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Sample records for soft magnetic material

  1. High performance soft magnetic materials

    CERN Document Server

    2017-01-01

    This book provides comprehensive coverage of the current state-of-the-art in soft magnetic materials and related applications, with particular focus on amorphous and nanocrystalline magnetic wires and ribbons and sensor applications. Expert chapters cover preparation, processing, tuning of magnetic properties, modeling, and applications. Cost-effective soft magnetic materials are required in a range of industrial sectors, such as magnetic sensors and actuators, microelectronics, cell phones, security, automobiles, medicine, health monitoring, aerospace, informatics, and electrical engineering. This book presents both fundamentals and applications to enable academic and industry researchers to pursue further developments of these key materials. This highly interdisciplinary volume represents essential reading for researchers in materials science, magnetism, electrodynamics, and modeling who are interested in working with soft magnets. Covers magnetic microwires, sensor applications, amorphous and nanocrystalli...

  2. Magnetism and metallurgy of soft magnetic materials

    CERN Document Server

    Chen, Chih-Wen

    2011-01-01

    Soft magnetic materials are economically and technologically the most important of all magnetic materials. In particular, the development of new materials and novel applications for the computer and telecommunications industries during the past few decades has immensely broadened the scope and altered the nature of soft magnetic materials. In addition to metallic substances, nonmetallic compounds and amorphous thin films are coming increasingly important. This thorough, well-organized volume - on of the most comprehensive treatments available - offers a coherent, logical presentation of the p

  3. Tailoring superelasticity of soft magnetic materials

    Science.gov (United States)

    Cremer, Peet; Löwen, Hartmut; Menzel, Andreas M.

    2015-10-01

    Embedding magnetic colloidal particles in an elastic polymer matrix leads to smart soft materials that can reversibly be addressed from outside by external magnetic fields. We discover a pronounced nonlinear superelastic stress-strain behavior of such materials using numerical simulations. This behavior results from a combination of two stress-induced mechanisms: a detachment mechanism of embedded particle aggregates and a reorientation mechanism of magnetic moments. The superelastic regime can be reversibly tuned or even be switched on and off by external magnetic fields and thus be tailored during operation. Similarities to the superelastic behavior of shape-memory alloys suggest analogous applications, with the additional benefit of reversible switchability and a higher biocompatibility of soft materials.

  4. Connection between microstructure and magnetic properties of soft magnetic materials

    International Nuclear Information System (INIS)

    Bertotti, G.

    2008-01-01

    The magnetic behavior of soft magnetic materials is discussed with some emphasis on the connection between macroscopic properties and underlying micromagnetic energy aspects. It is shown that important conceptual gaps still exist in the interpretation of macroscopic magnetic properties in terms of the micromagnetic formulation. Different aspects of hysteresis modeling, power loss prediction and magnetic non-destructive evaluation are discussed in this perspective

  5. Magnetic characterization of soft and hard magnetic materials

    International Nuclear Information System (INIS)

    Groessinger, R.; Mehmood, N.; Sato Turtelli, R.; Keplinger, F.

    2008-01-01

    Full text: For industrial applications many materials are used which are magnetic such as various kind of steels, but also soft respectively hard magnetic materials are applied in order to solve a certain technical problem. For this purpose the magnetic properties of these materials have to be known or even optimized. In solid state physics the magnetic characterization is often performed at low temperatures, which means from 4.2 K up to room temperature. Contrary, for industrial application the range of environmental temperatures (-20 o C - 120 o C) where such systems are used is of interest. Additionally ranges the shape and size between few mm up to several cm. It is the purpose of this paper to summarize measuring systems which are mainly suited for an industrial characterizations. The most important hysteresis measurement methods which are applicable for industrial purpose are summarized. Special emphasis is laid on the difference between soft or hard magnetic materials. Practical examples for each method are given. Additionally a strain gauge method which is useful for magnetostriction measurement is shown. (author)

  6. Three-dimensional magnetic properties of soft magnetic composite materials

    International Nuclear Information System (INIS)

    Lin, Z.W.; Zhu, J.G.

    2007-01-01

    A three-dimensional (3-D) magnetic property measurement system, which can control the three components of the magnetic flux density B vector and measure the magnetic field strength H vector in a cubic sample of soft magnetic material, has been developed and calibrated. This paper studies the relationship between the B and H loci in 3-D space, and the power losses features of a soft magnetic composite when the B loci are controlled to be circles with increasing magnitudes and ellipses evolving from a straight line to circle in three orthogonal planes. It is found that the B and H loci lie in the same magnetization plane, but the H loci and power losses strongly depend on the orientation, position, and process of magnetization. On the other hand, the H vector evolves into a unique locus, and the power loss approaches a unique value, respectively, when the B vector evolves into the round locus with the same magnitude from either a series of circles or ellipses

  7. Determination of 3D magnetic reluctivity tensor of soft magnetic composite material

    International Nuclear Information System (INIS)

    Guo Youguang; Zhu Jianguo; Lin Zhiwei; Zhong Jinjiang; Lu Haiyan; Wang Shuhong

    2007-01-01

    Soft magnetic composite (SMC) materials are especially suitable for construction of electrical machines with complex structures and three-dimensional (3D) magnetic fluxes. In the design and optimization of such 3D flux machines, the 3D vector magnetic properties of magnetic materials should be properly determined, modeled, and applied for accurate calculation of the magnetic field distribution, parameters, and performance. This paper presents the measurement of 3D vector magnetic properties and determination of 3D reluctivity tensor of SMC. The reluctivity tensor is a key factor for accurate numerical analysis of magnetic field in a 3D flux SMC motor

  8. Development of soft magnetic materials with special properties

    International Nuclear Information System (INIS)

    Mager, A.

    1979-01-01

    New steps in the development of soft magnetic alloys are based on a better understanding of the magnetizing processes in close connection with the development of magnetic forms and components for different applications. New result on the influence of crystal grains, inclusions, and mechanical stresses on the soft magnetic properties of Ni-Fe-alloys with ca. 50 to 75% Nickel-contents are given. Special soft magnetic alloys were developed and improved for low temperature applications, for small temperature coefficients, for different shapes of hysteresis loops, or for high wear resistance - and moreover forms, components, and basic designs of chokes for RFI suppression, of transformers for electronic power supplies, of transformers for ground-fault interrupters, and for magnetic shielding equipments. (orig.) 891 GSC/orig. 892 AV [de

  9. Beam loss reduction by magnetic shielding using beam pipes and bellows of soft magnetic materials

    Science.gov (United States)

    Kamiya, J.; Ogiwara, N.; Hotchi, H.; Hayashi, N.; Kinsho, M.

    2014-11-01

    One of the main sources of beam loss in high power accelerators is unwanted stray magnetic fields from magnets near the beam line, which can distort the beam orbit. The most effective way to shield such magnetic fields is to perfectly surround the beam region without any gaps with a soft magnetic high permeability material. This leads to the manufacture of vacuum chambers (beam pipes and bellows) with soft magnetic materials. A Ni-Fe alloy (permalloy) was selected for the material of the pipe parts and outer bellows parts, while a ferritic stainless steel was selected for the flanges. An austenitic stainless steel, which is non-magnetic material, was used for the inner bellows for vacuum tightness. To achieve good magnetic shielding and vacuum performances, a heat treatment under high vacuum was applied during the manufacturing process of the vacuum chambers. Using this heat treatment, the ratio of the integrated magnetic flux density along the beam orbit between the inside and outside of the beam pipe and bellows became small enough to suppress beam orbit distortion. The outgassing rate of the materials with this heat treatment was reduced by one order magnitude compared to that without heat treatment. By installing the beam pipes and bellows of soft magnetic materials as part of the Japan Proton Accelerator Research Complex 3 GeV rapid cycling synchrotron beam line, the closed orbit distortion (COD) was reduced by more than 80%. In addition, a 95.5% beam survival ratio was achieved by this COD improvement.

  10. Development of High-frequency Soft Magnetic Materials for Power Electronics

    Directory of Open Access Journals (Sweden)

    LIU Jun-chang

    2017-05-01

    Full Text Available The new requirements of high-frequency magnetic properties are put forward for electronic components with the rapid development of power electronics industry and the use of new electromagnetic materials. The properties of magnetic core, which is the key unit of electronic components, determine the performance of electronic components directly. Therefore, it's necessary to study the high-frequency soft magnetic materials. In this paper, the development history of four types of soft magnetic materials was reviewed. The advantages and disadvantages of each kind of soft magnetic materials and future development trends were pointed out. The emphases were placed on the popular soft magnetic composite materials in recent years. The tendency is to develop high-frequency soft magnetic composite materials with the particle size controllable, uniform coating layer on the core and a mass production method from laboratory to industrialization.

  11. Design-based modeling of magnetically actuated soft diaphragm materials

    Science.gov (United States)

    Jayaneththi, V. R.; Aw, K. C.; McDaid, A. J.

    2018-04-01

    Magnetic polymer composites (MPC) have shown promise for emerging biomedical applications such as lab-on-a-chip and implantable drug delivery. These soft material actuators are capable of fast response, large deformation and wireless actuation. Existing MPC modeling approaches are computationally expensive and unsuitable for rapid design prototyping and real-time control applications. This paper proposes a macro-scale 1-DOF model capable of predicting force and displacement of an MPC diaphragm actuator. Model validation confirmed both blocked force and displacement can be accurately predicted in a variety of working conditions i.e. different magnetic field strengths, static/dynamic fields, and gap distances. The contribution of this work includes a comprehensive experimental investigation of a macro-scale diaphragm actuator; the derivation and validation of a new phenomenological model to describe MPC actuation; and insights into the proposed model’s design-based functionality i.e. scalability and generalizability in terms of magnetic filler concentration and diaphragm diameter. Due to the lumped element modeling approach, the proposed model can also be adapted to alternative actuator configurations, and thus presents a useful tool for design, control and simulation of novel MPC applications.

  12. The Characterization of the Magnetic Properties of Soft Magnetic Materials

    DEFF Research Database (Denmark)

    Larsen, Raino Michael

    1996-01-01

    The hysteresis curve and magnetic properties such as permeability, saturation induction, residual induction, coercive force and hysteresis losses are presented. The design and construction of equipment making it possible to measure true DC-values as well as AC-properties of toroid rings and cylin......The hysteresis curve and magnetic properties such as permeability, saturation induction, residual induction, coercive force and hysteresis losses are presented. The design and construction of equipment making it possible to measure true DC-values as well as AC-properties of toroid rings...

  13. Magnetic measurement of soft magnetic composites material under 3D SVPWM excitation

    Science.gov (United States)

    Zhang, Changgeng; Jiang, Baolin; Li, Yongjian; Yang, Qingxin

    2018-05-01

    The magnetic properties measurement and analysis of soft magnetic material under the rotational space-vector pulse width modulation (SVPWM) excitation are key factors in design and optimization of the adjustable speed motor. In this paper, a three-dimensional (3D) magnetic properties testing system fit for SVPWM excitation is built, which includes symmetrical orthogonal excitation magnetic circuit and cubic field-metric sensor. Base on the testing system, the vector B and H loci of soft magnetic composite (SMC) material under SVPWM excitation are measured and analyzed by proposed 3D SVPWM control method. Alternating and rotating core losses under various complex excitation with different magnitude modulation ratio are calculated and compared.

  14. High performance of low cost soft magnetic materials

    Indian Academy of Sciences (India)

    Administrator

    The consistent interest in supporting research and development of magnetic materials during the last century is revealed in their ... type of nanocrystalline alloys, i.e. crystals 10–20 nm in ..... nonetheless useful for a qualitative analysis of phase.

  15. Advances in Powder Metallurgy Soft Magnetic Composite Materials

    Directory of Open Access Journals (Sweden)

    Bureš R.

    2017-06-01

    Full Text Available Powder metallurgy has grown with the expansion of various industry. Automotive industry had the most strong influence. Today, more than 90% of PM products are used in the transportation industry. Development of new materials such as magnetic materials is expected to meet the new trends of automotive industry, electric and hybrid vehicles.

  16. EXPERIMENTATION OF THREE PHASE OUTER ROTATING SWITCHED RELUCTANCE MOTOR WITH SOFT MAGNETIC COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    N. C. LENIN

    2017-01-01

    Full Text Available This paper presents the application of Soft Magnetic Composite (SMC material in Outer Rotating Switched Reluctance Motor (ORSRM. The presented stator core of the Switched Reluctance Motor was made of two types of material, the classical laminated silicon steel sheet and the soft magnetic composite material. First, the stator core made of laminated steel has been analysed. The next step is to analyse the identical geometry SRM with the soft magnetic composite material, SOMALOY for its stator core. The comparisons of both cores include the calculated torque and torque ripple, magnetic conditions, simplicity of fabrication and cost. The finite element method has been used to analyse the magnetic conditions and the calculated torque. Finally, tested results shows that SMC is a better choice for SRM in terms of torque ripple and power density.

  17. Frequency characterization of thin soft magnetic material layers used in spiral inductors

    International Nuclear Information System (INIS)

    Kriga, Adoum; Allassem, Désiré; Soultan, Malloum; Chatelon, Jean-Pierre; Siblini, Ali; Allard, Bruno; Rousseau, Jean Jacques

    2012-01-01

    The paper details the characterization of thin magnetic materials layers, particularly soft materials, with respect to their behaviour in frequency (from 10 MHz to 1 GHz). The proposed method is suitable for any soft but insulating magnetic material; Yttrium Iron Garnet (YIG) is used as an example. The principle is based on a comparison between simulations for different values of the permeability and measurement values versus frequency of planar inductor structures; an experimental validation is proposed as well. Thin magnetic material is first deposited on an alumina substrate using RF sputtering technique; a planar spiral winding of copper is then deposited on the magnetic material by the same technique. The effective permeability versus frequency is obtained by comparing two samples of spiral windings with and without magnetic material. Network analyser measurements on samples of various geometrical dimensions and of different thicknesses are necessary to determine the effective magnetic permeability; we have obtained a relative effective permeability of about 30 for seven turns spiral inductor of a 17 μm YIG film. - Highlights: ► A simple and original method is presented for the characterization of soft magnetic layer. ► This is a non-destructive method based on standard equipment. ► The principle is based on a comparison between simulations and measurement. ► An experimental validation is proposed as well.

  18. Simulation of motional eddy current phenomena in soft magnetic material

    Science.gov (United States)

    De Gersem, Herbert; Hameyer, Kay

    2001-05-01

    The finite element simulation of conductors moving in a magnetic field at elevated speeds, yields oscillatory solutions. To overcome the effect of the huge convection terms, the partial differential equation is stabilised by adding artificial diffusion. Accurate results are obtained by applying adaptive mesh refinement. A rotational magnetic brake with a solid ferromagnetic rotor is simulated.

  19. Simulation of motional eddy current phenomena in soft magnetic material

    International Nuclear Information System (INIS)

    Gersem, Herbert de; Hameyer, Kay

    2001-01-01

    The finite element simulation of conductors moving in a magnetic field at elevated speeds, yields oscillatory solutions. To overcome the effect of the huge convection terms, the partial differential equation is stabilised by adding artificial diffusion. Accurate results are obtained by applying adaptive mesh refinement. A rotational magnetic brake with a solid ferromagnetic rotor is simulated

  20. Analytical expression for initial magnetization curve of Fe-based soft magnetic composite material

    Energy Technology Data Exchange (ETDEWEB)

    Birčáková, Zuzana, E-mail: zuzana.bircakova@upjs.sk [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 04154 Košice (Slovakia); Kollár, Peter; Füzer, Ján [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 04154 Košice (Slovakia); Bureš, Radovan; Fáberová, Mária [Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice (Slovakia)

    2017-02-01

    The analytical expression for the initial magnetization curve for Fe-phenolphormaldehyde resin composite material was derived based on the already proposed ideas of the magnetization vector deviation function and the domain wall annihilation function, characterizing the reversible magnetization processes through the extent of deviation of magnetization vectors from magnetic field direction and the irreversible processes through the effective numbers of movable domain walls, respectively. As for composite materials the specific dependences of these functions were observed, the ideas were extended meeting the composites special features, which are principally the much higher inner demagnetizing fields produced by magnetic poles on ferromagnetic particle surfaces. The proposed analytical expression enables us to find the relative extent of each type of magnetization processes when magnetizing a specimen along the initial curve. - Highlights: • Analytical expression of the initial curve derived for SMC. • Initial curve described by elementary magnetization processes. • Influence of inner demagnetizing fields on magnetization process in SMC.

  1. Analysis of soft magnetic materials by electron backscatter diffraction as a powerful tool

    Directory of Open Access Journals (Sweden)

    David Schuller

    2018-04-01

    Full Text Available The current work demonstrates that electron backscatter diffraction (EBSD is a powerful and versatile characterization technique for investigating soft magnetic materials. The properties of soft magnets, e.g., magnetic losses strongly depend on the materials chemical composition and microstructure, including grain size and shape, texture, degree of plastic deformation and elastic strain. In electrical sheet stacks for e-motor applications, the quality of the machined edges/surfaces of each individual sheet is of special interest. Using EBSD, the influence of the punching process on the microstructure at the cutting edge is quantitatively assessed by evaluating the crystallographic misorientation distribution of the deformed grains. Using an industrial punching process, the maximum affected deformation depth is determined to be 200 - 300 μm. In the case of laser cutting, the affected deformation depth is determined to be approximately zero. Reliability and detection limits of the developed EBSD approach are evaluated on non-affected sample regions and model samples containing different indentation test bodies. A second application case is the investigation of the recrystallization process during the annealing step of soft magnetic composites (SMC toroids produced by powder metallurgy as a function of compaction pressure, annealing parameters and powder particle size. With increasing pressure and temperature, the recrystallized area fraction (e.g., grains with crystallographic misorientations 3°.

  2. Preparation and properties of Cobalt-based soft magnetic material prepared by novel powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Yogesh, E-mail: 123209001_yogesh@manit.ac.in; Srivastava, Sanjay

    2017-02-01

    The present work deals with the development of nanocrystalline 60Co–26Fe–14Al (wt%) soft magnetic materials via mechanical milling of elemental powders. The evolution of solid solution during milling proceeded with continuous decrease in atomic order and the crystallite size, and an introduction of internal strain and dislocations. The milling-induced lattice defects, crystallite size reduction, and atomic disorder exhibited a decrease in saturation magnetization, remanence magnetization, squareness ratio, and blocking temperature with increasing milling time. It has been demonstrated that, at subzero temperatures, the magnetization decreases with increasing temperature due to the development of an effective anisotropy caused by an evolution of canted spin structure owing to the introduction of lattice defects during milling. - Highlights: • Co-based HA have been fabricated by mechanical alloying. • The effect of milling time was investigated. • The saturation magnetization can be reached up to 140.79 emu/g.

  3. Magnetic properties measurement of soft magnetic composite material (SOMALOY 700) by using 3-D tester

    Science.gov (United States)

    Asari, Ashraf; Guo, Youguang; Zhu, Jianguo

    2017-08-01

    Core losses of rotating electrical machine can be predicted by identifying the magnetic properties of the magnetic material. The magnetic properties should be properly measured since there are some variations of vector flux density in the rotating machine. In this paper, the SOMALOY 700 material has been measured under x, y and z- axes flux density penetration by using the 3-D tester. The calibrated sensing coils are used in detecting the flux densities which have been generated by the Labview software. The measured sensing voltages are used in obtaining the magnetic properties of the sample such as magnetic flux density B, magnetic field strength H, hysteresis loop which can be used to calculate the total core loss of the sample. The results of the measurement are analyzed by using the Mathcad software before being compared to another material.

  4. PROCESSING OF SOFT MAGNETIC MATERIALS BY POWDER METALLURGY AND ANALYSIS OF THEIR PERFORMANCE IN ELECTRICAL MACHINES

    Directory of Open Access Journals (Sweden)

    W. H. D. Luna

    2017-12-01

    Full Text Available This article presents the use of finite elements to analyze the yield of electric machines based on the use of different soft magnetic materials for the rotor and the stator, in order to verify the performance in electric machine using powder metallurgy. Traditionally, the cores of electric machines are built from rolled steel plates, thus the cores developed in this work are obtained from an alternative process known as powder metallurgy, where powders of soft magnetic materials are compacted and sintered. The properties of interest were analyzed (magnetic, electric and mechanical properties and they were introduced into the software database. The topology of the rotor used was 400 W three-phase synchronous motor manufactured by WEG Motors. The results show the feasibility to replace the metal sheets of the electric machines by solid blocks obtained by powder metallurgy process with only 0.37% yield losses. In addition, the powder metallurgical process reduces the use of raw materials and energy consumption per kg of raw material processed.

  5. Development of a low-cost double rotor axial flux motor with soft magnetic composite and ferrite permanent magnet materials

    Science.gov (United States)

    Liu, Chengcheng; Zhu, Jianguo; Wang, Youhua; Guo, Youguang; Lei, Gang; Liu, Xiaojing

    2015-05-01

    This paper proposes a low-cost double rotor axial flux motor (DRAFM) with low cost soft magnetic composite (SMC) core and ferrite permanent magnets (PMs). The topology and operating principle of DRAFM and design considerations for best use of magnetic materials are presented. A 905 W 4800 rpm DRAFM is designed for replacing the high cost NdFeB permanent magnet synchronous motor (PMSM) in a refrigerator compressor. By using the finite element method, the electromagnetic parameters and performance of the DRAFM operated under the field oriented control scheme are calculated. Through the analysis, it is shown that that the SMC and ferrite PM materials can be good candidates for low-cost electric motor applications.

  6. Analysis of soft magnetic materials by electron backscatter diffraction as a powerful tool

    Science.gov (United States)

    Schuller, David; Hohs, Dominic; Loeffler, Ralf; Bernthaler, Timo; Goll, Dagmar; Schneider, Gerhard

    2018-04-01

    The current work demonstrates that electron backscatter diffraction (EBSD) is a powerful and versatile characterization technique for investigating soft magnetic materials. The properties of soft magnets, e.g., magnetic losses strongly depend on the materials chemical composition and microstructure, including grain size and shape, texture, degree of plastic deformation and elastic strain. In electrical sheet stacks for e-motor applications, the quality of the machined edges/surfaces of each individual sheet is of special interest. Using EBSD, the influence of the punching process on the microstructure at the cutting edge is quantitatively assessed by evaluating the crystallographic misorientation distribution of the deformed grains. Using an industrial punching process, the maximum affected deformation depth is determined to be 200 - 300 μm. In the case of laser cutting, the affected deformation depth is determined to be approximately zero. Reliability and detection limits of the developed EBSD approach are evaluated on non-affected sample regions and model samples containing different indentation test bodies. A second application case is the investigation of the recrystallization process during the annealing step of soft magnetic composites (SMC) toroids produced by powder metallurgy as a function of compaction pressure, annealing parameters and powder particle size. With increasing pressure and temperature, the recrystallized area fraction (e.g., grains with crystallographic misorientations particle boundaries or areas with existing plastic deformation. The progress of recrystallization is visualized as a function of time and of different particle to grain size distributions. Here, large particles with coarse internal grain structures show a favorable recrystallization behavior which results in large bulk permeability of up to 600 - 700 and lower amount of residual misorientations (>3°).

  7. Discontinuous spring magnet-type magnetostrictive Terfecohan/YFeCo multilayers: A novel nanostructured material principle for excellent magnetic softness

    International Nuclear Information System (INIS)

    Duc, N.H.; Huong Giang, D.T.

