bottom electrode to control the texture of overlaid PZT thin films. A single perovskite PZT thin film with absolute (100) texture was obtained, when lead oxide was used as the seeding crystal, whereas titanium dioxide resulted in highly [111]-oriented PZT films. The dielectric and ferroelectric properties of PZT films with different preferential orientations were evaluated systemically as a function of composition. The maximums of relative dielectric constant were obtained in the morphotropic phase boundary region for both (100)- and (111)-textured PZT films. The ferroelectric properties also greatly depend on films' texture and composition. The intrinsic and extrinsic contributions to dielectric and ferroelectric properties were discussed

Characterization And Operation Of PZT Ceramic Filters On Gamma-Radiation Environment

International Nuclear Information System (INIS)

Fawzy, Y.H.A.; Soliman, F.A.S.; Swidan, A.; Abdelmagid, A.

2008-01-01

The present paper deals with the gamma-ray effects on the electrical characteristics of ferroelectric materials used as an electronic frequency filters. After the recall of main observations, mechanisms are analyzed and proposed to take into account the effects in Lead- Zirconate-Titanate (PZT) based materials. In this concern, a wide frequency range samples, extends from 400 k Hz up to 6.5 MHz, were chosen for studying their frequency response and related terminologies, dynamic characteristics, and equivalent circuits. In general, for all samples, a shift on the frequency values was recorded, where the values of the center frequency, resonance frequency and anti-resonance frequency were shown to be shifted. The observed shift is mainly due to the noticed changes on the equivalent circuit elements of the devices, where a pronounced shift on the values of L,,,CP and R,, were recorded

Ceramics like PZT-PMN

International Nuclear Information System (INIS)

Droescher, R.E.; Sousa, V.C.; Bergman, C.P.

2009-01-01

The goal of this work was to achieve piezoelectric ceramics referring to the system PZT-PMN Pb(Mg 1 / 3 Nb 2 / 3 Zr 0 , 52 Ti 0 , 48 )O 3 . Have been analysed ceramics like 0,65PZT-0,35PMN ((Pb(Mg 0 , 1167 Nb 0 , 2300 Zr 0 , 3380 Ti 0 , 3120 )O 3 ), 0,75PZT-0,25PMN ((Pb(Mg 0 , 083 Nb 0 . 1675 Zr 0 , 3900 Ti 0 , 3600 )O3) and the 0,85PZT-0,15PMN ((Pb(Mg 0,0500 Nb 0 , 1000 Zr 0 , 4420 Ti 0 , 4080 )O 3 ). The influence of the calcination and concentration of PZT on the lattice phases, microstructure and density was evaluated. Then, the method used was the mixed-oxide method, the samples were taken under different temperatures of calcination before the final sinterizing. The DRX and SEM techniques were used to identify the phases formed and analyse the microstructure, respectively. The main result revealed that, the better way is to realize three burns before the final sinterizing at 1200 o C/4 h . Like that, on obtain for sure the average lattice phases, like: perovskite, pyrochlore and PbO and also tend to densify the samples. (author)

Design and fabrication of aspherical bimorph PZT optics

CERN Document Server

Tseng, T C; Yeh, Z C; Perng, S Y; Wang, D J; Kuan, C K; Chen, J R; Chen, C T

2001-01-01

Bimorph piezoelectric optics with a third-order-polynomial surface is designed and a prototype is fabricated as active optics. Two pairs of silicon (Si) and lead zirconate titanate (PZT) piezoelectric ceramic are bonded as Si-PZT-PZT-Si together with a multi-electrode or thin film resistor coating used as the control electrode between Si and PZT and metallic films as grounding between the interface of PZT ceramics. A linear voltage is applied to the bimorph PZT optics by probing the control electrodes from a two-channel controllable power supplier. In doing so, the optics surface can achieve a desired third-order-polynomial surface. Reducing hysteresis and creep in bimorph PZT X-ray optics is the only feasible way by inserting an appropriate capacitor in series with bimorph PZT optics to significantly reduce both effects.

Reversible Polarization Rotation in Epitaxial Ferroelectric Bilayers

DEFF Research Database (Denmark)

Liu, Guangqing; Zhang, Qi; Huang, Hsin-Hui

2016-01-01

Polarization rotation engineering is a promising path to giant dielectric and electromechanical responses in ferroelectric materials and devices. This work demonstrates robust and reversible in- to out-of-plane polarization rotation in ultrathin (nanoscale) epitaxial (001) tetragonal PbZr0.3Ti0.7O3...... large-scale polarization rotation switching (≈60 μC cm−2) and an effective d 33 response 500% (≈250 pm V−1) larger than the PZT-R layer alone. Furthermore, this enhancement is stable for more than 107 electrical switching cycles. These bilayers present a simple and highly controllable means to design...... and optimize rotational polar systems as an alternate to traditional composition-based approaches. The precise control of the subtle interface-driven interactions between the lattice and the external factors that control polarization opens a new door to enhanced—or completely new—functional properties....

Effect of La doping on the ferroic order in Pb-based perovskite-type relaxor ferroelectrics

Science.gov (United States)

Maier, B. J.; Welsch, A.-M.; Mihailova, B.; Angel, R. J.; Zhao, J.; Paulmann, C.; Engel, J. M.; Marshall, W. G.; Gospodinov, M.; Petrova, D.; Bismayer, U.

2011-04-01

The structural alteration induced by the substitution of three-valent cations with an isotropic electronic outermost shell for Pb2+ in perovskite-type relaxors was investigated in the solid solutions Pb1-xLaxSc(1+x)/2Ta(1-x)/2O3, x =0.08 (PST-La) and Pb1-xLaxSc(1+x)/2Nb(1-x)/2O3, x =0.23 (PSN-La). In order to distinguish the “charge” effects from “strain” effects associated with the incorporation of La3+ in the structure, Sr-containing PbSc0.5Nb0.5O3 was characterized as well. The structure of the compounds was analyzed by in situ Raman spectroscopy, single-crystal x-ray diffraction, and powder neutron diffraction at different temperatures or pressures. It is shown that the embedding of La3+ strongly affects the ferroic structural species due to strain effects through a disturbance of the system of lone-pair electrons associated with Pb2+ and a decrease in the tolerance factor. La doping suppresses the dynamical coupling between off-centered Pb and B-site cations and enhances antiphase BO6 octahedral tilting which, depending on the level of doping, may lead to long-range order of antiphase BO6 tilts at ambient conditions and frustrated antiferroelectric order of Pb ions at low temperatures.

Size effects on structural and dielectric properties of PZT thin films at compositions around the morpho tropic phase boundary

International Nuclear Information System (INIS)

Lima, Elton Carvalho; Araujo, Eudes Borges; Souza Filho, Antonio Gomes de; Bdikin, Igor

2011-01-01

Full text: The demand for portability in consumer electronics has motivated the understanding of size effects on ferroelectric thin films. The actual comprehension of these effects in ferroelectrics is unsatisfactory, since the polarization interacts more strongly than other order parameters such as strain and charge. As a result, extrinsic effects are produced if these variables are uncontrolled and problems such as ferroelectric paraelectric phase transition at nanometers scale remains an unsolved issue. In the present work, the effects of thickness and compositional fractions on the structural and dielectric properties of PbZr 1-x Ti x O 3 (PZT) thin films were studied at a composition around the morphotropic phase boundary (x = 0.50). For this purpose, thin films with different thicknesses and different PbO excess were deposited on Si(100) and Pt=T iO 2 =SiO 2 =Si substrates by a chemical method and crystallized in electric furnace at 700 deg C for 1 hour. The effects of substrate, pyrolysis temperature and excess lead addition in the films are reported. For films with 10 mol% PbO in excess, the pyrolysis in the regime of 300 deg C for 30 minutes was observed to yield PZT pyrochlore free thin films deposited on Pt=T iO 2 =SiO 2 =Si substrate. Out this condition, the transformation from amorphous to the pyrochlore metastable phase is kinetically more favorable that a transformation to the perovskite phase, which is thermodynamically stable. Rietveld refinements based on X-ray diffraction results showed that films present a purely tetragonal phase and that this phase does not change when the film thickness decreases. The dielectric permittivity measurements showed a monoclinic → tetragonal phase transition at 198K. Results showed that the dielectric permittivity (ε) increases continuously from 257 to 463, while the thickness of the PZT films increases from 200 to 710 nm. These results suggests that interface pinning centers can be the responsible mechanism by

Study of the structure, dielectric and ferroelectric behavior of BaBi{sub 4+δ}Ti{sub 4}O{sub 15} ceramics

Energy Technology Data Exchange (ETDEWEB)

Khokhar, Anita, E-mail: mails4anita@gmail.com, E-mail: goyalphy@gmail.com; Goyal, Parveen K., E-mail: mails4anita@gmail.com, E-mail: goyalphy@gmail.com; Sreenivas, K. [Department of Physics & Astrophysics, University of Delhi, Delhi-110 007 (India); Thakur, O. P. [Electroceramics Group, Solid State Physics Laboratory, Lucknow Road, Delhi 110 054 (India)

2016-05-23

The structure and ferroelectric properties of excess bismuth doped barium bismuth titanate BaBi{sub 4+δ}Ti{sub 4}O{sub 15} (δ = 2 - 10 wt.%)) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material with a change in the orthorhombic distortion with varying excess of bismuth content. There is no change in the phase transition temperature (T{sub m}) while the relaxor behaviour has been modified significantly with excess of bismuth doping. Saturated hysteresis loops with high remnant polarization (P{sub r} ~ 12.5  µC/cm{sup 2}), low coercive fields (E{sub c} ~ 26 kV/cm) are measured and a high piezoelectric coefficient (d{sub 33} ~ 29 pC/N) is achieved in poled BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics prepared with up to 8 wt.% of excess bismuth oxide. The improvement in the ferroelectric properties with increase in the excess bismuth content in BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of excess bismuth.

Electrical properties of niobium doped Bi4Ti3O12-SrBi4Ti4O15 intergrowth ferroelectrics

International Nuclear Information System (INIS)

Parida, Geetanjali; Bera, J.

2013-01-01

Bismuth layer structured ferroelectrics (BLSFs) have attracted much attention because of their potential applications in non-volatile ferroelectric random access memories and high temperature piezoelectric. They are very attractive for these applications due to their fatigue free nature and environment friendly lead-free composition. BLSF crystal structure has layers of bismuth oxide and pseudo perovskite block stacked alternately along their c-direction, For commercial application, numerous efforts have been made to improve the electrical properties of BLSFs. Some effective approaches are: (i) doping at A-site, (ii) high valentcation doping at B-site and (iii) formation of intergrowth between different BLSFs. The intergrowth BLSFs are consist of regular stacking of one half the unit cell of m-member structure and one half the unit cell of (m+1) member BLSF structure along their c-axis. In this report, Nb-doped Bi 4 Ti 3 O 12 -SrBi 4 Ti 4 O 15 intergrowth ceramics have been prepared by modified oxalate route. XRD phase analysis confirmed the formation of single phase compound. Nb-doping does not affect the basic crystal structure of the intergrowth. SEM micrographs showed that the grain size of the ceramics decreases with Nb-doping. The temperature dependence of dielectric constant and losses was investigated in the temperature range 30 to 800℃ and frequency range 1 kHz to 1 MHz. With Nb-doping, the T c of the ferroelectrics reduces and peak permittivity increases. Doping also introduces small relaxor behaviour in the ferroelectrics. The dc conductivity of the ceramics decreases with doping. The remnant polarization (Pr) of the intergrowth ferroelectrics is increased with Nb doping. (author)

PZT-5A4/PA and PZT-5A4/PDMS piezoelectric composite bimorphs

NARCIS (Netherlands)

Babu, I.; Hendrix, M.M.R.M.; With, de G.

2014-01-01

Disc type reinforced piezoelectric composite bimorphs with series connection were designed and the performance was investigated. The composite bimorphs (PZT/PA and PZT/PDMS (40/60 vol%)) were successfully fabricated by a compression molding and solution casting technique. The charge developed at an

Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting

DEFF Research Database (Denmark)

Xu, R.; Lei, A.; Christiansen, T. L.

2011-01-01

We present a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The most common piezoelectric energy harvesting devices utilize a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric material...

Impact of structural changes on dielectric and thermal properties of vinylidene fluoride–trifluoroethylene-based terpolymer/copolymer blends

Energy Technology Data Exchange (ETDEWEB)

Casar, G. [Jožef Stefan Institute and Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana (Slovenia); Li, X. [Department of Electrical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Malič, B. [Jožef Stefan Institute and Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana (Slovenia); Zhang, Q.M. [Department of Electrical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Bobnar, V., E-mail: vid.bobnar@ijs.si [Jožef Stefan Institute and Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana (Slovenia)

2015-03-15

We report dielectric and thermal properties of the poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) terpolymer [P(VDF–TrFE–CFE), a member of the relaxor polymer family that exhibits fast response speeds, giant electrostriction, high electric energy density, and large electrocaloric effect] blended with the ferroelectric poly(vinylidene fluoride–trifluoroethylene) copolymer, P(VDF–TrFE). Although the differential scanning calorimetry (DSC) clearly reveals that both components form separate crystalline phases, at low copolymer content blends entirely exhibit a relaxorlike linear dielectric response, since the interfacial couplings to the bulky defects in the terpolymer convert the normal ferroelectric copolymer into a relaxor. On the other hand, dielectric experiments evidence that in blends with 20–50 wt% of P(VDF–TrFE) the ferroelectric and relaxor states coexist. This coexistence is confirmed by DSC results, which further reveal the influence of blending on the terpolymer crystallinity and melting point. At last, the crystallinity data appropriately explain the variation of the dielectric constant in P(VDF–TrFE–CFE)/P(VDF–TrFE) blends.

Estimation of strain from piezoelectric effect and domain switching in morphotropic PZT by combined analysis of macroscopic strain measurements and synchrotron X-ray data

International Nuclear Information System (INIS)

Kungl, Hans; Theissmann, Ralf; Knapp, Michael; Baehtz, Carsten; Fuess, Hartmut; Wagner, Susanne; Fett, Theo; Hoffmann, Michael J.

2007-01-01

Morphotropic PZT ceramics are State of the art materials for ferroelectric actuators. Essential performance parameters for these materials are strain and hysteresis. On a microscopic scale the strain provided by an electric field is due to two different mechanisms. The piezoelectric effect causes an elongation of the unit cells, whereas domain switching changes their crystallographic orientation by aligning the polarization axis towards the field direction. A method is outlined to estimate the contribution of the two mechanisms to total strain by combining macroscopic strain measurements and X-ray diffraction (XRD) data. Results from macroscopic measurements of remanent and unipolar strain with the corresponding data on texture, derived from in situ synchrotron radiation XRD patterns, are analyzed and evaluated by a semi-empirical approach. The method was applied to six morphotropic, LaSr doped PZT materials of different Zr/Ti ratios. Results are discussed with respect to the differences between the materials

Flexoelectricity in PZT Nanoribbons and Biomembranes

Science.gov (United States)

2015-01-09

Flexoelectricity in PZT Nanoribbons and Biomembranes The objective of this grant was to study flexoelectric phenomena in solids and in biomembranes...Flexoelectricity in PZT Nanoribbons and Biomembranes Report Title The objective of this grant was to study flexoelectric phenomena in solids and...producing PZT nanoribbons for energy harvesters. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or

Photoelectron spectroscopy and spectro-microscopy of Pb(Zr,Ti)O{sub 3} (1 1 1) thin layers: Imaging ferroelectric domains with binding energy contrast

Energy Technology Data Exchange (ETDEWEB)

Huşanu, Marius A.; Popescu, Dana G.; Tache, Cristian A. [National Institute of Materials Physics, Atomistilor 105b, 077125 Magurele-Ilfov (Romania); Apostol, Nicoleta G. [National Institute of Materials Physics, Atomistilor 105b, 077125 Magurele-Ilfov (Romania); Elettra Sincrotrone Trieste, S.S. 14 – km 163,5, Area Science Park, 34169 Basovizza-Trieste (Italy); Barinov, Alexei; Lizzit, Silvano; Lacovig, Paolo [Elettra Sincrotrone Trieste, S.S. 14 – km 163,5, Area Science Park, 34169 Basovizza-Trieste (Italy); Teodorescu, Cristian M., E-mail: teodorescu@infim.ro [National Institute of Materials Physics, Atomistilor 105b, 077125 Magurele-Ilfov (Romania)

2015-10-15

Graphical abstract: - Highlights: • Achievement of well ordered PZT(1 1 1) surfaces with reasonable low energy electron diffraction patterns and good stoichiometry. • Ability of photoelectron spectromicroscopy to visualize ferroelectric domains with contrast of binding energy. • Model taking into account the influence of photogenerated carriers on the depolarization field and its torque on the polarization vector. • Evidence of domain wall migration induced by photogenerated carriers. • Segregation of metal Pb only on areas with out-of-plane component of the polarization pointing outwards. - Abstract: The ability of photoelectron spectro-microscopy with sub-micrometer lateral resolution to identify ferroelectric domains by analysis of surface band bendings is demonstrated on lead zirco-titanate PZT(1 1 1) thin films grown by pulsed laser deposition. Conventional synchrotron radiation X-ray photoelectron spectroscopy allowed one to derive the surface composition of the sample and evidenced shifts toward higher binding energy when the sample is subject to intense soft X-ray beam. A basic model is developed which supposes that photogenerated carriers reduce the depolarization field, yielding a lower torque applied to the ferroelectric polarization. As a consequence, the out-of-plane component of the polarization increases. Domain migration during irradiation with soft X-ray is inferred from the relative amplitude of the components with different binding energy. When the flux density of soft X-ray is on the order of 10{sup 11} photons/(s μm{sup 2}), metal Pb clusters are formed at the surface on areas with the out-of-plane component of the polarization pointing outwards only.

Influence of sintering parameters in the ferroelectric properties os strontium bismuth tantalate samples obtained by oxide mixture

International Nuclear Information System (INIS)

Souza, R.R. de; Pereira, A.S.; Sousa, V.C.; Egea, J.R.J.

2012-01-01

The family of compounds layered-type perovskite, know as Aurivilius presents great alternative not only by the absence of lead in the composition, but because the polarization retention, replacing PZT in FeRAM devices. The strontium bismuth tantalate (SrBi 2 Ta 2 O 9 ) or SBT is ferroelectric material that has attracted considerable interest, since it has high fatigue resistance, supporting high hysteresis loops, with the change in polarization.Checking polarization and depolarization currents stimulated by temperature it is possible to obtain, for example, information about the nature of charges and about the activation energy for the process of dielectric relaxation. For analysis of ferroelectric properties of this compound, it is essential to obtain specimens with a relative density around 95%. Thus, it is important the optimization of the sintering process in order to obtain a ceramic body with a high densification. The influence of sintering parameters to obtain SrBi 2 Ta 2 O 9 in the polarization properties and in the microstructure of sintered samples was investigated by thermostimulated currents and electronic microscopy, respectively. Results show that variation of these parameters may cause changes in the ferroelectric properties of the material. (author)

4.0-nm-thick amorphous Nb–Ni film as a conducting diffusion barrier layer for integrating ferroelectric capacitor on Si

International Nuclear Information System (INIS)

Dai, X.H.; Guo, J.X.; Zhang, L.; Jia, D.M.; Qi, C.G.; Zhou, Y.; Li, X.H.; Shi, J.B.; Fu, Y.J.; Wang, Y.L.; Lou, J.Z.; Ma, L.X.; Zhao, H.D.; Liu, B.T.

2015-01-01

Highlights: • 4-nm-thick amorphous Nb–Ni film is first used as the conducting barrier layer. • No obvious interdiffusion/reaction can be found from the LSCO/PZT/LSCO/Nb–Ni/Si. • The LSCO/PZT/LSCO capacitor, measured at 5 V, possesses very good properties. • Ultrathin amorphous Nb–Ni film is ideal to fabricate silicon-based FRAM. - Abstract: We have successfully integrated La 0.5 Sr 0.5 CoO 3 /PbZr 0.4 Ti 0.6 O 3 /La 0.5 Sr 0.5 CoO 3 (LSCO/PZT/LSCO) capacitors on silicon substrate using a ∼4.0-nm-thick amorphous Nb–Ni film as the conducting diffusion barrier layer. Transmission electron microscopy technique confirms that the Nb–Ni film is still amorphous after fabrication of the capacitors, and the interfaces related to Nb–Ni are clean and sharp without any findable interdiffusion/reaction. The LSCO/PZT/LSCO capacitor, measured at 5 V, possesses very good properties, such as large remanent polarization of ∼22.1 μC/cm 2 , small coercive voltage of ∼1.27 V, good fatigue-resistance, and small pulse width dependence, implying that ultrathin amorphous Nb–Ni film is ideal as the conducting diffusion barrier layer to fabricate high-density silicon-based ferroelectric random access memories

4.0-nm-thick amorphous Nb–Ni film as a conducting diffusion barrier layer for integrating ferroelectric capacitor on Si

Energy Technology Data Exchange (ETDEWEB)

Dai, X.H. [Hebei Key Lab of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University, Hebei 071002 (China); College of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401 (China); Guo, J.X.; Zhang, L.; Jia, D.M.; Qi, C.G.; Zhou, Y.; Li, X.H.; Shi, J.B.; Fu, Y.J.; Wang, Y.L.; Lou, J.Z. [Hebei Key Lab of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University, Hebei 071002 (China); Ma, L.X. [Department of Physics, Blinn College, Bryan, TX 77805 (United States); Zhao, H.D. [College of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401 (China); Liu, B.T., E-mail: btliu@hbu.cn [Hebei Key Lab of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University, Hebei 071002 (China)

2015-10-05

Highlights: • 4-nm-thick amorphous Nb–Ni film is first used as the conducting barrier layer. • No obvious interdiffusion/reaction can be found from the LSCO/PZT/LSCO/Nb–Ni/Si. • The LSCO/PZT/LSCO capacitor, measured at 5 V, possesses very good properties. • Ultrathin amorphous Nb–Ni film is ideal to fabricate silicon-based FRAM. - Abstract: We have successfully integrated La{sub 0.5}Sr{sub 0.5}CoO{sub 3}/PbZr{sub 0.4}Ti{sub 0.6}O{sub 3}/La{sub 0.5}Sr{sub 0.5}CoO{sub 3} (LSCO/PZT/LSCO) capacitors on silicon substrate using a ∼4.0-nm-thick amorphous Nb–Ni film as the conducting diffusion barrier layer. Transmission electron microscopy technique confirms that the Nb–Ni film is still amorphous after fabrication of the capacitors, and the interfaces related to Nb–Ni are clean and sharp without any findable interdiffusion/reaction. The LSCO/PZT/LSCO capacitor, measured at 5 V, possesses very good properties, such as large remanent polarization of ∼22.1 μC/cm{sup 2}, small coercive voltage of ∼1.27 V, good fatigue-resistance, and small pulse width dependence, implying that ultrathin amorphous Nb–Ni film is ideal as the conducting diffusion barrier layer to fabricate high-density silicon-based ferroelectric random access memories.

Very high frequency (beyond 100 MHz) PZT kerfless linear arrays.

Science.gov (United States)

Wu, Da-Wei; Zhou, Qifa; Geng, Xuecang; Liu, Chang-Geng; Djuth, Frank; Shung, K Kirk

2009-10-01

This paper presents the design, fabrication, and measurements of very high frequency kerfless linear arrays prepared from PZT film and PZT bulk material. A 12-microm PZT thick film fabricated from PZT-5H powder/solution composite and a piece of 15-microm PZT-5H sheet were used to fabricate 32-element kerfless high-frequency linear arrays with photolithography. The PZT thick film was prepared by spin-coating of PZT sol-gel composite solution. The thin PZT-5H sheet sample was prepared by lapping a PZT-5H ceramic with a precision lapping machine. The measured results of the 2 arrays were compared. The PZT film array had a center frequency of 120 MHz, a bandwidth of 60% with a parylene matching layer, and an insertion loss of 41 dB. The PZT ceramic sheet array was found to have a center frequency of 128 MHz with a poorer bandwidth (40% with a parylene matching layer) but a better sensitivity (28 dB insertion loss).

Lead-free relaxor ferroelectric ceramics in NaNbO.sub.3./sub.-Sr.sub.0.5./sub.NbO.sub.3./sub.-LiNbO.sub.3./sub. solid solution system

Czech Academy of Sciences Publication Activity Database

Raevskaya, S. I.; Dellis, J.L.; Reznichenko, L.A.; Prosandeev, S. A.; Raevski, I. P.; Lisitsina, S.O.; Jastrabík, Lubomír

2005-01-01

Roč. 317, - (2005), s. 241-243 ISSN 0015-0193 Institutional research plan: CEZ:AV0Z10100522 Keywords : diffuse phase transition * lead-free relaxors * solid solutions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.459, year: 2005

Enhanced pyroelectric and piezoelectric properties of PZT with aligned porosity for energy harvesting applications† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7ta00967d Click here for additional data file.

Science.gov (United States)

Zhang, Yan; Xie, Mengying; Roscow, James; Bao, Yinxiang; Zhou, Kechao

2017-01-01

This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction. As a result of the introduction of porosity into the ceramic microstructure, high piezoelectric and pyroelectric harvesting figures of merits were achieved for porous freeze-cast PZT compared to dense PZT due to the reduced permittivity and volume specific heat capacity. Experimental results were compared to parallel and series analytical models with good agreement and the PZT with porosity aligned parallel to the freezing direction exhibited the highest piezoelectric and pyroelectric harvesting response; this was a result of the enhanced interconnectivity of the ferroelectric material along the poling direction and reduced fraction of unpoled material that leads to a higher polarization. A complete thermal energy harvesting system, composed of a parallel-aligned PZT harvester element and an AC/DC converter, was successfully demonstrated by charging a storage capacitor. The maximum energy density generated by the 60 vol% porous parallel-connected PZT when subjected to thermal oscillations was 1653 μJ cm–3, which was 374% higher than that of the dense PZT with an energy density of 446 μJ cm–3. The results are beneficial for the design and manufacture of high performance porous pyroelectric and piezoelectric materials in devices for energy harvesting and sensor applications. PMID:28580142

Dielectric response of the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 in the nonergodic state after a DC electric field is turned off

International Nuclear Information System (INIS)

Kolpakova, N. N.; Czarnecki, P.

2006-01-01

The Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) relaxor system is used as an example to analyze the temperature dependences of the low-frequency dielectric permitivity (ε'(T)) measured during zero-field heating (ZFH) from T = 10 K to T = 300 K after using different field cooling (FC) conditions. No changes in the temperature dependences of the permittivity have been detected during the transition from a nonergodic relaxor state (NERS) into an ergodic relaxor state (ERS) (at T f ∼ 216 K). However, the difference Δε'(T) between the curves corresponding to different field cooling conditions in the same electric field has different shapes and different values below and above T → (T f + 9 K) - (for E dc = 1.52 kV/cm). The reduced permittivities ε' r (T, f) recorded under different cooling conditions are shown to change their behavior when passing through T = T f + 9 K. In NERS, these curves diverge: the stronger the field (0 ≤ E dc ≤ 3 kV/cm), the larger the divergence. In ERS, however, the ε' r (T, f) curves coincide under different cooling conditions irrespective of the field. The character of the changes in Δε'(T) and ε' r (T, f) during the NERS-ERS transition is frequency-independent. The difference in the behavior of the dielectric response during ZFH after cooling in different (ZFC, FC) modes (even in a weak field), for both transition through T f and cooling down to T = 10 K, indicates different NERSs forming under these conditions. The contribution to ε'(T) from slowly relaxing regions (ω ∼ 0.1 mHz), whose polarization is reoriented after the field is turned off, is responsible for the fact that, during the NERS-ERS transition, the ε' r (T, f) curves coincide at a temperature that is higher than T = T f

Effect of Pb content and solution concentration of Pb{sub x}TiO{sub 3} seed layer on (100)-texture and ferroelectric/dielectric behavior of PZT (52/48) thin films

Energy Technology Data Exchange (ETDEWEB)

Zhong, Jian; Batra, Vaishali; Han, Hui; Kotru, Sushma, E-mail: skotru@eng.ua.edu [Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, Alabama 35487 (United States); Pandey, Raghvendar K. [Ingram School of Engineering, Texas State University, San Marcos, Texas 78666 (United States)

2015-09-15

The effect of Pb content and solution concentration of lead titanate (Pb{sub x}TiO{sub 3}) seed layer on the texture and electric properties of Pb{sub 1.1}(Zr{sub 0.52},Ti{sub 0.48})O{sub 3} (PZT) thin films was investigated. A variety of seed layers (y Pb{sub x}TiO{sub 3}) with varying solution concentration (y = 0.02, 0.05, 0.1, and 0.2 M) and Pb content (x = 1.0, 1.05, 1.1, and 1.2) was deposited on Pt/TiO{sub 2}/SiO{sub 2}/Si substrates using chemical-solution deposition method. PZT films were then deposited on these seed layers using the same process. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy investigations of the seed layers confirm change in crystal structure with variation in the solution properties. XRD studies of PZT films deposited on seed layers demonstrate that the seed layer helps in enhancing (100)-texture and suppressing (111)-texture. It was observed that PZT films prepared on seed layers with lower solution concentrations results in highly (100)-textured films, which further helps to improve the electric properties. The polarization and dielectric constant of the PZT films were seen to increase while the coercive field decreased with increase in (100)-texture. Irrespective of the seed layer solution concentration, higher Pb content in the seed layer deteriorates the PZT film properties. Ninety-five percent to ninety-six percent (100)-texture was obtained from thin PZT films deposited on seed layers of 0.02 M solution concentration with 1.05 and 1.10 Pb contents, which is higher than the values reported for thick PZT films. Optimization of both Pb content and solution concentration of the seed layer is a promising route to achieve highly (100)-textured PZT films with improved electric properties.

Temperature dependence of high field electromechanical coupling in ferroelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Weaver, P M; Cain, M G; Stewart, M, E-mail: paul.weaver@npl.co.u [National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW (United Kingdom)

2010-04-28

A study of the temperature dependence of the electromechanical response of ferroelectric lead zirconate titanate (PZT) ceramics at high electric fields (up to 1.3 kV mm{sup -1}) is reported. Simultaneous measurements were performed of strain, electric field and polarization to form a complete response map from room temperature up to 200 {sup 0}C. An electrostrictive model is shown to provide an accurate description of the electromechanical response to high levels of induced polarization and electric field. This provides a method for decoupling strain contributions from thermal expansion and polarization changes. Direct measurements of electrostriction and thermal expansion, above and below the Curie temperature, are reported. Electrostriction coefficients are shown to be temperature dependent in these ceramic materials, with different values above and below the Curie temperature.

Combined intrinsic elastocaloric and electrocaloric properties of ferroelectrics

Science.gov (United States)

Khassaf, H.; Patel, T.; Alpay, S. P.

2017-04-01

In multiferroic materials, adiabatic temperature changes can be obtained by the combined application of electric, stress, and magnetic fields. These external stimuli provide additional channels of entropy variations resulting in a multi-caloric response. In ferroelectric (FE) materials, caloric responses can be obtained with the application of electric and mechanical fields. Here, we compute the intrinsic elastocaloric and stress-mediated electrocaloric behavior of prototypical FE materials using the Landau-Devonshire theory of phase transformations with appropriate electrical and electro-mechanical boundary conditions. We show that an elastocaloric adiabatic temperature variation of 12.7 °C can be obtained in PbTiO3 with the application of uniaxial tensile stress of 500 MPa near its Curie point. This is 59% higher than its pure intrinsic electrocaloric response for an electric field difference of 100 kV/cm. Moreover, external stresses allow the maximum electro-elastocaloric response to be tuned towards room temperature. Our calculations show that relaxor FEs should exhibit large adiabatic temperature variations in relatively broad temperature ranges. These findings indicate that caloric responses in ferroic materials can be deterministically controlled and enhanced by utilizing a variety of external stimuli.

Unraveling the nature of electric field- and stress- induced structural transformations in soft PZT by a new powder poling technique.

Science.gov (United States)

Kalyani, Ajay Kumar; V, Lalitha K; James, Ajit R; Fitch, Andy; Ranjan, Rajeev

2015-02-25

A 'powder-poling' technique was developed to study electric field induced structural transformations in ferroelectrics exhibiting a morphotropic phase boundary (MPB). The technique was employed on soft PZT exhibiting a large longitudinal piezoelectric response (d(33) ∼ 650 pC N(-1)). It was found that electric poling brings about a considerable degree of irreversible tetragonal to monoclinic transformation. The same transformation was achieved after subjecting the specimen to mechanical stress, which suggests an equivalence of stress and electric field with regard to the structural mechanism in MPB compositions. The electric field induced structural transformation was also found to be accompanied by a decrease in the spatial coherence of polarization.

Electron Emission And Beam Generation Using Ferroelectric Cathodes (electron Beam Generation, Lead Lanthanum Zicronate Titanate, High Power Traveling Wave Tube Amplfier)

CERN Document Server

Flechtner, D D

1999-01-01

In 1989, researchers at CERN published the discovery of significant electron emission (1– 100 A/cm2) from Lead- Lanthanum-Zirconate-Titanate (PLZT). The publication of these results led to international interest in ferroelectric cathodes studies for use in pulsed power devices. At Cornell University in 1991, experiments with Lead-Zirconate-Titanate (PZT) compositions were begun to study the feasibility of using this ferroelectric material as a cathode in the electron gun section of High Power Traveling Wave Tube Amplifier Experiments. Current-voltage characteristics were documented for diode voltages ranging from 50– 500,000 V with anode cathode gaps of.5– 6 cm. A linear current-voltage relation was found for voltages less than 50 kV. For diode voltages ≥ 200 kV, a typical Child-Langmuir V3/2 dependence was observed...

Switching kinetics of a relaxor ferroelectric Sr0.75Ba0.25Nb2O6 observed by the second harmonic generation method

International Nuclear Information System (INIS)

Volk, Tatyana; Isakov, Dmitry; Belsley, Michael Scott; Ivleva, Lyudmila

2009-01-01

In this work we present a study of the ferroelectric switching kinetic process in strontium-barium niobate (SBN). The kinetics of polarization deduced from the dynamics of the diffuse second harmonic generation is in good qualitative agreement with thekinetics observed by more traditional polarization methods. Our work highlights the specific characteristics of polarization reversal in SBN, which is fundamentally different from that which occurs in model ferroelectrics. The presented optical measurements of the polarization processes provide several experimental advantages over traditional electrical measurements. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Relaxor type perovskites: Primary candidates of nano-polar regions

Indian Academy of Sciences (India)

Unknown

between Pb and O ions. Kleeman et al5 ... sputtering,13 sol–gel14 etc. In the present work ..... Hence the barium-based non lead relaxor materials have been of ..... Kingon A I, Streiffer, Basceri C and Summerfelt S R 1996 Mater. Res. Soc. Bull.

Three-terminal ferroelectric synapse device with concurrent learning function for artificial neural networks

International Nuclear Information System (INIS)

Nishitani, Y.; Kaneko, Y.; Ueda, M.; Fujii, E.; Morie, T.

2012-01-01

Spike-timing-dependent synaptic plasticity (STDP) is demonstrated in a synapse device based on a ferroelectric-gate field-effect transistor (FeFET). STDP is a key of the learning functions observed in human brains, where the synaptic weight changes only depending on the spike timing of the pre- and post-neurons. The FeFET is composed of the stacked oxide materials with ZnO/Pr(Zr,Ti)O 3 (PZT)/SrRuO 3 . In the FeFET, the channel conductance can be altered depending on the density of electrons induced by the polarization of PZT film, which can be controlled by applying the gate voltage in a non-volatile manner. Applying a pulse gate voltage enables the multi-valued modulation of the conductance, which is expected to be caused by a change in PZT polarization. This variation depends on the height and the duration of the pulse gate voltage. Utilizing these characteristics, symmetric and asymmetric STDP learning functions are successfully implemented in the FeFET-based synapse device by applying the non-linear pulse gate voltage generated from a set of two pulses in a sampling circuit, in which the two pulses correspond to the spikes from the pre- and post-neurons. The three-terminal structure of the synapse device enables the concurrent learning, in which the weight update can be performed without canceling signal transmission among neurons, while the neural networks using the previously reported two-terminal synapse devices need to stop signal transmission for learning.

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

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

Synthesis and refinement of ferroelectric ceramic BaBi4Ti4O15 (BBT) using Rietveld Methods

International Nuclear Information System (INIS)

Silva, P.M.O.; Sales, A.J.M.; Carneiro, J.C.S.; Sancho, E.O.; Sales, J.C.; Sombra, A.S.B.

2012-01-01

The lead zirconate titanate (PZT) has potential application in nonvolatile ferroelectric memory and capacitors, however this material is linked to environmental pollution. In order to remedy this problem, we propose the synthesis of the compound, BaBi 4 TI 4 O 15 (BBT) because of similarity to PZT. The phase of the BBT has been prepared by the method of solid state. Reagents (BaCO 3 , Bi 2 O 3 and TiO 2 ) were ground for 6 hours at 360 rpm in a planetary ball mill and suffered high energy heat treatment for 2 hours at temperatures of 850, 900, 950 and 1000 ° C. The calcined powder was characterized by X-ray diffraction (XRD) and refined by the program DBWSTools 2.3 Beta based on the Rietveld method. The results obtained confirmed the refinement of the single-phase with tetragonal structure BaBi 4 TI 4 O 15 for all samples. The sample calcined at 950 °C presented the best densification (7.508 g/cm³). (author)

Fabrication of flexible piezoelectric PZT/fabric composite.

Science.gov (United States)

Chen, Caifeng; Hong, Daiwei; Wang, Andong; Ni, Chaoying

2013-01-01

Flexible piezoelectric PZT/fabric composite material is pliable and tough in nature which is in a lack of traditional PZT patches. It has great application prospect in improving the sensitivity of sensor/actuator made by piezoelectric materials especially when they are used for curved surfaces or complicated conditions. In this paper, glass fiber cloth was adopted as carrier to grow PZT piezoelectric crystal particles by hydrothermal method, and the optimum conditions were studied. The results showed that the soft glass fiber cloth was an ideal kind of carrier. A large number of cubic-shaped PZT nanocrystallines grew firmly in the carrier with a dense and uniform distribution. The best hydrothermal condition was found to be pH 13, reaction time 24 h, and reaction temperature 200°C.

Advantages of PZT thick film for MEMS sensors

DEFF Research Database (Denmark)

Hindrichsen, Christian Carstensen; Lou-Moller, R.; Hansen, K.

2010-01-01

For all MEMS devices a high coupling between the mechanical and electrical domain is desired. Figures of merit describing the coupling are important for comparing different piezoelectric materials. The existing figures of merit are discussed and a new figure of merit is introduced for a fair comp....... Improved figure of merit is reached in the piezoelectric PZT thick film, TF2100CIP, by using cold isostatic pressure in the PZT preparation process. The porosity of TF2100 is decreased 38%, hence, allowing an increase of charge sensitivity for MEMS sensors of 59%....... thin film and PZT thick film. It is shown that MEMS sensors with the PZT thick film TF2100 from InSensor A/S have potential for significant higher voltage sensitivities compared to PZT thin film base MEMS sensors when the total thickness of the MEMS cantilever, beam, bridge or membrane is high...