    2007-01-01

    Novel physics and reversal mechanisms of the whole system switching (WS) and individual switching (IS) type are reported for hard/soft TbFeCo/YFeCo exchange-spring multilayers. The WS type usually occurs in multilayered systems, in which the magnetic anisotropy of hard TbFeCo layers is neglectable. For such a system, the ferrimagnetically coupled hard/soft multilayered state is recovered after removing applied fields from the magnetized state. At low negative fields, the magnetization switching occurs collectively for all magnetic moments in the whole system. In this case, the low-coercivity mechanism is discussed on the basis of a hard/soft interfacial point contact. This configuration is realized for TbFeCo/YFeCo discontinuous exchange-spring multilayers, in which the magnetic (Fe,Co) nanograins coexist with non-magnetic amorphous phase in the soft layers. In this state, a magnetic coercivity as small as 0.4 mT is achieved. It is considered as an excellent magnetic softness of rare-earth-based systems. Enhancing the magnetic anisotropy in the hard TbFeCo layers, the magnetization switching follows the IS type at low temperatures. Starting to decrease the applied magnetic field from the high-field state, one observes the first reversal of the magnetic moments in the soft high-magnetization YFeCo-layers in positive magnetic fields. This is the reason for the observation of the negative coercivity as well as negative-biasing phenomena

  8. Moving interfacial crack between two dissimilar soft ferromagnetic materials in uniform magnetic field

    International Nuclear Information System (INIS)

    Zhao, She Xu; Lee, Kang Yong

    2007-01-01

    This paper presents the dynamic magnetoelastic stress intensity factors of a Yoffe-type moving crack at the interface between two dissimilar soft ferromagnetic elastic half-planes. The solids are subjected to a uniform in-plane magnetic field and the crack is opened by internal normal and shear tractions. The problem is considered within the framework of linear magnetoelasticity. By application of the Fourier integral transform, the mixed boundary problem is reduced to a pair of integral equations of the second kind with Cauchy-type singularities. The singular integral equations are solved by means of a Jacobi polynomial expansion method. For a particular case, closed-form solutions are obtained. It is shown that the magnetoelastic stress intensity factors depend on the moving velocity of the crack, the magnetic field and the magnetoelastic properties of the materials

  9. Dynamic properties of micro-magnetic noise in soft ferromagnetic materials

    Science.gov (United States)

    Stupakov, A.; Perevertov, A.

    2018-06-01

    Dynamic response of magnetic hysteresis, magnetic Barkhausen noise and magneto-acoustic emission in a soft ribbon and electrical steels was studied comprehensively. The measurements were performed under controllable magnetization conditions: sinusoidal/triangular waveforms of the magnetic induction and a triangular waveform of the magnetic field. Magnetizing frequency was varied in a wide range: fmag = 0.5 - 500 and 0.5-100 Hz for the ribbon and the electrical steels, respectively. Magnetization amplitude was fixed on a near-saturation level Hmax ≃ 100 A/m. Barkhausen noise signal was detected by a sample-wrapping/surface-mounted coil and differently filtered. It was found that intensity of the Barkhausen noise rises approximately as a square root function of the magnetizing frequency. Whereas, level of the magneto-acoustic emission follows the hysteresis loss trend with an additional linear term (classical loss component).

  10. Soft-Material Robotics

    OpenAIRE

    Wang, L; Nurzaman, SG; Iida, Fumiya

    2017-01-01

    There has been a boost of research activities in robotics using soft materials in the past ten years. It is expected that the use and control of soft materials can help realize robotic systems that are safer, cheaper, and more adaptable than the level that the conventional rigid-material robots can achieve. Contrary to a number of existing review and position papers on soft-material robotics, which mostly present case studies and/or discuss trends and challenges, the review focuses on the fun...

  11. Soft X-ray microscopy to 25 nm with applications to biology and magnetic materials

    CERN Document Server

    Denbeaux, G; Chao, W; Eimueller, T; Johnson, L; Köhler, M; Larabell, C; Legros, M; Fischer, P; Pearson, A; Schuetz, G; Yager, D; Attwood, D

    2001-01-01

    We report both technical advances in soft X-ray microscopy (XRM) and applications furthered by these advances. With new zone plate lenses we record test pattern features with good modulation to 25 nm and smaller. In combination with fast cryofixation, sub-cellular images show very fine detail previously seen only in electron microscopy, but seen here in thick, hydrated, and unstained samples. The magnetic domain structure is studied at high spatial resolution with X-ray magnetic circular dichroism (X-MCD) as a huge element-specific magnetic contrast mechanism, occurring e.g. at the L sub 2 sub , sub 3 edges of transition metals. It can be used to distinguish between in-plane and out-of-plane contributions by tilting the sample. As XRM is a photon based technique, the magnetic images can be obtained in unlimited varying external magnetic fields. The images discussed have been obtained at the XM-1 soft X-ray microscope on beamline 6.1 at the Advanced Light Source in Berkeley.

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

    Directory of Open Access Journals (Sweden)

    Alfredo García-Arribas

    2014-04-01

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

  13. Mechanics of soft materials

    CERN Document Server

    Volokh, Konstantin

    2016-01-01

    This book provides a concise introduction to soft matter modelling. It offers an up-to-date review of continuum mechanical description of soft and biological materials from the basics to the latest scientific materials. It includes multi-physics descriptions, such as chemo-, thermo-, electro- mechanical coupling. It derives from a graduate course at Technion that has been established in recent years. It presents original explanations for some standard materials and features elaborated examples on all topics throughout the text. PowerPoint lecture notes can be provided to instructors. .

  14. AN INVESTIGATION ON SOFT MAGNETIC AND NON-MAGNETIC MATERIALS UNDER LOW FREQUENCY FOR BIOMEDICAL SENSOR APPLICATION

    Directory of Open Access Journals (Sweden)

    Sheroz Khan

    2012-02-01

    Full Text Available In consequence of the recent development of magnetic sensors in biomedical sector, the investigation of magneticmaterials has been a contributing factor in application stage. This paper proposes a novel technique to investigate materials by obtaining unique distinctive impedance peaks with unique impedance values. A magneto-inductive sensoris used to measure the induction of magnetic and non-magnetic impedance peaks related to the change in permeability, thus characterizing the materials under low frequency.

  15. Compensation of the Persistent Current Multipoles in the LHC Dipoles by making the Coil Protection Sheet from Soft Magnetic Material

    CERN Document Server

    Völlinger, C

    2000-01-01

    This note presents a scheme for compensating the persistent current multipole errors of the LHC dipoles by making the coil protection sheets from soft magnetic material of 0.5 mm thickness. The material properties assumed in this study are those of iron sheets with a very low content of impurities (99.99% pure Fe). The non-linearities in the upramp cycle on the b3 multipole component can be reduced by the factor of four (while decreasing the b5 variation by the factor of two. Using sheets of slightly different thicknesses offers a tuning possibility for the series magnet coils and can compensate deviations arising from cables of different suppliers. The calculation method is based on a semi-analytical hysteresis model for hard superconductors and an M(B) - iteration using the method of coupled boundary elements - finite elements (BEM - FEM). It is now possible to compute persistent current multipole errors of geometries with arbitrarily shaped iron yokes and thin layers of soft magnetic material such as tunin...

  16. Structure and properties of nanocrystalline soft magnetic composite materials with silicon polymer matrix

    International Nuclear Information System (INIS)

    Dobrzanski, L.A.; Nowosielski, R.; Konieczny, J.; PrzybyI, A.; WysIocki, J.

    2005-01-01

    The paper concerns investigation of nanocrystalline composites technology preparation. The composites in the form of rings with rectangular transverse section, and with polymer matrix and nanocrystalline metallic powders fulfillment were made, for obtaining good ferromagnetic properties. The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling of metallic glasses strips in an as-quenched state. Generally for investigation, Co matrix alloys with the silicon polymer were used. Magnetic properties in the form of hysteresis loop by rings method were measured. Generally composite cores showed lower soft ferromagnetic properties than winded cores of nanocrystalline strips, but composite cores showed interesting mechanical properties. Furthermore, the structure of strips and powders on properties of composites were investigated

  17. Fracture in Soft Materials

    DEFF Research Database (Denmark)

    Hassager, Ole

    Fracture is a phenomenon that is generally associated with solids. A key element in fracture theory is the so-called weakest link idea that fracture initiates from the largest pre-existing material imperfection. However, recent work has demonstrated that fracture can also happen in liquids, where...... surface tension will act to suppress such imperfections. Therefore, the weakest link idea does not seem immediately applicable to fracture in liquids. This presentation will review fracture in liquids and argue that fracture in soft liquids is a material property independent of pre-existing imperfections....... The following questions then emerge: What is the material description needed to predict crack initiation, crack speed and crack shape in soft materials and liquids....

  18. Iron losses evaluation in soft magnetic materials with a sinusoidal voltage supply

    DEFF Research Database (Denmark)

    Nedelcu, Steluţa; Ritchie, Ewen; Leban, Krisztina Monika

    2013-01-01

    This paper presents an evaluation method of for specific iron losses in non-oriented laminated steel suitable for electric motors and transformers in the case of a sinusoidal excitation. The model is based on the separation of loss contribution due to hysteresis, eddy currents and excess losses...... (between 0.35 mm and 0.65 mm) and alloy compositions. Hysteresis and eddy currents loss coefficients have been considered as dependent on the frequency. For curve fitting of these coefficients third and fourth polynomials were employed, with good result for all the frequencies and magnetic flux density...... and it is proposing an identification procedure for the model coefficients from multi-frequency single sheet tests. The frequencies used are in the range 10 Hz and 150 Hz and with the values of magnetic flux density in the range 0.1 T and 1.4 T. The model was applied on six magnetic materials of different thicknesses...

  19. Dynamic magnetization models for soft ferromagnetic materials with coarse and fine domain structures

    Energy Technology Data Exchange (ETDEWEB)

    Zirka, S.E., E-mail: zirka@email.dp.ua [Department of Physics and Technology, Dnepropetrovsk National University, Gagarin 72, 49050 Dnepropetrovsk (Ukraine); Moroz, Y.I. [Department of Physics and Technology, Dnepropetrovsk National University, Gagarin 72, 49050 Dnepropetrovsk (Ukraine); Steentjes, S.; Hameyer, K. [Institute of Electrical Machines, RWTH Aachen University, Schinkelstr. 4, 52056 Aachen (Germany); Chwastek, K. [Faculty of Electrical Engineering, Czestochowa University of Technology, al. AK 17, 42-201 Czestochowa (Poland); Zurek, S. [Megger Instruments Ltd., Archcliffe Road, Dover, Kent, CT17 9EN (United Kingdom); Harrison, R.G. [Department of Electronics, Carleton University, Ottawa, Canada K1S 5B6 (Canada)

    2015-11-15

    We consider dynamic models, both numerical and analytical, that reproduce the magnetization field H(B) and the energy loss in ferromagnetic sheet materials with different domain structures. Conventional non-oriented (NO) and grain-oriented (GO) electrical steels are chosen as typical representatives of fine-domain and coarse-domain materials. The commonly-accepted loss separation procedures in these materials are critically analyzed. The use of a well-known simplified (“classical”) expression for the eddy-current loss is identified as the primary source of mistaken evaluations of excess loss in NO steel, in which the loss components can only be evaluated using the Maxwell (penetration) equation. The situation is quite different in GO steel, in which the loss separation is uncertain, but the total dynamic loss is several times higher than that explained by any version (numerical or analytical) of the classical approach. To illustrate the uncertainty of the loss separation in GO steel, we show that the magnetization field, and thus the total loss, in this material can be represented with equal accuracy using either the existing three-component approach or our proposed two-component technique, which makes no distinction between classical eddy-current and excess fields and losses. - Highlights: • Critical analysis of a ferromagnetic-material loss-separation principle. • This is to warn materials-science engineers about the inaccuracies resulting from this principle. • A transient model having a single dynamic component is proposed.

  20. Induced magnetic anisotropy in Si-free nanocrystalline soft magnetic materials: A transmission x-ray diffraction study

    International Nuclear Information System (INIS)

    Parsons, R.; Suzuki, K.; Yanai, T.; Kishimoto, H.; Kato, A.; Ohnuma, M.

    2015-01-01

    In order to better understand the origin of field-induced anisotropy (K u ) in Si-free nanocrystalline soft magnetic alloys, the lattice spacing of the bcc-Fe phase in nanocrystalline Fe 94−x Nb 6 B x (x = 10, 12, 14) alloys annealed under an applied magnetic field has been investigated by X-ray diffraction in transmission geometry (t-XRD) with the diffraction vector parallel and perpendicular to the field direction. The saturation magnetostriction (λ s ) of nanocrystalline Fe 94−x Nb 6 B x was found to increase linearly with the volume fraction of the residual amorphous phase and is well described by taking into account the volume-weighted average of two local λ s values for the bcc-Fe nanocrystallites (−5 ± 2 ppm) and the residual amorphous matrix (+8 ± 2 ppm). The lattice distortion required to produce the measured K u values (∼100 J/m 3 ) was estimated via the inverse magnetostrictive effect using the measured λ s values and was compared to the lattice spacing estimations made by t-XRD. The lattice strain required to produce K u under the magnetoelastic model was not observed by the t-XRD experiments and so the findings of this study suggest that the origin of magnetic field induced K u cannot be explained through the magnetoelastic effect

  1. A 2D finite element study on the role of material properties on eddy current losses in soft magnetic composites

    Science.gov (United States)

    Ren, Xiaotao; Corcolle, Romain; Daniel, Laurent

    2016-02-01

    The use of soft magnetic composites (SMCs) in electrical engineering applications is growing. SMCs provide an effective alternative to laminated steels because they exhibit a high permeability with low eddy current losses. Losses are a critical feature in the design of electrical machines, and it is necessary to evaluate the role of microstructure and constitutive properties of SMCs during the predesign stage. In this paper we propose a simplified finite element approach to compute eddy current losses in these materials. The computations allow to quantify the role of exciting source and material properties on eddy current losses. This analysis can later be used in the development of homogenization models for SMC. Contribution to the topical issue "Numelec 2015 - Elected submissions", edited by Adel Razek

  2. Interaction of ultra soft magnetic materials with the high-T{sub c} superconductor YBCO

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, Claudia; Treiber, Sebastian; Schuetz, Gisela [Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart (Germany); Walker, Patrick [Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart (Germany); Aalen University, Beethovenstrasse 1, 73430 Aalen (Germany); Albrecht, Joachim [Aalen University, Beethovenstrasse 1, 73430 Aalen (Germany)

    2013-07-01

    We have grown bilayers of optimally doped YBa{sub 2}Cu{sub 3}O{sub 7-δ} (YBCO) and ferromagnetic CoFeB on single-crystalline substrates by pulsed laser deposition and sputtering. These heterostructures are typically composed of about 100 nm YBCO and several 10 nm of CoFeB. Regarding the superconductor, the properties of the YBCO film change as a consequence of the vicinity of the ferromagnet. In detail we investigated the critical current density as a function of temperature, applied field and time as well as the transition temperature by SQUID magnetization measurements and quantitative magneto-optical measurements. The amorphous material CoFeB exhibits an in plane anisotropy and a very low coercivity. From magneto-optical images we find that the flux line lattice of the superconductor is mapped into the magnet and still visible as significant magnetic out-of-plane contrast at room temperature. We discuss this phenomenon as a new route to high-resolution mapping of the flux line distribution on a nanometer scale.

  3. Magnetic Materials

    Science.gov (United States)

    Spaldin, Nicola A.

    2003-04-01

    Magnetic materials are the foundation of multi-billion dollar industries and the focus of intensive research across many disciplines. This book covers the fundamentals, basic theories and applications of magnetism and conventional magnetic materials. Based on a lecture course given by Nicola Spaldin in the Materials Department at University of California, Santa Barbara, the book is ideal for a one- semester course in magnetic materials. It contains numerous homework problems and solutions.

  4. Induced magnetic anisotropy in Si-free nanocrystalline soft magnetic materials: A transmission x-ray diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, R., E-mail: rparsons01@gmail.com; Suzuki, K. [Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800 (Australia); Yanai, T. [Graduate School of Engineering, Nagasaki University, Nagasaki 852-8521 (Japan); Kishimoto, H.; Kato, A. [Toyota Motor Corporation, Mishuku, Susono, Shizuoka 410-1193 (Japan); Ohnuma, M. [Faculty and Graduate School of Engineering, Hokkaido University, Sapporo 060-8628 (Japan)

    2015-05-07

    In order to better understand the origin of field-induced anisotropy (K{sub u}) in Si-free nanocrystalline soft magnetic alloys, the lattice spacing of the bcc-Fe phase in nanocrystalline Fe{sub 94−x}Nb{sub 6}B{sub x} (x = 10, 12, 14) alloys annealed under an applied magnetic field has been investigated by X-ray diffraction in transmission geometry (t-XRD) with the diffraction vector parallel and perpendicular to the field direction. The saturation magnetostriction (λ{sub s}) of nanocrystalline Fe{sub 94−x}Nb{sub 6}B{sub x} was found to increase linearly with the volume fraction of the residual amorphous phase and is well described by taking into account the volume-weighted average of two local λ{sub s} values for the bcc-Fe nanocrystallites (−5 ± 2 ppm) and the residual amorphous matrix (+8 ± 2 ppm). The lattice distortion required to produce the measured K{sub u} values (∼100 J/m{sup 3}) was estimated via the inverse magnetostrictive effect using the measured λ{sub s} values and was compared to the lattice spacing estimations made by t-XRD. The lattice strain required to produce K{sub u} under the magnetoelastic model was not observed by the t-XRD experiments and so the findings of this study suggest that the origin of magnetic field induced K{sub u} cannot be explained through the magnetoelastic effect.

  5. Characterisation of soft magnetic materials by measurement: Evaluation of uncertainties up to 1.8 T and 9 kHz

    Science.gov (United States)

    Elfgen, S.; Franck, D.; Hameyer, K.

    2018-04-01

    Magnetic measurements are indispensable for the characterization of soft magnetic material used e.g. in electrical machines. Characteristic values are used as quality control during production and for the parametrization of material models. Uncertainties and errors in the measurements are reflected directly in the parameters of the material models. This can result in over-dimensioning and inaccuracies in simulations for the design of electrical machines. Therefore, existing influencing factors in the characterization of soft magnetic materials are named and their resulting uncertainties contributions studied. The analysis of the resulting uncertainty contributions can serve the operator as additional selection criteria for different measuring sensors. The investigation is performed for measurements within and outside the currently prescribed standard, using a Single sheet tester and its impact on the identification of iron loss parameter is studied.

  6. Forces between a permanent magnet and a soft magnetic plate

    Czech Academy of Sciences Publication Activity Database

    Beleggia, M.; Vokoun, David; DeGraef, M.

    2012-01-01

    Roč. 3, č. 5 (2012), 0500204/1-0500204/4 ISSN 1949-307X R&D Projects: GA ČR GPP108/12/P111 Institutional research plan: CEZ:AV0Z10100520 Keywords : electromagnetics * hard magnetic materials * soft magnetic materials Subject RIV: BM - Solid Matter Physics ; Magnetism http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6313974

  7. Soft magnetic moldable composites: Properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Leif, E-mail: leif.svensson@iprod.lth.se [Lund University, Division of Production and Materials Engineering, Box 188, 221 00 Lund (Sweden); Frogner, Kenneth, E-mail: kenneth.frogner@iprod.lth.se [Lund University, Division of Production and Materials Engineering, Box 188, 221 00 Lund (Sweden); Jeppsson, Peter, E-mail: peter.jeppsson@iprod.lth.se [Lund University, Division of Production and Materials Engineering, Box 188, 221 00 Lund (Sweden); Cedell, Tord, E-mail: tord.cedell@iprod.lth.se [Lund University, Division of Production and Materials Engineering, Box 188, 221 00 Lund (Sweden); Andersson, Mats, E-mail: mats.andersson@iprod.lth.se [Lund University, Division of Production and Materials Engineering, Box 188, 221 00 Lund (Sweden)

    2012-09-15

    A new type of electromagnetic soft magnetic material (SMM) is introduced, based on spherical iron powder particles and a suitable polymer binder. A key feature of this material is that it can be cast or molded into almost any 3D shape, hence the denotation soft magnetic moldable composite (SM{sup 2}C). The SM{sup 2}C is compared with a set of reference materials, such as ferrites, laminated steels, and soft magnetic composites, in terms of primary properties such as permeability and loss, and other properties, such as thermal conductivity and manufacturability. The SM{sup 2}C has the obvious disadvantage of relatively low permeability, but offers benefits such as relatively low losses and high potential for close integration into electromagnetic circuits. Some recent SM{sup 2}C applications are illustrated, and design and manufacturing aspects are discussed. - Highlights: Black-Right-Pointing-Pointer A new type of soft magnetic composite is introduced. Black-Right-Pointing-Pointer Properties are compared to other flux core materials. Black-Right-Pointing-Pointer The new material has low losses but also low permeability. Black-Right-Pointing-Pointer Potential benefits in freedom of design and manufacturing issues.

  8. Localized Induced Current Stimulation to Neuronal Culture Using Soft Magnetic Material

    Science.gov (United States)

    Saito, Atsushi; Saito, Aki; Moriguchi, Hiroyuki; Kotani, Kiyoshi; Jimbo, Yasuhiko

    To establish precisely focused magnetic stimulation, we developed a Mu-meal based low-frequency localized induced current (LIC) stimulation system with micro-fabricated dual cell-culture chamber. The dual cell-culture chamber was arranged in a concentric circle manner. Between the inner and outer chambers, 4 or 8 connecting micro-channels were fabricated using polydimethylsiloxane (PDMS). Rat cortical neurons were separately cultured in outer and inner chambers. Through the micro-channels, functional synaptic connections were formed. Mu-metal that has very high magnetic permeability was aligned along the outer circle, which allowed us of LIC stimulation to the cells in the outer chamber. Applying low-frequency magnetic fields to the Mu-metal, induced currents were generated and the electrical activity of the cells in the outer chamber was modified depending on the stimulation intensity. Following the modified activity in the outer circles, the cells in the inner chamber also showed slightly depressed activity patterns. These results suggested that our system would be promising for localized stimulation of neuronal networks and highly regulation of network activities.

  9. A comprehensive study of soft magnetic materials based on FeSi spheres and polymeric resin modified by silica nanorods

    Czech Academy of Sciences Publication Activity Database

    Strečková, M.; Füzer, J.; Kobera, Libor; Brus, Jiří; Fáberová, M.; Bureš, R.; Kollár, P.; Lauda, M.; Medvecký, L.; Girman, V.; Hadraba, Hynek; Baťková, M.; Baťko, I.

    2014-01-01

    Roč. 147, č. 3 (2014), s. 649-660 ISSN 0254-0584 Institutional support: RVO:61389013 ; RVO:68081723 Keywords : composite materials * magnetic materials * chemical synthesis Subject RIV: CD - Macromolecular Chemistry; JH - Ceramics, Fire-Resistant Materials and Glass (UFM-A) Impact factor: 2.259, year: 2014

  10. Magnetism and magnetic materials

    International Nuclear Information System (INIS)

    1990-01-01

    It describes the actual status of physics in Brazil concerning the study of magnetism and magnetic materials. It gives an overview of different research groups in Brazil, their needs, as well as the investments needed to improve the area. (A.C.A.S.)

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

    Science.gov (United States)

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

    2017-10-01

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

  12. A comprehensive study of soft magnetic materials based on FeSi spheres and polymeric resin modified by silica nanorods

    International Nuclear Information System (INIS)

    Strečková, M.; Füzer, J.; Kobera, L.; Brus, J.; Fáberová, M.; Bureš, R.; Kollár, P.; Lauda, M.; Medvecký, Ĺ.; Girman, V.; Hadraba, H.; Bat'ková, M.; Bat'ko, I.

    2014-01-01

    A novel soft magnetic composite (SMC) based on spherical FeSi particles precisely covered by hybrid phenolic resin was designed. The hybrid resin including silica nano-rods chemically incorporated into the phenolic polymer matrix was prepared by the modified sol–gel method. A chemical bridge connecting silica nano-rods with the base polymeric net was verified by FTIR, 13 C and 29 Si NMR spectroscopy, whereas the shape and size of silica nano-rods were determined by TEM. It is shown that the modification of polymeric resin by silica nano-rods generally leads to the improved thermal and mechanical properties of the final samples. The hybrid resin serves as a perfect insulating coating deposited on FeSi particles and the core–shell particles can be further compacted by standard powder metallurgy methods in order to prepare final samples for mechanical, electric and magnetic testing. SEM images evidence negligible porosity, uniform distribution of the hybrid resin around FeSi particles, as well as, dimensional shape stability of the final samples after thermal treatment. The hardness, flexural strength and density of the final samples are comparable to the sintered SMCs, but they simultaneously exhibit much higher specific resistivity along with only slightly lower coercivity and permeability. - Highlights: • Soft magnetic composites are designed for electrotechnical applications. • Electroinsulating layer consists of phenolic resin modified with silica nano-rods. • NMR, FTIR and DSC analysis is used to characterize hybrid resin. • Spherical Fe–Si particles covered by hybrid resin form a core–shell composite. • Mechanical, electrical and magnetic properties are described in detail

  13. Cluster-Assembled Soft Magnets for Power Electronics Applications

    National Research Council Canada - National Science Library

    Leslie-Pelecky, Diandra L

    2006-01-01

    This project used inert-gas condensation (IGC) to fabricate model nanostructured systems with the goal of better understanding the mechanisms responsible for decreasing the coercivity in soft magnetic materials...