Regulation of depletion layer width in Pb(Zr,Ti)O3/Nb:SrTiO3 heterostructures

Science.gov (United States)

Bai, Yu; Jie Wang, Zhan; Cui, Jian Zhong; Zhang, Zhi Dong

2018-05-01

Improving the tunability of depletion layer width (DLW) in ferroelectric/semiconductor heterostructures is important for the performance of some devices. In this work, 200-nm-thick Pb(Zr0.4Ti0.6)O3 (PZT) films were deposited on different Nb-doped SrTiO3 (NSTO) substrates, and the tunability of DLW at PZT/NSTO interfaces were studied. Our results showed that the maximum tunability of the DLW was achieved at the NSTO substrate with 0.5 wt% Nb. On the basis of the modified capacitance model and the ferroelectric semiconductor theory, we suggest that the tunability of the DLW in PZT/NSTO heterostructures can be attributed to a delicate balance of the depletion layer charge and the ferroelectric polarization charge. Therefore, the performance of some devices related to the tunability of DLW in ferroelectric/semiconductor heterostructures can be improved by modulating the doping concentration in semiconducting electrode materials.

Experimental characterization of PZT fibers using IDE electrodes

Science.gov (United States)

Wyckoff, Nicholas; Ben Atitallah, Hassene; Ounaies, Zoubeida

2016-04-01

Lead zirconate titanate (PZT) fibers are mainly used in active fiber composites (AFC) where they are embedded in a polymer matrix. Interdigitated electrodes (IDE) along the direction of the fibers are used to achieve planar actuation, hereby exploiting the d33 coefficient of PZT. When embedded in the AFC, the PZT fibers are subjected to mechanical loading as well as non-uniform electric field as a result of the IDEs. Therefore, it is important to characterize the electrical and electromechanical behavior of these fibers ex-situ using the IDE electrodes to assess the impact of nonuniform electric field on the properties of the fibers. For that reason, this work aims at quantifying the impact of IDE electrodes on the electrical and electromechanical behavior of PZT fibers, which is necessary for their successful implementation in devices like AFC. The tested fibers were purchased from Advanced Cerametrics and they have an average diameter of 250 micrometers. The IDE electrodes were screen printed on an acrylic substrate. The PZT fibers were subjected to frequency sweeps at low voltages to determine permittivity for parallel and interdigitated electrodes. The piezoelectric e33 constant is determined from electromechanical testing of PZT fibers in parallel electrodes to compare the electromechanical behavior for PZT in bulk and fiber form. The dielectric constant and e33 were found to be lower for the IDE and parallel electrodes compared to bulk but comparable to results published in literature.

Modeling and Implementation of HfO2-based Ferroelectric Tunnel Junctions

Science.gov (United States)

Pringle, Spencer Allen

HfO2-based ferroelectric tunnel junctions (FTJs) represent a unique opportunity as both a next-generation digital non-volatile memory and as synapse devices in braininspired logic systems, owing to their higher reliability compared to filamentary resistive random-access memory (ReRAM) and higher speed and lower power consumption compared to competing devices, including phase-change memory (PCM) and state-of-the-art FTJ. Ferroelectrics are often easier to deposit and have simpler material structure than films for magnetic tunnel junctions (MTJs). Ferroelectric HfO2 also enables complementary metal-oxide-semiconductor (CMOS) compatibility, since lead zirconate titanate (PZT) and BaTiO3-based FTJs often are not. No other groups have yet demonstrated a HfO2-based FTJ (to best of the author's knowledge) or applied it to a suitable system. For such devices to be useful, system designers require models based on both theoretical physical analysis and experimental results of fabricated devices in order to confidently design control systems. Both the CMOS circuitry and FTJs must then be designed in layout and fabricated on the same die. This work includes modeling of proposed device structures using a custom python script, which calculates theoretical potential barrier heights as a function of material properties and corresponding current densities (ranging from 8x103 to 3x10-2 A/cm 2 with RHRS/RLRS ranging from 5x105 to 6, depending on ferroelectric thickness). These equations were then combined with polynomial fits of experimental timing data and implemented in a Verilog-A behavioral analog model in Cadence Virtuoso. The author proposes tristate CMOS control systems, and circuits, for implementation of FTJ devices as digital memory and presents simulated performance. Finally, a process flow for fabrication of FTJ devices with CMOS is presented. This work has therefore enabled the fabrication of FTJ devices at RIT and the continued investigation of them as applied to any

Fabrication and comparison of PMN-PT single crystal, PZT and PZT-based 1-3 composite ultrasonic transducers for NDE applications.

Science.gov (United States)

Kim, Ki-Bok; Hsu, David K; Ahn, Bongyoung; Kim, Young-Gil; Barnard, Daniel J

2010-08-01

This paper describes fabrication and comparison of PMN-PT single crystal, PZT, and PZT-based 1-3 composite ultrasonic transducers for NDE applications. As a front matching layer between test material (Austenite stainless steel, SUS316) and piezoelectric materials, alumina ceramics was selected. The appropriate acoustic impedance of the backing materials for each transducer was determined based on the results of KLM model simulation. Prototype ultrasonic transducers with the center frequencies of approximately 2.25 and 5MHz for contact measurement were fabricated and compared to each other. The PMN-PT single crystal ultrasonic transducer shows considerably improved performance in sensitivity over the PZT and PZT-based 1-3 composite ultrasonic transducers. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Two-dimensional ferroelectrics

Energy Technology Data Exchange (ETDEWEB)

Blinov, L M; Fridkin, Vladimir M; Palto, Sergei P [A.V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow, Russian Federaion (Russian Federation); Bune, A V; Dowben, P A; Ducharme, Stephen [Department of Physics and Astronomy, Behlen Laboratory of Physics, Center for Materials Research and Analysis, University of Nebraska-Linkoln, Linkoln, NE (United States)

2000-03-31

The investigation of the finite-size effect in ferroelectric crystals and films has been limited by the experimental conditions. The smallest demonstrated ferroelectric crystals had a diameter of {approx}200 A and the thinnest ferroelectric films were {approx}200 A thick, macroscopic sizes on an atomic scale. Langmuir-Blodgett deposition of films one monolayer at a time has produced high quality ferroelectric films as thin as 10 A, made from polyvinylidene fluoride and its copolymers. These ultrathin films permitted the ultimate investigation of finite-size effects on the atomic thickness scale. Langmuir-Blodgett films also revealed the fundamental two-dimensional character of ferroelectricity in these materials by demonstrating that there is no so-called critical thickness; films as thin as two monolayers (1 nm) are ferroelectric, with a transition temperature near that of the bulk material. The films exhibit all the main properties of ferroelectricity with a first-order ferroelectric-paraelectric phase transition: polarization hysteresis (switching); the jump in spontaneous polarization at the phase transition temperature; thermal hysteresis in the polarization; the increase in the transition temperature with applied field; double hysteresis above the phase transition temperature; and the existence of the ferroelectric critical point. The films also exhibit a new phase transition associated with the two-dimensional layers. (reviews of topical problems)

Standing wave brass-PZT square tubular ultrasonic motor.

Science.gov (United States)

Park, Soonho; He, Siyuan

2012-09-01

This paper reports a standing wave brass-PZT tubular ultrasonic motor. The motor is composed of a brass square tube with two teeth on each tube end. Four PZT plates are attached to the outside walls of the brass tube. The motor requires only one driving signal to excite vibration in a single bending mode to generate reciprocating diagonal trajectories of teeth on the brass tube ends, which drive the motor to rotate. Bi-directional rotation is achieved by exciting different pairs of PZT plates to switch the bending vibration direction. Through using the brass-PZT tube structure, the motor can take high magnitude vibration to achieve a high output power in comparison to PZT tube based ultrasonic motors. Prototypes are fabricated and tested. The dimension of the brass-PZT tube is 3.975mm×3.975mm×16mm. Measured performance is a no-load speed of >1000RPM, a stall torque of 370μNm and a maximum output power of 16 mW when a sinusoidal driving voltage of 50V is applied. The working frequencies of the motor are 46,050Hz (clockwise) and 46,200Hz (counter-clockwise). Copyright © 2012. Published by Elsevier B.V.

Using microwave for processing nanostructured PZT ceramics; Utilizacao de microondas no processamento de ceramicas nanoestruturadas de PZT

Energy Technology Data Exchange (ETDEWEB)

Lanza, A.C.; Berti, T.G.; Thomazini, D.; Gelfuso, M.V., E-mail: lanza.work@gmail.com [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Instituto de Engenharia Mecanica; Eiras, J.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Dept. de Fisica

2012-07-01

The PZT ceramics have dielectric and piezoelectric properties of technological interest. The method of microwave assisted hydrothermal synthesis becomes interesting since it occurs in a closed environment, the low temperature and time, compared to conventional methods. In this work, PZT powders were dissolved in acid medium, and by adjusting the pH of the solutions obtained were precipitated, subjected to hydrothermal treatment at 120 °C for intervals of 15, 30 and 60 min. The powders were characterized by differential thermal and gravimetric analysis, X-ray diffraction and scanning electron microscopy. The results confirm the formation of PZT phase in one hour with particle size around 55 nm, showing the feasibility of the proposed method. (author)

Comparative face-shear piezoelectric properties of soft and hard PZT ceramics

Science.gov (United States)

Miao, Hongchen; Chen, Xi; Cai, Hairong; Li, Faxin

2015-12-01

The face-shear ( d 36 ) mode may be the most practical shear mode in piezoelectrics, while theoretically this mode cannot appear in piezoelectric ceramics because of its transversally isotropic symmetry. Recently, we realized piezoelectric coefficient d 36 up to 206pC/N in soft PbZr1-xTixO3 (PZT) ceramics via ferroelastic domain engineering [H. C. Miao and F. X. Li, Appl. Phys. Lett. 107, 122902 (2015)]. In this work, we further realized the face-shear mode in both hard and soft PZT ceramics including PZT-4 (hard), PZT-51(soft), and PZT-5H (soft) and investigated the electric properties systematically. The resonance methods are derived to measure the d 36 coefficients using both square patches and narrow bar samples, and the obtained values are consistent with that measured by a modified d 33 meter previously. For all samples, the pure d 36 mode can only appear near the resonance frequency, and the coupled d 36 - d 31 mode dominates off resonance. It is found that both the piezoelectric coefficient d 36 and the electromechanical coupling factor k 36 of soft PZT ceramics (PZT-5H and PZT-51) are considerably larger than those of the hard PZT ceramics (PZT-4). The obtained d 36 of 160-275pC/N, k 36 ˜ 0.24, and the mechanical quality factor Q 36 of 60-90 in soft PZT ceramics are comparable with the corresponding properties of the d 31 mode sample. Therefore, the d 36 mode in modified soft PZT ceramics is more promising for industrial applications such as face-shear resonators and shear horizontal wave generators.

The behaviour of the ferroelectric ceramics: BaTiO3, Pb(Zr,Ti)O3 and Pb(Sn,Zr,Ti)O3 When hit by a projectile from a 30 mm bore gun

International Nuclear Information System (INIS)

David, Jean

1971-10-01

The liberation of the electrical charges and energy stored in a ferroelectric material as a result of induced dynamic pressure was studied. The pressure was generated by the impact of a cylindrical projectile fired from a special 30 mm bore gun. A brief description of the gun, experimental set up, and the measurements made is given. It was shown that below a certain pressure P Emax , corresponding to the maximum energy liberated, barium titanate and PZT materials behave similarly. The maximum energy obtained with a PZT 95/5 material, was 700 mJ/cm 3 and was dissipated in a 5 Ω resistance. It is expected that improved material compositions will allow an energy density higher than 1 J /cm 3 to be reached [fr

Process induced poling and plasma induced damage of thin films PZT

NARCIS (Netherlands)

Wang, J.; Houwman, Evert Pieter; Salm, Cora; Nguyen, Duc Minh; Vergeer, Kurt; Schmitz, Jurriaan

2017-01-01

This paper treats processing sequence induced changes on PZT. Two kinds of metal-PZT-metal capacitors are compared. The top surface and sidewall of PZT in one kind of capacitor is directly bombarded by energetic particles during ion milling process, whereas PZT in the other kind of capacitor is not.

A comparative study of the Aurivillius phase ferroelectrics CaBi 4Ti 4O 15 and BaBi 4Ti 4O 15

Science.gov (United States)

Tellier, J.; Boullay, Ph.; Manier, M.; Mercurio, D.

2004-06-01

The room temperature structures of the four-layer Aurivillius phase ferroelectrics CaBi 4Ti 4O 15 and BaBi 4Ti 4O 15 are determined by means of single crystal X-ray diffraction. Regarding the CaBi 4Ti 4O 15 phase, in agreement with the tolerance factor, a significant deformation of the perovskite blocks is observed. The rotation system of the octahedra is typical from even layer Aurivillius phases and leads to the use of the space group A2 1am. For the BaBi 4Ti 4O 15 phase, only a weak variation with respect to the F2 mm space group can be suggested from single crystal X-ray diffraction. A significant presence of Ba atoms in the [ M2O 2] slabs is confirmed in agreement with the previous works but specific Ba 2+ and Bi 3+ sites have to be considered due to the large difference in bounding requirement of these cations. Possible origins for the ferroelectric relaxor behavior of the Ba-based compound are discussed in view of the presented structural analyses.

Characterization of Pb(Zr, Ti)O3 thin films fabricated by plasma enhanced chemical vapor deposition on Ir-based electrodes

International Nuclear Information System (INIS)

Lee, Hee-Chul; Lee, Won-Jong

2002-01-01

Structural and electrical characteristics of Pb(Zr, Ti)O 3 (PZT) ferroelectric thin films deposited on various Ir-based electrodes (Ir, IrO 2 , and Pt/IrO 2 ) using electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated. On the Ir electrode, stoichiometric PZT films with pure perovskite phase could be obtained over a very wide range of processing conditions. However, PZT films prepared on the IrO 2 electrode contain a large amount of PbO x phases and exhibited high Pb-excess composition. The deposition characteristics were dependent on the behavior of PbO molecules on the electrode surface. The PZT thin film capacitors prepared on the Ir bottom electrode showed different electrical properties depending on top electrode materials. The PZT capacitors with Ir, IrO 2 , and Pt top electrodes showed good leakage current characteristics, whereas those with the Ru top electrode showed a very high leakage current density. The PZT capacitor exhibited the best fatigue endurance with an IrO 2 top electrode. An Ir top electrode provided better fatigue endurance than a Pt top electrode. The PZT capacitor with an Ir-based electrode is thought to be attractive for the application to ferroelectric random access memory devices because of its wide processing window for a high-quality ferroelectric film and good polarization, fatigue, and leakage current characteristics

Preparation and properties of porous PMN-PZT ceramics doped with strontium

International Nuclear Information System (INIS)

Zeng Tao; Dong Xianlin; Mao Chaoliang; Chen Shutao; Chen Heng

2006-01-01

The piezoelectric and dielectric properties of lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramics were investigated as a function of density for transducer applications. A decrease in density increased elastic compliance and improved acoustic impedance matching between PMN-PZT ceramics and ambient media. The reduced dielectric constant (ε 33 ) and enhanced hydrostatic figure of merit (d h g h ) of PMN-PZT were observed with decreased density. The results showed the d h g h of PMN-PZT ceramic with density of about 5.4 g/cm 3 reached 4000 x 10 -15 m 2 /N, and the ε 33 was very close to 2000, which demonstrates that porous PMN-PZT ceramic is a promising material for transducer applications. Moreover, the low density PMN-PZT ceramics exhibited lower dielectric loss than high density PMN-PZT ceramics during the temperature from 250 deg. C to 500 deg. C

PVDF-PZT nanocomposite film based self-charging power cell.

Science.gov (United States)

Zhang, Yan; Zhang, Yujing; Xue, Xinyu; Cui, Chunxiao; He, Bin; Nie, Yuxin; Deng, Ping; Lin Wang, Zhong

2014-03-14

A novel PVDF-PZT nanocomposite film has been proposed and used as a piezoseparator in self-charging power cells (SCPCs). The structure, composed of poly(vinylidene fluoride) (PVDF) and lead zirconate titanate (PZT), provides a high piezoelectric output, because PZT in this nanocomposite film can improve the piezopotential compared to the pure PVDF film. The SCPC based on this nanocomposite film can be efficiently charged up by the mechanical deformation in the absence of an external power source. The charge capacity of the PVDF-PZT nanocomposite film based SCPC in 240 s is ∼0.010 μA h, higher than that of a pure PVDF film based SCPC (∼0.004 μA h). This is the first demonstration of using PVDF-PZT nanocomposite film as a piezoseparator for SCPC, and is an important step for the practical applications of SCPC for harvesting and storing mechanical energy.

PZT Thin-Film Micro Probe Device with Dual Top Electrodes

Science.gov (United States)

Luo, Chuan

Lead zirconate titanate (PZT) thin-film actuators have been studied intensively for years because of their potential applications in many fields. In this dissertation, a PZT thin-film micro probe device is designed, fabricated, studied, and proven to be acceptable as an intracochlear acoustic actuator. The micro probe device takes the form of a cantilever with a PZT thin-film diaphragm at the tip of the probe. The tip portion of the probe will be implanted in cochlea later in animal tests to prove its feasibility in hearing rehabilitation. The contribution of the dissertation is three-fold. First, a dual top electrodes design, consisting of a center electrode and an outer electrode, is developed to improve actuation displacement of the PZT thin-film diaphragm. The improvement by the dual top electrodes design is studied via a finite element model. When the dimensions of the dual electrodes are optimized, the displacement of the PZT thin-film diaphragm increases about 30%. A PZT thin-film diaphragm with dual top electrodes is fabricated to prove the concept, and experimental results confirm the predictions from the finite element analyses. Moreover, the dual electrode design can accommodate presence of significant residual stresses in the PZT thin-film diaphragm by changing the phase difference between the two electrodes. Second, a PZT thin-film micro probe device is fabricated and tested. The fabrication process consists of PZT thin-film deposition and deep reactive ion etching (DRIE). The uniqueness of the fabrication process is an automatic dicing mechanism that allows a large number of probes to be released easily from the wafer. Moreover, the fabrication is very efficient, because the DRIE process will form the PZT thin-film diaphragm and the special dicing mechanism simultaneously. After the probes are fabricated, they are tested with various possible implantation depths (i.e., boundary conditions). Experimental results show that future implantation depths

Impedance spectroscopy and ferromagnetic properties of Bi{sub 0.8}Gd{sub 0.2}FeO{sub 3} multiferroics

Energy Technology Data Exchange (ETDEWEB)

Tian, Yahui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Xue, Fei [Center of Collaboration and Innovation, Jiangxi University of Technology, Nanchang, Jiangxi 330098 (China); Fu, Qiuyun, E-mail: fuqy@mail.hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhou, Dongxiang; Hu, Yunxiang; Zhou, Ling; Zheng, Zhiping; Xin, Zengnian [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China)

2017-08-01

Highlights: • BGFO ceramics exhibited high density, strong ferroelectricity, and good magnetism. • BGFO ceramics exhibited typical relaxor behavior. • There are different conductivity mechanisms at different temperatures for BGFO. - Abstract: Multiferroic Bi{sub 0.8}Gd{sub 0.2}FeO{sub 3} (BGFO) ceramics were prepared by a rapid-liquid phase sintering process. BGFO ceramics can be sintered at a sintering temperature range of 875 °C–940 °C and shown a pure orthorhombic (space group, Pnma) structure. The crystal symmetry and lattice parameters were determined from the Rietveld analysis for the experimental data. BGFO ceramics sintered at 900 °C exhibited high theoretical relative density (∼98%), strong ferroelectricity and good magnetism. BGFO ceramics exhibited the similar dielectric relaxation properties to the typical relaxor ferroelectrics. The role of oxygen vacancies at high temperature in dielectric and ac conductivity behavior was also discussed. The diffusing of structure defects between the grain and grain boundary was established using Impedance Spectroscopy (IS).

Optimization of parameters in the synthesis of 0.90Pb(Zn1/3Nb2/3)O3–0.10PbTiO3 (PZN-10PT) powders obtained by the mixed oxides method

Energy Technology Data Exchange (ETDEWEB)

Raigoza, C.F.V.; Garcia, D.; Eiras, J.A.; Kiminami, R.H.G.A.

2017-07-01

Preventing the formation of the pyrochlore phase in the synthesis of PZN-PT powders requires controlling calcination parameters such as temperature, soaking time and atmosphere. These parameters were examined extensively to determine the time and temperature at which the perovskite phase is the majority phase, as well as the atmosphere that facilitates the formation of this phase. A maximum of 74% of perovskite phase was obtained under the following conditions: 1000°C, 4h in nitrogen atmosphere. In this work, we studied the influence of these parameters, which were optimized, on the formation the perovskite phase in PZN-10PT powders synthesized by the conventional solid state method. (Author)

Interfacial morphology and domain configurations in 0-3 PZT-Portland cement composites

International Nuclear Information System (INIS)

Jaitanong, N.; Zeng, H.R.; Li, G.R.; Yin, Q.R.; Vittayakorn, W.C.; Yimnirun, R.; Chaipanich, A.

2010-01-01

Cement-based piezoelectric composites have attracted great attention recently due to their promising applications as sensors in smart structures. Lead zirconate titanate (PZT) and Portland cement (PC) composite were fabricated using 60% of PZT by volume. Scanning Electron Microscope and piezoresponse force microscope were used to investigate the morphology and domain configurations at the interfacial zone of PZT-Portland cement composites. Angular PZT ceramic grains were found to bind well with the cement matrix. The submicro-scale domains were clearly observed by piezoresponse force microscope at the interfacial regions between the piezoelectric PZT phase and Portland cement phase, and are clearer than the images obtained for pure PZT. This is thought to be due to the applied internal stress of cement to the PZT ceramic particle which resulted to clearer images.

PZT crack detection in suspension-based dual stage actuator [for HDDs

CERN Document Server

Yung Ping Yeh; Ku, C

2000-01-01

An impedance method is proposed to detect cracks of PZT bars in suspension based dual stage-actuators. The frequency response amplitude of impedance at the resonance of 1.95 MHz, the PZT bar width extension mode, was very sensitive to the cracks in PZT material. As cracks in the PZT bars propagated from invisible micro cracks to visible macro cracks, the impedance gain at 1.95 MHz dropped suddenly. (3 refs).

Effect of electrical and mechanical poling history on domain orientation and piezoelectric properties of soft and hard PZT ceramics

International Nuclear Information System (INIS)

Marsilius, Mie; Granzow, Torsten; Jones, Jacob L

2011-01-01

The superior piezoelectric properties of all polycrystalline ferroelectrics are based on the extent of non-180 0 domain wall motion under electrical and mechanical poling loads. To distinguish between 180 0 and non-180 0 domain wall motion in a soft-doped and a hard-doped lead zirconate titanate (PZT) ceramic, domain texture measurements were performed using x-ray and neutron diffraction after different loading procedures. Comparing the results to measurements of the remanent strain and piezoelectric coefficient allowed the differentiation between different microstructural contributions to the macroscopic parameters. Both types of ceramic showed similar behavior under electric field, but the hard-doped material was more susceptible to mechanical load. A considerable fraction of the piezoelectric coefficient originated from poling by the preferred orientation of 180 0 domains.

Effect of electrical and mechanical poling history on domain orientation and piezoelectric properties of soft and hard PZT ceramics

Science.gov (United States)

Marsilius, Mie; Granzow, Torsten; Jones, Jacob L.

2011-02-01

The superior piezoelectric properties of all polycrystalline ferroelectrics are based on the extent of non-180° domain wall motion under electrical and mechanical poling loads. To distinguish between 180° and non-180° domain wall motion in a soft-doped and a hard-doped lead zirconate titanate (PZT) ceramic, domain texture measurements were performed using x-ray and neutron diffraction after different loading procedures. Comparing the results to measurements of the remanent strain and piezoelectric coefficient allowed the differentiation between different microstructural contributions to the macroscopic parameters. Both types of ceramic showed similar behavior under electric field, but the hard-doped material was more susceptible to mechanical load. A considerable fraction of the piezoelectric coefficient originated from poling by the preferred orientation of 180° domains.

High Performance Lead--free Piezoelectric Materials

OpenAIRE

Gupta, Shashaank

2013-01-01

Piezoelectric materials find applications in number of devices requiring inter-conversion of mechanical and electrical energy.  These devices include different types of sensors, actuators and energy harvesting devices. A number of lead-based perovskite compositions (PZT, PMN-PT, PZN-PT etc.) have dominated the field in last few decades owing to their giant piezoresponse and convenient application relevant tunability. With increasing environmental concerns, in the last one decade, focus has be...

Humidity and polarity influence on MIM PZT capacitor degradation and breakdown

NARCIS (Netherlands)

Wang, Jiahui; Salm, Cora; Houwman, Evert; Schmitz, Jurriaan; Nguyen, Minh

2016-01-01

This paper presents a reliability study on unpackaged metal-PZT-metal capacitors. Both ramped voltage stress (RVS) and time dependent dielectric breakdown (TDDB) measurements show that environmental humidity dramatically worsens the PZT reliability. Visible breakdown spots on the surface of PZT

The effect of Nb doping on ferroelectric properties of PZT thin films prepared from polymeric precursors

International Nuclear Information System (INIS)

Souza, E.C.F.; Simoes, A.Z.; Cilense, M.; Longo, E.; Varela, J.A.

2004-01-01

Pure and Nb doped PbZr 0.4 Ti 0.6 O 3 thin films was prepared by the polymeric precursor method and deposited by spin coating on Pt/Ti/SiO 2 /Si (100) substrates and annealed at 700 deg. C. The films are oriented in (1 1 0) and (1 0 0) direction. The electric properties of PZT thin films show strong dependence of the crystallographic orientation. The P-E hysteresis loops for the thin film with composition PbZr 0.39 Ti 0.6 Nb 0.1 O 3 showed good saturation, with values for coercive field (E c ) equal to 60 KV cm -1 and for remanent polarization (P r ) equal to 20 μC cm -2 . The measured dielectric constant (ε) is 1084 for this film. These results show good potential for application in FERAM

Phase-Field Simulations of Topological Structures and Topological Phase Transitions in Ferroelectric Oxide Heterostructures

Science.gov (United States)

Zijian Hong

Ferroelectrics are materials that exhibit spontaneous electric polarization which can be switched between energy-degenerated states by external stimuli (e.g., mechanical force and electric field) that exceeds a critical value. They have wide potential applications in memories, capacitors, piezoelectric and pyroelectric sensors, and nanomechanical systems. Topological structures and topological phase transitions have been introduced to the condensed matter physics in the past few decades and have attracted broad attentions in various disciplines due to the rich physical insights and broad potential applications. Ferromagnetic topological structures such as vortex and skyrmion are known to be stabilized by the antisymmetric chiral interaction (e.g., Dzyaloshinskii-Moriya interaction). Without such interaction, ferroelectric topological structures (i.e., vortex, flux-closure, skyrmions, and merons) have been studied only recently with other designing strategies, such as reducing the dimension of the ferroelectrics. The overarching goal of this dissertation is to investigate the topological structures in ferroelectric oxide perovskites as well as the topological phase transitions under external applied forces. Pb(Zr,Ti)O3 (PZT) with morphotropic phase boundary is widely explored for high piezoelectric and dielectric properties. The domain structure of PZT tetragonal/rhombohedral (T/R) bilayer is investigated. Strong interfacial coupling is shown, with large polarization rotation to a lower symmetry phase near the T/R interface. Interlayer domain growth can also be captured, with T-domains in the R layer and R-domains in the T layer. For thin PZT bilayer with 5nm of T-layer and 20 nm of R-layer, the a1/a 2 twin domain structure is formed in the top T layer, which could be fully switched to R domains under applied bias. While a unique flux-closure pattern is observed both theoretically and experimentally in the thick bilayer film with 50 nm of thickness for both T and R

Investigation of top electrode for PZT thick films based MEMS sensors

DEFF Research Database (Denmark)

Hindrichsen, Christian Carstensen; Pedersen, Thomas; Kristiansen, Paw T.

2010-01-01

In this work processing of screen printed piezoelectric PZT thick films on silicon substrates is investigated for use in future MEMS devices. E-beam evaporated Al and Pt are patterned on PZT as a top electrode using a lift-off process with a line width down to 3 mu m. Three test structures are used...... to investigate the optimal thickness of the top electrode, the degradation of the piezoelectric properties of the PZT film in absence of a diffusion barrier layer and finally how to fabricate electrical interconnects down the edge of the PZT thick film. The roughness of the PZT is found to have a strong...... influence on the conductance of the top electrode influencing the optimal top electrode thickness. A 100 nm thick top electrode on the PZT thick film with a surface roughness of 273 nm has a 4.5 times higher resistance compared to a similar wire on a planar SiO2 surface which has a surface roughness of less...

Power harvesting using PZT ceramics embedded in orthopedic implants.

Science.gov (United States)

Chen, Hong; Liu, Ming; Jia, Chen; Wang, Zihua

2009-09-01

Battery lifetime has been the stumbling block for many power-critical or maintenance-free real-time embedded applications, such as wireless sensors and orthopedic implants. Thus a piezoelectric material that could convert human motion into electrical energy provides a very attractive solution for clinical implants. In this work, we analyze the power generation characteristics of stiff lead zirconate titanate (PZT) ceramics and the equivalent circuit through extensive experiments. Our experimental framework allows us to explore many important design considerations of such a PZT-based power generator. Overall we can achieve a PZT element volume of 0.5 x 0.5 x 1.8 cm, which is considerably smaller than the results reported so far. Finally, we outline the application of our PZT elements in a total knee replacement (TKR) implant.

Effect of top electrode material on radiation-induced degradation of ferroelectric thin film structures

Energy Technology Data Exchange (ETDEWEB)

Brewer, Steven J.; Bassiri-Gharb, Nazanin [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Deng, Carmen Z.; Callaway, Connor P. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Paul, McKinley K. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Woodward Academy, College Park, Georgia 30337 (United States); Fisher, Kenzie J. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Riverwood International Charter School, Atlanta, Georgia 30328 (United States); Guerrier, Jonathon E.; Jones, Jacob L. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Rudy, Ryan Q.; Polcawich, Ronald G. [Army Research Laboratory, Adelphi, Maryland 20783 (United States); Glaser, Evan R.; Cress, Cory D. [Naval Research Laboratory, Washington, DC 20375 (United States)

2016-07-14

The effects of gamma irradiation on the dielectric and piezoelectric responses of Pb[Zr{sub 0.52}Ti{sub 0.48}]O{sub 3} (PZT) thin film stacks were investigated for structures with conductive oxide (IrO{sub 2}) and metallic (Pt) top electrodes. The samples showed, generally, degradation of various key dielectric, ferroelectric, and electromechanical responses when exposed to 2.5 Mrad (Si) {sup 60}Co gamma radiation. However, the low-field, relative dielectric permittivity, ε{sub r}, remained largely unaffected by irradiation in samples with both types of electrodes. Samples with Pt top electrodes showed substantial degradation of the remanent polarization and overall piezoelectric response, as well as pinching of the polarization hysteresis curves and creation of multiple peaks in the permittivity-electric field curves post irradiation. The samples with oxide electrodes, however, were largely impervious to the same radiation dose, with less than 5% change in any of the functional characteristics. The results suggest a radiation-induced change in the defect population or defect energy in PZT with metallic top electrodes, which substantially affects motion of internal interfaces such as domain walls. Additionally, the differences observed for stacks with different electrode materials implicate the ferroelectric–electrode interface as either the predominant source of radiation-induced effects (Pt electrodes) or the site of healing for radiation-induced defects (IrO{sub 2} electrodes).

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.

Low-Temperature Preparation of (111)-oriented Pb(Zr,Ti)O3 Films Using Lattice-Matched (111)SrRuO3/Pt Bottom Electrode by Metal-Organic Chemical Vapor Deposition

Science.gov (United States)

Kuwabara, Hiroki; Sumi, Akihiro; Okamoto, Shoji; Hoko, Hiromasa; Cross, Jeffrey S.; Funakubo, Hiroshi

2009-04-01

Pb(Zr0.35Ti0.65)O3 (PZT) films 170 nm thick were prepared at 415 °C by pulsed metal-organic chemical vapor deposition. The (111)-oriented PZT films with local epitaxial growth were obtained on (111)SrRuO3/(111)Pt/TiO2/SiO2/Si substrates and their ferroelectricities were ascertained. Ferroelectricity was improved by postannealing under O2 gas flow up to 550 °C. Larger remanent polarization and better fatigue endurance were obtained using a SrRuO3 top electrode compared to a Pt top electrode for PZT films after annealing at 500 °C.

Far-infrared soft-mode behavior in PbSc.sub.1/2./sub.Ta.sub.1/2./sub.O.sub.3./sub. thin films

Czech Academy of Sciences Publication Activity Database

Kamba, Stanislav; Berta, Milan; Kempa, Martin; Hlinka, Jiří; Petzelt, Jan; Brinkman, K.; Setter, N.

2005-01-01

Roč. 98, - (2005), 074103/1-074103/5 ISSN 0021-8979 R&D Projects: GA AV ČR(CZ) IAA1010213; GA ČR(CZ) GA202/04/0993; GA MŠk(CZ) OC 525.20 Institutional research plan: CEZ:AV0Z10100520 Keywords : relaxor ferroelectric * slim films * ferroelectric soft mode * central mode Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.498, year: 2005

Sensitivity of PZT Impedance Sensors for Damage Detection of Concrete Structures.

Science.gov (United States)

Yang, Yaowen; Hu, Yuhang; Lu, Yong

2008-01-21

Piezoelectric ceramic Lead Zirconate Titanate (PZT) based electro-mechanicalimpedance (EMI) technique for structural health monitoring (SHM) has been successfullyapplied to various engineering systems. However, fundamental research work on thesensitivity of the PZT impedance sensors for damage detection is still in need. In thetraditional EMI method, the PZT electro-mechanical (EM) admittance (inverse of theimpedance) is used as damage indicator, which is difficult to specify the effect of damage onstructural properties. This paper uses the structural mechanical impedance (SMI) extractedfrom the PZT EM admittance signature as the damage indicator. A comparison study on thesensitivity of the EM admittance and the structural mechanical impedance to the damages ina concrete structure is conducted. Results show that the SMI is more sensitive to the damagethan the EM admittance thus a better indicator for damage detection. Furthermore, this paperproposes a dynamic system consisting of a number of single-degree-of-freedom elementswith mass, spring and damper components to model the SMI. A genetic algorithm isemployed to search for the optimal value of the unknown parameters in the dynamic system.An experiment is carried out on a two-storey concrete frame subjected to base vibrations thatsimulate earthquake. A number of PZT sensors are regularly arrayed and bonded to the framestructure to acquire PZT EM admittance signatures. The relationship between the damageindex and the distance of the PZT sensor from the damage is studied. Consequently, thesensitivity of the PZT sensors is discussed and their sensing region in concrete is derived.

Thickness dependence of electrical properties in (0 0 1) oriented lead zirconate titanate films by laser ablation

International Nuclear Information System (INIS)

Zhu, T.J.; Lu, L.; Lai, M.O.; Soh, A.K.

2007-01-01

Highly (0 0 1)-oriented Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films with LaNiO 3 (LNO) bottom electrodes have been fabricated on amorphous TiN buffered Si substrates by pulsed laser deposition. The polarization-electric field (P-E) hysteresis of the deposited PZT films with different thickness ranging from 25 to 850 nm was measured. Results showed that the coercive field increases with the film thickness scaling down. No P-E loops could be obtained for the film of thickness of 25 nm. The deterioration of ferroelectric property in the thinnest film was attributed to extrinsic effect other than intrinsic size effect. Current-voltage (I-V) characteristics measurement showed the increase in leakage current of the PZT films with the decrease in the thickness of the films under the same bias voltage. At a high field regime, the leakage current of the PZT films of 25 nm thickness remained unchanged with increasing applied voltage. A totally depleted back-to-back Shottky barrier model was used to explain the effect of electrode interfaces on leakage current in the PZT films. It is believed that ferroelectric/electrode interfaces play an important role in the electrical properties of ferroelectric thin films with thickness at nanometer level

Properties of RF-Sputtered PZT Thin Films with Ti/Pt Electrodes

Directory of Open Access Journals (Sweden)

Cui Yan

2014-01-01

Full Text Available Effect of annealing temperature and thin film thickness on properties of Pb(Zr0.53Ti0.47O3 (PZT thin film deposited via radiofrequency magnetron sputtering technique onto Pt/Ti/SiO2/Si substrate was investigated. Average grain sizes of the PZT thin film were measured by atomic force microscope; their preferred orientation was studied through X-ray diffraction analysis. Average residual stress in the thin film was estimated according to the optimized Stoney formula, and impedance spectroscopy characterization was performed via an intelligent LCR measuring instrument. Average grain sizes of PZT thin films were 60 nm~90 nm and their average roughness was less than 2 nm. According to X-ray diffraction analysis, 600°C is the optimal annealing temperature to obtain the PZT thin film with better crystallization. Average residual stress showed that thermal mismatch was the decisive factor of residual stress in Pt/Ti/SiO2/Si substrate; the residual stress in PZT thin film decreased as their thickness increased and increased with annealing temperature. The dielectric constant and loss angle tangent were extremely increased with the thickness of PZT thin films. The capacitance of the device can be adjusted according to the thickness of PZT thin films.

Ferroelectric switching of elastin

Science.gov (United States)

Liu, Yuanming; Cai, Hong-Ling; Zelisko, Matthew; Wang, Yunjie; Sun, Jinglan; Yan, Fei; Ma, Feiyue; Wang, Peiqi; Chen, Qian Nataly; Zheng, Hairong; Meng, Xiangjian; Sharma, Pradeep; Zhang, Yanhang; Li, Jiangyu

2014-01-01

Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present compelling evidence that elastin, the key ECM protein found in connective tissues, is ferroelectric, and we elucidate the molecular mechanism of its switching. Nanoscale piezoresponse force microscopy and macroscopic pyroelectric measurements both show that elastin retains ferroelectricity at 473 K, with polarization on the order of 1 μC/cm2, whereas coarse-grained molecular dynamics simulations predict similar polarization with a Curie temperature of 580 K, which is higher than most synthetic molecular ferroelectrics. The polarization of elastin is found to be intrinsic in tropoelastin at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics, and it switches via thermally activated cooperative rotation of dipoles. Our study sheds light onto a long-standing question on ferroelectric switching in biology and establishes ferroelectricity as an important biophysical property of proteins. This is a critical first step toward resolving its physiological significance and pathological implications. PMID:24958890

Optimum Operating Conditions for PZT Actuators for Vibrotactile Wearables

Science.gov (United States)

Logothetis, Irini; Matsouka, Dimitra; Vassiliadis, Savvas; Vossou, Clio; Siores, Elias

2018-04-01

Recently, vibrotactile wearables have received much attention in fields such as medicine, psychology, athletics and video gaming. The electrical components presently used to generate vibration are rigid; hence, the design and creation of ergonomical wearables are limited. Significant advances in piezoelectric components have led to the production of flexible actuators such as piezoceramic lead zirconate titanate (PZT) film. To verify the functionality of PZT actuators for use in vibrotactile wearables, the factors influencing the electromechanical conversion were analysed and tested. This was achieved through theoretical and experimental analyses of a monomorph clamped-free structure for the PZT actuator. The research performed for this article is a three-step process. First, a theoretical analysis presents the equations governing the actuator. In addition, the eigenfrequency of the film was analysed preceding the experimental section. For this stage, by applying an electric voltage and varying the stimulating electrical characteristics (i.e., voltage, electrical waveform and frequency), the optimum operating conditions for a PZT film were determined. The tip displacement was measured referring to the mechanical energy converted from electrical energy. From the results obtained, an equation for the mechanical behaviour of PZT films as actuators was deduced. It was observed that the square waveform generated larger tip displacements. In conjunction with large voltage inputs at the predetermined eigenfrequency, the optimum operating conditions for the actuator were achieved. To conclude, PZT films can be adapted to assist designers in creating comfortable vibrotactile wearables.