  14. Advanced Magnetic Materials for Aircraft Power Applications

    National Research Council Canada - National Science Library

    McHenry, Michael

    2003-01-01

    ... new materials with improved magnetic and mechanical properties at high temperature. The group worked on the refinement of existing soft bulk materials while conducting research on novel nanocrystalline magnets in parallel...

  15. Soft material for optical storage

    International Nuclear Information System (INIS)

    Lucchetti, L.; Simoni, F.

    2000-01-01

    The aim of transforming electronic networking into optical networking is producing a major effort in studying all optical processing and as a consequence in investigating the nonlinear optical properties of materials for this purpose. In this research area soft materials like polymers and liquid crystals are more and more attractive because they are cheap and they are more easily integrated in microcircuits hardware with respect to the well-known highly nonlinear crystals. Since optical processing spans a too wide field to be treated in one single paper, the authors will focus on one specific subject within this field and give a review of the most recent advances in studying the soft-materials properties interesting for the storage of optical information. The efforts in research of new materials and techniques for optical storage are motivated by the need to store and retrieve large amounts of data with short access time and high data rate at a competitive cost

  16. Soft Magnetic Multilayered Thin Films for HF Applications

    Science.gov (United States)

    Loizos, George; Giannopoulos, George; Serletis, Christos; Maity, Tuhin; Roy, Saibal; Lupu, Nicoleta; Kijima, Hanae; Yamaguchi, Masahiro; Niarchos, Dimitris

    Multilayered thin films from various soft magnetic materials were successfully prepared by magnetron sputtering in Ar atmosphere. The magnetic properties and microstructure were investigated. It is found that the films show good soft magnetic properties: magnetic coercivity of 1-10 Oe and saturation magnetization higher than 1T. The initial permeability of the films is greater than 300 and flattens up to 600 MHz. The multilayer thin film properties in combination with their easy, fast and reproducible fabrication indicate that they are potential candidates for high frequency applications.

  17. Advanced Nanostructured Magnetic Materials

    National Research Council Canada - National Science Library

    Sellmyer, David J

    2004-01-01

    ... out. Novel physical systems have been synthesized and studied including: hard/soft nanocomposites, magnetic nanowires, thermally processed multilayer films, and nanoparticle-assembled composites...

  18. Hysteretic behavior of soft magnetic elastomer composites

    Energy Technology Data Exchange (ETDEWEB)

    Krautz, Maria; Werner, David [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Schrödner, Mario [Thuringian Institute of Textile and Plastics Research e.V., Breitscheidstraße 97, D-07407 Rudolstadt (Germany); Funk, Alexander [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Jantz, Alexander; Popp, Jana [Thuringian Institute of Textile and Plastics Research e.V., Breitscheidstraße 97, D-07407 Rudolstadt (Germany); Eckert, Jürgen [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, A-8700 Leoben (Austria); Department of Materials Physics, Montanuniversität Leoben, Jahnstraße 12, A-8700 Leoben (Austria); Waske, Anja [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)

    2017-03-15

    Composites of polymer and micron-sized particles of carbonyl-iron were investigated in terms of their magnetization behavior. Thermoplastic elastomers with varying Young's modulus (E{sub Polymer}=0.14–14.6 MPa) were used as matrix material. Field dependent magnetization curves reveal that the hysteretic behavior of the composites strongly depends on both the particle fraction (7, 10, 14, 21, 31 vol%) and on the mechanical properties of the polymer. It is shown that hysteresis only appears above a certain fraction of magnetic particles which can be accounted to the magnetic exchange between the particles. However, hysteresis is suppressed in the composite with largest Young's modulus of the polymer matrix, even at largest particle fraction. - Highlights: • Composites with soft magnetic Iron Particles show hysteretic magnetization behavior. • Origin of the hysteresis is the alignment of particles along field direction. • Hysteresis depends on both, mechanical properties of matrix and particle fraction.

  19. Magnetic Cluster States in Nanostructured Materials

    International Nuclear Information System (INIS)

    Leslie-Pelecky, Diandra

    2008-01-01

    The goal of this work is to fabricate model nanomaterials with different types of disorder and use atomic-scale characterization and macroscopic magnetization measurements to understand better how specific types of disorder affects macroscopic magnetic behavior. This information can be used to produce magnetic nanomaterials with specific properties for applications such as permanent magnets, soft magnetic material for motors and biomedical applications.

  20. Physics and measurements of magnetic materials

    CERN Document Server

    Sgobba, S

    2010-01-01

    Magnetic materials, both hard and soft, are used extensively in several components of particle accelerators. Magnetically soft iron-nickel alloys are used as shields for the vacuum chambers of accelerator injection and extraction septa; Fe-based material is widely employed for cores of accelerator and experiment magnets; soft spinel ferrites are used in collimators to damp trapped modes; innovative materials such as amorphous or nanocrystalline core materials are envisaged in transformers for high-frequency polyphase resonant convertors for application to the International Linear Collider (ILC). In the field of fusion, for induction cores of the linac of heavy-ion inertial fusion energy accelerators, based on induction accelerators requiring some 107 kg of magnetic materials, nanocrystalline materials would show the best performance in terms of core losses for magnetization rates as high as 105 T/s to 107 T/s. After a review of the magnetic properties of materials and the different types of magnetic behaviour...

  1. Magnets and magnetic materials

    International Nuclear Information System (INIS)

    Meuris, Ch.; Rifflet, J.M.

    2007-01-01

    The Large Hadron Collider (LHC), the world's largest highest-energy particle collider that the CERN plans to commission in 2008, gets a double boost from superconducting magnet technology. Superconducting magnets are first used to guide the particles scheduled for collision through the accelerator, and then to observe the events triggered by the collision inside giant detectors in a known magnetic field. Despite the installation's massive dimensions, all this is done with minimal expenditure of energy. (author)

  2. Novel functional magnetic materials fundamentals and applications

    CERN Document Server

    2016-01-01

    This book presents current research on advanced magnetic materials and multifunctional composites. Recent advances in technology and engineering have resulted from the development of advanced magnetic materials with improved functional magnetic and magneto-transport properties. Certain industrial sectors, such as magnetic sensors, microelectronics, and security, demand cost-effective materials with reduced dimensionality and desirable magnetic properties such as enhanced magnetic softness, giant magnetic field sensitivity, and large magnetocaloric effect.  Expert chapters present the most up-to-date information on the fabrication process, processing, tailoring of properties, and applications of different families of modern functional materials for advanced smart applications. Topics covered include novel magnetic materials and applications; amorphous and nanocrystalline magnetic materials and applications; hard magnetic materials; magnetic shape memory alloys; and magnetic oxides. The book's highly interdis...

  3. Forces Between a Permanent Magnet and a Soft Magnetic Plate

    DEFF Research Database (Denmark)

    Beleggia, Marco; Vokoun, David; De Graef, Marc

    2012-01-01

    Forces between a hard/permanent magnet of arbitrary shape and an ideally soft magnetic plate in close proximity are derived analytically from the image method applied to magnetostatics. We found that the contact force, defined as the force required to detach the hard magnet from the plate, coinci...

  4. Magnetic materials fundamentals, products, properties, applications

    CERN Document Server

    Hilzinger, Rainer

    2013-01-01

    At a practical level, this compendium reviews the basics of soft and hard magnetic materials, discusses the advantages of the different processing routes for the exploitation of the magnetic properties and hence assists in proper, fail-safe and economic application of magnetic materials. Essential guidelines and formulas for the calculation of the magnetic and electrical properties, temperature and long-term stability of permanent magnets, of inductive components and magnetic shielding are compiled. Selected fields of application and case studies illustrate the large diversity of technical applications. Application engineers will appreciate the comprehensive compilation of the properties and detailed characteristic curves of modern soft and hard magnetic materials. Materials scientists will enjoy the presentation of the different processing routes and their impact on the magnetic properties and students will profit from the survey from the basics of magnetism down to the applications in inductive components, ...

  5. Magnetic and physical-mechanical properties of polymer composites with soft magnetic fillers

    International Nuclear Information System (INIS)

    Usakova, M.; Usak, E.; Olah, V.; Rekosova, J.

    2013-01-01

    In this paper the influence of soft magnetic ferrite fillers on magnetic and physical-mechanical properties of the prepared composite samples based in natural rubber matrix was studied. The soft magnetic ferrite materials with the chemical composition Mn_0_._3_7Zn_0_._5_7Fe_2_._0_6O_4 and Ni_0_._3_3Zn_0_._6_7Fe_2O_4 were used as magnetic filler in various concentrations. Further, the effect of thermo-oxidative ageing on the prepared composite materials was investigated. Magneto-rheological elastomers are solid analogues to magneto-rheological fluids. These materials are considered as smart materials comprising of micro- or submicro-sized magnetic particles dispersed in non-magnetic matrix. (authors)

  6. Scalable manufacturing processes with soft materials

    OpenAIRE

    White, Edward; Case, Jennifer; Kramer, Rebecca

    2014-01-01

    The emerging field of soft robotics will benefit greatly from new scalable manufacturing techniques for responsive materials. Currently, most of soft robotic examples are fabricated one-at-a-time, using techniques borrowed from lithography and 3D printing to fabricate molds. This limits both the maximum and minimum size of robots that can be fabricated, and hinders batch production, which is critical to gain wider acceptance for soft robotic systems. We have identified electrical structures, ...

  7. Synthesis of FeSiBPNbCu nanocrystalline soft-magnetic alloys with high saturation magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zongzhen [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Wang, Anding; Chang, Chuntao [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 519 Zhuangshi Road, Zhenhai District, Ningbo, Zhejiang 315201 (China); Wang, Yanguo [Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing 100080 (China); Dong, Bangshao [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Zhou, Shaoxiong, E-mail: sxzhou@atmcn.com [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China)

    2014-10-25

    Highlights: • Thermal stability of the FeSiBPNbCu alloys is strongly dependent on the Fe content. • The FeSiBPNbCu alloys with high Fe content exhibit good soft magnetic properties. • The coexistence of Cu, P and Nb leads to the excellent soft magnetic properties. - Abstract: A series of [Fe{sub 0.76+x}(Si{sub 0.4}B{sub 0.4}P{sub 0.2}){sub 0.24−x}]{sub 98.25}Nb{sub 1}Cu{sub 0.75} (x = 0–0.08) nanocrystalline soft-magnetic alloys with high saturation magnetization were synthesized by adjusting Fe content and improving the crystallization behavior, soft-magnetic properties and microstructure. It is found that the temperature interval between the two crystallization peaks is significantly enlarged from 50 to 180 °C when the Fe content of the alloys increases from x = 0 to x = 0.08, which greatly expands the optimum annealing temperature range. The alloys with higher Fe content are prone to form more uniform nanocomposite microstructure with better thermal stability and soft magnetic properties. The Fe-rich FeSiBPNbCu nanocrystalline alloys with x = 0.08 exhibit excellent soft-magnetic properties, including the high saturation magnetic flux density of up to 1.74 T, low coercivity of about 3.3 A/m and high effective permeability of more than 2.2 × 10{sup 4} at 1 kHz under a field of 1 A/m. The combination of excellent soft-magnetic properties, low cost and good productivity makes the FeSiBPNbCu alloys to be a kind of promising soft-magnetic materials for electrical and electronic industry applications.

  8. Applications of soft magnetic materials for photovoltaic industry%软磁材料在光伏产业中的应用

    Institute of Scientific and Technical Information of China (English)

    郭晓东; 何俊; 颜冲; 仇义俊

    2012-01-01

    随着全球经济的快速发展,传统化石能源的大量消耗使全球面临着能源危机,世界各国都在致力于新能源的开发和利用.太阳能以其资源丰富、可以再生、不污染环境等优点,成为最具开发潜力的新能源之一.在过去的十多年中,全球光伏产业取得重大发展.逆变器是光伏电站的核心部件,其性能的优劣和效率的高低直接影响光伏电站的好坏和转换效率.本文介绍了能够应用于光伏产业的软磁材料及其特性.%Along with the rapid development of global economic, the world is facing energy crisis because of excessive traditional fossil energy consumption. Countries all over the world are devoting to development and utilization of new energy. Solar energy is resourceful, renewable, non-pollution and has become one of the most potential new energy. During the last more than ten years, there has been a global growth of photovoltaic generation systems. The inverter is the key device in photovoltaic generation systems. The soft magnetic materials for photovoltaic inverter are introduced in this paper.

  9. Bat head contains soft magnetic particles: evidence from magnetism.

    Science.gov (United States)

    Tian, Lanxiang; Lin, Wei; Zhang, Shuyi; Pan, Yongxin

    2010-10-01

    Recent behavioral observations have indicated that bats can sense the Earth's magnetic field. To unravel the magnetoreception mechanism, the present study has utilized magnetic measurements on three migratory species (Miniopterus fuliginosus, Chaerephon plicata, and Nyctalus plancyi) and three non-migratory species (Hipposideros armiger, Myotis ricketti, and Rhinolophus ferrumequinum). Room temperature isothermal remanent magnetization acquisition and alternating-field demagnetization showed that the bats' heads contain soft magnetic particles. Statistical analyses indicated that the saturation isothermal remanent magnetization of brains (SIRM(1T_brain)) of migratory species is higher than those of non-migratory species. Furthermore, the SIRM(1T_brain) of migratory bats is greater than their SIRM(1T_skull). Low-temperature magnetic measurements suggested that the magnetic particles are likely magnetite (Fe3O4). This new evidence supports the assumption that some bats use magnetite particles for sensing and orientation in the Earth's magnetic field.

  10. Soft magnetic tweezers: a proof of principle.

    Science.gov (United States)

    Mosconi, Francesco; Allemand, Jean François; Croquette, Vincent

    2011-03-01

    We present here the principle of soft magnetic tweezers which improve the traditional magnetic tweezers allowing the simultaneous application and measurement of an arbitrary torque to a deoxyribonucleic acid (DNA) molecule. They take advantage of a nonlinear coupling regime that appears when a fast rotating magnetic field is applied to a superparamagnetic bead immersed in a viscous fluid. In this work, we present the development of the technique and we compare it with other techniques capable of measuring the torque applied to the DNA molecule. In this proof of principle, we use standard electromagnets to achieve our experiments. Despite technical difficulties related to the present implementation of these electromagnets, the agreement of measurements with previous experiments is remarkable. Finally, we propose a simple way to modify the experimental design of electromagnets that should bring the performances of the device to a competitive level.

  11. MFM study of magnetic interaction between recording and soft magnetic layers

    International Nuclear Information System (INIS)

    Honda, Yukio; Tanahashi, Kiwamu; Hirayama, Yoshiyuki; Kikukawa, Atsushi; Futamoto, Masaaki

    2001-01-01

    Magnetic force microscopy was used to study the magnetic interaction between the recording and the soft magnetic layers in double-layer perpendicular media by observing the magnetization structure from the soft magnetic layer side. There was a strong magnetic interaction between the recording and the soft magnetic layers. Introducing a thin nonmagnetic intermediate layer between the two layers greatly reduced the magnetic interaction and drastically reduced the medium noise

  12. Frontiers in Magnetic Materials

    CERN Document Server

    Narlikar, Anant V

    2005-01-01

    Frontiers in Magnetic Materials focuses on the current achievements and state-of-the-art advancements in magnetic materials. Several lines of development- High-Tc Superconductivity, Nanotechnology and refined experimental techniques among them – raised knowledge and interest in magnetic materials remarkably. The book comprises 24 chapters on the most relevant topics written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students.

  13. Development of magnetic materials

    International Nuclear Information System (INIS)

    Bar'yakhtar, V.

    2000-01-01

    In the paper are presented both experimental and theoretical basic results of physics of magnetic materials. The special attention is given to a problem of creation of magnetic materials for recording and reproduction of the information. The influence of fundamental scientific results on process of creation of materials with the given properties and constriction of devices and facilities of new generation, and return influence of financing of scientific researches on process of discovering of new unknown fundamental properties of magnetic materials is considered. (author)

  14. Electron holography of Fe-based nanocrystalline magnetic materials (invited)

    International Nuclear Information System (INIS)

    Shindo, Daisuke; Park, Young-Gil; Gao, Youhui; Park, Hyun Soon

    2004-01-01

    Magnetic domain structures of nanocrystalline magnetic materials were extensively investigated by electron holography with a change in temperature or magnetic field applied. In both soft and hard magnetic materials, the distribution of lines of magnetic flux clarified in situ by electron holography was found to correspond well to their magnetic properties. An attempt to produce a strong magnetic field using a sharp needle made of a permanent magnet, whose movement is controlled by piezo drives has been presented. This article demonstrates that the attempt is promising to investigate the magnetization process of hard magnetic materials by electron holography

  15. Active Surfaces and Interfaces of Soft Materials

    Science.gov (United States)

    Wang, Qiming

    A variety of intriguing surface patterns have been observed on developing natural systems, ranging from corrugated surface of white blood cells at nanometer scales to wrinkled dog skins at millimeter scales. To mimetically harness functionalities of natural morphologies, artificial transformative skin systems by using soft active materials have been rationally designed to generate versatile patterns for a variety of engineering applications. The study of the mechanics and design of these dynamic surface patterns on soft active materials are both physically interesting and technologically important. This dissertation starts with studying abundant surface patterns in Nature by constructing a unified phase diagram of surface instabilities on soft materials with minimum numbers of physical parameters. Guided by this integrated phase diagram, an electroactive system is designed to investigate a variety of electrically-induced surface instabilities of elastomers, including electro-creasing, electro-cratering, electro-wrinkling and electro-cavitation. Combing experimental, theoretical and computational methods, the initiation, evolution and transition of these instabilities are analyzed. To apply these dynamic surface instabilities to serving engineering and biology, new techniques of Dynamic Electrostatic Lithography and electroactive anti-biofouling are demonstrated.

  16. Optimizing the field distribution of a Halbach type permanent magnet cylinder using the soft iron and superhard magnet

    Science.gov (United States)

    Xu, Xiaonong; Lu, Dingwei; Xu, Xibin; Yu, Yang; Gu, Min

    2018-01-01

    When a conventional Halbach type Hollow Cylindrical Permanent Magnet Array (HCPMA) is used to generate magnetic induction over the magnitude of coercivity μ0Hc, some detrimental parasitic magnetic phenomena, such as the demagnetization, magnetization reversal, and vortexes of magnetization, can appear in the interior of the magnets. We present a self-consistent quantitative analysis of the magnetization and magnetic induction distributions inside the magnetic array by considering the anisotropic and nonlinear magnetization functions of the materials consisting of the array. These numeric simulations reveal novel magnetization structures resulted from the self-field of array. We demonstrate that both the field uniformity and magnetic flux in the pole gap can be modulated by partially substituting the magnets of high energy products with the soft irons and the superhard magnets. We also show how the optimized substitution parameters can be obtained for a HCPMA achieving the best field uniformity or the maximum magnetic flux.

  17. Soft Active Materials for Actuation, Sensing, and Electronics

    OpenAIRE

    Kramer, Rebecca Krone

    2012-01-01

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components ...

  18. Improvement of maglev model using high Tc superconductors and soft magnetic materials; Koon chodendotai to nanjiseitai wo kumiawaseta jiki fujo kiko no kairyo

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsui, Y [Yasukawa Electric Corp., Kitakyushu (Japan). Basic Research Lab.; Higuchi, T [Kanagawa Academy of Science and Technology, Kawasaki (Japan); Kondo, N [Univ. of Tokyo, Tokyo (Japan)

    1995-02-25

    In this study, in a magnetic levitation system using pinning force of high temperature superconductors, for a propose of magnification of the stable contactless gap length and exclusion of mass regulation of a floater, a magnetic levitation model was improved. That is, the tangential component of an attractive force between a high temperature superconductor where magnetic flux was pinned and magnetic material is used for levitation and stable force in up and down directions, and restoring force generated due to pinned flux gathering was used for horizontal stabilization. For a floater made by using this principle, weight addition was necessary for letting the center of gravity down, however self-weight regulation of a floater is originally unnecessary. Thus, a magnetic levitation apparatus can be made without self-weight regulation of suspension and having a wide stable gap by using this levitation method. Since the floater was constructed under two rails, there are good points on easily dealing with the safety countermeasure in cases of which levitation would reduce or disappear. 4 refs., 7 figs.

  19. Laser induced forward transfer of soft materials

    International Nuclear Information System (INIS)

    Palla-Papavlu, A; Dinca, V; Luculescu, C; Dinescu, M; Shaw-Stewart, J; Lippert, T; Nagel, M

    2010-01-01

    A strong research effort is presently aimed at patterning methodologies for obtaining controlled defined micrometric polymeric structures for a wide range of applications, including electronics, optoelectronics, sensors, medicine etc. Lasers have been identified as appropriate tools for processing of different materials, such as ceramics and metals, but also for soft, easily damageable materials (biological compounds and polymers). In this work we study the dynamics of laser induced forward transfer (LIFT) with a gap between the donor and the receiver substrates, which is the basis for possible applications that require multilayer depositions with high spatial resolution

  20. Large poroelastic deformation of a soft material

    Science.gov (United States)

    MacMinn, Christopher W.; Dufresne, Eric R.; Wettlaufer, John S.

    2014-11-01

    Flow through a porous material will drive mechanical deformation when the fluid pressure becomes comparable to the stiffness of the solid skeleton. This has applications ranging from hydraulic fracture for recovery of shale gas, where fluid is injected at high pressure, to the mechanics of biological cells and tissues, where the solid skeleton is very soft. The traditional linear theory of poroelasticity captures this fluid-solid coupling by combining Darcy's law with linear elasticity. However, linear elasticity is only volume-conservative to first order in the strain, which can become problematic when damage, plasticity, or extreme softness lead to large deformations. Here, we compare the predictions of linear poroelasticity with those of a large-deformation framework in the context of two model problems. We show that errors in volume conservation are compounded and amplified by coupling with the fluid flow, and can become important even when the deformation is small. We also illustrate these results with a laboratory experiment.

  1. Eddy current effect in soft magnetic backlayer for PMR media

    International Nuclear Information System (INIS)

    Tanaka, T.; Yamamoto, S.; Kurisu, H.; Matsuura, M.

    2005-01-01

    Flux density distributions in the recording layer and soft magnetic backlayer of a perpendicular magnetic recording medium were calculated up to 5 GHz using a three-dimensional finite element method electromagnetic field analysis simulator, where eddy current effects in the high-frequency recording process were considered. It is presented that the flux density distribution in a recording layer hardly depends on the eddy current effect, although flux density distribution in a soft magnetic backlayer changes depending on the recording frequency and resistivity of the soft magnetic backlayer

  2. Interplay of domain walls and magnetization rotation on dynamic magnetization process in iron/polymer–matrix soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Dobák, Samuel, E-mail: samuel.dobak@student.upjs.sk [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 041 54 Košice (Slovakia); Füzer, Ján; Kollár, Peter [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 041 54 Košice (Slovakia); Fáberová, Mária; Bureš, Radovan [Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 043 53 Košice (Slovakia)

    2017-03-15

    This study sheds light on the dynamic magnetization process in iron/resin soft magnetic composites from the viewpoint of quantitative decomposition of their complex permeability spectra into the viscous domain wall motion and magnetization rotation. We present a comprehensive view on this phenomenon over the broad family of samples with different average particles dimension and dielectric matrix content. The results reveal the pure relaxation nature of magnetization processes without observation of spin resonance. The smaller particles and higher amount of insulating resin result in the prevalence of rotations over domain wall movement. The findings are elucidated in terms of demagnetizing effects rising from the heterogeneity of composite materials. - Highlights: • A first decomposition of complex permeability into domain wall and rotation parts in soft magnetic composites. • A pure relaxation nature of dynamic magnetization processes. • A complete loss separation in soft magnetic composites. • The domain walls activity is considerably suppressed in composites with smaller iron particles and higher matrix content. • The demagnetizing field acts as a significant factor at the dynamic magnetization process.