Flexible PZT Thin Film Tactile Sensor for Biomedical Monitoring

Directory of Open Access Journals (Sweden)

Wen-Jong Wu

2013-04-01

Full Text Available This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 μm on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT tactile sensors can overcome the diverse topology of various human regions and sense the corresponding signals from human bodies. The measured arterial pulse waveform can be used to diagnose hypertension and cardiac failure in patients. The proposed sensors have several advantages, such as flexibility, reliability, high strain, low cost, simple fabrication, and low temperature processing. The PZT thin-film deposition process includes a pyrolysis process at 150 °C/500 °C for 10/5 min, followed by an annealing process at 650 °C for 10 min. Finally, the consistent pulse wave velocity (PWV was demonstrated based on human pulse measurements from apical to radial, brachial to radial, and radial to ankle. It is characterized that the sensitivity of our PZT-based tactile sensor was approximately 0.798 mV/g.

Flexible PZT thin film tactile sensor for biomedical monitoring.

Science.gov (United States)

Tseng, Hong-Jie; Tian, Wei-Cheng; Wu, Wen-Jong

2013-04-25

This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 μm on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT tactile sensors can overcome the diverse topology of various human regions and sense the corresponding signals from human bodies. The measured arterial pulse waveform can be used to diagnose hypertension and cardiac failure in patients. The proposed sensors have several advantages, such as flexibility, reliability, high strain, low cost, simple fabrication, and low temperature processing. The PZT thin-film deposition process includes a pyrolysis process at 150 °C/500 °C for 10/5 min, followed by an annealing process at 650 °C for 10 min. Finally, the consistent pulse wave velocity (PWV) was demonstrated based on human pulse measurements from apical to radial, brachial to radial, and radial to ankle. It is characterized that the sensitivity of our PZT-based tactile sensor was approximately 0.798 mV/g.

Damped soft phonons and diffuse scattering in 40%Pb(Mg1/3Nb2/3)O3-60%PbTiO3

International Nuclear Information System (INIS)

Stock, C.; Ellis, D.; Swainson, I. P.; Xu, Guangyong; Hiraka, H.; Shirane, G.; Zhong, Z.; Luo, H.; Zhao, X.; Viehland, D.; Birgeneau, R. J.

2006-01-01

Using neutron elastic and inelastic scattering and high-energy x-ray diffraction, we present a comparison of 40% Pb(Mg 1/3 Nb 2/3 )O 3 -60% PbTiO 3 (PMN-60PT) with pure Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) and PbTiO 3 (PT). We measure the structural properties of PMN-60PT to be identical to pure PT, however, the lattice dynamics are exactly that previously found in relaxors PMN and Pb(Zn 1/3 Nb 2/3 )O 3 (PZN). PMN-60PT displays a well-defined macroscopic structural transition from a cubic to tetragonal unit cell at 550 K. The diffuse scattering is shown to be weak indicating that the structural distortion is long-range in PMN-60PT and short-range polar correlations (polar nanoregions) are not present. Even though polar nanoregions are absent, the soft optic mode is short-lived for wave vectors near the zone center. Therefore PMN-60PT displays the same waterfall effect as prototypical relaxors PMN and PZN. We conclude that it is random fields resulting from the intrinsic chemical disorder which is the reason for the broad transverse optic mode observed in PMN and PMN-60PT near the zone center and not due to the formation of short-ranged polar correlations. Through our comparison of PMN, PMN-60PT, and pure PT, we interpret the dynamic and static properties of the PMN-xPT system in terms of a random field model in which the cubic anisotropy term dominates with increasing doping of PbTiO 3

Magnetic enhancement of ferroelectric polarization in a self-grown ferroelectric-ferromagnetic composite

Science.gov (United States)

Kumar, Amit; Narayan, Bastola; Pachat, Rohit; Ranjan, Rajeev

2018-02-01

Ferroelectric-ferromagnetic multiferroic composites are of great interest both from the scientific and technological standpoints. The extent of coupling between polarization and magnetization in such two-phase systems depends on how efficiently the magnetostrictive and electrostrictive/piezoelectric strain gets transferred from one phase to the other. This challenge is most profound in the easy to make 0-3 ferroelectric-ferromagnetic particulate composites. Here we report a self-grown ferroelectric-ferromagnetic 0-3 particulate composite through controlled spontaneous precipitation of ferrimagnetic barium hexaferrite phase (BaF e12O19 ) amid ferroelectric grains in the multiferroic alloy system BiFe O3-BaTi O3 . We demonstrate that a composite specimen exhibiting merely ˜1% hexaferrite phase exhibits ˜34% increase in saturation polarization in a dc magnetic field of ˜10 kOe. Using modified Rayleigh analysis of the polarization field loop in the subcoercive field region we argue that the substantial enhancement in the ferroelectric switching is associated with the reduction in the barrier heights of the pinning centers of the ferroelectric-ferroelastic domain walls in the stress field generated by magnetostriction in the hexaferrite grains when the magnetic field is turned on. Our study proves that controlled precipitation of the magnetic phase is a good strategy for synthesis of 0-3 ferroelectric-ferromagnetic particulate multiferroic composite as it not only helps in ensuring a good electrical insulating character of the composite, enabling it to sustain high enough electric field for ferroelectric switching, but also the factors associated with the spontaneity of the precipitation process ensure efficient transfer of the magnetostrictive strain/stress to the surrounding ferroelectric matrix making domain wall motion easy.

Piezoelectric and mechanical properties of structured PZT-epoxy composites

NARCIS (Netherlands)

James, N.K.; Ende, D.A. van den; Lafont, U.; Zwaag, S. van der; Groen, W.A.

2013-01-01

Structured lead zirconium titanate (PZT)-epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage

Molecular ferroelectrics: where electronics meet biology.

Science.gov (United States)

Li, Jiangyu; Liu, Yuanming; Zhang, Yanhang; Cai, Hong-Ling; Xiong, Ren-Gen

2013-12-28

In the last several years, we have witnessed significant advances in molecular ferroelectrics, with the ferroelectric properties of molecular crystals approaching those of barium titanate. In addition, ferroelectricity has been observed in biological systems, filling an important missing link in bioelectric phenomena. In this perspective, we will present short historical notes on ferroelectrics, followed by an overview of the fundamentals of ferroelectricity. The latest developments in molecular ferroelectrics and biological ferroelectricity will then be highlighted, and their implications and potential applications will be discussed. We close by noting molecular ferroelectric as an exciting frontier between electronics and biology, and a number of challenges ahead are also described.

Study of pyroelectric activity of PZT/PVDF-HFP composite

Directory of Open Access Journals (Sweden)

Luiz Francisco Malmonge

2003-12-01

Full Text Available Flexible, free-standing piezo and pyroelectric composite with 0 to 3 connectivity was made up from Lead Zirconate Titanate (PZT powder and poly(vinylidene fluoride-hexafluoropropylene (PVDF-HFP copolymer. The pyroelectric and the piezoelectric longitudinal (d33 coefficients were measured. A 50/50 vol.% PZT/PVDF-HFP composite resulted in piezo and pyroelectric coefficients of d33 = 25.0 pC/N and p = 4.5 × 10-4 C/m²K at 70 °C, respectively. Analysis of the complex permittivity in a wide range of frequency was carried out indicating lower permittivity of the composite in comparison with a permittivity of the PZT ceramic. The low value of the permittivity gives a high pyroelectric figure of merit indicating that this material can be used to build a temperature sensor in spite of the lower pyroelectric coefficient compared with PZT.

Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT-ionomer composites

NARCIS (Netherlands)

James, N.K.; Lafont, U.; Zwaag, S. van der; Groen, W.A.

2014-01-01

Piezoelectric ceramic-polymer composites with 0-3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT-Zn ionomer and PZT-EMAA composites were prepared by melt

Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT-ionomer composites

Science.gov (United States)

James, N. K.; Lafont, U.; van der Zwaag, S.; Groen, W. A.

2014-05-01

Piezoelectric ceramic-polymer composites with 0-3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT-Zn ionomer and PZT-EMAA composites were prepared by melt extrusion followed by hot pressing. The effects of poling conditions such as temperature, time and electric field on the piezoelectric properties of the composites were investigated. The experimentally observed piezoelectric charge coefficient and dielectric constant of the composites were compared with theoretical models. The results show that PZT-Zn ionomer composites have better piezoelectric properties compared to PZT-EMAA composites. The static and fatigue properties of the composites were investigated. The PZT-Zn ionomer composites were found to have excellent fatigue resistance even at strain levels of 4%. Due to the self-healing capabilities of the ionomer matrix, the loss of piezoelectric properties after high strain tensile cyclic loading could be partially recovered by thermal healing.

Experimental research on dynamic mechanical properties of PZT ceramic under hydrostatic pressure

International Nuclear Information System (INIS)

Wang, S.; Liu, K.X.

2011-01-01

Highlights: → We developed an experimental device to examine dynamic mechanical properties of PZT. → Ductile behavior of PZT was seen when hydrostatic pressure was involved. → Compressive strength was shown sensitive to hydrostatic pressure and strain-rate. → A failure criterion was suggested to explain the failure behavior of PZT. - Abstract: An experimental technique for initially applied hydrostatic pressure in specimens subjected to axial impact has been developed to study the dynamic mechanical properties of materials. The technique was employed for the purpose of examining the dynamic mechanical properties of lead zirconate titanate (PZT) at zero to 15 MPa hydrostatic pressures. Experimental results unambiguously exhibit the ductile behavior of PZT when hydrostatic pressure is involved. The compressive strength is demonstrated sensitive to the initial hydrostatic pressure and the strain-rate. The fracture modes are analyzed by means of scanning electron microscopy (SEM). Moreover, a failure criterion based on Mohr-Coulomb failure theory is suggested to explain the brittle and ductile failure of PZT.

Nanocomposites with increased energy density through high aspect ratio PZT nanowires.

Science.gov (United States)

Tang, Haixiong; Lin, Yirong; Andrews, Clark; Sodano, Henry A

2011-01-07

High energy storage plays an important role in the modern electric industry. Herein, we investigated the role of filler aspect ratio in nanocomposites for energy storage. Nanocomposites were synthesized using lead zirconate titanate (PZT) with two different aspect ratio (nanowires, nanorods) fillers at various volume fractions dispersed in a polyvinylidene fluoride (PVDF) matrix. The permittivity constants of composites containing nanowires (NWs) were higher than those with nanorods (NRs) at the same inclusion volume fraction. It was also indicated that the high frequency loss tangent of samples with PZT nanowires was smaller than for those with nanorods, demonstrating the high electrical energy storage efficiency of the PZT NW nanocomposite. The high aspect ratio PZT NWs showed a 77.8% increase in energy density over the lower aspect ratio PZT NRs, under an electric field of 15 kV mm(-1) and 50% volume fraction. The breakdown strength was found to decrease with the increasing volume fraction of PZT NWs, but to only change slightly from a volume fraction of around 20%-50%. The maximum calculated energy density of nanocomposites is as high as 1.158 J cm(-3) at 50% PZT NWs in PVDF. Since the breakdown strength is lower compared to a PVDF copolymer such as poly(vinylidene fluoride-tertrifluoroethylene-terchlorotrifluoroethylene) P(VDF-TreEE-CTFE) and poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP), the energy density of the nanocomposite could be significantly increased through the use of PZT NWs and a polymer with greater breakdown strength. These results indicate that higher aspect ratio fillers show promising potential to improve the energy density of nanocomposites, leading to the development of advanced capacitors with high energy density.

The effects of sintering behavior on piezoelectric properties of porous PZT ceramics for hydrophone application

International Nuclear Information System (INIS)

Zeng Tao; Dong Xianlin; Chen Heng; Wang Yonglin

2006-01-01

Porous lead zirconate titanate (PZT) ceramics were fabricated by adding polymethyl methacrylate (PMMA) and the effects of sintering behavior on their microstructure and piezoelectric properties were investigated. The porosity of PZT ceramics decreased with an increase in the sintering temperature at a fixed PMMA addition. The dielectric constant (ε), longitudinal piezoelectric coefficient (d 33 ) and hydrostatic figures of merit (d h g h ) of 34% porous PZT ceramics increased with an increase in sintering temperature from 1050 to 1300 deg. C. When sintered at 1300 deg. C, longitudinal piezoelectric coefficient of 34% porous PZT ceramic was very close to that of 95% dense PZT ceramics, while the hydrostatic figures of merit of 34% porous PZT ceramics is about fifteen times more than that of 95% dense PZT ceramics. Compared with PZT-polymer composites, the dielectric constant of 34% porous PZT sintered at 1300 deg. C is much higher, which can be more efficient to resist the interference in receiving sensitivities caused by loading effect of the cable

Ferroelectrics principles, structure and applications

CERN Document Server

Merchant, Serena

2014-01-01

Ferroelectric physics is a theory on ferroelectric phase transition for explaining various related phenomena, which is different from dielectric physics. Ferroelectric materials are important functional materials for various applications such as NVRAMs, high energy density capacitors, actuators, MEMs, sonar sensors, microphones and scanning electron microscopes (SEM). This book investigates the dielectric, ferroelectric and energy storage properties of barium zirconate-titanate/barium calcium-titanate (BZT-BCT) based ceramic for high energy density capacitors. It also compares the energy storage capabilities of ceramic powders with polymer-ceramic nanocomposites; and discusses dielectric properties of ferroelectricity in composition distributions.

Uncertainty quantification for PZT bimorph actuators

Science.gov (United States)

Bravo, Nikolas; Smith, Ralph C.; Crews, John

2018-03-01

In this paper, we discuss the development of a high fidelity model for a PZT bimorph actuator used for micro-air vehicles, which includes the Robobee. We developed a high-fidelity model for the actuator using the homogenized energy model (HEM) framework, which quantifies the nonlinear, hysteretic, and rate-dependent behavior inherent to PZT in dynamic operating regimes. We then discussed an inverse problem on the model. We included local and global sensitivity analysis of the parameters in the high-fidelity model. Finally, we will discuss the results of Bayesian inference and uncertainty quantification on the HEM.

Comparison of the Thermal Degradation of Heavily Nb-Doped and Normal PZT Thin Films.

Science.gov (United States)

Yang, Jeong-Suong; Kang, YunSung; Kang, Inyoung; Lim, SeungMo; Shin, Seung-Joo; Lee, JungWon; Hur, Kang Heon

2017-03-01

The degradation of niobium-doped lead zirconate titanate (PZT) and two types of PZT thin films were investigated. Undoped PZT, two-step PZT, and heavily Nb-doped PZT (PNZT) around the morphotropic phase boundary were in situ deposited under optimum condition by RF-magnetron sputtering. All 2- [Formula: see text]-thick films had dense perovskite columnar grain structure and self-polarized (100) dominant orientation. PZT thin films were deposited on Pt/TiO x bottom electrode on Si wafer, and PNZT thin film was on Ir/TiW electrode with the help of orientation control. Sputtered PZT films formed on microelectromechanical system (MEMS) gyroscope and the degradation rates were compared at different temperatures. PNZT showed the best resistance to the thermal degradation, followed by two-step PZT. To clarify the effect of oxygen vacancies on the degradation of the film at high temperature, photoluminescence measurement was conducted, which confirmed that oxygen vacancy rate was the lowest in heavy PNZT. Nb-doping PZT thin films suppressed the oxygen deficit and made high imprint with self-polarization. This defect distribution and high internal field allowed PNZT thin film to make the piezoelectric sensors more stable and reliable at high temperature, such as reflow process of MEMS packaging.

Dielectric and AC-conductivity studies of Dy2O3 doped (K0.5Na0.5NbO3 ceramics

Directory of Open Access Journals (Sweden)

Mahesh Peddigari

2014-08-01

Full Text Available (K0.5Na0.5NbO3 + x wt.% Dy2O3 (x = 0–1.5 ferroelectric ceramics were prepared by conventional solid state reaction method. XRD patterns revealed that orthorhombic symmetry has transformed into psuedocubic symmetry with increasing the substitution of Dy3+ in the Na+ site. Temperature and frequency dependences of relative dielectric permittivity maximum conforms the transformation from normal ferroelectric to relaxor ferroelectric behaviour. Frequency dependence of the relative dielectric permittivity maximum temperature observed for the samples with x ≥ 1.0 and satisfied the Vogel–Fulcher law. The diffuseness exponent γ (1.27–1.95 estimated from the high temperature slopes of the diffused dielectric permittivity data reveals that the degree of relaxor behavior increases with increasing the amount of Dy2O3. The temperature dependence of AC-conductivity σAC (T analysis in the range 310 K < T < 470 K reveals the existence of variable range hopping of charge carriers with average hopping length RH and hopping energy EH are in the range 8.5–27 Å and 48–153 meV, respectively. Voltage dependent dielectric constant measurements confirm the ferroelectric nature of KNN+ x wt% Dy2O3 ceramics.

Dynamics of ferroelectric nanodomains in BaTiO3 epitaxial thin films via piezoresponse force microscopy

International Nuclear Information System (INIS)

Pertsev, N A; Petraru, A; Kohlstedt, H; Waser, R; Bdikin, I K; Kiselev, D; Kholkin, A L

2008-01-01

Ferroelectric nanodomains were created in BaTiO 3 thin films by applying a voltage to a sharp conducting tip of a scanning force microscope (SFM). The films were epitaxially grown on SrRuO 3 -covered (001)-oriented SrTiO 3 substrates by a high-pressure sputtering. They appeared to be single-crystalline with the (001) crystallographic orientation relative to the substrate. Using the piezoresponse mode of the SFM to detect the out-of-plane film polarization, the domain sizes were measured as a function of the applied writing voltage and the pulse time. It was found that the time dependence of the domain diameter in a 60 nm thick BaTiO 3 film deviates significantly from the logarithmic law observed earlier in Pb(Zr 0.2 Ti 0.8 )O 3 (PZT) films. At a given writing time, the domain size increases nonlinearly with increasing applied voltage, in contrast to the linear behavior reported earlier for PZT films and LiNbO 3 single crystals. The dynamics of domain growth is analyzed theoretically taking into account the strong inhomogeneity of the external electric field in the film and the influence of the bottom electrode. It is shown that the observed writing time and voltage dependences of the domain size can be explained by the domain-wall creep in the presence of random-bond disorder

Integration of epitaxial Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films on GaN/AlGaN/GaN/Si(111) substrates using rutile TiO{sub 2} buffer layers

Energy Technology Data Exchange (ETDEWEB)

Elibol, K. [MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); Nguyen, M.D. [MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); SolMateS B.V., Drienerlolaan 5, Building 6, 7522NB Enschede (Netherlands); International Training Institute for Materials Science, Hanoi University of Science and Technology, No.1 Dai Co Viet road, Hanoi 10000 (Viet Nam); Hueting, R.J.E. [MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); Gravesteijn, D.J. [MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); NXP Semiconductors Research, High Tech Campus 46, 5656AE Eindhoven (Netherlands); Koster, G., E-mail: g.koster@utwente.nl [MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); Rijnders, G. [MESA + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands)

2015-09-30

The integration of ferroelectric layers on gallium nitride (GaN) offers a great potential for various applications. Lead zirconate titanate (PZT), in particular Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3}, is an interesting candidate. For that a suitable buffer layer should be grown on GaN in order to prevent the reaction between PZT and GaN, and to obtain PZT with a preferred orientation and phase. Here, we study pulsed laser deposited (100) rutile titanium oxide (R-TiO{sub 2}) as a potential buffer layer candidate for ferroelectric PZT. For this purpose, the growth, morphology and the surface chemical composition of R-TiO{sub 2} films were analyzed by reflection high-energy electron diffraction, atomic force microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We find optimally (100) oriented R-TiO{sub 2} growth on GaN (0002) using a 675 °C growth temperature and 2 Pa O{sub 2} deposition pressure as process conditions. More importantly, the R-TiO{sub 2} buffer layer grown on GaN/Si substrates prevents the unwanted formation of the PZT pyrochlore phase. Finally, the remnant polarization and coercive voltage of the PZT film on TiO{sub 2}/GaN/Si with an interdigitated-electrode structure were found to be 25.6 μC/cm{sup 2} and 8.1 V, respectively. - Highlights: • Epitaxial rutile TiO{sub 2} films were grown on GaN layer buffered Si substrate using pulsed laser deposition. • The rutile-TiO{sub 2} layer suppresses the formation of the pyrochlore phase in the epitaxial PZT film grown on GaN/Si. • An epitaxial PZT film on GaN/Si substrate with rutile TiO{sub 2} buffer layer exhibits good ferroelectric properties.

Synthesis, Structural, Optical and Dielectric Properties of Nanostructured 0-3 PZT/PVDF Composite Films.

Science.gov (United States)

Revathi, S; Kennedy, L John; Basha, S K Khadheer; Padmanabhan, R

2018-07-01

Nanostructured PbZr0.52Ti0.48O3 (PZT) powder was synthesized at 500 °C-800 °C using sol-gel route. X-ray diffraction and Rietveld analysis confirmed the formation of perovskite structure. The sample heat treated at 800 °C alone showed the formation of morphotropic phase boundary with coexistence of tetragonal and rhombohedral phase. The PZT powder and PVDF were used in 0-3 connectivity to form the PZT/PVDF composite film using solvent casting method. The composite films containing 10%, 50%, 70% and 80% volume fraction of PZT in PVDF were fabricated. The XRD spectra validated that the PZT structure remains unaltered in the composites and was not affected by the presence of PVDF. The scanning electron microscopy images show good degree of dispersion of PZT in PVDF matrix and the formation of pores at higher PZT loading. The quantitative analysis of elements and their composition were confirmed from energy dispersive X-ray analysis. The optical band gap of the PVDF film is 3.3 eV and the band gap decreased with increase in volume fraction of PZT fillers. The FTIR spectra showed the bands corresponding to different phases of PVDF (α, β, γ) and perovskite phase of PZT. The thermogravimetric analysis showed that PZT/PVDF composite films showed better thermal stability than the pure PVDF film and hydrophobicity. The dielectric constant was measured at frequency ranging from 1 Hz to 6 MHz and for temperature ranging from room temperature to 150 °C. The composite with 50% PZT filler loading shows the maximum dielectric constant at the studied frequency and temperature range with flexibility.

Dielectric behaviors of lead zirconate titanate ceramics with coplanar electrodes

International Nuclear Information System (INIS)

Wang, Y.; Cheng, Y.L.; Zhang, Y.W.; Chan, H.L.W.; Choy, C.L.

2003-01-01

This paper reports on the dielectric behaviors of lead zirconate titanate (PZT) capacitors with coplanar electrodes. Usually a ferroelectric device has a metal-ferroelectric-metal configuration (parallel plate capacitor); when both the electrodes are on one side of a ceramic to form a coplanar capacitor, different dielectric behaviors will be anticipated because of the change in the distribution of the test field inside the dielectrics. This paper describes how the capacitance and dielectric loss of PZT-based coplanar capacitors change with electrode distance, area and test frequency

Metalorganic solution deposition of lead zirconate titanate films onto an additively manufactured Ni-based superalloy

International Nuclear Information System (INIS)

Patel, T.; Khassaf, H.; Vijayan, S.; Bassiri-Gharb, N.; Aindow, M.; Alpay, S.P.; Hebert, R.J.

2017-01-01

Recent advances in additive manufacturing of high-temperature alloys for structural aerospace applications has led to interest in integrating additional functionality into such parts. Lead zirconate titanate (PZT) is a prototypical ferroelectric ceramic used as the electro-active material in many piezoelectric sensors and actuators. In this study, 300 nm thick PbZr_0_._2Ti_0_._8O_3 (PZT 20/80) films were grown using metalorganic solution deposition onto additively manufactured substrates of Inconel 718. The microstructures of the films and the nature of the film/substrate interfaces were characterized using a combination of X-ray diffraction and electron microscopy techniques. Electrical measurements were performed to determine the ferroelectric, dielectric, and conductive responses of the PZT films. Our findings show that the PZT films exhibit robust ferroelectricity characterized by well-defined polarization-applied electric field (P-E) hysteresis loops. The samples display internal bias of up to ∼40 kV/cm. The room temperature remnant polarization and the small signal dielectric permittivity are ∼70 μC/cm"2 and 205, respectively. The dielectric loss (tan δ) and the leakage current at 1 kHz are 9% and 1 nA at 1 V, respectively. We attribute the internal bias observed in the hysteresis loops and the overall large dielectric losses to the presence of an intermediate oxide layer at the PZT/Inconel interface, which forms during the high temperature crystallization of the ferroelectric film. These results show that it is possible to grow functional oxides with promising electrical properties onto additively manufactured metallic substrates.

Conventional and two step sintering of PZT-PCN ceramics

Science.gov (United States)

Keshavarzi, Mostafa; Rahmani, Hooman; Nemati, Ali; Hashemi, Mahdieh

2018-02-01

In this study, PZT-PCN ceramic was made via sol-gel seeding method and effects of conventional sintering (CS) as well as two-step sintering (TSS) were investigated on microstructure, phase formation, density, dielectric and piezoelectric properties. First, high quality powder was achieved by seeding method in which the mixture of Co3O4 and Nb2O5 powder was added to the prepared PZT sol to form PZT-PCN gel. After drying and calcination, pyrochlore free PZT-PCN powder was synthesized. Second, CS and TSS were applied to achieve dense ceramic. The optimum temperature used for 2 h of conventional sintering was obtained at 1150 °C; finally, undesired ZrO2 phase formed in CS procedure was removed successfully with TSS procedure and dielectric and piezoelectric properties were improved compared to the CS procedure. The best electrical properties obtained for the sample sintered by TSS in the initial temperature of T 1 = 1200 °C and secondary temperature of T 2 = 1000 °C for 12 h.

Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric

Science.gov (United States)

Ghoneim, M. T.; Hussain, M. M.

2015-08-01

Flexible memory can enable industrial, automobile, space, and smart grid centered harsh/extreme environment focused electronics application(s) for enhanced operation, safety, and monitoring where bent or complex shaped infrastructures are common and state-of-the-art rigid electronics cannot be deployed. Therefore, we report on the physical-mechanical-electrical characteristics of a flexible ferroelectric memory based on lead zirconium titanate as a key memory material and flexible version of bulk mono-crystalline silicon (100). The experimented devices show a bending radius down to 1.25 cm corresponding to 0.16% nominal strain (high pressure of ˜260 MPa), and full functionality up to 225 °C high temperature in ambient gas composition (21% oxygen and 55% relative humidity). The devices showed unaltered data retention and fatigue properties under harsh conditions, still the reduced memory window (20% difference between switching and non-switching currents at 225 °C) requires sensitive sense circuitry for proper functionality and is the limiting factor preventing operation at higher temperatures.

Dielectric and acoustical high frequency characterisation of PZT thin films

International Nuclear Information System (INIS)

Conde, Janine; Muralt, Paul

2010-01-01

Pb(Zr, Ti)O 3 (PZT) is an interesting material for bulk acoustic wave resonator applications due to its high electromechanical coupling constant, which would enable fabrication of large bandwidth frequency filters. The major challenge of the PZT solid solution system is to overcome mechanical losses generally observed in PZT ceramics. To increase the understanding of these losses in textured thin films, thin film bulk acoustic resonators (TFBAR's) based on PZT thin films with compositions either in the tetragonal region or at the morphotropic phase boundary and (111) or {100} textures were fabricated and studied up to 2 GHz. The dielectric and elastic materials coefficients were extracted from impedance measurements at the resonance frequency. The dispersion of the dielectric constant was obtained from impedance measurements up to 2 GHz. The films with varying compositions, textures and deposition methods (sol-gel or sputtering) were compared in terms of dielectric and acoustical properties.

Dielectric and acoustical high frequency characterisation of PZT thin films

Science.gov (United States)

Conde, Janine; Muralt, Paul

2010-02-01

Pb(Zr, Ti)O3 (PZT) is an interesting material for bulk acoustic wave resonator applications due to its high electromechanical coupling constant, which would enable fabrication of large bandwidth frequency filters. The major challenge of the PZT solid solution system is to overcome mechanical losses generally observed in PZT ceramics. To increase the understanding of these losses in textured thin films, thin film bulk acoustic resonators (TFBAR's) based on PZT thin films with compositions either in the tetragonal region or at the morphotropic phase boundary and (111) or {100} textures were fabricated and studied up to 2 GHz. The dielectric and elastic materials coefficients were extracted from impedance measurements at the resonance frequency. The dispersion of the dielectric constant was obtained from impedance measurements up to 2 GHz. The films with varying compositions, textures and deposition methods (sol-gel or sputtering) were compared in terms of dielectric and acoustical properties.

Highly-efficient, flexible piezoelectric PZT thin film nanogenerator on plastic substrates.

Science.gov (United States)

Park, Kwi-Il; Son, Jung Hwan; Hwang, Geon-Tae; Jeong, Chang Kyu; Ryu, Jungho; Koo, Min; Choi, Insung; Lee, Seung Hyun; Byun, Myunghwan; Wang, Zhong Lin; Lee, Keon Jae

2014-04-23

A highly-efficient, flexible piezoelectric PZT thin film nanogenerator is demonstrated using a laser lift-off (LLO) process. The PZT thin film nanogenerator harvests the highest output performance of ∼200 V and ∼150 μA·cm(-2) from regular bending motions. Furthermore, power sources generated from a PZT thin film nanogenerator, driven by slight human finger bending motions, successfully operate over 100 LEDs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiscale modeling for ferroelectric materials: identification of the phase-field model’s free energy for PZT from atomistic simulations

International Nuclear Information System (INIS)

Völker, Benjamin; Landis, Chad M; Kamlah, Marc

2012-01-01

Within a knowledge-based multiscale simulation approach for ferroelectric materials, the atomic level can be linked to the mesoscale by transferring results from first-principles calculations into a phase-field model. A recently presented routine (Völker et al 2011 Contin. Mech. Thermodyn. 23 435–51) for adjusting the Helmholtz free energy coefficients to intrinsic and extrinsic ferroelectric material properties obtained by DFT calculations and atomistic simulations was subject to certain limitations: caused by too small available degrees of freedom, an independent adjustment of the spontaneous strains and piezoelectric coefficients was not possible, and the elastic properties could only be considered in cubic instead of tetragonal symmetry. In this work we overcome such restrictions by expanding the formulation of the free energy function, i.e. by motivating and introducing new higher-order terms that have not appeared in the literature before. Subsequently we present an improved version of the adjustment procedure for the free energy coefficients that is solely based on input parameters from first-principles calculations performed by Marton and Elsässer, as documented in Völker et al (2011 Contin. Mech. Thermodyn. 23 435–51). Full sets of adjusted free energy coefficients for PbTiO 3 and tetragonal Pb(Zr,Ti)O 3 are presented, and the benefits of the newly introduced higher-order free energy terms are discussed. (paper)

Preisach modeling of temperature-dependent ferroelectric response of piezoceramics at sub-switching regime

Science.gov (United States)

Ochoa, Diego Alejandro; García, Jose Eduardo

2016-04-01

The Preisach model is a classical method for describing nonlinear behavior in hysteretic systems. According to this model, a hysteretic system contains a collection of simple bistable units which are characterized by an internal field and a coercive field. This set of bistable units exhibits a statistical distribution that depends on these fields as parameters. Thus, nonlinear response depends on the specific distribution function associated with the material. This model is satisfactorily used in this work to describe the temperature-dependent ferroelectric response in PZT- and KNN-based piezoceramics. A distribution function expanded in Maclaurin series considering only the first terms in the internal field and the coercive field is proposed. Changes in coefficient relations of a single distribution function allow us to explain the complex temperature dependence of hard piezoceramic behavior. A similar analysis based on the same form of the distribution function shows that the KNL-NTS properties soften around its orthorhombic to tetragonal phase transition.

Polymer Ferroelectric Memory for Flexible Electronics

KAUST Repository

Khan, Mohd Adnan

2013-01-01

With the projected growth of the flexible and plastic electronics industry, there is renewed interest in the research community to develop high performance all-polymeric memory which will be an essential component of any electronic circuit. Some of the efforts in polymer memories are based on different mechanisms such as filamentary conduction, charge trapping effects, dipole alignment, and reduction-oxidation to name a few. Among these the leading candidate are those based on the mechanism of ferroelectricity. Polymer ferroelectric memory can be used in niche applications like smart cards, RFID tags, sensors etc. This dissertation will focus on novel material and device engineering to fabricate high performance low temperature polymeric ferroelectric memory for flexible electronics. We address and find solutions to some fundamental problems affecting all polymer ferroelectric memory like high coercive fields, fatigue and thermal stability issues, poor breakdown strength and poor p-type hole mobilities. Some of the strategies adopted in this dissertation are: Use of different flexible substrates, electrode engineering to improve charge injection and fatigue properties of ferroelectric polymers, large area ink jet printing of ferroelectric memory devices, use of polymer blends to improve insulating properties of ferroelectric polymers and use of oxide semiconductors to fabricate high mobility p-type ferroelectric memory. During the course of this dissertation we have fabricated: the first all-polymer ferroelectric capacitors with solvent modified highly conducting polymeric poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) [PEDOT:PSS] electrodes on plastic substrates with performance as good as devices with metallic Platinum-Gold electrodes on silicon substrates; the first all-polymer high performance ferroelectric memory on banknotes for security applications; novel ferroelectric capacitors based on blends of ferroelectric poly(vinylidene fluoride

Polymer Ferroelectric Memory for Flexible Electronics

KAUST Repository

Khan, Mohd Adnan

2013-11-01

With the projected growth of the flexible and plastic electronics industry, there is renewed interest in the research community to develop high performance all-polymeric memory which will be an essential component of any electronic circuit. Some of the efforts in polymer memories are based on different mechanisms such as filamentary conduction, charge trapping effects, dipole alignment, and reduction-oxidation to name a few. Among these the leading candidate are those based on the mechanism of ferroelectricity. Polymer ferroelectric memory can be used in niche applications like smart cards, RFID tags, sensors etc. This dissertation will focus on novel material and device engineering to fabricate high performance low temperature polymeric ferroelectric memory for flexible electronics. We address and find solutions to some fundamental problems affecting all polymer ferroelectric memory like high coercive fields, fatigue and thermal stability issues, poor breakdown strength and poor p-type hole mobilities. Some of the strategies adopted in this dissertation are: Use of different flexible substrates, electrode engineering to improve charge injection and fatigue properties of ferroelectric polymers, large area ink jet printing of ferroelectric memory devices, use of polymer blends to improve insulating properties of ferroelectric polymers and use of oxide semiconductors to fabricate high mobility p-type ferroelectric memory. During the course of this dissertation we have fabricated: the first all-polymer ferroelectric capacitors with solvent modified highly conducting polymeric poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) [PEDOT:PSS] electrodes on plastic substrates with performance as good as devices with metallic Platinum-Gold electrodes on silicon substrates; the first all-polymer high performance ferroelectric memory on banknotes for security applications; novel ferroelectric capacitors based on blends of ferroelectric poly(vinylidene fluoride

Comparison of lead zirconate titanate thin films on ruthenium oxide and platinum electrodes

OpenAIRE

Bursill, Les A.; Reaney, Ian M.; Vijay, Dilip P.; Desu, Seshu B.

1994-01-01

High-resolution and bright- and dark-field transmission electron microscopy are used to characterize and compare the interface structures and microstructure of PZT/RuO2/SiO2/Si and PZT/Pt/Ti/SiO2/Si ferroelectric thin films, with a view to understanding the improved fatigue characteristics of PZT thin films with RuO2 electrodes. The RuO2/PZT interface consists of a curved pseudoperiodic minimal surface. The interface is chemically sharp with virtually no intermixing of RuO2 and PZT, as eviden...

Comparison of structural and electric properties of PbZr0.2Ti0.8O3 and CoFe2O4/PbZr0.2Ti0.8O3 films on (100)LaAlO3

Science.gov (United States)

Zhang, X. D.; Dho, Joonghoe; Park, Sungmin; Kwon, Hyosang; Hwang, Jihwan; Park, Gwangseo; Kwon, Daeyoung; Kim, Bongju; Jin, Yeryeong; Kim, Bog. G.; Karpinsky, D.; Kholkin, A. L.

2011-09-01

In this work, we investigated structural, electrical, and magnetic properties of ferroelectric PbZr0.2Ti0.8O3 (PZT) and ferrimagnetic/ferroelectric [CoFe2O4(CFO)/PZT] bilayers grown on (100)LaAlO3 (LAO) substrates supplied with bottom 50 nm thick LaNiO3 electrodes. Interestingly, structural and electrical properties of the PZT layer exhibited remarkable changes after the top-layer CFO deposition. X-ray diffraction data suggested that both the c- and a-domains exist in the PZT layer and the tetragonality of the PZT decreases upon the top-layer deposition. A variation in the electrical properties of the PZT layer upon the CFO deposition was investigated by polarization versus voltage (P-V), capacitance versus voltage (C-V), and capacitance versus frequency (C-f) measurements. The CFO deposition induced a slight decrease of the remnant polarization and more symmetric behavior of P-V loops as well as led to the improvement of fatigue behavior. The tentative origin of enhanced fatigue endurance is discussed based on the measurement results. These results were corroborated by local piezoelectric measurements. Ferrimagnetic property of the CFO/PZT bilayer was confirmed by magnetic measurement at room temperature.