  3. Handbook of Advanced Magnetic Materials

    CERN Document Server

    Liu, Yi; Shindo, Daisuke

    2006-01-01

    From high-capacity, inexpensive hard drives to mag-lev trains, recent achievements in magnetic materials research have made the dreams of a few decades ago reality. The objective of Handbook of Advanced Magnetic Materials is to provide a timely, comprehensive review of recent progress in magnetic materials research. This broad yet detailed reference consists of four volumes: 1.) Nanostructured advanced magnetic materials, 2.) Characterization and simulation of advanced magnetic materials, 3.) Processing of advanced magnetic materials, and 4.) Properties and applications of advanced magnetic materials The first volume documents and explains recent development of nanostructured magnetic materials, emphasizing size effects. The second volume provides a comprehensive review of both experimental methods and simulation techniques for the characterization of magnetic materials. The third volume comprehensively reviews recent developments in the processing and manufacturing of advanced magnetic materials. With the co...

  4. 软模法磁性有序介孔炭的合成与表征%Synthesis and characterization of magnetic ordered mesoporous carbon materials using soft templating method

    Institute of Scientific and Technical Information of China (English)

    王加; 林汉森; 王秀芳

    2012-01-01

    Magnetic ordered mesoporous carbon is synthesized through soft templating method by using triblock-copolymer Pluronic F127 as soft template,resorcinol-formaldehyde (RF) as carbon precursor and ferric nitrate as an iron source. HC1 is used as the catalyst for RF polymerization. The resultant materials are characterized by X-ray diffraction, N2 sorption and vibrating-sample magnetometer measurements. The results show that magnetic ordered mesoporous carbons are obtained when the Fe/R ratio is 0. 025. For those with Fe/R ratios greater than this value,the ordering,the BET surface area,pore volume and pore size decrease. N2 sorption isotherms of all the samples show representative type IV curves with HI hysteresis loops, which indicates a typical mesoporous material. Magnetic hysteresis loops show that the remanent magnetization of Fe/OMC samples increases with the increase of the content of Fe. This research can provide scientific proof for the optimized synthesis and application in magnetic separation for magnetic ordered mesoporous carbons.%以三嵌段共聚物为软模,间苯二酚-甲醛为炭前躯体,硝酸铁为铁源合成了磁性有序介孔炭,用XRD、氮气吸附、磁性测试等方法对样品进行表征.结果表明,当硝酸铁与间苯二酚摩尔比为0.025、0.05及0.10时得到的介孔炭具有有序性,随着铁质量分数的增加,有序性降低,比表面积、孔容都相应减小.基本磁化曲线结果表明,随着铁质量分数的增加,饱和磁化强度随之增加(0.01~0.10 emu/g),材料具有较好的磁性,容易从溶液中分离,表现出良好的分离性能.为磁性有序介孔炭的优化合成及磁性分离应用提供科学依据.

  5. Superconducting materials and magnets

    International Nuclear Information System (INIS)

    1991-04-01

    The Technical Committee Meeting on Superconducting Materials and Magnets was convened by the IAEA and held by invitation of the Japanese government on September 4-6, 1989 in Tokyo. The meeting was hosted by the National Research Institute for Metals. Topics of the conference related to superconducting magnets and technology with particular application to fusion and the superconducting supercollider. Technology using both high and low-temperature superconductors was discussed. This document is a compendium of the papers presented at the meeting. Refs, figs and tabs

  6. Soft X-ray resonant scattering from magnetic heterostructures

    International Nuclear Information System (INIS)

    Grabis, J.

    2005-01-01

    Heterogenous magnetic multilayers are of great interest both because of their relevance for technological applications and since they provide model systems to understand magnetic behavior and interactions. Soft x-ray resonant magnetic scattering (XRMS) allows to determine element-specific and depth-resolving information of the local magnetic order of such systems. Within the framework of the present thesis the diffractometer ALICE for soft XRMS has been constructed. XRMS measurements of two different physical systems are presented in this thesis: The antiferromagnetic and ferromagnetic order in interlayer exchange-coupled Fe/Cr(001) superlattices are studied as a function of the applied field by measuring the reflected intensity at different positions in reciprocal space. Thin films and multilayers of the Heusler compound Co 2 MnGe are studied by means of soft x-ray absorption spectroscopy, magnetic circular dichroism and resonant magnetic scattering

  7. Developing bulk exchange spring magnets

    Science.gov (United States)

    Mccall, Scott K.; Kuntz, Joshua D.

    2017-06-27

    A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

  8. Magnetically Assisted Bilayer Composites for Soft Bending Actuators

    Directory of Open Access Journals (Sweden)

    Sung-Hwan Jang

    2017-06-01

    Full Text Available This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward one side of the structure. The nonhomogeneous distribution of the particles induces bending of the structure when inflated, as a result of asymmetric stiffness of the composite. The bilayer composites were then characterized with a scanning electron microscopy and thermogravimetric analysis. The bending performance and the axial expansion of the actuator were discussed for manipulation applications in soft robotics and bioengineering. The magnetically assisted manufacturing process for the soft bending actuator is a promising technique for various applications in soft robotics.

  9. Magnetically Assisted Bilayer Composites for Soft Bending Actuators.

    Science.gov (United States)

    Jang, Sung-Hwan; Na, Seon-Hong; Park, Yong-Lae

    2017-06-12

    This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward one side of the structure. The nonhomogeneous distribution of the particles induces bending of the structure when inflated, as a result of asymmetric stiffness of the composite. The bilayer composites were then characterized with a scanning electron microscopy and thermogravimetric analysis. The bending performance and the axial expansion of the actuator were discussed for manipulation applications in soft robotics and bioengineering. The magnetically assisted manufacturing process for the soft bending actuator is a promising technique for various applications in soft robotics.

  10. Visualization of Magnetic Flux Distribution at Soft Magnetic Composite(Special Issue to the Asia-Pacific Symposium on Applied Electromagnetics and Mechanics (APSAEM06))

    OpenAIRE

    Z. W., Lin; J. G., Zhu; Y. G., Guo; J. J., Zhong; W. Y., Yu; Centre for Electrical Machines and Power Electronics, Faculty of Engineering, University of Technology; Centre for Electrical Machines and Power Electronics, Faculty of Engineering, University of Technology; Centre for Electrical Machines and Power Electronics, Faculty of Engineering, University of Technology; Centre for Electrical Machines and Power Electronics, Faculty of Engineering, University of Technology; Baosteel Group Shanghai Iron and Steel Research Institute

    2007-01-01

    Soft magnetic composite (SMC), as one of soft magnetic materials, is being used increasingly in electromagnetic devices due to its magnetic isotropy, high electrical resistivity and easy formation. This paper presents the magnetic field distribution at the compressing surface of SMC by means of magneto-optical imaging technique. It is found that the flux density is non-uniform inside the sample, even within one particle region. Although there are interactions between neighbouring particles, t...

  11. Nanomodified composite magnetic materials and their molding technologies

    Directory of Open Access Journals (Sweden)

    I. Timoshkov

    2018-05-01

    Full Text Available Advanced electro-magnetic machines and systems require new materials with improved properties. Heterogeneous 3D nanomodified soft magnetic materials could be efficiently applied. Multistage technology of iron particle surface nanomodification by sequential oxidation and Si-organic coatings will be reported. The thickness of layers is 0.5-5 nm. Compaction and annealing are the final steps of magnetic parts and components shaping. The soft magnetic composite material shows the features: resistivity is controlled by insulating coating thickness and equals up to ρ =10-4 Ω⋅m for metallic state and ρ =104 Ω⋅m for insulator state, maximum magnetic permeability is μm = 2500 and μm = 300 respectively, induction is up to Bm=2.1 T. These properties of composite soft magnetic material allow applying for transformers, throttles, stator-rotor of high-efficient and powerful electric machines in 10 kHz–1MGz frequency range. For microsystems and microcomponents application, good opportunity to improve their reliability is the use of nanocomposite materials. Electroplating technology of nanocomposite magnetic materials into the ultra-thick micromolds will be presented. Co-deposition of the soft magnetic alloys with inert hard nanoparticles allows obtaining materials with magnetic permeability up to μm=104, magnetic induction of Bs=(0.62–1.3 T. Such LIGA-like technology will be applied in MEMS to produce high reliable devices with advanced physical properties.

  12. Nanomodified composite magnetic materials and their molding technologies

    Science.gov (United States)

    Timoshkov, I.; Gao, Q.; Govor, G.; Sakova, A.; Timoshkov, V.; Vetcher, A.

    2018-05-01

    Advanced electro-magnetic machines and systems require new materials with improved properties. Heterogeneous 3D nanomodified soft magnetic materials could be efficiently applied. Multistage technology of iron particle surface nanomodification by sequential oxidation and Si-organic coatings will be reported. The thickness of layers is 0.5-5 nm. Compaction and annealing are the final steps of magnetic parts and components shaping. The soft magnetic composite material shows the features: resistivity is controlled by insulating coating thickness and equals up to ρ =10-4 Ωṡm for metallic state and ρ =104 Ωṡm for insulator state, maximum magnetic permeability is μm = 2500 and μm = 300 respectively, induction is up to Bm=2.1 T. These properties of composite soft magnetic material allow applying for transformers, throttles, stator-rotor of high-efficient and powerful electric machines in 10 kHz-1MGz frequency range. For microsystems and microcomponents application, good opportunity to improve their reliability is the use of nanocomposite materials. Electroplating technology of nanocomposite magnetic materials into the ultra-thick micromolds will be presented. Co-deposition of the soft magnetic alloys with inert hard nanoparticles allows obtaining materials with magnetic permeability up to μm=104, magnetic induction of Bs=(0.62-1.3) T. Such LIGA-like technology will be applied in MEMS to produce high reliable devices with advanced physical properties.

  13. Minnealloy: a new magnetic material with high saturation flux density and low magnetic anisotropy

    Science.gov (United States)

    Mehedi, Md; Jiang, Yanfeng; Suri, Pranav Kumar; Flannigan, David J.; Wang, Jian-Ping

    2017-09-01

    We are reporting a new soft magnetic material with high saturation magnetic flux density, and low magnetic anisotropy. The new material is a compound of iron, nitrogen and carbon, α‧-Fe8(NC), which has saturation flux density of 2.8  ±  0.15 T and magnetic anisotropy of 46 kJ m-3. The saturation flux density is 27% higher than pure iron, a widely used soft magnetic material. Soft magnetic materials are very important building blocks of motors, generators, inductors, transformers, sensors and write heads of hard disk. The new material will help in the miniaturization and efficiency increment of the next generation of electronic devices.

  14. Soft Active Materials for Actuation, Sensing, and Electronics

    Science.gov (United States)

    Kramer, Rebecca Krone

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components increases, the challenges for functionality revert to basic questions of fabrication, materials, and design - whereas such aspects are far more developed for traditional rigid-bodied systems. This thesis will highlight preliminary materials and designs that address the need for soft actuators and sensors, as well as emerging fabrication techniques for manufacturing stretchable circuits and devices based on liquid-embedded elastomers.

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

    Science.gov (United States)

    Liu, Liping; Sharma, Pradeep

    2013-10-01

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

  16. FeSiBP bulk metallic glasses with high magnetization and excellent magnetic softness

    Energy Technology Data Exchange (ETDEWEB)

    Makino, Akihiro [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan)], E-mail: amakino@imr.tohoku.ac.jp; Kubota, Takeshi; Chang, Chuntao [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan); Makabe, Masahiro [Makabe R and D Co., Ltd., 3-1-25 Nagatake, Sendai 983-0036 (Japan); Inoue, Akihisa [Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan)

    2008-10-15

    Fe-based amorphous alloy ribbons are one of the major soft magnetic materials, because of their superior magnetic properties such as the relatively high saturation magnetization (J{sub s}) of 1.5-1.6 T and good magnetic softness. However, the preparation of the ordinary amorphous magnetic alloys requires cooling rates higher than 10{sup 4} K/s due to the low glass-forming ability (GFA) and thus restricts the material outer shape. Recently, Fe-metalloid-based bulk metallic glasses (BMGs) containing glass-forming elements such as Al, Ga, Nb, Mo, Y and so forth have been developed. These alloys have high GFA, leading to the formation of BMG rod with diameters of mm-order. However, the glass-forming metal elements in BMGs result in a remarkable decrease in magnetization. Basically, J{sub s} depends on Fe content; hence, high J{sub s} requires high Fe content in the Fe-based amorphous alloys or BMGs. On the other hand, high GFA requires a large amount of glass-forming elements in the alloys, which results in lower Fe content. Therefore, in substances, the coexistence of high J{sub s} and high GFA is difficult. Since this matter should be immensely important from academia to industry in the material field, a great deal of effort has been devoted; however, it has remained unsolved for many years. In this paper, we present a novel Fe-rich FeSiBP BMG with high J{sub s} of 1.51 T comparable to the ordinary Fe-Si-B amorphous alloy now in practical use as well as with high GFA leading to a rod-shaped specimen of 2.5 mm in diameter, obtained by Cu-mold casting in air.

  17. Viscoelastic characterization of soft biological materials

    Science.gov (United States)

    Nayar, Vinod Timothy

    elastic material. The effects of sample stiffness were evaluated by testing both the quasi-static and dynamic mechanical properties of different concentration agar samples, ranging from 0.5% to 5.0%. The dynamic nanoindentation protocol showed some sensitivity to sample stiffness, but characterization remained consistently applicable to soft biological materials. Comparative experiments were performed on both 0.5% and 5.0% agar as well as porcine eye tissue samples using published dynamic macrocompression standards. By comparing these new tests to those obtained with nanoindentation, the effects due to length-scale, stiffness, size, viscoelastic, and methodological conditions are evaluated. Both testing methodologies can be adapted for the environmental and mounting conditions, but the limitations of standardized macro-scale tests are explored. The factors affecting mechanical characterization of soft and thin viscoelastic biological materials are researched and a comprehensive protocol is presented. This work produces material mechanical properties for use in improving future medical implant designs on a wide variety of biological tissue and materials.

  18. Soft magnetic properties of FeRuGaSi alloy films: SOFMAX

    International Nuclear Information System (INIS)

    Hayashi, K.; Hayakawa, M.; Ishikawa, W.; Ochiai, Y.; Iwasaki, Y.; Aso, K.

    1988-01-01

    To advance new soft magnetic materials of an FeGaSi alloy into the commercial world, improvements on various properties were designed by introducing additive elements without sacrificing its high saturation magnetic induction. The detailed studies on the diversified properties, such as saturation magnetic induction, film internal stress, wear resistivity, and so on, were performed. High-frequency permeability of the laminated structure film was also investigated. As a result, the Ru-added FeRuGaSi alloy films, whose typical compositions are Fe 72 Ru 4 Ga 7 Si 17 and Fe 68 Ru 8 Ga 7 Si 17 (at. %), prove to be excellent soft magnetic materials especially appropriate for the magnetic recording/playback head core use

  19. Magnetically Assisted Bilayer Composites for Soft Bending Actuators

    OpenAIRE

    Jang, Sung-Hwan; Na, Seon-Hong; Park, Yong-Lae

    2017-01-01

    This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically distributed them by applying a strong non-uniform magnetic field to one side of the mold during the curing process. The biased magnetic field induces sedimentation of the ferromagnetic particles toward o...

  20. Topological excitations in magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D., E-mail: bazeia@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Doria, M.M. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Dipartimento di Fisica, Università di Camerino, I-62032 Camerino (Italy); Rodrigues, E.I.B. [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil)

    2016-05-20

    In this work we propose a new route to describe topological excitations in magnetic systems through a single real scalar field. We show here that spherically symmetric structures in two spatial dimensions, which map helical excitations in magnetic materials, admit this formulation and can be used to model skyrmion-like structures in magnetic materials.

  1. A Magnetic Resonance Compatible Soft Wearable Robotic Glove for Hand Rehabilitation and Brain Imaging.

    Science.gov (United States)

    Hong Kai Yap; Kamaldin, Nazir; Jeong Hoon Lim; Nasrallah, Fatima A; Goh, James Cho Hong; Chen-Hua Yeow

    2017-06-01

    In this paper, we present the design, fabrication and evaluation of a soft wearable robotic glove, which can be used with functional Magnetic Resonance imaging (fMRI) during the hand rehabilitation and task specific training. The soft wearable robotic glove, called MR-Glove, consists of two major components: a) a set of soft pneumatic actuators and b) a glove. The soft pneumatic actuators, which are made of silicone elastomers, generate bending motion and actuate finger joints upon pressurization. The device is MR-compatible as it contains no ferromagnetic materials and operates pneumatically. Our results show that the device did not cause artifacts to fMRI images during hand rehabilitation and task-specific exercises. This study demonstrated the possibility of using fMRI and MR-compatible soft wearable robotic device to study brain activities and motor performances during hand rehabilitation, and to unravel the functional effects of rehabilitation robotics on brain stimulation.

  2. The recording characteristics of particulate double layers with hard-magnetic and soft-magnetic underlayers

    NARCIS (Netherlands)

    Lalbahadoersing, S.; Groenland, J.P.J.; Luitjens, S.B.; Lodder, J.C.

    2002-01-01

    Particulate double-layer tape samples with magnetic underlayers have been investigated by performing magnetic recording measurements and by computer simulation.The presence of soft-magnetic underlayers resulted in decreased signal output and better overwrite behavior. Hard-magnetic underlayers

  3. Resonant magnetic scattering of polarized soft x rays

    Energy Technology Data Exchange (ETDEWEB)

    Sacchi, M. [Centre Universitaire Paris-Sud, Orsay (France); Hague, C.F. [Universite Pierre et Marie Curie, Paris (France); Gullikson, E.M.; Underwood, J. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    Magnetic effects on X-ray scattering (Bragg diffraction, specular reflectivity or diffuse scattering) are a well known phenomenon, and they also represent a powerful tool for investigating magnetic materials since it was shown that they are strongly enhanced when the photon energy is tuned across an absorption edge (resonant process). The resonant enhancement of the magnetic scattering has mainly been investigated at high photon energies, in order to match the Bragg law for the typical lattice spacings of crystals. In the soft X-ray range, even larger effects are expected, working for instance at the 2p edges of transition metals of the first row or at the 3d edges of rare earths (300-1500 eV), but the corresponding long wavelengths prevent the use of single crystals. Two approaches have been recently adopted in this energy range: (i) the study of the Bragg diffraction from artificial structures of appropriate 2d spacing; (ii) the analysis of the specular reflectivity, which contains analogous information but has no constraints related to the lattice spacing. Both approaches have their own specific advantages: for instance, working under Bragg conditions provides information about the (magnetic) periodicity in ordered structures, while resonant reflectivity can easily be related to electronic properties and absorption spectra. An important aspect common to all the resonant X-ray scattering techniques is the element selectivity inherent to the fact of working at a specific absorption edge: under these conditions, X-ray scattering becomes in fact a spectroscopy. Results are presented for films of iron and cobalt.

  4. Nanocomposite permanent magnetic materials Nd-Fe-B type: The influence of nanocomposite on magnetic properties

    Directory of Open Access Journals (Sweden)

    Talijan Nadežda M.

    2005-01-01

    Full Text Available The influence on the magnetic properties of nanocristalline ribbons and powders has character of microstructure, between others – the grain size volume of hard and soft magnetic phases and their distribution. Magnetic properties of ribbons and powders depend mainly on their chemical composition and parameters of their heat treatment [1]. Technology of magnets from nanocristalline ribbon consists of the following process: preparing the Nd-Fe- B alloy, preparing the ribbon, powdering of the ribbon, heat treatment of the powder and finally preparing the magnets. Nanocomposite permanent magnet materials based on Nd-Fe- B alloy with Nd low content are a new type of permanent magnetic material. The microstructure of this nanocomposite permanent magnet is composed of a mixture of magnetically soft and hard phases which provide so called exchange coupling effect.

  5. Exploiting the Dynamics of Soft Materials for Machine Learning.

    Science.gov (United States)

    Nakajima, Kohei; Hauser, Helmut; Li, Tao; Pfeifer, Rolf

    2018-06-01

    Soft materials are increasingly utilized for various purposes in many engineering applications. These materials have been shown to perform a number of functions that were previously difficult to implement using rigid materials. Here, we argue that the diverse dynamics generated by actuating soft materials can be effectively used for machine learning purposes. This is demonstrated using a soft silicone arm through a technique of multiplexing, which enables the rich transient dynamics of the soft materials to be fully exploited as a computational resource. The computational performance of the soft silicone arm is examined through two standard benchmark tasks. Results show that the soft arm compares well to or even outperforms conventional machine learning techniques under multiple conditions. We then demonstrate that this system can be used for the sensory time series prediction problem for the soft arm itself, which suggests its immediate applicability to a real-world machine learning problem. Our approach, on the one hand, represents a radical departure from traditional computational methods, whereas on the other hand, it fits nicely into a more general perspective of computation by way of exploiting the properties of physical materials in the real world.

  6. Material parameter identification and inverse problems in soft tissue biomechanics

    CERN Document Server

    Evans, Sam

    2017-01-01

    The articles in this book review hybrid experimental-computational methods applied to soft tissues which have been developed by worldwide specialists in the field. People developing computational models of soft tissues and organs will find solutions for calibrating the material parameters of their models; people performing tests on soft tissues will learn what to extract from the data and how to use these data for their models and people worried about the complexity of the biomechanical behavior of soft tissues will find relevant approaches to address this complexity.

  7. Composite nanoplatelets combining soft-magnetic iron oxide with hard-magnetic barium hexaferrite

    Science.gov (United States)

    Primc, D.; Makovec, D.

    2015-01-01

    By coupling two different magnetic materials inside a single composite nanoparticle, the shape of the magnetic hysteresis can be engineered to meet the requirements of specific applications. Sandwich-like composite nanoparticles composed of a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic spinel iron oxide maghemite (γ-Fe2O3) layers were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe3+/Fe2+ ions in an aqueous suspension of hexaferrite core nanoparticles. The required close control of the supersaturation of the precipitating species was enabled by the controlled release of the Fe3+ ions from the nitrate complex with urea ([Fe((H2N)2C&z.dbd;O)6](NO3)3) and by using Mg(OH)2 as a solid precipitating agent. The platelet Ba-hexaferrite nanoparticles of different sizes were used as the cores. The controlled coating resulted in an exclusively heterogeneous nucleation and the topotactic growth of the spinel layers on both basal surfaces of the larger hexaferrite nanoplatelets. The direct magnetic coupling between the core and the shell resulted in a strong increase of the energy product |BH|max. Ultrafine core nanoparticles reacted with the precipitating species and homogeneous product nanoparticles were formed, which differ in terms of the structure and composition compared to any other compound in the BaO-Fe2O3 system.By coupling two different magnetic materials inside a single composite nanoparticle, the shape of the magnetic hysteresis can be engineered to meet the requirements of specific applications. Sandwich-like composite nanoparticles composed of a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic spinel iron oxide maghemite (γ-Fe2O3) layers were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe3+/Fe2+ ions in an aqueous suspension of hexaferrite core nanoparticles. The required close control of the

  8. Effects of material properties on soft contact dynamics

    International Nuclear Information System (INIS)

    Khurshid, A.; Malik, M.A.; Ghafoor, A.

    2009-01-01

    The superiority of deformable human fingertips as compared to hard robot gripper fingers for grasping and manipulation has led to a number of investigations with robot hands employing elastomers or materials such as fluids or powders beneath a membrane at the fingertips. In this paper, to analyze the stability of dynamic control of an object grasped between two soft fingertips through a soft interface using the viscoelastic material between the manipulating fingers and a manipulated object is modeled through bond graph method (BGM). The fingers are made viscoelastic by using springs and dampers. Detailed bond graph modeling (BGM) of the contact phenomenon with two soft-finger contacts considered to be placed against each other on the opposite sides of the grasped object as is generally the case in a manufacturing environment is presented. The stiffness of the springs is exploited in order to achieve the stability in the soft-grasping which includes friction between the soft finger contact surfaces and the object, The paper also analyses stability of dynamic control through a soft interface between a manipulating finger and a manipulated object. It is shown in the paper that the system stability depends on the visco-elastic material properties of the soft interface. Method of root locus is used to analyze this phenomenon. The paper shows how the weight of the object coming downward is controlled by the friction between the fingers and the object during the application of contact forces by varying the damping and the stiffness in the soft finger. (author)

  9. Magnetically assisted bilayer composites for soft bending actuators

    NARCIS (Netherlands)

    Jang, S.H.; Na, Seon Hong; Park, Yong Lae

    2017-01-01

    This article presents a soft pneumatic bending actuator using a magnetically assisted bilayer composite composed of silicone polymer and ferromagnetic particles. Bilayer composites were fabricated by mixing ferromagnetic particles to a prepolymer state of silicone in a mold and asymmetrically

  10. Mechanical design and analysis of an eight-pole superconducting vector magnet for soft x-ray magnetic dichroism measurements

    Energy Technology Data Exchange (ETDEWEB)

    Arbelaez, D.; Black, A.; Prestemon, S.O.; Wang, S.; Chen, J.; Arenholz, E.