Antiferrodistortive phase transitions and ground state of PZT ceramics

International Nuclear Information System (INIS)

Pandey, Dhananjai

2013-01-01

The ground state of the technologically important Pb(Zr x Ti (1-x) )O 3 , commonly known as PZT, ceramics is currently under intense debate. The phase diagram of this material shows a morphotropic phase boundary (MPB) for x∼0.52 at 300K, across which a composition induced structural phase transition occurs leading to maximization of the piezoelectric properties. In search for the true ground state of the PZT in the MPB region, Beatrix Noheda and coworkers first discovered a phase transition from tetragonal (space group P4mm) to an M A type monoclinic phase (space group Cm) at low temperatures for x=0.52. Soon afterwards, we discovered yet another low temperature phase transition for the same composition in which the M A type (Cm) monoclinic phase transforms to another monoclinic phase with Cc space group. We have shown that the Cm to Cc phase transition is an antiferrodistortive (AFD) transition involving tilting of oxygen octahedra leading to unit cell doubling and causing appearance of superlattice reflections which are observable in the electron and neutron diffraction patterns only and not in the XRD patterns, as a result of which Noheda and coworkers missed the Cc phase in their synchrotron XRD studies at low temperatures. Our findings were confirmed by leading groups using neutron, TEM, Raman and high pressure diffraction studies. The first principles calculations also confirmed that the true ground state of PZT in the MPB region has Cc space group. However, in the last couple of years, the Cc space group of the ground state has become controversial with an alternative proposal of R3c as the space group of the ground state phase which is proposed to coexist with the metastable Cm phase. In order to resolve this controversy, we recently revisited the issue using pure PZT and 6% Sr 2+ substituted PZT, the latter samples show larger tilt angle on account of the reduction in the average cationic radius at the Pb 2+ site. Using high wavelength neutrons and high

PREFACE: 12th Russia/CIS/Baltic/Japan Symposium on Ferroelectricity and 9th International Conference on Functional Materials and Nanotechnologies (RCBJSF-2014-FM&NT)

Science.gov (United States)

Sternberg, Andris; Grinberga, Liga; Sarakovskis, Anatolijs; Rutkis, Martins

2015-03-01

The joint International Symposium RCBJSF-2014-FM&NT successfully has united two international events - 12th Russia/CIS/Baltic/Japan Symposium on Ferroelectricity (RCBJSF-12) and 9th International Conference Functional Materials and Nanotechnologies (FM&NT-2014). The RCBJSF symposium is a continuation of series of meetings on ferroelectricity, the first of which took place in Novosibirsk (USSR) in 1976. FM&NT conferences started in 2006 and have been organized by Institute of Solid State Physics, University of Latvia in Riga. In 2012 the International program committee decided to transform this conference into a traveling Baltic State conference and the FM&NT-2013 was organized by the Institute of Physics, University of Tartu, Estonia. In 2014 the joint international symposium RCBJSF-2014-FM&NT was organized by the Institute of Solid State Physics, University of Latvia and was part of Riga - 2014, the European Capital of Culture event. The purpose of the joint Symposium was to bring together scientists, students and high-level experts in solid state physics, materials science, engineering and related disciplines. The number of the registered participants from 26 countries was over 350. During the Symposium 128 high quality scientific talks (5 plenary, 42 invited, 81 oral) and over 215 posters were presented. All presentations were divided into 4 parallel sessions according to 4 main topics of the Symposium: Ferroelectricity, including ferroelectrics and multiferroics, pyroelectrics, piezoelectrics and actuators, integrated ferroelectrics, relaxors, phase transitions and critical phenomena. Multifunctional Materials, including theory, multiscale and multiphenomenal material modeling and simulation, advanced inorganic, organic and hybrid materials. Nanotechnologies, including progressive methods, technologies and design for production, investigation of nano- particles, composites, structures, thin films and coatings. Energy, including perspective materials and

The giant piezoelectric effect: electric field induced monoclinic phase or piezoelectric distortion of the rhombohedral parent?

International Nuclear Information System (INIS)

Kisi, E H; Piltz, R O; Forrester, J S; Howard, C J

2003-01-01

Lead zinc niobate-lead titanate (PZN-PT) single crystals show very large piezoelectric strains for electric fields applied along the unit cell edges e.g. [001] R . It has been widely reported that this effect is caused by an electric field induced phase transition from rhombohedral (R3m) to monoclinic (Cm or Pm) symmetry in an essentially continuous manner. Group theoretical analysis using the computer program ISOTROPY indicates phase transitions between R3m and Cm (or Pm) must be discontinuous under Landau theory. An analysis of the symmetry of a strained unit cell in R3m and a simple expansion of the piezoelectric strain equation indicate that the piezoelectric distortion due to an electric field along a cell edge in rhombohedral perovskite-based ferroelectrics is intrinsically monoclinic (Cm), even for infinitesimal electric fields. PZN-PT crystals have up to nine times the elastic compliance of other piezoelectric perovskites and it might be expected that the piezoelectric strains are also very large. A field induced phase transition is therefore indistinguishable from the piezoelectric distortion and is neither sufficient nor necessary to understand the large piezoelectric response of PZN-PT

Crystallization behavior and domain structure in textured Pb(Zr0.52Ti0.48)O3 thin films by different annealing processes

International Nuclear Information System (INIS)

Huang, W.; Jiang, S.W.; Li, Y.R.; Zhu, J.; Zhang, Y.; Wei, X.H.; Zeng, H.Z.

2006-01-01

Amorphous Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films were prepared on the Pt/Ti/SiO 2 /Si substrates by radio-frequency magnetron sputtering at room temperature. After rapid thermal annealing (RTA) and conventional furnace annealing (CFA) at different temperatures, the films were transformed into polycrystalline PZT thin films with (111) and (100) orientation, respectively. The phase formation and ferroelectric domains correlated with different orientation were systematically investigated by X-ray diffraction and piezoresponse force microscopy. The results showed that the perovskite PZT crystal with [111] orientation hetero-nucleated preferentially on top of the PtPb intermetallic phase at the PZT/Pt interface during RTA process. It is of interest to find that the domain self-organized into a structure with rounded shape at the early stage of crystallization. While the nucleation of the films treated by CFA dominantly homo-nucleated, thus the (100) orientation grains with minimum surface energy were easy to grow. The texture effects on ferroelectric properties of PZT films were also discussed in relation to the domain structure

Magnetoelastic coupling in multilayered ferroelectric/ferromagnetic thin films: A quantitative evaluation

Energy Technology Data Exchange (ETDEWEB)

Chiolerio, A., E-mail: alessandro.chiolerio@iit.it [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10129 Turin (Italy); Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, IT-10129 Turin (Italy); Quaglio, M. [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, IT-10129 Turin (Italy); Lamberti, A. [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10129 Turin (Italy); Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, IT-10129 Turin (Italy); Celegato, F. [Electromagnetism Division, INRIM, Strada delle Cacce 91, IT-10135 Turin (Italy); Balma, D.; Allia, P. [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10129 Turin (Italy)

2012-08-01

The electrical control of magnetization in a thin film, achieved by means of magnetoelastic coupling between a ferroelectric and a ferromagnetic layer represents an attractive way to implement magnetic information storage and processing within logical architectures known as Magnetic Quantum Cellular Automata (MQCA). Such systems have been addressed as multiferroics. We exploited cost-effective techniques to realize multi-layered multiferroic systems, such as sol-gel deposition and RF sputtering, introducing a specific technique to control the crystal structure and film roughness effect on the magnetic domain wall motion and reconfiguration, induced by magnetoelastic coupling, by evaluating the 2-dimensional statistical properties of enhanced MFM matrices. A RF sputtered 50-nm-thick Co layer on a Si/SiO{sub 2}/Si{sub 3}N{sub 4}/Ti/Pt/PbTiO{sub 3}/Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3} substrate was realized, exploiting two differently engineered PZT nano-crystalline structures and the conditions leading to a favorable compromise in order to realize functional devices were elucidated.

Micro-machined high-frequency (80 MHz) PZT thick film linear arrays.

Science.gov (United States)

Zhou, Qifa; Wu, Dawei; Liu, Changgeng; Zhu, Benpeng; Djuth, Frank; Shung, K

2010-10-01

This paper presents the development of a micromachined high-frequency linear array using PZT piezoelectric thick films. The linear array has 32 elements with an element width of 24 μm and an element length of 4 mm. Array elements were fabricated by deep reactive ion etching of PZT thick films, which were prepared from spin-coating of PZT sol-gel composite. Detailed fabrication processes, especially PZT thick film etching conditions and a novel transferring-and-etching method, are presented and discussed. Array designs were evaluated by simulation. Experimental measurements show that the array had a center frequency of 80 MHz and a fractional bandwidth (-6 dB) of 60%. An insertion loss of -41 dB and adjacent element crosstalk of -21 dB were found at the center frequency.

In situ 2D diffraction as a tool to characterize ferroelectric and piezoelectric thin films

Science.gov (United States)

Khamidy, N. I.; Kovacova, V.; Bernasconi, A.; Le Rhun, G.; Vaxelaire, N.

2017-08-01

In this paper the application of 2D x-ray diffraction (XRD2) as a technique to characterize in situ during electrical cycling the properties of a ferroelectric and piezoelectric thin film is discussed. XRD2 is one type of XRD on which a 2D detector is used instead of a point detector. This technique enables simultaneous recording of many sample information in a much shorter time compared to conventional XRD. The discussion is focused especially on the data processing technique of the huge data acquired. The methodology to calculate an effective piezoelectric coefficient, analyze the phase and texture, and estimate the domain size and shape is described in this paper. This methodology is then applied to a lead zirconate titanate (PZT) thin film at the morphotropic phase boundary (MPB) composition (i.e. Pb[Zr0.52Ti0.48]O3) with a preferred orientation of (1 0 0). The in situ XRD2 characterization was conducted in the European synchrotron radiation facility (ESRF) in Grenoble, France. Since a high-energy beam with vertical resolution as small as 100 nm was used, a cross-sectional scan of the sample was performed over the entire thickness of the film. From these experimental results, a better understanding on the piezoelectricity phenomena in PZT thin film at MPB composition were achieved, providing original feedback between the elaboration processes and functional properties of the film.

Dielectric and acoustical high frequency characterisation of PZT thin films

Energy Technology Data Exchange (ETDEWEB)

Conde, Janine; Muralt, Paul, E-mail: janine.conde@epfl.ch [Department of Materials Science, EPFL (Switzerland)

2010-02-15

Pb(Zr, Ti)O{sub 3} (PZT) is an interesting material for bulk acoustic wave resonator applications due to its high electromechanical coupling constant, which would enable fabrication of large bandwidth frequency filters. The major challenge of the PZT solid solution system is to overcome mechanical losses generally observed in PZT ceramics. To increase the understanding of these losses in textured thin films, thin film bulk acoustic resonators (TFBAR's) based on PZT thin films with compositions either in the tetragonal region or at the morphotropic phase boundary and (111) or {l_brace}100{r_brace} textures were fabricated and studied up to 2 GHz. The dielectric and elastic materials coefficients were extracted from impedance measurements at the resonance frequency. The dispersion of the dielectric constant was obtained from impedance measurements up to 2 GHz. The films with varying compositions, textures and deposition methods (sol-gel or sputtering) were compared in terms of dielectric and acoustical properties.

Impedance-Based Cable Force Monitoring in Tendon-Anchorage Using Portable PZT-Interface Technique

Directory of Open Access Journals (Sweden)

Thanh-Canh Huynh

2014-01-01

Full Text Available In this paper, a portable PZT interface for tension force monitoring in the cable-anchorage subsystem is developed. Firstly, the theoretical background of the impedance-based method is presented. A few damage evaluation approaches are outlined to quantify the variation of impedance signatures. Secondly, a portable PZT interface is designed to monitor impedance signatures from the cable-anchorage subsystem. One degree-of-freedom analytical model of the PZT interface is established to explain how to represent the loss of cable force from the change in the electromechanical impedance of the PZT interface as well as reducing the sensitive frequency band by implementing the interface device. Finally, the applicability of the proposed PZT-interface technique is experimentally evaluated for cable force-loss monitoring in a lab-scaled test structure.

Effect of Nb doping on sintering and dielectric properties of PZT ceramics

Directory of Open Access Journals (Sweden)

Ali Mirzaei

2016-09-01

Full Text Available The extensive use of piezoelectric ceramics such as lead zirconate titanate (PZT in different applications became possible with the development of donor or acceptor dopants. Therefore, studies on the effect of dopants on the properties of PZT ceramics are highly demanded. In this study undoped and 2.4 mol% Nb-doped PZT (PZTN powders were successfully obtained by a solid-state reaction and calcination at 850 °C for 2 h. Crystallinity and phase formation of the prepared powders were studied using X-ray diffraction (XRD. In order to study morphology of powders, scanning electron microscopy (SEM was performed. The crystalline PZT and Nb-doped PZT powders were pelleted into discs and sintered at 1100, 1150 and 1200 °C, with a heating rate of 10 °C/min, and holding time of 1–6 h to find the optimum combination of temperature and time to produce high density ceramics. Microstructural characterization was conducted on the fractured ceramic surfaces using SEM. Density measurements showed that maximal density of 95% of the theoretical density was achieved after sintering of PZT and PZTN ceramics at 1200 °C for 2 h and 4 h, respectively. However, the results of dielectric measurements showed that PZTN ceramics have higher relative permittivity (εr ∼17960 with lower Curie temperature (∼358 °C relative to PZT (εr = 16000 at ∼363 °C as a result of fine PZTN structure as well as presence of vacancies. In addition, dielectric loss (at 1 kHz of PZT and PZTN ceramics with 95% theoretical density was 0.0087 and 0.02, respectively. The higher dielectric loss in PZTN was due to easier domain wall motions in PZTN ceramics.

MEMS-based thick film PZT vibrational energy harvester

DEFF Research Database (Denmark)

Lei, Anders; Xu, Ruichao; Thyssen, Anders

2011-01-01

We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using a mechan......We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using...... a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The fabricated harvester device produces 14.0 μW with an optimal resistive load of 100 kΩ from 1g (g=9.81 m s-2) input acceleration at its resonant frequency of 235 Hz....

Ferroelectricity at the nanoscale basics and applications

CERN Document Server

Fridkin, Vladimir

2014-01-01

This book examines a wide range of ferroelectric materials. It explains the theoretical background of ultrathin ferroelectric films,  presents applications of ferroelectric materials, and displays the mechanism of switching of nanosized ferroelectric films.

Mechanically activated synthesis of PZT and its electromechanical properties

Energy Technology Data Exchange (ETDEWEB)

Liu, X.; Akdogan, E.K.; Safari, A.; Riman, R.E. [Rutgers the State University of New Jersey, Department of Ceramic and Materials Engineering, Piscataway, NJ (United States)

2005-08-01

Mechanical activation was successfully used to synthesize nanostructured phase-pure Pb(Zr{sub 0.7}Ti{sub 0.3})O{sub 3} (PZT) powders. Lead-zirconium-titanium (PbZrTi) hydrous oxide precursor, synthesized from chemical co-precipitation, was mechanically activated in a NaCl matrix. The synthesized PZT particles were characterized by using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, laser-light diffraction, and nitrogen adsorption. Thermogravimetric analysis and differential thermal analysis were used to monitor dehydration and phase transformation of PbZrTi hydrous oxide precursor during mechanical activation. The best mechanical activation conditions corresponded to mechanically activating PbZrTi hydrous oxide precursor in a NaCl matrix with a NaCl/precursor weight ratio of 4:1 for 8 h. These conditions resulted in a dispersible phase-pure PZT powder with a median secondary-particle size of {proportional_to}110 nm. The properties of PZT 70/30 from mechanically activated powder, as measured on discs sintered at 1150 C for 2 h, were found to be in close conformity to those obtained by a conventional mixed oxide solid state reaction route. (orig.)

Mechanically activated synthesis of PZT and its electromechanical properties

Science.gov (United States)

Liu, X.; Akdogan, E. K.; Safari, A.; Riman, R. E.

2005-08-01

Mechanical activation was successfully used to synthesize nanostructured phase-pure Pb(Zr0.7Ti0.3)O3 (PZT) powders. Lead zirconium titanium (PbZrTi) hydrous oxide precursor, synthesized from chemical co-precipitation, was mechanically activated in a NaCl matrix. The synthesized PZT particles were characterized by using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, laser-light diffraction, and nitrogen adsorption. Thermogravimetric analysis and differential thermal analysis were used to monitor dehydration and phase transformation of PbZrTi hydrous oxide precursor during mechanical activation. The best mechanical activation conditions corresponded to mechanically activating PbZrTi hydrous oxide precursor in a NaCl matrix with a NaCl/precursor weight ratio of 4:1 for 8 h. These conditions resulted in a dispersible phase-pure PZT powder with a median secondary-particle size of ˜110 nm. The properties of PZT 70/30 from mechanically activated powder, as measured on discs sintered at 1150 °C for 2 h, were found to be in close conformity to those obtained by a conventional mixed oxide solid state reaction route.

Effect of External Vibration on PZT Impedance Signature

Directory of Open Access Journals (Sweden)

Yaowen Yang

2008-11-01

Full Text Available Piezoelectric ceramic Lead Zirconate Titanate (PZT transducers, working on the principle of electromechanical impedance (EMI, are increasingly applied for structural health monitoring (SHM in aerospace, civil and mechanical engineering. The PZT transducers are usually surface bonded to or embedded in a structure and subjected to actuation so as to interrogate the structure at the desired frequency range. The interrogation results in the electromechanical admittance (inverse of EMI signatures which can be used to estimate the structural health or integrity according to the changes of the signatures. In the existing EMI method, the monitored structure is only excited by the PZT transducers for the interrogating of EMI signature, while the vibration of the structure caused by the external excitations other than the PZT actuation is not considered. However, many structures work under vibrations in practice. To monitor such structures, issues related to the effects of vibration on the EMI signature need to be addressed because these effects may lead to misinterpretation of the structural health. This paper develops an EMI model for beam structures, which takes into account the effect of beam vibration caused by the external excitations. An experimental study is carried out to verify the theoretical model. A lab size specimen with different external excitations is tested and the effect of vibration on EMI signature is discussed.

Effect of External Vibration on PZT Impedance Signature.

Science.gov (United States)

Yang, Yaowen; Miao, Aiwei

2008-11-01

Piezoelectric ceramic Lead Zirconate Titanate (PZT) transducers, working on the principle of electromechanical impedance (EMI), are increasingly applied for structural health monitoring (SHM) in aerospace, civil and mechanical engineering. The PZT transducers are usually surface bonded to or embedded in a structure and subjected to actuation so as to interrogate the structure at the desired frequency range. The interrogation results in the electromechanical admittance (inverse of EMI) signatures which can be used to estimate the structural health or integrity according to the changes of the signatures. In the existing EMI method, the monitored structure is only excited by the PZT transducers for the interrogating of EMI signature, while the vibration of the structure caused by the external excitations other than the PZT actuation is not considered. However, many structures work under vibrations in practice. To monitor such structures, issues related to the effects of vibration on the EMI signature need to be addressed because these effects may lead to misinterpretation of the structural health. This paper develops an EMI model for beam structures, which takes into account the effect of beam vibration caused by the external excitations. An experimental study is carried out to verify the theoretical model. A lab size specimen with different external excitations is tested and the effect of vibration on EMI signature is discussed.

Electro-mechanical properties of free standing micro- and nano-scale polymer-ceramic composites for energy density capacitors

Energy Technology Data Exchange (ETDEWEB)

Singh, Paritosh; Borkar, Hitesh [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi, 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory (CSIR-NPL) Campus, Dr. K. S. Krishnan Road, New Delhi, 110012 (India); Singh, B.P.; Singh, V.N. [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi, 110012 (India); Kumar, Ashok, E-mail: ashok553@nplindia.org [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi, 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory (CSIR-NPL) Campus, Dr. K. S. Krishnan Road, New Delhi, 110012 (India)

2015-11-05

The integration of inorganic fillers in polymer matrix is useful for superior mechanical strength and functional properties of polymer-ceramic composites. We report the fabrication and characterization of polyvinylidene fluoride-CoFe{sub 2}O{sub 4} (PVDF-CFO) (wt% 80:20, respectively) and PVDF-Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3}–CoFe{sub 2}O{sub 4} (PVDF-PZT-CFO) (wt% 80:10:10, respectively) free standing 50 μm thick ferroelectric-polymer-ceramic composites films. X-ray diffraction (XRD) patterns and Raman spectra revealed the presence of major semi-crystalline β-PVDF along with α-phase which is responsible for ferroelectric nature in both the composite systems. Ferroelectric, dielectric and mechanical strength measurements were performed in order to evaluate the effects of CFO and PZT inorganic fillers in PVDF matrix. The inclusion of CFO and PZT micro-/nano-particles in PVDF polymer matrix improved the polarization behavior, dielectric properties and mechanical strength. The energy density was calculated by polarization-electric field hysteresis loop and found in the range of 6–8 J/cm{sup 3} may be useful for microelectronics. - Graphical abstract: Large area PVDF-PZT-CFO nano- and micro-composite films have been fabricated for high energy density storage flexible capacitor. Presence of nanocrystalline PZT and CFO particles in polymer matrix significantly enhanced their energy density capacity. - Highlights: • Physical interaction of cobalt iron oxide with polymer matrix results β-PVDF phase. • Evidence of Micro and Nano crystalline CFO and PZT fillers in polymer matrix. • The CFO and PZT fillers provide better mechanical strength to composite films. • PVDF-ceramic nanocomposites show low leakage behavior for high electric field.

Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage

International Nuclear Information System (INIS)

Bhushan, Bharat; Palacio, Manuel; Kwak, Kwang Joo

2008-01-01

In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum silicide at the near-surface. Nanoindentation, nanoscratch and wear experiments were performed to evaluate the mechanical properties and wear performance at high velocities. The thermally treated tip exhibited lower wear than the untreated tip. The tip wear mechanism is adhesive and abrasive wear with some evidence of impact wear. The enhancement in mechanical properties and wear resistance in the thermally treated film is attributed to silicide formation in the near-surface. Auger electron spectroscopy and electrical resistivity measurements confirm the formation of platinum silicide. This study advances the understanding of thin film nanoscale surface interactions

Effect of elastic compliances and higher order Landau coefficients on the phase diagram of single domain epitaxial Pb(Zr,TiO3 (PZT thin films

Directory of Open Access Journals (Sweden)

M. Mtebwa

2014-12-01

Full Text Available We report the qualitative study of the influence of both elastic compliances and higher order terms of Landau free energy potential on the phase diagram of Pb(Zr0.5Ti0.5O3 thin films by using a single domain Landau theory. Although the impact of elastic compliances and higher order terms of the Landau free energy potential on the phase diagram of ferroelectric thin films are known, the sensitivity of the phase diagram of PZT thin film on these parameters have not been reported. It is demonstrated that, while values of elastic compliances affect the positions of the phase boundaries including phase transition temperature of the cubic phase; higher order terms can potentially introduce an a1a2-phase previously predicted in PbTiO3 phase diagram.

Electric-field-induced tetragonal phase in [Pb(Mg.sub.1/3./sub.Nb.sub.2/3./sub.)O.sub.3./sub.].sub.0.68./sub.-[PbTiO.sub.3./sub.].sub.0.32./sub. by Raman scattering

Czech Academy of Sciences Publication Activity Database

Rafalovskyi, Iegor; Gregora, Ivan; Hlinka, Jiří

2016-01-01

Roč. 89, 7-8 (2016), s. 816-822 ISSN 0141-1594 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : phase transition * MPB * relaxor ferroelectric Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.060, year: 2016

Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric

Energy Technology Data Exchange (ETDEWEB)

Ghoneim, M. T.; Hussain, M. M., E-mail: muhammadmustafa.hussain@kaust.edu.sa [Integrated Nanotechnology Lab, Electrical Engineering, Computer Electrical Mathematical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

2015-08-03

Flexible memory can enable industrial, automobile, space, and smart grid centered harsh/extreme environment focused electronics application(s) for enhanced operation, safety, and monitoring where bent or complex shaped infrastructures are common and state-of-the-art rigid electronics cannot be deployed. Therefore, we report on the physical-mechanical-electrical characteristics of a flexible ferroelectric memory based on lead zirconium titanate as a key memory material and flexible version of bulk mono-crystalline silicon (100). The experimented devices show a bending radius down to 1.25 cm corresponding to 0.16% nominal strain (high pressure of ∼260 MPa), and full functionality up to 225 °C high temperature in ambient gas composition (21% oxygen and 55% relative humidity). The devices showed unaltered data retention and fatigue properties under harsh conditions, still the reduced memory window (20% difference between switching and non-switching currents at 225 °C) requires sensitive sense circuitry for proper functionality and is the limiting factor preventing operation at higher temperatures.

Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric

International Nuclear Information System (INIS)

Ghoneim, M. T.; Hussain, M. M.

2015-01-01

Flexible memory can enable industrial, automobile, space, and smart grid centered harsh/extreme environment focused electronics application(s) for enhanced operation, safety, and monitoring where bent or complex shaped infrastructures are common and state-of-the-art rigid electronics cannot be deployed. Therefore, we report on the physical-mechanical-electrical characteristics of a flexible ferroelectric memory based on lead zirconium titanate as a key memory material and flexible version of bulk mono-crystalline silicon (100). The experimented devices show a bending radius down to 1.25 cm corresponding to 0.16% nominal strain (high pressure of ∼260 MPa), and full functionality up to 225 °C high temperature in ambient gas composition (21% oxygen and 55% relative humidity). The devices showed unaltered data retention and fatigue properties under harsh conditions, still the reduced memory window (20% difference between switching and non-switching currents at 225 °C) requires sensitive sense circuitry for proper functionality and is the limiting factor preventing operation at higher temperatures

Study of harsh environment operation of flexible ferroelectric memory integrated with PZT and silicon fabric

KAUST Repository

Ghoneim, Mohamed T.

2015-08-05

Flexible memory can enable industrial, automobile, space, and smart grid centered harsh/extreme environment focused electronics application(s) for enhanced operation, safety, and monitoring where bent or complex shaped infrastructures are common and state-of-the-art rigid electronics cannot be deployed. Therefore, we report on the physical-mechanical-electrical characteristics of a flexible ferroelectric memory based on lead zirconium titanate as a key memory material and flexible version of bulk mono-crystalline silicon (100). The experimented devices show a bending radius down to 1.25 cm corresponding to 0.16% nominal strain (high pressure of ∼260 MPa), and full functionality up to 225 °C high temperature in ambient gas composition (21% oxygen and 55% relative humidity). The devices showed unaltered data retention and fatigue properties under harsh conditions, still the reduced memory window (20% difference between switching and non-switching currents at 225 °C) requires sensitive sense circuitry for proper functionality and is the limiting factor preventing operation at higher temperatures.

Properties of morphotropic phase boundary Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} films with submicrometre range thickness on Si-based substrates

Energy Technology Data Exchange (ETDEWEB)

Alguero, M; Ricote, J; Calzada, M L [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain); Stewart, M; Cain, M G [National Physical Laboratory, Hampton Road, Teddington TW11 0LW (United Kingdom); Ramos, P [Departamento de Electronica, Universidad de Alcala. 28871 Alcala de Henares (Spain)

2010-05-26

The electrical properties of (1 - x)Pb(Mg{sub 1/3} Nb{sub 2/3})O{sub 3} - xPbTiO{sub 3} films with composition in the morphotropic phase boundary region around x = 0.35, submicrometre thickness and columnar microstructure, prepared on Si-based substrates by chemical solution deposition are presented and discussed in relation to the properties of coarse and fine grained ceramics. The films show relaxor characteristics that are proposed to result from a grain size effect on the kinetics of the relaxor to ferroelectric transition. The transition is slowed down for grain sizes in the submicrometre range, and as a consequence intermediate polar domain configurations with typical length scales in the submicrometre- and nanoscales are stabilized. A high saturation polarization can be attained under field, but fast polarization relaxation occurs after its removal, and negligible remanent values are obtained. At the same time, they also show spontaneous piezoelectricity and pyroelectricity. Self-polarization is thus present, which indicates the existence of an internal electric field that is most probably a substrate effect. Films would then be in a phase instability, at an intermediate state between the relaxor and ferroelectric ones, and under a bias electric field, which would explain the very high spontaneous pyroelectric response found.

Enhanced Output Power of PZT Nanogenerator by Controlling Surface Morphology of Electrode.

Science.gov (United States)

Jung, Woo-Suk; Lee, Won-Hee; Ju, Byeong-Kwon; Yoon, Seok-Jin; Kang, Chong-Yun

2015-11-01

Piezoelectric power generation using Pb(Zr,Ti)O3(PZT) nanowires grown on Nb-doped SrTiO3(nb:STO) substrate has been demonstrated. The epitaxial PZT nanowires prepared by a hydrothermal method, with a diameter and length of approximately 300 nm and 7 μm, respecively, were vertically aligned on the substrate. An embossed Au top electrode was applied to maximize the effective power generation area for non-uniform PZT nanowires. The PZT nanogenerator produced output power density of 0.56 μW/cm2 with a voltage of 0.9 V and current of 75 nA. This research suggests that the morphology control of top electrode can be useful to improve the efficiency of piezoelectric power generation.

Feasibility Verification of Mountable PZT-Interface for Impedance Monitoring in Tendon-Anchorage

Directory of Open Access Journals (Sweden)

Thanh-Canh Huynh

2015-01-01

Full Text Available This study has been motivated to numerically evaluate the performance of the mountable PZT-interface for impedance monitoring in tendon-anchorage. Firstly, electromechanical impedance monitoring and feature classification methods are outlined. Secondly, a structural model of tendon-anchorage subsystem with mountable PZT-interface is designed for impedance monitoring. Finally, the feasibility of the mountable PZT-interface is numerically examined. A finite element (FE model is designed for the lab-scaled tendon-anchorage. The FE model of the PZT-interface is tuned as its impedance signatures meet the experimental test results at the same frequency ranges and also with identical patterns. Equivalent model properties of the FE model corresponding to prestress forces inflicted on the lab-tested structure are identified from the fine-tuning practice.

Synthesis and characterization of tungsten or calcium doped PZT ceramics; Sintese e caracterizacao do PZT dopado com W ou Ca

Energy Technology Data Exchange (ETDEWEB)

Santos, D.M.; Caracas, L.B.; Noronha, R.G.; Santos, M.M.T. dos [Universidade Federal do Maranhao (UFMA), Sao Luis, MA (Brazil). Dept. de Desenho e Tecnologia. Curso de Desenho Industrial; Paiva-Santos, C.O., E-mail: denilson@ufma.b [Universidade Estadual Paulista (IQ/UNESP), Araraquara, SP (Brazil). Inst. de Quimica

2009-07-01

Pure and doped (tungsten or calcium) PZT ceramics were prepared by association of the polymeric precursor and partial oxalate method. The phase formation was investigated by thermal analysis (TG/DSC) and X-ray diffraction (XRD). The affect of W or Ca doping PZT and their electrical properties was evaluated. Substitution of W by Ti and Ca by Pb leads to an increase of Curie temperature and broadening of dielectric constant. A typical hysteresis loop was observed at room temperature and the remnant polarization was increased with the content of W and Ca. (author)

Characterization of highly (110)- and (111)-oriented Pb(Zr,Ti)O3 films on BaPbO3 electrode using Ru conducting barrier

International Nuclear Information System (INIS)

Liang, C.-S.; Wu, J.-M.

2005-01-01

Highly non-(001)-oriented Pb(Zr,Ti)O 3 (PZT) films have been fabricated by rf-magnetron sputtering. The preferential (110)-oriented BaPbO 3 (BPO) deposited on Ru buffer layer induces the growth of (110)-oriented PZT film. With the aid of self-organized growth of PZT, the orientation of the film deposited on random-oriented BPO/Pt(111)/Ru(002) is (111)-preferred. The insertion of Pt layer between BPO and Ru changes the orientation of PZT from (110) to (111) and prevents the oxygen diffusion. These non-(001)-oriented PZT films possess more superior ferroelectric, fatigue, and retention properties than those of (001)-oriented PZT films

Revisiting the blocking force test on ferroelectric ceramics using high energy x-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Daniel, L., E-mail: laurent.daniel@u-psud.fr [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); GeePs (CNRS UMR8507, CentraleSupelec, UPMC, Univ Paris-Sud), 91192 Gif sur Yvette cedex (France); Hall, D. A.; Withers, P. J. [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Koruza, J.; Webber, K. G. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); King, A. [European Synchrotron Radiation Facility (ESRF), 6 rue J. Horowitz, 38043 Grenoble (France); Synchrotron SOLEIL, BP 48, 91192 Gif sur Yvette cedex (France)

2015-05-07

The blocking force test is a standard test to characterise the properties of piezoelectric actuators. The aim of this study is to understand the various contributions to the macroscopic behaviour observed during this experiment that involves the intrinsic piezoelectric effect, ferroelectric domain switching, and internal stress development. For this purpose, a high energy diffraction experiment is performed in-situ during a blocking force test on a tetragonal lead zirconate titanate (PZT) ceramic (Pb{sub 0.98}Ba{sub 0.01}(Zr{sub 0.51}Ti{sub 0.49}){sub 0.98}Nb{sub 0.02}O{sub 3}). It is shown that the usual macroscopic linear interpretation of the test can also be performed at the single crystal scale, allowing the identification of local apparent piezoelectric and elastic properties. It is also shown that despite this apparent linearity, the blocking force test involves significant non-linear behaviour mostly due to domain switching under electric field and stress. Although affecting a limited volume fraction of the material, domain switching is responsible for a large part of the macroscopic strain and explains the high level of inter- and intra-granular stresses observed during the course of the experiment. The study shows that if apparent piezoelectric and elastic properties can be identified for PZT single crystals from blocking stress curves, they may be very different from the actual properties of polycrystalline materials due to the multiplicity of the physical mechanisms involved. These apparent properties can be used for macroscopic modelling purposes but should be considered with caution if a local analysis is aimed at.

Microelectromechanical Systems (MEMS) Photoacoustic (PA) Detector of Terahertz (THz) Radiation for Chemical Sensing

Science.gov (United States)

2014-03-01

films. The seed layer established the desired orientation and texture for the preferential crystal formation of the PZT . Deposited by chemical...34Stoichiometry and crystal orientation of YAG-PLD derived ferroelectric PZT thin film," Journal of the European Ceramic Society, vol. 24, no. 6, pp...results performed on the lead zirconate titanate ( PZT ) target used in previous attempts at fabricating piezoelectric cantilever. It is shown that the

Ferroelectric devices

CERN Document Server

Uchino, Kenji

2009-01-01

Updating its bestselling predecessor, Ferroelectric Devices, Second Edition assesses the last decade of developments-and setbacks-in the commercialization of ferroelectricity. Field pioneer and esteemed author Uchino provides insight into why this relatively nascent and interdisciplinary process has failed so far without a systematic accumulation of fundamental knowledge regarding materials and device development.Filling the informational void, this collection of information reviews state-of-the-art research and development trends reflecting nano and optical technologies, environmental regulat

Thermal-induced structural transition and depolarization behavior in (Bi0.5Na0.5)TiO3-BiAlO3 ceramics

Science.gov (United States)

Peng, Ping; Nie, Hengchang; Cheng, Guofeng; Liu, Zhen; Wang, Genshui; Dong, Xianlin

2018-03-01

The depolarization temperature Td determines the upper temperature limit for the application of piezoelectric materials. However, the origin of depolarization behavior for Bi-based materials still remains controversial and the mechanism is intricate for different (Bi0.5Na0.5)TiO3-based systems. In this work, the structure and depolarization behavior of (1-x)(Bi0.5Na0.5)TiO3-xBiAlO3 (BNT-BA, x = 0, 0.02, 0.04, 0.06, 0.07) ceramics were investigated using a combination of X-ray diffraction and electrical measurements. It was found that as temperature increased, the induced long-range ferroelectric phase irreversibly transformed to the relaxor phase as evidenced by the temperature-dependent ferroelectric and dielectric properties, which corresponded to a gradual structural change from the rhombohedral to the pseudocubic phase. Therefore, the thermal depolarization behavior of BNT-BA ceramics was proposed to be directly related to the rhombohedral-pseudocubic transition. Furthermore, Td (obtained from thermally stimulated depolarization currents curves) was higher than the induced ferroelectric-relaxor phase transition temperature TFR (measured from dielectric curves). The phenomenon was quite different from other reported BNT-based systems, which may suggest the formation of polar nanoregions (PNRs) within macrodomains prior to the detexturation of short-range ferroelectric domains with PNRs or nanodomains.

Influence of microstructure on electromechanical properties of nano-crystalline La-Pb(Ni{sub 1/3}Sb{sub 2/3})-PbZrTiO{sub 3} ferroelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Kumar, H.H.; Lonkar, C.M. [Armament Research and Development Establishment, Pune (India); Balasubramanian, K. [Defence Institute of Advanced Technology (Deemed University), Pune (India)

2017-10-15

A ferroelectric ceramic composition, Pb{sub 0.98}La{sub 0.02}(Ni{sub 1/3}Sb{sub 2/3}){sub 0.05}[(Zr{sub 0.52}Ti{sub 0.48}){sub 0.995}] {sub 0.95}O{sub 3}, has been synthesized by columbite precursor method followed by mechanical activation for 10 h (MA-10) using high-energy ball mill. Formation of desired perovskite phase during activation was confirmed from analysis of X-ray diffraction patterns, while powder particle size, in nano-meter range, was revealed from high-resolution transmission electron microscopic (HRTEM) investigations. Samples were sintered between 1170 and 1320 C, and were investigated for microstructure and its influence on electromechanical properties. Increment in grain size with sintering temperature was noticed. 1220 C sintering temperature posed denser and uniform microstructure amongst all the temperatures and also showed composition close to morphotropic phase boundary (MPB) of PZT with optimum tetragonality which resulted in better electromechanical properties, suggesting the suitability of this composition for power harvesting applications. Phase transition studies revealed normal ferroelectric behaviour with transition temperature of 286 C. (orig.)

Ferroelectric ultrathin perovskite films

Science.gov (United States)

Rappe, Andrew M; Kolpak, Alexie Michelle

2013-12-10

Disclosed herein are perovskite ferroelectric thin-film. Also disclosed are methods of controlling the properties of ferroelectric thin films. These films can be used in a variety materials and devices, such as catalysts and storage media, respectively.

Enhanced dielectric constant and fatigue-resistance of PbZr0.4Ti0.6O3 capacitor with magnetic intermetallic FePt top electrode

Science.gov (United States)

Liu, B. T.; Zhao, J. W.; Li, X. H.; Zhou, Y.; Bian, F.; Wang, X. Y.; Zhao, Q. X.; Wang, Y. L.; Guo, Q. L.; Wang, L. X.; Zhang, X. Y.

2010-06-01

Both FePt/PbZr0.4Ti0.6O3(PZT)/Pt and Pt/PZT/Pt ferroelectric capacitors have been fabricated on Si substrates. It is found that up to 109 switching cycles, the FePt/PZT/Pt capacitor, measured at 50 kHz, with polarization decreased by 57%, is superior to the Pt/PZT/Pt capacitor by 82%, indicating that an intermetallic FePt top electrode can also improve the fatigue-resistance of a PZT capacitor. Maximum dielectric constants are 980 and 770 for PZT capacitors with FePt and Pt, respectively. This is attributed to the interface effect between PZT film and the top electrode since the interfacial capacitance of FePt/PZT is 3.5 times as large as that of Pt/PZT interface.

A new traveling wave ultrasonic motor using thick ring stator with nested PZT excitation.