    2010-01-13

    An eight-pole superconducting magnet is being developed for soft x-ray magnetic dichroism (XMD) experiments at the Advanced Light Source, Lawrence Berkley National Laboratory (LBNL). Eight conical Nb{sub 3}Sn coils with Holmium poles are arranged in octahedral symmetry to form four dipole pairs that provide magnetic fields of up to 5 T in any direction relative to the incoming x-ray beam. The dimensions of the magnet yoke as well as pole taper, diameter, and length were optimized for maximum peak field in the magnet center using the software package TOSCA. The structural analysis of the magnet is performed using ANSYS with the coil properties derived using a numerical homogenization scheme. It is found that the use of orthotropic material properties for the coil has an important influence in the design of the magnet.

  11. Frequency and Magnetic Field Dependence of the Skin Depth in Co-rich Soft Magnetic Microwires

    Directory of Open Access Journals (Sweden)

    A. Zhukov

    2016-11-01

    Full Text Available We studied giant magnetoimpedance (GMI effect in magnetically soft amorphous Co-rich microwires in the extended frequency range. From obtained experimentally dependences of GMI ratio on magnetic field and different frequencies we estimated the penetration depth and its dependence on applied magnetic field and frequency

  12. Round table discussion: Present and future applications of nanocrystalline magnetic materials

    International Nuclear Information System (INIS)

    Herzer, G.; Vazquez, M.; Knobel, M.; Zhukov, A.; Reininger, T.; Davies, H.A.; Groessinger, R.; Sanchez Ll, J.L.

    2005-01-01

    Examples of existing or potential applications of nanocrystalline magnetic materials, ranging from soft to hard magnetic alloys, are presented and discussed by experts in the respective fields of research and technology

  13. Nanostructured electronic and magnetic materials

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    and magnetic materials are provided. Advantages of nanocrystalline magnetic mate- rials in the context of ... 2.2 Phosphors for high definition TV. Better resolution of television screens could be ..... materials and that of preparing nanoparticles. This will remain a challenge for the future if nanomaterials are to be competitive.

  14. Magnetic spectroscopy and microscopy of functional materials

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Catherine Ann [Univ. of Mainz (Germany)

    2011-05-01

    Heusler intermetallics Mn2Y Ga and X2MnGa (X; Y =Fe, Co, Ni) undergo tetragonal magnetostructural transitions that can result in half metallicity, magnetic shape memory, or the magnetocaloric effect. Understanding the magnetism and magnetic behavior in functional materials is often the most direct route to being able to optimize current materials for todays applications and to design novel ones for tomorrow. Synchrotron soft x-ray magnetic spectromicroscopy techniques are well suited to explore the the competing effects from the magnetization and the lattice parameters in these materials as they provide detailed element-, valence-, and site-specifc information on the coupling of crystallographic ordering and electronic structure as well as external parameters like temperature and pressure on the bonding and exchange. Fundamental work preparing the model systems of spintronic, multiferroic, and energy-related compositions is presented for context. The methodology of synchrotron spectroscopy is presented and applied to not only magnetic characterization but also of developing a systematic screening method for future examples of materials exhibiting any of the above effects. The chapter progression is as follows: an introduction to the concepts and materials under consideration (Chapter 1); an overview of sample preparation techniques and results, and the kinds of characterization methods employed (Chapter 2); spectro- and microscopic explorations of X2MnGa/Ge (Chapter 3); spectroscopic investigations of the composition series Mn2Y Ga to the logical Mn3Ga endpoint (Chapter 4); and a summary and overview of upcoming work (Chapter 5). Appendices include the results of a Think Tank for the Graduate School of Excellence MAINZ (Appendix A) and details of an imaging project now in progress on magnetic reversal and domain wall observation in the classical Heusler material Co2FeSi (Appendix B).

  15. Accuracy Verification of Magnetic Resonance Imaging (MRI) Technology for Lower-Limb Prosthetic Research: Utilising Animal Soft Tissue Specimen and Common Socket Casting Materials

    OpenAIRE

    Safari, Mohammad Reza; Rowe, Philip; Buis, Arjan

    2012-01-01

    Lower limb prosthetic socket shape and volume consistency can be quantified using MRI technology. Additionally, MRI images of the residual limb could be used as an input data for CAD-CAM technology and finite element studies. However, the accuracy of MRI when socket casting materials are used has to be defined. A number of six, 46 mm thick, cross-sections of an animal leg were used. Three specimens were wrapped with Plaster of Paris (POP) and the other three with commercially available silico...

  16. Microfluidic magnetic separator using an array of soft magnetic elements

    DEFF Research Database (Denmark)

    Smistrup, Kristian; Lund-Olesen, Torsten; Hansen, Mikkel Fougt

    2006-01-01

    We present the design, fabrication, characterization, and demonstration of a new passive magnetic bead separator. The device operates in an effective state when magnetized by an external magnetic field of only 50 mT, which is available from a tabletop electromagnet. We demonstrate the complete...... capture of 1.0 mu m fluorescent magnetic beads from a 7.5 mu L sample volume traveling at an average linear fluid velocity of 5 mm/s....

  17. Accuracy verification of magnetic resonance imaging (MRI) technology for lower-limb prosthetic research: utilising animal soft tissue specimen and common socket casting materials.

    Science.gov (United States)

    Safari, Mohammad Reza; Rowe, Philip; Buis, Arjan

    2012-01-01

    Lower limb prosthetic socket shape and volume consistency can be quantified using MRI technology. Additionally, MRI images of the residual limb could be used as an input data for CAD-CAM technology and finite element studies. However, the accuracy of MRI when socket casting materials are used has to be defined. A number of six, 46 mm thick, cross-sections of an animal leg were used. Three specimens were wrapped with Plaster of Paris (POP) and the other three with commercially available silicone interface liner. Data was obtained by utilising MRI technology and then the segmented images compared to corresponding calliper measurement, photographic imaging, and water suspension techniques. The MRI measurement results were strongly correlated with actual diameter, surface area, and volume measurements. The results show that the selected scanning parameters and the semiautomatic segmentation method are adequate enough, considering the limit of clinical meaningful shape and volume fluctuation, for residual limb volume and the cross-sectional surface area measurements.

  18. Accuracy Verification of Magnetic Resonance Imaging (MRI Technology for Lower-Limb Prosthetic Research: Utilising Animal Soft Tissue Specimen and Common Socket Casting Materials

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Safari

    2012-01-01

    Full Text Available Lower limb prosthetic socket shape and volume consistency can be quantified using MRI technology. Additionally, MRI images of the residual limb could be used as an input data for CAD-CAM technology and finite element studies. However, the accuracy of MRI when socket casting materials are used has to be defined. A number of six, 46 mm thick, cross-sections of an animal leg were used. Three specimens were wrapped with Plaster of Paris (POP and the other three with commercially available silicone interface liner. Data was obtained by utilising MRI technology and then the segmented images compared to corresponding calliper measurement, photographic imaging, and water suspension techniques. The MRI measurement results were strongly correlated with actual diameter, surface area, and volume measurements. The results show that the selected scanning parameters and the semiautomatic segmentation method are adequate enough, considering the limit of clinical meaningful shape and volume fluctuation, for residual limb volume and the cross-sectional surface area measurements.

  19. Magnetic Performance of a Nanocomposite Permanent Material

    International Nuclear Information System (INIS)

    Liu Min; Han Guang-Bing; Gao Ru-Wei

    2011-01-01

    We build a sandwiched structure model in which the intergranular phase (IP) is homogeneously distributed between soft and hard magnetic grains, and gives a continuously anisotropic expression of the coupling part under the assumption that the IP weakens the intergrain exchange-coupling interaction. Based on the idea that the hardening mechanism is of the pinning type, we calculate the effect of the IP's thickness d and its anisotropy constant K 1 (0) on the intrinsic coercivity of a nanocomposite permanent material. The calculated results indicate that the domain wall goes twice through irreversible domain wall displacement during the process of moving from soft to hard magnetic grains, and the intrinsic coercivity increases with increasing d, but decreases with increasing K 1 (0). When d and K 1 (0) take 2 nm and 0.7K h , respectively, with K h being the anisotropy constant in the inner part of the hard magnetic grain, the calculated intrinsic coercivity is in good agreement with the experimental data. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  20. Development of Ferrite-Coated Soft Magnetic Composites: Correlation of Microstructure to Magnetic Properties

    Science.gov (United States)

    Sunday, Katie Jo

    Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and boast high melting temperatures, thus providing adequate electrical barriers between metallic particles. These insulating layers are necessary for reducing eddy current losses by increasing resistivity in order to improve the overall magnetic efficiency and subsequent frequency range. The goals of this work are to correlate ferrite-coated Fe powder composites microstructure for the coating and core powder to magnetic properties such as permeability, coercivity, and core loss. We first explore the relevant concepts of SMC materials from their composition to processing steps to pertinent properties. This thesis employs a suite of characterization techniques for powder and composite properties. We use X-ray diffraction, scanning electron microscopy, and transmission electron microscopy to provide a complete understanding of the effect of processing conditions on ferrite-coated Fe-based SMCs. Magnetic, mechanical, and electrical properties are then analyzed to correlate microstructural features and determine their effect on such properties. In the second part of this thesis, we present a proof of concept study on Al2O3- and Al2O3- Fe3O4-coated Fe powder composites, illustrating magnetization is highly dependent on ferromagnetic volume. We then expand on previous work to compare an ideal, crystalline state using Fe3O 4-Fe thin film heterostructures to a highly strained state using bulk powder studies. Fe3O4-coated Fe composites are produced via mechanical

  1. Annual Conference on Magnetism and Magnetic Materials, 29th, Pittsburgh, PA, November 8-11, 1983, Proceedings

    International Nuclear Information System (INIS)

    Hasegawa, R.; Koon, N.C.; Cooper, B.R.

    1984-01-01

    Various topics on magnetism and magnetic materials are addressed. The subjects considered include: spin glasses, amorphous magnetism, actinide and rare earth intermetallics, magnetic excitation, itinerant magnetism and magnetic structure, valence instabilities, Kondo effect, transport and Hall effects, mixed valence and Kondo compounds, superconductivity and magnetism, d and f electron magnetism and superconductivity, Fe-based microcrystalline and permanent magnetic alloys, hard and soft magnetic materials, and magnetooptics. Also discussed are: numerical methods for magnetic field computation, recording theory and experiments, recording heads and media, magnetic studies via hyperfine interactions, magnetic semiconductors, magnet insulators, transition metal systems, random fields, critical phenomena and magnetoelastic effects and resonance, surfaces and interfaces, magnetostatic waves and resonance, bubble materials and implantation, bubble devices and physics, magnetic separation, ferrofluids, magnetochemistry, new techniques and materials, and new applications

  2. Magnetic resonance imaging of pediatric soft-tissue vascular anomalies

    International Nuclear Information System (INIS)

    Navarro, Oscar M.

    2016-01-01

    Magnetic resonance (MR) imaging can be used in the management of pediatric soft-tissue vascular anomalies for diagnosing and assessing extent of lesions and for evaluating response to therapy. MR imaging studies often involve a combination of T1- and T2-weighted images in addition to MR angiography and fat-suppressed post-contrast sequences. The MR imaging features of these vascular anomalies when combined with clinical findings can aid in diagnosis. In cases of complex vascular malformations and syndromes associated with vascular anomalies, MR imaging can be used to evaluate accompanying soft-tissue and bone anomalies. This article reviews the MR imaging protocols and appearances of the most common pediatric soft-tissue vascular anomalies. (orig.)

  3. Extreme Toughening of Soft Materials with Liquid Metal.

    Science.gov (United States)

    Kazem, Navid; Bartlett, Michael D; Majidi, Carmel

    2018-05-01

    Soft and tough materials are critical for engineering applications in medical devices, stretchable and wearable electronics, and soft robotics. Toughness in synthetic materials is mostly accomplished by increasing energy dissipation near the crack tip with various energy dissipation techniques. However, bio-materials exhibit extreme toughness by combining multi-scale energy dissipation with the ability to deflect and blunt an advancing crack tip. Here, we demonstrate a synthetic materials architecture that also exhibits multi-modal toughening, whereby embedding a suspension of micron sized and highly deformable liquid metal (LM) droplets inside a soft elastomer, the fracture energy dramatically increases by up to 50x (from 250 ± 50 J m -2 to 11,900 ± 2600 J m -2 ) over an unfilled polymer. For some LM-embedded elastomer (LMEE) compositions, the toughness is measured to be 33,500 ± 4300 J m -2 , which far exceeds the highest value previously reported for a soft elastic material. This extreme toughening is achieved by (i) increasing energy dissipation, (ii) adaptive crack movement, and (iii) effective elimination of the crack tip. Such properties arise from the deformability of the LM inclusions during loading, providing a new mechanism to not only prevent crack initiation, but also resist the propagation of existing tears for ultra tough, soft materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Magnetic materials. Properties and applications

    International Nuclear Information System (INIS)

    Bar'yakhtar, V.

    1998-01-01

    Main theoretical and experimental results of physics of magnetic materials have been stated. Special attention was paid to the problem of creation of magnetic materials for information recording and presentation. The results of fundamental researches have been considered for their effect on creation of magnetic materials with the properties required for production as well as the reverse effect of production financing on the development of fundamental investigations. The relations between the development of high technologies and the society requirements, financing volumes and the level of NIKOR. (author)

  5. Bi-magnetic microwires: a novel family of materials with controlled magnetic behavior

    International Nuclear Information System (INIS)

    Pirota, K.R.; Provencio, M.; Garcia, K.L.; Escobar-Galindo, R.; Mendoza Zelis, P.; Hernandez-Velez, M.; Vazquez, M.

    2005-01-01

    A novel technique involving combined sputtering and electroplating procedures has been recently developed to deposit metallic (magnetic or not) nano and microlayer tubes onto glass-coated amorphous magnetic microwires to enable the tailoring of their magnetic behavior. Here, after introducing the general aspects of that technique, we present the latest results on a new family of two-phase magnetic samples: bi-magnetic multilayer microwires. They consist of a magnetically soft nucleus (typically a Fe or Co base amorphous microwire, coated by Pyrex layer) onto which a 30 nm thick Au layer is first sputtered followed by the electroplating of a harder microlayer, namely Co x Ni (1- x ) layer, with x controlled by the current density during electrodeposition whose micrometric thickness is also controlled by plating time. The hysteresis loops present a two-step reversal process typical of two-phase magnetic material. The magnetization reversal of the soft nucleus and the harder layer takes place at around 1 Oe and up to about 200 Oe, respectively. The presence of sputtered and electroplated layers induces significant stresses in the soft magnetic nucleus that modify its magnetization easy axis. This technique allowing us the tailoring of the magnetic behavior of multilayer magnetic microwires opens new possibilities for applying these novel materials as sensing elements in various devices

  6. Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Vernieres, Jerome, E-mail: Jerome.vernieres@oist.jp; Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Diaz, Rosa E. [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Bobo, Jean-François [Centre d’Elaboration de Materiaux et d’Etudes Structurales (CEMES), 29 rue Jeanne Marvig, 31055 Toulouse Cedex 4 (France); Sowwan, Mukhles, E-mail: Mukhles@oist.jp [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Nanotechnology Research Laboratory, Al-Quds University, P.O. Box 51000, East Jerusalem, Palestine (Country Unknown)

    2014-11-01

    Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO{sub 3} phase) and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g) and low coercivity (less than 20 Oe) at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

  7. Electronic, magnetic, and optical materials

    CERN Document Server

    Fulay, Pradeep

    2013-01-01

    Technological aspects of ferroelectric, piezoelectric and pyroelectric materials are discussed in detail, in a way that should allow the reader to select an optimal material for a particular application. The basics of magnetostatics are described clearly, as are a wide range of magnetic properties of materials … .-Tony Harker, Department of Physics and Astronomy, University College London

  8. Soft electron processor for surface sterilization of food material

    International Nuclear Information System (INIS)

    Baba, Takashi; Kaneko, Hiromi; Taniguchi, Shuichi

    2004-01-01

    As frozen or chilled foods have become popular nowadays, it has become very important to provide raw materials with lower level microbial contamination to food processing companies. Consequently, the sterilization of food material is one of the major topics for food processing. Dried materials like grains, beans and spices, etc., are not typically deeply contaminated by microorganisms, which reside on the surfaces of materials, so it is very useful to take low energetic, lower than 300 keV, electrons with small penetration power (Soft-Electrons), as a sterilization method for such materials. Soft-Electrons is researched and named by Dr. Hayashi et al. This is a non-thermal method, so one can keep foods hygienic without serious deterioration. It is also a physical method, so is free from residues of chemicals in foods. Recently, Nissin-High Voltage Co., Ltd. have developed and manufactured equipment for commercial use of Soft-Electrons (Soft Electron Processor), which can process 500 kg/h of grains. This report introduces the Soft Electron Processor and shows the results of sterilization of wheat and brown rice by the equipment

  9. Earthquake statistics and plastic events in soft-glassy materials

    NARCIS (Netherlands)

    Benzi, Roberto; Kumar, Pinaki; Toschi, Federico; Trampert, Jeannot

    2016-01-01

    We propose a new approach for generating synthetic earthquakes based on the physics of soft glasses. The continuum approach produces yield-stress materials based on Lattice–Boltzmann simulations. We show that if the material is stimulated below yield stress, plastic events occur, which have strong

  10. Dual-tip magnetic force microscopy with suppressed influence on magnetically soft samples

    International Nuclear Information System (INIS)

    Precner, Marián; Fedor, Ján; Šoltýs, Ján; Cambel, Vladimír

    2015-01-01

    Standard magnetic force microscopy (MFM) is considered as a powerful tool used for magnetic field imaging at nanoscale. The method consists of two passes realized by the magnetic tip. Within the first one, the topography pass, the magnetic tip directly touches the magnetic sample. Such contact perturbs the magnetization of the sample explored. To avoid the sample touching the magnetic tip, we present a new approach to magnetic field scanning by segregating the topological and magnetic scans with two different tips located on a cut cantilever. The approach minimizes the disturbance of sample magnetization, which could be a major problem in conventional MFM images of soft magnetic samples. By cutting the cantilever in half using the focused ion beam technique, we create one sensor with two different tips—one tip is magnetized, and the other one is left non-magnetized. The non-magnetized tip is used for topography and the magnetized one for the magnetic field imaging. The method developed we call dual-tip magnetic force microscopy (DT-MFM). We describe in detail the dual-tip fabrication process. In the experiments, we show that the DT-MFM method reduces significantly the perturbations of the magnetic tip as compared to the standard MFM method. The present technique can be used to investigate microscopic magnetic domain structures in a variety of magnetic samples and is relevant in a wide range of applications, e.g., data storage and biomedicine. (paper)

  11. Energy-based ferromagnetic material model with magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Steentjes, Simon, E-mail: simon.steentjes@iem.rwth-aachen.de [Institute of Electrical Machines - RWTH Aachen University, Schinkelstr. 4, D-52056 Aachen (Germany); Henrotte, François, E-mail: francois.henrotte@uclouvain.be [Institute of Mechanics Materials and Civil Engineering - UCL, Av. G. Lemaître 4-6, B-1348 Louvain-la-Neuve (Belgium); Hameyer, Kay [Institute of Electrical Machines - RWTH Aachen University, Schinkelstr. 4, D-52056 Aachen (Germany)

    2017-03-01

    Non-oriented soft magnetic materials are commonly assumed to be magnetically isotropic. However, due to the rolling process a preferred direction exists along the rolling direction. This uniaxial magnetic anisotropy, and the related magnetostriction effect, are critical to the accurate calculation of iron losses and magnetic forces in rotating electrical machines. This paper proposes an extension of an isotropic energy-based vector hysteresis model to account for these two effects. - Highlights: • Energy-based vector hysteresis model with magnetic anisotropy. • Two-scale model to account for pinning field distribution. • Pinning force and reluctivity are extended to anisotropic case.

  12. The influence of the surface topography on the magnetization dynamics in soft magnetic thin films

    NARCIS (Netherlands)

    Craus, CB; Palasantzas, G; Chezan, AR; De Hosson, JTM; Boerma, DO; Niesen, L

    2005-01-01

    In this work we study the influence of surface roughness on the magnetization dynamics of soft magnetic nanocrystalline Fe-Zr-N thin films deposited (under identical conditions) onto a Si oxide, a thin polymer layer, and a thin Cu layer. The substrate temperature during deposition was approximately

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

    Science.gov (United States)

    Chen, Lei; Wang, Yao

    2016-05-01

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

  14. Research Update: Computational materials discovery in soft matter

    Directory of Open Access Journals (Sweden)

    Tristan Bereau

    2016-05-01

    Full Text Available Soft matter embodies a wide range of materials, which all share the common characteristics of weak interaction energies determining their supramolecular structure. This complicates structure-property predictions and hampers the direct application of data-driven approaches to their modeling. We present several aspects in which these methods play a role in designing soft-matter materials: drug design as well as information-driven computer simulations, e.g., histogram reweighting. We also discuss recent examples of rational design of soft-matter materials fostered by physical insight and assisted by data-driven approaches. We foresee the combination of data-driven and physical approaches a promising strategy to move the field forward.

  15. Magnetic imaging with full-field soft X-ray microscopies

    International Nuclear Information System (INIS)

    Fischer, Peter; Im, Mi-Young; Baldasseroni, Chloe; Bordel, Catherine; Hellman, Frances; Lee, Jong-Soo; Fadley, Charles S.

    2013-01-01

    Progress toward a fundamental understanding of magnetism continues to be of great scientific interest and high technological relevance. To control magnetization on the nanoscale, external magnetic fields and spin polarized currents are commonly used. In addition, novel concepts based on spin manipulation by electric fields or photons are emerging which benefit from advances in tailoring complex magnetic materials. Although the nanoscale is at the very origin of magnetic behavior, there is a new trend toward investigating mesoscale magnetic phenomena, thus adding complexity and functionality, both of which will become crucial for future magnetic devices. Advanced analytical tools are thus needed for the characterization of magnetic properties spanning the nano- to the meso-scale. Imaging magnetic structures with high spatial and temporal resolution over a large field of view and in three dimensions is therefore a key challenge. A variety of spectromicroscopic techniques address this challenge by taking advantage of variable-polarization soft X-rays, thus enabling X-ray dichroism effects provide magnetic contrast. These techniques are also capable of quantifying in an element-, valence- and site-sensitive way the basic properties of ferro(i)- and antiferro-magnetic systems, such as spin and orbital moments, spin configurations from the nano- to the meso-scale and spin dynamics with sub-ns time resolution. This paper reviews current achievements and outlines future trends with one of these spectromicroscopies, magnetic full field transmission soft X-ray microscopy (MTXM) using a few selected examples of recent research on nano- and meso-scale magnetic phenomena. The complementarity of MTXM to X-ray photoemission electron microscopy (X-PEEM) is also emphasized

  16. Magnetic imaging with full-field soft X-ray microscopies

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Peter, E-mail: PJFischer@lbl.gov [Center for X-ray Optics, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Im, Mi-Young [Center for X-ray Optics, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Baldasseroni, Chloe [Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720 (United States); Bordel, Catherine; Hellman, Frances [Department of Physics, University of California Berkeley, Berkeley, CA 94720 (United States); Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94270 (United States); Lee, Jong-Soo [Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873 (Korea, Republic of); Fadley, Charles S. [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94270 (United States)

    2013-08-15

    Progress toward a fundamental understanding of magnetism continues to be of great scientific interest and high technological relevance. To control magnetization on the nanoscale, external magnetic fields and spin polarized currents are commonly used. In addition, novel concepts based on spin manipulation by electric fields or photons are emerging which benefit from advances in tailoring complex magnetic materials. Although the nanoscale is at the very origin of magnetic behavior, there is a new trend toward investigating mesoscale magnetic phenomena, thus adding complexity and functionality, both of which will become crucial for future magnetic devices. Advanced analytical tools are thus needed for the characterization of magnetic properties spanning the nano- to the meso-scale. Imaging magnetic structures with high spatial and temporal resolution over a large field of view and in three dimensions is therefore a key challenge. A variety of spectromicroscopic techniques address this challenge by taking advantage of variable-polarization soft X-rays, thus enabling X-ray dichroism effects provide magnetic contrast. These techniques are also capable of quantifying in an element-, valence- and site-sensitive way the basic properties of ferro(i)- and antiferro-magnetic systems, such as spin and orbital moments, spin configurations from the nano- to the meso-scale and spin dynamics with sub-ns time resolution. This paper reviews current achievements and outlines future trends with one of these spectromicroscopies, magnetic full field transmission soft X-ray microscopy (MTXM) using a few selected examples of recent research on nano- and meso-scale magnetic phenomena. The complementarity of MTXM to X-ray photoemission electron microscopy (X-PEEM) is also emphasized.

  17. High strain-rate soft material characterization via inertial cavitation

    Science.gov (United States)

    Estrada, Jonathan B.; Barajas, Carlos; Henann, David L.; Johnsen, Eric; Franck, Christian

    2018-03-01

    Mechanical characterization of soft materials at high strain-rates is challenging due to their high compliance, slow wave speeds, and non-linear viscoelasticity. Yet, knowledge of their material behavior is paramount across a spectrum of biological and engineering applications from minimizing tissue damage in ultrasound and laser surgeries to diagnosing and mitigating impact injuries. To address this significant experimental hurdle and the need to accurately measure the viscoelastic properties of soft materials at high strain-rates (103-108 s-1), we present a minimally invasive, local 3D microrheology technique based on inertial microcavitation. By combining high-speed time-lapse imaging with an appropriate theoretical cavitation framework, we demonstrate that this technique has the capability to accurately determine the general viscoelastic material properties of soft matter as compliant as a few kilopascals. Similar to commercial characterization algorithms, we provide the user with significant flexibility in evaluating several constitutive laws to determine the most appropriate physical model for the material under investigation. Given its straightforward implementation into most current microscopy setups, we anticipate that this technique can be easily adopted by anyone interested in characterizing soft material properties at high loading rates including hydrogels, tissues and various polymeric specimens.

  18. Magnetic losses in composite materials

    International Nuclear Information System (INIS)

    Ramprecht, J; Sjoeberg, D

    2008-01-01

    We discuss some of the problems involved in homogenization of a composite material built from ferromagnetic inclusions in a nonmagnetic background material. The small signal permeability for a ferromagnetic spherical particle is combined with a homogenization formula to give an effective permeability for the composite material. The composite material inherits the gyrotropic structure and resonant behaviour of the single particle. The resonance frequency of the composite material is found to be independent of the volume fraction, unlike dielectric composite materials. The magnetic losses are described by a magnetic conductivity which can be made independent of frequency and proportional to the volume fraction by choosing a certain bias. Finally, some concerns regarding particles of small size, i.e. nanoparticles, are treated and the possibility of exciting exchange modes are discussed. These exchange modes may be an interesting way to increase losses in composite materials

  19. Fabrication of a solenoid-type inductor with Fe-based soft magnetic core

    International Nuclear Information System (INIS)

    Lei Chong; Zhou Yong; Gao Xiaoyu; Ding Wen; Cao Ying; Choi, Hyung; Won, Jonghwa

    2007-01-01

    A solenoid-type inductor was fabricated by MEMS (Microelectromechanical systems) technique. The fabrication process uses UV-LIGA, dry etching, fine polishing, and electroplating technique to achieve high performance of the solenoid-type inductor. Fe-based soft magnetic thin film was sputtered as the magnetic core, and polyimide was used as the insulation materials. The inductor was in size of 4x4 mm with coil width of 20 μm and space of 35 μm. The inductance is 1.61 μH at a frequency of 5 MHz with the maximum quality factor of 1.42

  20. Dynamic compressive mechanical response of a soft polymer material

    NARCIS (Netherlands)

    Fan, J.T.; Weerheijm, J.; Sluys, L.J.

    2015-01-01

    The dynamic mechanical behaviour of a soft polymer material (Clear Flex 75) was studied using a split Hopkinson pressure bar (SHPB) apparatus. Mechanical properties have been determined at moderate to high strain rates. Real time deformation and fracture were recorded using a high-speed camera.

  1. Effect of soft underlayer magnetic anisotropy on perpendicular recording process

    International Nuclear Information System (INIS)

    Lim, C.K.; Kim, E.S.; Yoon, S.Y.; Kong, S.H.; Lee, H.S.; Oh, H.S.; Kim, Y.S.

    2007-01-01

    The presence of the soft magnetic underlayer (SUL) in perpendicular magnetic recording (PMR) media is essential for the application. It is commonly understood that the SUL provides the return flux path and enhances the writing field by enhancing the recording field from the write pole. However, SUL increases the magnetic noise during the read back process due to magnetic domain walls in the SUL. Hence, it is common to grow SUL with large uniaxial or unidirectional magnetic anisotropy field (H k ) to reduce domain wall noise. In this paper, we explore the effect of increasing SUL H k on the recording process. We studied this effect by using the finite element micromagnetic simulation. Our simulation results show that the contribution of SUL to the writing field amplitude is reduced with increasing H k . This reduction in magnetic field from high H k SUL actually improves the recording performance due to the better field gradient at SUL. The simulation results are qualitatively consistent with the actual experimental data obtained from the Guzik measurement

  2. Crops: a green approach toward self-assembled soft materials.

    Science.gov (United States)

    Vemula, Praveen Kumar; John, George

    2008-06-01

    To date, a wide range of industrial materials such as solvents, fuels, synthetic fibers, and chemical products are being manufactured from petroleum resources. However, rapid depletion of fossil and petroleum resources is encouraging current and future chemists to orient their research toward designing safer chemicals, products, and processes from renewable feedstock with an increased awareness of environmental and industrial impact. Advances in genetics, biotechnology, process chemistry, and engineering are leading to a new manufacturing concept for converting renewable biomass to valuable fuels and products, generally known as the biorefinery concept. The swift integration of crop-based materials synthesis and biorefinery manufacturing technologies offers the potential for new advances in sustainable energy alternatives and biomaterials that will lead to a new manufacturing paradigm. This Account presents a novel and emerging concept of generating various forms of soft materials from crops (an alternate feedstock). In future research, developing biobased soft materials will be a fascinating yet demanding practice, which will have direct impact on industrial applications as an economically viable alternative. Here we discuss some remarkable examples of glycolipids generated from industrial byproducts such as cashew nut shell liquid, which upon self-assembly produced soft nanoarchitectures including lipid nanotubes, twisted/helical nanofibers, low-molecular-weight gels, and liquid crystals. Synthetic methods applied to a "chiral pool" of carbohydrates using the selectivity of enzyme catalysis yield amphiphilic products derived from biobased feedstock including amygdalin, trehalose, and vitamin C. This has been achieved with a lipase-mediated regioselective synthetic procedure to obtain such amphiphiles in quantitative yields. Amygdalin amphiphiles showed unique gelation behavior in a broad range of solvents such as nonpolar hexanes to polar aqueous solutions

  3. Formation of soft magnetic high entropy amorphous alloys composites containing in situ solid solution phase

    Science.gov (United States)

    Wei, Ran; Sun, Huan; Chen, Chen; Tao, Juan; Li, Fushan

    2018-03-01

    Fe-Co-Ni-Si-B high entropy amorphous alloys composites (HEAACs), which containing high entropy solid solution phase in amorphous matrix, show good soft magnetic properties and bending ductility even in optimal annealed state, were successfully developed by melt spinning method. The crystallization phase of the HEAACs is solid solution phase with body centered cubic (BCC) structure instead of brittle intermetallic phase. In addition, the BCC phase can transformed into face centered cubic (FCC) phase with temperature rise. Accordingly, Fe-Co-Ni-Si-B high entropy alloys (HEAs) with FCC structure and a small amount of BCC phase was prepared by copper mold casting method. The HEAs exhibit high yield strength (about 1200 MPa) and good plastic strain (about 18%). Meanwhile, soft magnetic characteristics of the HEAs are largely reserved from HEAACs. This work provides a new strategy to overcome the annealing induced brittleness of amorphous alloys and design new advanced materials with excellent comprehensive properties.

  4. Elastic Characterization of Transversely Isotropic Soft Materials by Dynamic Shear and Asymmetric Indentation

    Science.gov (United States)

    Namani, R.; Feng, Y.; Okamoto, R. J.; Jesuraj, N.; Sakiyama-Elbert, S. E.; Genin, G. M.; Bayly, P. V.

    2012-01-01

    The mechanical characterization of soft anisotropic materials is a fundamental challenge because of difficulties in applying mechanical loads to soft matter and the need to combine information from multiple tests. A method to characterize the linear elastic properties of transversely isotropic soft materials is proposed, based on the combination of dynamic shear testing (DST) and asymmetric indentation. The procedure was demonstrated by characterizing a nearly incompressible transversely isotropic soft material. A soft gel with controlled anisotropy was obtained by polymerizing a mixture of fibrinogen and thrombin solutions in a high field magnet (B = 11.7 T); fibrils in the resulting gel were predominantly aligned parallel to the magnetic field. Aligned fibrin gels were subject to dynamic (20–40 Hz) shear deformation in two orthogonal directions. The shear storage modulus was 1.08 ± 0. 42 kPa (mean ± std. dev.) for shear in a plane parallel to the dominant fiber direction, and 0.58 ± 0.21 kPa for shear in the plane of isotropy. Gels were indented by a rectangular tip of a large aspect ratio, aligned either parallel or perpendicular to the normal to the plane of transverse isotropy. Aligned fibrin gels appeared stiffer when indented with the long axis of a rectangular tip perpendicular to the dominant fiber direction. Three-dimensional numerical simulations of asymmetric indentation were used to determine the relationship between direction-dependent differences in indentation stiffness and material parameters. This approach enables the estimation of a complete set of parameters for an incompressible, transversely isotropic, linear elastic material. PMID:22757501

  5. Observation of elastic topological states in soft materials.

    Science.gov (United States)

    Li, Shuaifeng; Zhao, Degang; Niu, Hao; Zhu, Xuefeng; Zang, Jianfeng

    2018-04-10

    Topological elastic metamaterials offer insight into classic motion law and open up opportunities in quantum and classic information processing. Theoretical modeling and numerical simulation of elastic topological states have been reported, whereas the experimental observation remains relatively unexplored. Here we present an experimental observation and numerical simulation of tunable topological states in soft elastic metamaterials. The on-demand reversible switch in topological phase has been achieved by changing filling ratio, tension, and/or compression of the elastic metamaterials. By combining two elastic metamaterials with distinct topological invariants, we further demonstrate the formation and dynamic tunability of topological interface states by mechanical deformation, and the manipulation of elastic wave propagation. Moreover, we provide a topological phase diagram of elastic metamaterials under deformation. Our approach to dynamically control interface states in soft materials paves the way to various phononic systems involving thermal management and soft robotics requiring better use of energy.

  6. Soft magnetic nanoparticles of BaFe sub 1 sub 2 O sub 1 sub 9 fabricated under mild conditions

    CERN Document Server

    Che Shan; Chen Qian Wang

    2003-01-01

    Nanoparticles of barium hexaferrite, with an average size of 12 nm, were prepared by a hydrothermal route at relatively low temperatures (140-180 deg C). The effects of reaction temperature and time on the particle size and magnetic properties were discussed. The nanoparticles show a soft magnetic feature with a saturation magnetization of 1.1 emu g sup - sup 1 and coercivity of 221.0 Oe, rather than the hard magnetic characteristic that the corresponding bulk material exhibits. Annealing treatment in air at 800 deg C led to an order-of-magnitude increase of the saturation magnetization (67.3 emu g sup - sup 1) and coercive force (4511 Oe). It is suggested that the oxygen vacancies should be responsible for the soft magnetic characteristic that appeared for the as-prepared barium hexaferrite nanoparticles. (letter to the editor)

  7. The effect of compaction parameters and dielectric composition on properties of soft magnetic composites

    Science.gov (United States)

    Xiao, Ling; Sun, Y. H.; Yu, Lie

    2011-07-01

    This paper investigated the effect of compaction parameters and dielectric composition on mechanical, magnetic and electrical properties of iron-organosilicon epoxy resin soft magnetic composites. In this work, iron powders with high purity were covered by an organic material (organosilicon epoxy resin) and then by coupling agent (KH-550). The coated powders were then cold compacted at 600, 800 and 1000 MPa and cured under vacuum respectively. The results show that the saturation magnetic flux density and electrical resistivity are dependent on compaction pressure and resin content. Increase in the organic phase content leads to decrease of the saturation magnetic flux density, while increase of the electrical resistivity. Furthermore, the samples with 0.9 wt% resins + 0.1 wt% coupling agent at compaction pressure of 800 MPa shows better properties than the others.

  8. The effect of compaction parameters and dielectric composition on properties of soft magnetic composites

    International Nuclear Information System (INIS)

    Xiao Ling; Yu Lie; Sun, Y H

    2011-01-01

    This paper investigated the effect of compaction parameters and dielectric composition on mechanical, magnetic and electrical properties of iron-organosilicon epoxy resin soft magnetic composites. In this work, iron powders with high purity were covered by an organic material (organosilicon epoxy resin) and then by coupling agent (KH-550). The coated powders were then cold compacted at 600, 800 and 1000 MPa and cured under vacuum respectively. The results show that the saturation magnetic flux density and electrical resistivity are dependent on compaction pressure and resin content. Increase in the organic phase content leads to decrease of the saturation magnetic flux density, while increase of the electrical resistivity. Furthermore, the samples with 0.9 wt% resins + 0.1 wt% coupling agent at compaction pressure of 800 MPa shows better properties than the others.

  9. Superconducting materials suitable for magnets

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit

    2002-01-01

    The range of materials available for superconducting magnets is steadily expanding, even as the choice of material becomes potentially more complex. When virtually all magnets were cooled by helium at ~2-5 K it was easy to separate the domain of Nb-Ti from those of Nb$_{3}$Sn applications and very little surprise that more than 90% of all magnets are still made from Nb-Ti. But the development of useful conductors of the Bi-Sr-Ca-Cu-O and YBa2Cu3Ox high temperature superconductors, coupled to the recent discovery of the 39 K superconductor MgB2 and the developing availability of cryocoolers suggests that new classes of higher temperature, medium field magnets based on other than Nb-based conductors could become available in the next 5-10 years. My talks will discuss the essential physics and materials science of these 5 classes of material - Nb-Ti, Nb$_{3}$Sn, MgB2, Bi-Sr-Ca-Cu-O and YBa2Cu3Ox - in the context of those aspects of their science, properties and fabrication properties, which circumscribe their ap...

  10. Studies of SmCo5/Fe nanocomposite magnetic bilayers with magnetic soft x-ray transmission microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shahzad, F.; Siddiqi, S. A.; Im, M.-Y.; Avallone, A.; Fischer, P.; Hussain, Z.; Siddiqi, I.; Hellman, F.; Zhao, J.

    2009-12-04

    A hard/soft SmCo{sub 5}/Fe nanocomposite magnetic bilayer system has been fabricated on X-ray transparent 100-200 nm thin Si{sub 3}N{sub 4} membranes by magnetron sputtering. The microscopic magnetic domain pattern and its behavior during magnetization reversal in the hard and soft magnetic phases have been individually studied by element specific magnetic soft x-ray microscopy at a spatial resolution of better than 25nm. We observe that the domain patterns for soft and hard phases switch coherently throughout the full hysteresis cycle upon applying external magnetic fields. We derived local M(H) curves from the images for Fe and SmCo5 separately and found switching for both hard and soft phases same.

  11. A general 3-D nonlinear magnetostrictive constitutive model for soft ferromagnetic materials

    International Nuclear Information System (INIS)

    Zhou Haomiao; Zhou Youhe; Zheng Xiaojing; Ye Qiang; Wei Jing

    2009-01-01

    In this paper, a new general nonlinear magnetostrictive constitutive model is proposed for soft ferromagnetic materials, and it can predict magnetostrictive strain and magnetization curves under various pre-stresses. From the viewpoint of magnetic domain, it is based on the important physical fact that a nonlinear part of the elastic strain produced by magnetic domain wall motion under a pre-stress is responsible for the change of the maximum magnetostrictive strain in accordance with the pre-stress. Then the reduction of magnetostrictive strain from the maximum is caused by the domain rotation. Meanwhile, the magnetization under various pre-stresses in this model is introduced by magnetostrictive effect under the same pre-stress. A simplified 3-D model is put forward by means of linearizing the nonlinear function, i.e. the nonlinear part of the elastic strain produced by domain wall motion, and by using the quartic of magnetization to describe domain rotation. Besides, for the convenience of engineering applications, two-dimensional (plate or film) and one-dimensional (rod) models are also given for isotropic materials and their application ranges are discussed too. In comparison with the experimental data of Kuruzar and Jiles, it is found that this model can predict magnetostrictive strain and magnetization curves under various pre-stresses. The numerical simulation further illustrates that the new model can effectively describe the effects of the pre-stress or residual stress on the magnetization and magnetostrictive strain curves. Additionally, this model can be degenerated to the existing magnetostrictive constitutive model for giant magnetostrictive materials (GMM), i.e. a special soft ferromagnetic material

  12. Magnetic resonance and porous materials

    International Nuclear Information System (INIS)

    McDonald, P.; Strange, J.

    1998-01-01

    Mention the words magnetic resonance to your medical advisor and he or she will immediately think of a multi-million pound scanner that peers deep into the brain. A chemist, on the other hand, will imagine a machine that costs several hundred thousand pounds and produces high-resolution spectra for chemical analysis. Food technologists will probably think of a bench-top instrument for determining moisture content, while an oil prospector will envisage a device that can be operated several kilometres down an oil well. To a physicist the term is more likely to conjure up a mental picture of nuclear spins precessing in a magnetic field. These examples illustrate the diverse aspects of a phenomenon discovered by physicists over 50 years ago. Electron spin resonance was first discovered by Russian scientists, and nuclear magnetic resonance was discovered in the US shortly afterwards by Ed Purcell at Harvard University and Felix Bloch at Stanford University. Today, nuclear magnetic resonance (NMR) is the most widely used technique. Modern NMR machines are making it possible to probe microstructure and molecular movement in materials as diverse as polymers, cements, rocks, soil and foods. NMR allows the distribution of different components in a material to be determined with a resolution approaching 1μm, although the signal can be sensitive to even smaller lengthscales. In this article the authors describe how physicists are still developing magnetic resonance to exploit a range of new applications. (UK)

  13. Final Report: Nanoscale Dynamical Heterogeneity in Complex Magnetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kevan, Stephen [Univ. of Oregon, Eugene, OR (United States)

    2016-05-27

    A magnetic object can be demagnetized by dropping it on a hard surface, but what does ‘demagnetized’ actually mean? In 1919 Heinrich Barkhausen proved the existence of magnetic domains, which are regions of uniform magnetization that are much larger than atoms but much smaller than a macroscopic object. A material is fully magnetized when domain magnetizations are aligned, while it is demagnetized when the domain magnetizations are randomly oriented and the net magnetization is zero. The heterogeneity of a demagnetized object leads to interesting questions. Magnets are unstable when their poles align, and stable when their poles anti-align, so why is the magnetized state ever stable? What do domains look like? What is the structure of a domain wall? How does the magnetized state transform to the demagnetized state? How do domains appear and disappear? What are the statistical properties of domains and how do these vary as the domain pattern evolves? Some of these questions remain the focus of intense study nearly a century after Barkhausen’s discovery. For example, just a few years ago a new kind of magnetic texture called a skyrmion was discovered. A skyrmion is a magnetic domain that is a nanometer-scale, topologically protected vortex. ‘Topologically protected’ means that skyrmions are hard to destroy and so are stable for extended periods. Skyrmions are characterized by integral quantum numbers and are observed to move with little dissipation and so could store and process information with very low power input. Our research project uses soft x-rays, which offer very high magnetic contrast, to probe magnetic heterogeneity and to measure how it evolves in time under external influences. We will condition a soft x-ray beam so that the wave fronts will be coherent, that is, they will be smooth and well-defined. When coherent soft x-ray beam interacts with a magnetic material, the magnetic heterogeneity is imprinted onto the wave fronts and projected into

  14. Plasma processing of soft materials for development of flexible devices

    International Nuclear Information System (INIS)

    Setsuhara, Yuichi; Cho, Ken; Takenaka, Kosuke; Shiratani, Masaharu; Sekine, Makoto; Hori, Masaru

    2011-01-01

    Plasma-polymer interactions have been studied as a basis for development of next-generation processing of flexible devices with soft materials by means of low-damage plasma technologies (soft materials processing technologies). In the present article, interactions between argon plasmas and polyethylene terephthalate (PET) films have been examined for investigations of physical damages induced by plasma exposures to the organic material via chemical bonding-structure analyses using hard X-ray photoelectron spectroscopy (HXPES) together with conventional X-ray photoelectron spectroscopy (XPS). The PET film has been selected as a test material for investigations in the present study not merely because of its specific applications, such as a substrate material, but because PET is one of the well defined organic materials containing major components in a variety of functional soft materials; C-C main chain, CH bond, oxygen functionalities (O=C-O bond and C-O bond) and phenyl group. Especially, variations of the phenyl group due to argon plasma exposures have been investigated in the present article in order to examine plasma interactions with π-conjugated system, which is in charge of electronic functions in many of the π-conjugated electronic organic materials to be utilized as functional layer for advanced flexible device formations. The PET films have been exposed to argon plasmas sustained via inductive coupling of RF power with low-inductance antenna modules. The HXPES analyses exhibited that the degradations of the oxygen functionalities and the phenyl group in the deeper regions up to 50 nm from the surface of the samples were insignificant indicating that the bond scission and/or the degradations of the chemical bonding structures due to photoirradiation from the plasma and/or surface heating via plasma exposure were relatively insignificant as compared with damages in the vicinity of the surface layers.

  15. Modeling of magnetic hystereses in soft MREs filled with NdFeB particles

    Science.gov (United States)

    Kalina, K. A.; Brummund, J.; Metsch, P.; Kästner, M.; Borin, D. Yu; Linke, J. M.; Odenbach, S.

    2017-10-01

    Herein, we investigate the structure-property relationships of soft magnetorheological elastomers (MREs) filled with remanently magnetizable particles. The study is motivated from experimental results which indicate a large difference between the magnetization loops of soft MREs filled with NdFeB particles and the loops of such particles embedded in a comparatively stiff matrix, e.g. an epoxy resin. We present a microscale model for MREs based on a general continuum formulation of the magnetomechanical boundary value problem which is valid for finite strains. In particular, we develop an energetically consistent constitutive model for the hysteretic magnetization behavior of the magnetically hard particles. The microstructure is discretized and the problem is solved numerically in terms of a coupled nonlinear finite element approach. Since the local magnetic and mechanical fields are resolved explicitly inside the heterogeneous microstructure of the MRE, our model also accounts for interactions of particles close to each other. In order to connect the microscopic fields to effective macroscopic quantities of the MRE, a suitable computational homogenization scheme is used. Based on this modeling approach, it is demonstrated that the observable macroscopic behavior of the considered MREs results from the rotation of the embedded particles. Furthermore, the performed numerical simulations indicate that the reversion of the sample’s magnetization occurs due to a combination of particle rotations and internal domain conversion processes. All of our simulation results obtained for such materials are in a good qualitative agreement with the experiments.

  16. Creep deformation of a soft magnetic iron-cobalt alloy

    OpenAIRE

    Fingers, Richard T.; Coate, Jack E.; Dowling, Norman E.

    1999-01-01

    The U.S. Air Force is in the process of developing magnetic bearings, as well as an aircraft integrated power unit and an internal starter/generator for main propulsion engines. These developments are the driving force for the new emphasis on the development of high saturation, low loss magnets capable of maintaining structural integrity in high stress and high temperature environments. It is this combination of desired material characteristics that is the motivation of this effort to measure...

  17. Dynamical Origin of Highly Efficient Energy Dissipation in Soft Magnetic Nanoparticles for Magnetic Hyperthermia Applications

    Science.gov (United States)

    Kim, Min-Kwan; Sim, Jaegun; Lee, Jae-Hyeok; Kim, Miyoung; Kim, Sang-Koog

    2018-05-01

    We explore robust magnetization-dynamic behaviors in soft magnetic nanoparticles in single-domain states and find their related high-efficiency energy-dissipation mechanism using finite-element micromagnetic simulations. We also make analytical derivations that provide deeper physical insights into the magnetization dynamics associated with Gilbert damping parameters under applications of time-varying rotating magnetic fields of different strengths and frequencies and static magnetic fields. Furthermore, we find that the mass-specific energy-dissipation rate at resonance in the steady-state regime changes remarkably with the strength of rotating fields and static fields for given damping constants. The associated magnetization dynamics are well interpreted with the help of the numerical calculation of analytically derived explicit forms. The high-efficiency energy-loss power can be obtained using soft magnetic nanoparticles in the single-domain state by tuning the frequency of rotating fields to the resonance frequency; what is more, it is controllable via the rotating and static field strengths for a given intrinsic damping constant. We provide a better and more efficient means of achieving specific loss power that can be implemented in magnetic hyperthermia applications.

  18. Nonlinear machine learning in soft materials engineering and design

    Science.gov (United States)

    Ferguson, Andrew

    The inherently many-body nature of molecular folding and colloidal self-assembly makes it challenging to identify the underlying collective mechanisms and pathways governing system behavior, and has hindered rational design of soft materials with desired structure and function. Fundamentally, there exists a predictive gulf between the architecture and chemistry of individual molecules or colloids and the collective many-body thermodynamics and kinetics. Integrating machine learning techniques with statistical thermodynamics provides a means to bridge this divide and identify emergent folding pathways and self-assembly mechanisms from computer simulations or experimental particle tracking data. We will survey a few of our applications of this framework that illustrate the value of nonlinear machine learning in understanding and engineering soft materials: the non-equilibrium self-assembly of Janus colloids into pinwheels, clusters, and archipelagos; engineering reconfigurable ''digital colloids'' as a novel high-density information storage substrate; probing hierarchically self-assembling onjugated asphaltenes in crude oil; and determining macromolecular folding funnels from measurements of single experimental observables. We close with an outlook on the future of machine learning in soft materials engineering, and share some personal perspectives on working at this disciplinary intersection. We acknowledge support for this work from a National Science Foundation CAREER Award (Grant No. DMR-1350008) and the Donors of the American Chemical Society Petroleum Research Fund (ACS PRF #54240-DNI6).

  19. Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices

    Science.gov (United States)

    Agarwal, Gunjan; Besuchet, Nicolas; Audergon, Basile; Paik, Jamie

    2016-09-01

    Soft actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes’ (linear and bending actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body.

  20. Development of high magnetic field soft X-ray spectroscopy and its application to the study of surface and interface

    International Nuclear Information System (INIS)

    Nakamura, Tetsuya; Narumi, Yasuo

    2014-01-01

    Magnetic materials are generally synthesized and used as alloys and compounds. They are also stacked as a multilayer film for spintronics device such as a reading-head sensor of a hard disk drive. The evaluation of magnetization is the most fundamental characterization in studies of magnetic materials. Especially, in alloys and compounds involving more than two magnetic elements, a partial magnetization with respect to each element, we call as an element specific magnetization, promises to provide the deeper understanding of their magnetic property. X-ray magnetic circular dichroism (XMCD) in absorption spectroscopy provides an element specific magnetization. As XMCD became increasingly popular, high-magnetic-field environment for XMCD measurements also became very important in order to investigate paramagnetic, antiferromagnetic, and meta-magnetic materials. Under the circumstance, a high-magnetic-field XMCD measurement technique of the soft-X-ray regime has been developed using a non-destructive pulse magnet having capability of generating 40 T at the twin helical undulators beamline, BL25SU, of SPring-8. In this review, we first introduce the concept and the technical features of high magnetic field XMCD and then show recent examples of the experiments. (author)

  1. AC magnetic properties of the soft magnetic composites based on Supermalloy nanocrystalline powder prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Neamtu, B.V., E-mail: bogdan.neamtu@stm.utcluj.ro [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France); Geoffroy, O. [Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France); Grenoble Electrical Engineering, University J. Fourier, BP 46, F-38402 Saint-Martin d' Heres Cedex (France); Chicinas, I. [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Isnard, O. [Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Nanocrystalline soft magnetic composites were obtained. Black-Right-Pointing-Pointer The cutting frequency of the produced nanocrystalline SMC exceeds 100 kHz. Black-Right-Pointing-Pointer A long annealing at low temperature leads to an improvement of the permeability (12%). - Abstract: The preparation and characterization of the nanocrystalline soft magnetic composite core based on Supermalloy powder obtained via mechanical alloying route are presented. The AC magnetic properties of the compacts were determined in frequency range from 100 Hz to 100 kHz for flux densities of 0.05 and 0.1 T. Composite materials were obtained by covering the Supermalloy particles with a polymer binder, then compacted into toroidal shape and finally polymerized. It is found that an increase of the compacting pressure from 600 MPa to 800 MPa leads to an increase of the compacts permeability by more than 8%. Also, reducing the polymer content from 2 wt.% to 0.5 wt.% leads to an increase of the magnetic losses (at 100 kHz and 0.1 T) by 380%. The removal of the stresses induced during compaction has been accomplished by a heat treatment at 170 Degree-Sign C for 120 h. This leads to a significant increase (12%) of the relative initial permeability of the compacts.

  2. Magnetic Characterization of Organic Materials

    Science.gov (United States)

    2016-12-12

    full doughnut. • 3D organization of these doughnuts are currently under study. • A nano doughnut formation requires 2D bending of the lamella...AFRL-AFOSR-JP-TR-2017-0005 Magnetic Characterization of Organic Materials Dongho Kim YONSEI UNIVERSITY UNIVERSITY- INDUSTRY FOUNDATION Final Report 12...NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) YONSEI UNIVERSITY UNIVERSITY- INDUSTRY FOUNDATION 50 Yonsei-ro, Seodaemun-g SEOUL, 120-749 KR

  3. Applications of Friction Stir Processing during Engraving of Soft Materials

    Directory of Open Access Journals (Sweden)

    V. Kočović

    2015-12-01

    Full Text Available Friction stir processing has extensive application in many technological operations. Application area of friction stir processing can be extended to the processing of non-metallic materials, such as wood. The paper examines the friction stir processing contact between a specially designed hard and temperature-resistant rotating tool and workpiece which is made of wood. Interval of speed slip and temperature level under which the combustion occurs and carbonization layer of soft material was determined. The results of the research can be applied in technological process of wood engraving operations which may have significant technological and aesthetic effects.

  4. Fundamentals and applications of magnetic materials

    CERN Document Server

    Krishnan, Kannan M

    2016-01-01

    Students and researchers looking for a comprehensive textbook on magnetism, magnetic materials and related applications will find in this book an excellent explanation of the field. Chapters progress logically from the physics of magnetism, to magnetic phenomena in materials, to size and dimensionality effects, to applications. Beginning with a description of magnetic phenomena and measurements on a macroscopic scale, the book then presents discussions of intrinsic and phenomenological concepts of magnetism such as electronic magnetic moments and classical, quantum, and band theories of magnetic behavior. It then covers ordered magnetic materials (emphasizing their structure-sensitive properties) and magnetic phenomena, including magnetic anisotropy, magnetostriction, and magnetic domain structures and dynamics. What follows is a comprehensive description of imaging methods to resolve magnetic microstructures (domains) along with an introduction to micromagnetic modeling. The book then explores in detail size...

  5. Machine learning and data science in soft materials engineering.

    Science.gov (United States)

    Ferguson, Andrew L

    2018-01-31

    In many branches of materials science it is now routine to generate data sets of such large size and dimensionality that conventional methods of analysis fail. Paradigms and tools from data science and machine learning can provide scalable approaches to identify and extract trends and patterns within voluminous data sets, perform guided traversals of high-dimensional phase spaces, and furnish data-driven strategies for inverse materials design. This topical review provides an accessible introduction to machine learning tools in the context of soft and biological materials by 'de-jargonizing' data science terminology, presenting a taxonomy of machine learning techniques, and surveying the mathematical underpinnings and software implementations of popular tools, including principal component analysis, independent component analysis, diffusion maps, support vector machines, and relative entropy. We present illustrative examples of machine learning applications in soft matter, including inverse design of self-assembling materials, nonlinear learning of protein folding landscapes, high-throughput antimicrobial peptide design, and data-driven materials design engines. We close with an outlook on the challenges and opportunities for the field.

  6. Machine learning and data science in soft materials engineering

    Science.gov (United States)

    Ferguson, Andrew L.

    2018-01-01

    In many branches of materials science it is now routine to generate data sets of such large size and dimensionality that conventional methods of analysis fail. Paradigms and tools from data science and machine learning can provide scalable approaches to identify and extract trends and patterns within voluminous data sets, perform guided traversals of high-dimensional phase spaces, and furnish data-driven strategies for inverse materials design. This topical review provides an accessible introduction to machine learning tools in the context of soft and biological materials by ‘de-jargonizing’ data science terminology, presenting a taxonomy of machine learning techniques, and surveying the mathematical underpinnings and software implementations of popular tools, including principal component analysis, independent component analysis, diffusion maps, support vector machines, and relative entropy. We present illustrative examples of machine learning applications in soft matter, including inverse design of self-assembling materials, nonlinear learning of protein folding landscapes, high-throughput antimicrobial peptide design, and data-driven materials design engines. We close with an outlook on the challenges and opportunities for the field.

  7. DEGREE OF AWARENESS OF SOFT RELINING MATERIALS BY DENTAL TECHNICIANS

    Directory of Open Access Journals (Sweden)

    Ilian Hristov

    2017-10-01

    Full Text Available The aim of the current investigation is to analyze the dental-technicians’ awareness of the soft relining materials, their characteristics, advantages, shortcomings and methods for relining. Materials and methods: For the purpose of this investigation a standard questionnaire has been presented. A direct survey method, documentary and statistical method, as well as graphical methods, including tables, charts, graphics and figures, were used. Data were analysed with the help of IBM SPSS Statistics (ver. 19. Results: One hundred and eight dental technicians were included in the survey, evenly distributed by gender. Removable and fixed prosthodontics is the most commonly mentioned spheres of dental activities. Almost all included in the investigation point out the laboratory relining method as the most frequently used. Acrylic and silicone SRM are the most used groups of relining materials. Change of colour and hardness are the most frequently noticed shortcomings of these materials. The majority of the dental technicians declare that they have never done replacement of SRM or the relining has lasted more than a year. Discussion: The correlation between the age and the years of labour service among the participants is quite obvious. Most of them start working soon after their graduation. Removable prosthodontics is among the priorities for the majority of the labs. Conclusion: Although their unambiguous advantages, the soft relining materials have lots of shortcomings as well. The major problems are connected with their change of colour and hardness. Nevertheless, the dental technicians find them useful and reliable in overcoming specific prosthetic problems.

  8. Excited eigenmodes in magnetic vortex states of soft magnetic half-spheres and spherical caps

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Myoung-Woo; Lee, Jae-Hyeok; Kim, Sang-Koog, E-mail: sangkoog@snu.ac.kr [National Creative Research Initiative Center for Spin Dynamics and Spin-Wave Devices, Nanospinics Laboratory, Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-12-14

    We studied the magnetization dynamics of excitation modes in special geometrical confinements of soft magnetic half-spheres and spherical caps in magnetic vortex states using finite-element micromagnetic numerical calculations. We found additional fine features of the zeroth- and first-order gyrotropic modes and asymmetric m = +1 and m = −1 azimuthal spin-wave modes, which detailed information is unobtainable from two-dimensional mesh-cell based numerical calculations. Moreover, we examined the perpendicular bias field dependence of the excited eigenmodes, which data provide for an efficient means of control over the excited modes. Such numerical calculations offer additional details or new underlying physics on dynamic features in arbitrary-shape magnetic nano-elements such as half-spheres and spherical caps in magnetic vortex states.

  9. Annealing effects on magnetic properties of silicone-coated iron-based soft magnetic composites

    Science.gov (United States)

    Wu, Shen; Sun, Aizhi; Zhai, Fuqiang; Wang, Jin; Zhang, Qian; Xu, Wenhuan; Logan, Philip; Volinsky, Alex A.

    2012-03-01

    This paper focuses on novel iron-based soft magnetic composites synthesis utilizing high thermal stability silicone resin to coat iron powder. The effect of an annealing treatment on the magnetic properties of synthesized magnets was investigated. The coated silicone insulating layer was characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Silicone uniformly coated the powder surface, resulting in a reduction of the imaginary part of the permeability, thereby increasing the electrical resistivity and the operating frequency of the synthesized magnets. The annealing treatment increased the initial permeability, the maximum permeability, and the magnetic induction, and decreased the coercivity. Annealing at 580 °C increased the maximum permeability by 72.5%. The result of annealing at 580 °C shows that the ferromagnetic resonance frequency increased from 2 kHz for conventional epoxy resin coated samples to 80 kHz for the silicone resin insulated composites.

  10. Stress induced anisotropy in CoFeMn soft magnetic nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Leary, A. M., E-mail: leary@cmu.edu; Keylin, V.; McHenry, M. E. [Materials Science and Engineering Department, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Ohodnicki, P. R. [Functional Materials Development Division, National Energy Technology Laboratory (NETL), 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236 (United States)

    2015-05-07

    The use of processing techniques to create magnetic anisotropy in soft magnetic materials is a well-known method to control permeability and losses. In nanocomposite materials, field annealing below the Curie temperature results in uniaxial anisotropy energies up to ∼2 kJ/m{sup 3}. Higher anisotropies up to ∼10 kJ/m{sup 3} result after annealing Fe-Si compositions under stress due to residual stress in the amorphous matrix acting on body centered cubic crystals. This work describes near zero magnetostriction Co{sub 80−x−y}Fe{sub x}Mn{sub y}Nb{sub 4}B{sub 14}Si{sub 2} soft magnetic nanocomposites, where x and y < 8 at.% with close packed crystalline grains that show stress induced anisotropies up to ∼50 kJ/m{sup 3} and improved mechanical properties with respect to Fe-Si compositions. Difference patterns measured using transmission X-ray diffraction show evidence of affine strain with respect to the stress axis.

  11. Eddy current and total power loss separation in the iron-phosphate-polyepoxy soft magnetic composites

    International Nuclear Information System (INIS)

    Taghvaei, A.H.; Shokrollahi, H.; Janghorban, K.; Abiri, H.

    2009-01-01

    This work investigates the magnetic properties of iron-phosphate-polyepoxy soft magnetic composite materials. FTIR spectra, EDX analysis, distribution maps, X-ray diffraction pattern and density measurements show that the particles surface layer contains a thin layer of nanocrystalline/amorphous phosphate with high coverage of powders surface. In this paper, a formula for calculating the eddy current loss and total loss components by loss separation method is presented and finally the different parts of power losses are calculated. The results show that, the contribution of eddy current in the bulk material for single coating layer (k b = 0.18) is higher in comparison with double coating layer (k b = 0.09). Moreover, iron-phosphate-polyepoxy composites (P = 0.000004f 2 ) have lower power loss in comparison with iron-phosphate composites (P = 0.00002f 2 ).

  12. Soft computing in design and manufacturing of advanced materials

    Science.gov (United States)

    Cios, Krzysztof J.; Baaklini, George Y; Vary, Alex

    1993-01-01

    The potential of fuzzy sets and neural networks, often referred to as soft computing, for aiding in all aspects of manufacturing of advanced materials like ceramics is addressed. In design and manufacturing of advanced materials, it is desirable to find which of the many processing variables contribute most to the desired properties of the material. There is also interest in real time quality control of parameters that govern material properties during processing stages. The concepts of fuzzy sets and neural networks are briefly introduced and it is shown how they can be used in the design and manufacturing processes. These two computational methods are alternatives to other methods such as the Taguchi method. The two methods are demonstrated by using data collected at NASA Lewis Research Center. Future research directions are also discussed.

  13. New Soft Polymeric Materials Applicable as Elastomeric Transducers

    DEFF Research Database (Denmark)

    Bejenariu, Anca Gabriela; Skov, Anne Ladegaard

    An elastomer is a material characterized by the capability to regain its original size and shape after being deformed (stretched or distorted). An ideal elastomer for electroactive polymer (EAP) applications is a system characterized by high extensibility, flexibility and a good mechanical fatigue....... Dielectric elastomers (DEs) are part of electronic EAPs presenting a good combination of electromechanical properties such as high achievable strains and stresses, fast response speeds, long lifetime, high reliability and high efficiency1. Subjected to a voltage, a polymeric electroactive material sandwiched...... easy to handle. From a mechanical point of view, the materials for EAPs use have to be soft with sufficient mechanical strength so the rupture of the material can be avoided at high strain actuation. Considering the EAP requirements and the experimental data for the hyperswollen networks based...

  14. Introducing Magneto-Optical Functions into Soft Materials

    Science.gov (United States)

    2017-05-03

    including organic and bio materials by using magnetic nanomaterials. This final report includes the successful developments of magneto-optical... successful developments of magneto-optical properties in both organic and bio magnetic nanocomposites during the project period of three years...proteins on the photoluminescence of nanodiamond. J. Appl . Phys. 2011, 109 (3), 034704. 7, Xu, H.; Hung, C.E.; Cheng, C.L.; Hu, B., Magneto-electric

  15. Temperature-dependent magnetic properties of a magnetoactive elastomer: Immobilization of the soft-magnetic filler

    Science.gov (United States)

    Bodnaruk, Andrii V.; Brunhuber, Alexander; Kalita, Viktor M.; Kulyk, Mykola M.; Snarskii, Andrei A.; Lozenko, Albert F.; Ryabchenko, Sergey M.; Shamonin, Mikhail

    2018-03-01

    The magnetic properties of a magnetoactive elastomer (MAE) filled with μm-sized soft-magnetic iron particles have been experimentally studied in the temperature range between 150 K and 310 K. By changing the temperature, the elastic modulus of the elastomer matrix was modified, and it was possible to obtain magnetization curves for an invariable arrangement of particles in the sample and in the case when the particles were able to change their position within the MAE under the influence of magnetic forces. At low (less than 220 K) temperatures, when the matrix becomes rigid, the magnetization of the MAE does not show a hysteresis behavior, and it is characterized by a negative value of the Rayleigh constant. At room temperature, when the polymer matrix is compliant, a magnetic hysteresis exists where the dependence of the differential magnetic susceptibility on the magnetic field exhibits local maxima. The appearance of these maxima is explained by the elastic resistance of the matrix to the displacement of particles under the action of magnetic forces.

  16. Corrections for hysteresis curves for rare earth magnet materials measured by open magnetic circuit methods

    International Nuclear Information System (INIS)

    Nakagawa, Yasuaki

    1996-01-01

    The methods for testing permanent magnets stipulated in the usual industrial standards are so-called closed magnetic circuit methods which employ a loop tracer using an iron-core electromagnet. If the coercivity exceeds the highest magnetic field generated by the electromagnet, full hysteresis curves cannot be obtained. In the present work, magnetic fields up to 15 T were generated by a high-power water-cooled magnet, and the magnetization was measured by an induction method with an open magnetic circuit, in which the effect of a demagnetizing field should be taken into account. Various rare earth magnets materials such as sintered or bonded Sm-Co and Nd-Fe-B were provided by a number of manufacturers. Hysteresis curves for cylindrical samples with 10 nm in diameter and 2 mm, 3.5 mm, 5 mm, 14 mm or 28 mm in length were measured. Correction for the demagnetizing field is rather difficult because of its non-uniformity. Roughly speaking, a mean demagnetizing factor for soft magnetic materials can be used for the correction, although the application of this factor to hard magnetic material is hardly justified. Thus the dimensions of the sample should be specified when the data obtained by the open magnetic circuit method are used as industrial standards. (author)

  17. Enhanced magnetic properties of Fe soft magnetic composites by surface oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Guoliang; Wu, Chen, E-mail: chen_wu@zju.edu.cn; Yan, Mi, E-mail: mse_yanmi@zju.edu.cn

    2016-02-01

    Fe soft magnetic composites (SMCs) with low core loss were fabricated via surface oxidation of the Fe powders by H{sub 2}O and O{sub 2} at elevated temperatures. Surface oxidation prevents magnetic dilution due to the formation of the ferromagnetic iron oxide coating layer, giving rise to high magnetic flux density and effective permeability of the SMCs compared with those fabricated with traditional phosphate coating. Mechanism of the oxidation process has been investigated where Fe{sub 3}O{sub 4} forms by reactions of Fe with H{sub 2}O and O{sub 2}. The Fe{sub 3}O{sub 4} coating layer tends to convert into γ-Fe{sub 2}O{sub 3} with increased oxidation temperature and time. By controlling composition of the coating layer, low core loss of 688.9 mW/cm{sup 3} (measured at 50 mT and 100 kHz) and higher effective permeability of 88.3 can be achieved for the Fe SMCs. - Highlights: • Surface oxidation as a new method to fabricate Fe Soft magnetic composite (SMCs). • Oxidation mechanism revealed where Fe reacts with H2O and O2 at high temperatures. • Evolution of the iron oxide coating with growth temperature and time investigated. • The iron oxide insulation coating results in improved magnetic performance.

  18. Synthesis, structural and magnetic characterization of soft magnetic nanocrystalline ternary FeNiCo particles

    Energy Technology Data Exchange (ETDEWEB)

    Toparli, Cigdem [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey); Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf (Germany); Ebin, Burçak [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey); Nuclear Chemistry and Industrial Material Recycling, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, S-412 96 Gothenburg (Sweden); Gürmen, Sebahattin, E-mail: gurmen@itu.edu.tr [Department of Metallurgical & Materials Eng., Istanbul Technical University, 34469 Istanbul (Turkey)

    2017-02-01

    The present study focuses on the synthesis, microstructural and magnetic properties of ternary FeNiCo nanoparticles. Nanocrystalline ternary FeNiCo particles were synthesized via hydrogen reduction assisted ultrasonic spray pyrolysis method in single step. The effect of precursor concentration on the morphology and the size of particles was investigated. The syntheses were performed at 800 °C. Structure, morphology and magnetic properties of the as-prepared products were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) studies. Scherer calculation revealed that crystallite size of the ternary particles ranged between 36 and 60 nm. SEM and TEM investigations showed that the particle size was strongly influenced by the precursor concentration and Fe, Ni, Co elemental composition of individual particles was homogeneous. Finally, the soft magnetic properties of the particles were observed to be a function of their size. - Highlights: • Ternary FeNiCo alloy nanocrystalline particles were synthesized in a single step. • Cubic crystalline structure and spherical morphology was observed by XRD, SEM and TEM investigations. • The analysis of magnetic properties indicates the soft magnetic features of particles.

  19. Materials for Room Temperature Magnetic Refrigeration

    DEFF Research Database (Denmark)

    Hansen, Britt Rosendahl

    Magnetic refrigeration is a cooling method, which holds the promise of being cleaner and more efficient than conventional vapor-compression cooling. Much research has been done during the last two decades on various magnetic materials for this purpose and today a number of materials are considered...... candidates as they fulfill many of the requirements for a magnetic refrigerant. However, no one material stands out and the field is still active with improving the known materials and in the search for a better one. Magnetic cooling is based on the magnetocaloric effect, which causes a magnetic material...... to change its temperature when a magnetic field is applied or removed. For room temperature cooling, one utilizes that the magnetocaloric effect peaks near magnetic phase transitions and so the materials of interest all have a critical temperature within the range of 250 – 310 K. A magnetic refrigerant...

  20. Secondary emission yield at low-primary energies of magnetic materials for anti-multipactor applications

    CERN Document Server

    Aguilera, L; Olano, L; Casas, A; Morales, P; Vázquez, M; Galán, L; Caspers, F; Costa-Pinto, P; Taborelli, M; Raboso, D

    2014-01-01

    Secondary electron emission processes under electron bombardment are central to many effects at surfaces and interfaces, and to many in vacuum high power RF electronic devices where multipactor can be very intense [1,2]. Ferrite materials are usually used in microwave components used in space telecommunication systems, as circulators, phase-shifters, switches, and isolators. The physics of the multipactor phenomenon existing in microwave devices based on ferrite materials is an important issue and it is urgent to be researched [3]. One difficulty in the analysis of the multipactor effect in RF components containing ferrite lies on the fact that this material is an anysotropic magnetic medium controlled by an applied permanent magnetic field, which is used to magnetize the ferrite material. SEY and other properties (structure, magnetic behaviour,...) of soft-magnetic materials were studied in this work. MnZn soft ferrites magnets are suitable in the situation of frequency < 3MHz, low loss and high μi. Comp...

  1. Magnetic resonance imaging appearance of soft-tissue metastases: our experience at an orthopedic oncology center

    International Nuclear Information System (INIS)

    Sammon, Jennifer; Jain, Abhishek; Bleakney, Robert; Mohankumar, Rakesh

    2017-01-01

    To assess the prevalence and magnetic resonance imaging appearance of metastasis presenting as a soft-tissue mass. A retrospective chart review was performed on 51 patients who presented to an orthopedic oncology center with soft-tissue masses, with a histology-proven diagnosis of soft-tissue metastasis, over a 14-year period. Their magnetic resonance imaging, primary origin, and follow-up have been assessed. Soft-tissue metastasis was identified in patients ranging from 18 to 85 years old. Most (80%) of the masses were located deep to the deep fascia. In our cohort of patients, melanoma was the most common primary malignancy contributing to soft-tissue metastasis (21.8%). Among soft-tissue metastasis from solid organs, breast and lung were the most frequent (9.1% each). Five patients had soft-tissue metastases from an unknown primary. Imaging diagnosis of soft-tissue metastases is challenging as it can demonstrate imaging appearances similar to primary soft-tissue sarcoma. The presence of a known malignancy may not be evident in everyone, and even if available, histopathology will be necessary for diagnosis if this is the only site of recurrence/metastasis to differentiate from a primary soft-tissue sarcoma. Moreover, soft-tissue metastasis may be the initial presentation of a malignancy. Primary malignancies with soft-tissue metastasis carry a poor prognosis; hence, prompt diagnosis and management in essential. (orig.)

  2. Magnetic resonance imaging appearance of soft-tissue metastases: our experience at an orthopedic oncology center

    Energy Technology Data Exchange (ETDEWEB)

    Sammon, Jennifer; Jain, Abhishek; Bleakney, Robert; Mohankumar, Rakesh [Mount Sinai Hospital and University of Toronto, Division of Musculoskeletal Imaging, Joint Department of Medical Imaging, Toronto, Ontario (Canada)

    2017-04-15

    To assess the prevalence and magnetic resonance imaging appearance of metastasis presenting as a soft-tissue mass. A retrospective chart review was performed on 51 patients who presented to an orthopedic oncology center with soft-tissue masses, with a histology-proven diagnosis of soft-tissue metastasis, over a 14-year period. Their magnetic resonance imaging, primary origin, and follow-up have been assessed. Soft-tissue metastasis was identified in patients ranging from 18 to 85 years old. Most (80%) of the masses were located deep to the deep fascia. In our cohort of patients, melanoma was the most common primary malignancy contributing to soft-tissue metastasis (21.8%). Among soft-tissue metastasis from solid organs, breast and lung were the most frequent (9.1% each). Five patients had soft-tissue metastases from an unknown primary. Imaging diagnosis of soft-tissue metastases is challenging as it can demonstrate imaging appearances similar to primary soft-tissue sarcoma. The presence of a known malignancy may not be evident in everyone, and even if available, histopathology will be necessary for diagnosis if this is the only site of recurrence/metastasis to differentiate from a primary soft-tissue sarcoma. Moreover, soft-tissue metastasis may be the initial presentation of a malignancy. Primary malignancies with soft-tissue metastasis carry a poor prognosis; hence, prompt diagnosis and management in essential. (orig.)

  3. Elastic properties of synthetic materials for soft tissue modeling

    International Nuclear Information System (INIS)

    Mansy, H A; Grahe, J R; Sandler, R H

    2008-01-01

    Mechanical models of soft tissue are useful for studying vibro-acoustic phenomena. They may be used for validating mathematical models and for testing new equipment and techniques. The objective of this study was to measure density and visco-elastic properties of synthetic materials that can be used to build such models. Samples of nine different materials were tested under dynamic (0.5 Hz) compressive loading conditions. The modulus of elasticity of the materials was varied, whenever possible, by adding a softener during manufacturing. The modulus was measured over a nine month period to quantify the effect of ageing and softener loss on material properties. Results showed that a wide range of the compression elasticity modulus (10 to 1400 kPa) and phase (3.5 0 -16.7 0 ) between stress and strain were possible. Some materials tended to exude softener over time, resulting in a weight loss and elastic properties change. While the weight loss under normal conditions was minimal in all materials (<3% over nine months), loss under accelerated weight-loss conditions can reach 59%. In the latter case an elasticity modulus increase of up to 500% was measured. Key advantages and limitations of candidate materials were identified and discussed

  4. SYNTHESIS AND CHARACTERIZATION OF ADVANCED MAGNETIC MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Monica Sorescu

    2004-09-22

    The work described in this grant report was focused mainly on the properties of novel magnetic intermetallics. In the first project, we synthesized several 2:17 intermetallic compounds, namely Nd{sub 2}Fe{sub 15}Si{sub 2}, Nd{sub 2}Fe{sub 15}Al{sub 2}, Nd{sub 2}Fe{sub 15}SiAl and Nd{sub 2}Fe{sub 15}SiMn, as well as several 1:12 intermetallic compounds, such as NdFe{sub 10}Si{sub 2}, NdFe{sub 10}Al{sub 2}, NdFe{sub 10}SiAl and NdFe{sub 10}MnAl. In the second project, seven compositions of Nd{sub x}Fe{sub 100-x-y}B{sub y} ribbons were prepared by a melt spinning method with Nd and B content increasing from 7.3 and 3.6 to 11 and 6, respectively. The alloys were annealed under optimized conditions to obtain a composite material consisting of the hard magnetic Nd{sub 2}Fe{sub 14}B and soft magnetic {alpha}-Fe phases, typical of a spring magnet structure. In the third project, intermetallic compounds of the type Zr{sub 1}Cr{sub 1}Fe{sub 1}T{sub 0.8} with T = Al, Co and Fe were subjected to hydrogenation. In the fourth project, we performed three crucial experiments. In the first experiment, we subjected a mixture of Fe{sub 3}O{sub 4} and Fe (80-20 wt %) to mechanochemical activation by high-energy ball milling, for time periods ranging from 0.5 to 14 hours. In the second experiment, we ball-milled Fe{sub 3}O{sub 4}:Co{sup 2+} (x = 0.1) for time intervals between 2.5 and 17.5 hours. Finally, we exposed a mixture of Fe{sub 3}O{sub 4} and Co (80-20 wt %) to mechanochemical activation for time periods ranging from 0.5 to 10 hours. In all cases, the structural and magnetic properties of the systems involved were elucidated by X-ray diffraction (XRD), Moessbauer spectroscopy and hysteresis loop measurements. The four projects resulted in four papers, which were published in Intermetallics, IEEE Transactions on Magnetics, Journal of Materials Science Letters and Materials Chemistry and Physics. The contributions reveal for the first time in literature the effect of

  5. Magnetic imaging and its applications to materials

    CERN Document Server

    De Graef, Marc

    2000-01-01

    Volume 36 provides an extensive introduction to magnetic imaging,including theory and practice, utilizing a wide range of magnetic sensitive imaging methods. It also illustrates the applications of these modern experimental techniques together with imaging calculations to today's advanced magnetic materials. This book is geared towards the upper-level undergraduate students and entry-level graduate students majoring in physics or materials science who are interested in magnetic structure and magnetic imaging. Researchers involved in studying magnetic materials should alsofind the book usef

  6. Performance investigation on DCSFCL considering different magnetic materials

    Science.gov (United States)

    Yuan, Jiaxin; Zhou, Hang; Zhong, Yongheng; Gan, Pengcheng; Gao, Yanhui; Muramatsu, Kazuhiro; Du, Zhiye; Chen, Baichao

    2018-05-01

    In order to protect high voltage direct current (HVDC) system from destructive consequences caused by fault current, a novel concept of HVDC system fault current limiter (DCSFCL) was proposed previously. Since DCSFCL is based on saturable core reactor theory, iron core becomes the key to the final performance of it. Therefore, three typical kinds of soft magnetic materials were chosen to find out their impact on performances of DCSFCL. Different characteristics of materials were compared and their theoretical deductions were carried out, too. In the meanwhile, 3D models applying those three materials were built separately and finite element analysis simulations were performed to compare these results and further verify the assumptions. It turns out that materials with large saturation flux density value Bs like silicon steel and short demagnetization time like ferrite might be the best choice for DCSFCL, which can be a future research direction of magnetic materials.

  7. High performance permanent magnet materials

    International Nuclear Information System (INIS)

    Sankar, S.G.; Herbst, J.F.; Koon, N.C.

    1987-01-01

    This book contains 25 selections. Some of the titles are: Initial magnetization behavior of rapidly quenched neodymium-iron-boron magnets; Optimization of liquid dynamic compaction for Fe-Nd-B magnet alloys; Misch-metal and/or aluminum substitutions in Nd-Fe-B permanent magnets; and NdFeB magnets with improved temperature characteristics

  8. Magnetic properties of soft layer/FePt-MgO exchange coupled composite Perpendicular recording media

    Institute of Scientific and Technical Information of China (English)

    Yin Jin-Hua; Takao Suzuki; Pan Li-Qing

    2008-01-01

    The magnetic properties of exchange coupled composite(ECC)media that are composed of perpendicular magnetic recording media FePt-MgO and two kinds of soft layers have been studied by using an x-ray diffractometer,a polar Kerr magneto-optical system(PMOKE)and a vibrating sample magnetometer(VSM).The results show that ECC media can reduce the coercivities of perpendicular magnetic recording media FePt-MgO.The ECC media with granular-type soft layers have weaker exchange couplings between magnetic grains and the magnetization process,for ECC media of this kind mainly follow the Stoner-Wohlfarth model.

  9. Steinmetz law in iron–phenolformaldehyde resin soft magnetic composites

    International Nuclear Information System (INIS)

    Kollár, Peter; Vojtek, Vladimír; Birčáková, Zuzana; Füzer, Ján; Fáberová, Mária; Bureš, Radovan

    2014-01-01

    The validity of Steinmetz law describing the dc energy losses as a function of maximum induction has been investigated for iron based soft magnetic composites (SMCs) up to 1.4 T with the effort to find a physical meaning of the coefficients in Steinmetz law. In the Rayleigh region the coefficients were expressed mathematically using the Rayleigh law. Further the “range of validity of Steinmetz law” was found to be from 0.3 T to 1.2 T. The typical “straight” shape of hysteresis loops of SMCs at lower maximum induction was approximated by linear functions in order to express the dc losses in form of Steinmetz law. - Highlights: • The exponent x in Steinmetz law in Rayleigh region for Fe-based SMC is equal to 3. • The validity of Steinmetz law is from 0.3 T to 1.2 T with exponent x=1.5. • The straight shape of hysteresis loop is approximated by linear functions. • This approximation provides the relation for dc losses in form of Steinmetz law

  10. The cation inversion and magnetization in nanopowder zinc ferrite obtained by soft mechanochemical processing

    International Nuclear Information System (INIS)

    Milutinović, A.; Lazarević, Z.; Jovalekić, Č.; Kuryliszyn-Kudelska, I.; Romčević, M.; Kostić, S.; Romčević, N.

    2013-01-01

    Graphical abstract: - Highlights: • Nano powder of ZnFe 2 O 4 prepared by a soft mechanochemical route after 18 h milling. • Phase formation controlled by XRD, Raman spectroscopy and magnetic measurements. • Size, strain and cation inversion degree determined by Rietveld refinement. • We were able to estimate the degree of inversion at most 0.348 and 0.4. • Obtained extremely high values of saturation magnetizations at T = 4.5 K. - Abstract: Two zinc ferrite nanoparticle materials were prepared by the same method – soft mechanochemical synthesis, but starting from different powder mixtures: (1) Zn(OH) 2 /α-Fe 2 O 3 and (2) Zn(OH) 2 /Fe(OH) 3 . In both cases a single phase system was obtained after 18 h of milling. The progress of the synthesis was controlled by X-ray diffractometry (XRD), Raman spectroscopy, TEM and magnetic measurements. Analysis of the XRD patterns by Rietveld refinement allowed determination of the cation inversion degree for both obtained single phase ZnFe 2 O 4 samples. The sample obtained from mixture (1) has the cation inversion degree 0.3482 and the sample obtained from mixture (2) 0.400. Magnetization measurements were confirmed that the degrees of the inversion were well estimated. Comparison with published data shows that used method of synthesis gives nano powder samples with extremely high values of saturation magnetizations: sample (1) 78.3 emu g −1 and sample (2) 91.5 emu g −1 at T = 4.5 K

  11. Materials for room temperature magnetic refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Rosendahl Hansen, B.

    2010-07-15

    Magnetic refrigeration is a cooling method, which holds the promise of being cleaner and more efficient than conventional vapor-compression cooling. Much research has been done during the last two decades on various magnetic materials for this purpose and today a number of materials are considered candidates as they fulfill many of the requirements for a magnetic refrigerant. However, no one material stands out and the field is still active with improving the known materials and in the search for a better one. Magnetic cooling is based on the magnetocaloric effect, which causes a magnetic material to change its temperature when a magnetic field is applied or removed. For room temperature cooling, one utilizes that the magnetocaloric effect peaks near magnetic phase transitions and so the materials of interest all have a critical temperature within the range of 250 - 310 K. A magnetic refrigerant should fulfill a number of criteria, among these a large magnetic entropy change, a large adiabatic temperature change, preferably little to no thermal or magnetic hysteresis and the material should have the stability required for long term use. As the temperature range required for room temperature cooling is some 40 - 50 K, the magnetic refrigerant should also be able to cover this temperature span either by exhibiting a very broad peak in magnetocaloric effect or by providing the opportunity for creating a materials series with varying transition temperatures. (Author)

  12. Modified thermogravimetric apparatus to measure magnetic susceptibility on-line during annealing of metastable ferromagnetic materials

    International Nuclear Information System (INIS)

    Luciani, G.; Constantini, A.; Branda, F.; Ausanio, G.; Hison, C.; Iannotti, V.; Luponio, C.; Lanotte, L.

    2004-01-01

    The insertion of proper coils to generate a magnetic field, with controlled gradient, in a standard thermogravimetric apparatus is shown to be a valid solution to measure on-line, upon heat treatment, the magnetic susceptibility in ribbon shaped samples of a metastable ferromagnetic material. The method is very useful to individuate the annealing conditions that optimise soft or hard magnetic properties without using separate apparatuses for heat treatment, control of the structural phase transition and characterization of magnetic susceptibility

  13. Effect of magnetic soft phase on the magnetic properties of bulk anisotropic Nd2Fe14B/α-Fe nanocomposite permanent magnets

    Science.gov (United States)

    Li, Yuqing; Yue, Ming; Zhao, Guoping; Zhang, Hongguo

    2018-01-01

    The effects of soft phase with different particle sizes and distributions on the Nd2Fe14B/α-Fe nanocomposite magnets have been studied by the micro-magnetism simulation. The calculated results show that smaller and/or scattered distribution of soft phase can benefit to the coercivity (H ci) of the nanocomposite magnets. The magnetization moment evolution during magnetic reversal is systematically analyzed. On the other hand, magnetic properties of anisotropic Nd-Fe-B/α-Fe nanocomposite magnets prepared by hot pressing and hot deformation methods also provide evidences for the calculated results.

  14. Magnetism and magnetic materials probed with neutron scattering

    International Nuclear Information System (INIS)

    Velthuis, S.G.E. te; Pappas, C.

    2014-01-01

    Neutron scattering techniques are becoming increasingly accessible to a broader range of scientific communities, in part due to the onset of next-generation, high-power spallation sources, high-performance, sophisticated instruments and data analysis tools. These technical advances also advantageously impact research into magnetism and magnetic materials, where neutrons play a major role. In this Current Perspective series, the achievements and future prospects of elastic and inelastic neutron scattering, polarized neutron reflectometry, small angle neutron scattering, and neutron imaging, are highlighted as they apply to research into magnetic frustration, superconductivity and magnetism at the nanoscale. - Highlights: • Introduction to Current Perspective series titled Magnetism and Magnetic Materials probed with Neutron Scattering. • Elastic and inelastic neutron scattering in systems with magnetic frustration and superconductivity. • Small angle neutron scattering and polarized neutron reflectometry in studying magnetism at the nanoscale. • Imaging of magnetic fields and domains

  15. Magnetism and magnetic materials probed with neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Velthuis, S.G.E. te, E-mail: tevelthuis@anl.gov [Materials Science Division, Argonne National Laboratory, 9700 S Cass Ave, Argonne, IL 60439 (United States); Pappas, C. [Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, NL-2629JB Delft (Netherlands)

    2014-01-15

    Neutron scattering techniques are becoming increasingly accessible to a broader range of scientific communities, in part due to the onset of next-generation, high-power spallation sources, high-performance, sophisticated instruments and data analysis tools. These technical advances also advantageously impact research into magnetism and magnetic materials, where neutrons play a major role. In this Current Perspective series, the achievements and future prospects of elastic and inelastic neutron scattering, polarized neutron reflectometry, small angle neutron scattering, and neutron imaging, are highlighted as they apply to research into magnetic frustration, superconductivity and magnetism at the nanoscale. - Highlights: • Introduction to Current Perspective series titled Magnetism and Magnetic Materials probed with Neutron Scattering. • Elastic and inelastic neutron scattering in systems with magnetic frustration and superconductivity. • Small angle neutron scattering and polarized neutron reflectometry in studying magnetism at the nanoscale. • Imaging of magnetic fields and domains.

  16. Magnetic and microstructural properties of Fe{sub 3}O{sub 4}-coated Fe powder soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Jo Sunday, Katie [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States); Hanejko, Francis G. [Hoeganaes Corporation, Cinnaminson, NJ08077 (United States); Taheri, Mitra L., E-mail: mtaheri@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, PA19104 (United States)

    2017-02-01

    Soft magnetic composites (SMCs) comprised of ferrite-coated ferrous powder permit isotropic magnetic flux capabilities, lower core losses, and complex designs through the use of traditional powder metallurgy techniques. Current coating materials and methods are vastly limited by the nonmagnetic properties of organic and some inorganic coatings and their inability to withstand high heat treatments for proper stress relief of core powder after compaction. Ferrite-based coatings are ferrimagnetic, highly resistive, and possess high melting temperatures, thus providing adequate electrical barriers between metallic particles. In this work, iron powder was coated with Fe{sub 3}O{sub 4} particles via mechanical milling, then compacted and cured in an inert gas environment. We find density and coercivity to improve with increasing temperatures; however, core loss greatly increases, which is attributed to the formation of a more conductive iron-oxide phase and less resistive Fe volume. Our work begins to exemplify the unique qualities and potential for ferrite-based coatings using traditional powder metallurgy techniques and higher curing temperatures for electromagnetic devices. - Highlights: • Fe{sub 3}O{sub 4}-coated Fe powder was produced via mechanical milling, then compacted and cured into composite form. • SEM/EDS confirm Fe particles are individually isolated with iron-oxide coating material. • Larger particle sizes show improved core loss and coercivity measurements. • We report good magnetic properties for compaction at 800 MPa and a curing temperature of 700 °C.

  17. VISCO-ELASTIC PROPERTIES OF SOFT RELINING MATERIALS – REVIEW

    Directory of Open Access Journals (Sweden)

    Ilian Hristov

    2017-05-01

    Full Text Available Despite the achievements of modern dentistry in fields of implantology and CAD-CAM technologies, the challenges associated with edentulous patients, treatment are still remaining. Difficulties are getting even greater, when it is a matter of highly atrophied alveolar ridges, covered with very thin mucosa, people suffering from xerostomia, exostosis, very well developed torus palatinus or tuberae maxillae. Problems of the patients with removable dentures usually are poor adhesion and stability, pain, wounds, difficult adaptation with the new dentures, etc. At this moment there are only two possibilities to help these people. The first one is the use of implants; the second one is to use soft relining materials. There are some obstacles that reduce the use of implants in all patients, because of medical, anatomical, psychological and financial concerns. While in the second option the contraindications are quite less.

  18. Statistical analysis of magnetically soft particles in magnetorheological elastomers

    Science.gov (United States)

    Gundermann, T.; Cremer, P.; Löwen, H.; Menzel, A. M.; Odenbach, S.

    2017-04-01

    The physical properties of magnetorheological elastomers (MRE) are a complex issue and can be influenced and controlled in many ways, e.g. by applying a magnetic field, by external mechanical stimuli, or by an electric potential. In general, the response of MRE materials to these stimuli is crucially dependent on the distribution of the magnetic particles inside the elastomer. Specific knowledge of the interactions between particles or particle clusters is of high relevance for understanding the macroscopic rheological properties and provides an important input for theoretical calculations. In order to gain a better insight into the correlation between the macroscopic effects and microstructure and to generate a database for theoretical analysis, x-ray micro-computed tomography (X-μCT) investigations as a base for a statistical analysis of the particle configurations were carried out. Different MREs with quantities of 2-15 wt% (0.27-2.3 vol%) of iron powder and different allocations of the particles inside the matrix were prepared. The X-μCT results were edited by an image processing software regarding the geometrical properties of the particles with and without the influence of an external magnetic field. Pair correlation functions for the positions of the particles inside the elastomer were calculated to statistically characterize the distributions of the particles in the samples.

  19. Numerical study and design optimization of electromagnetic energy harvesters integrated with flexible magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sang Won [Hanyang University, Seoul (Korea, Republic of)

    2017-05-15

    This study presents a new design of an electromagnetic energy harvester integrated with a soft magnetic material. The harvester design optimizes the magnetic material characteristics and the size of a rectangular permanent magnet. The design employs a complete magnetic circuit made of (1) a thin-film soft magnetic material that facilitates a flexible but highly (magnetically) permeable beam and (2) an optimally-sized magnet that maximizes the harvester performance. The design is demonstrated to reduce magnetic flux leakage, and thus considerably enhances both magnetic flux density (B) and its change by time (dB/dt), which both influence harvester performance. The improvement in harvester performances strongly depends on critical design parameters, especially, the magnet size and characteristics of magnetic materials, including permeability, stiffness, and thickness. The analyses conclude that recently-introduced nanomaterials (having ultrahigh magnetic permeability) can potentially innovate harvester performances. However, the performance may be degraded without design optimization. Once optimized, the integrated nanomaterials facilitate a significant improvement compared with a conventional design without integrated magnetic materials.

  20. Numerical study and design optimization of electromagnetic energy harvesters integrated with flexible magnetic materials

    International Nuclear Information System (INIS)

    Yoon, Sang Won

    2017-01-01

    This study presents a new design of an electromagnetic energy harvester integrated with a soft magnetic material. The harvester design optimizes the magnetic material characteristics and the size of a rectangular permanent magnet. The design employs a complete magnetic circuit made of (1) a thin-film soft magnetic material that facilitates a flexible but highly (magnetically) permeable beam and (2) an optimally-sized magnet that maximizes the harvester performance. The design is demonstrated to reduce magnetic flux leakage, and thus considerably enhances both magnetic flux density (B) and its change by time (dB/dt), which both influence harvester performance. The improvement in harvester performances strongly depends on critical design parameters, especially, the magnet size and characteristics of magnetic materials, including permeability, stiffness, and thickness. The analyses conclude that recently-introduced nanomaterials (having ultrahigh magnetic permeability) can potentially innovate harvester performances. However, the performance may be degraded without design optimization. Once optimized, the integrated nanomaterials facilitate a significant improvement compared with a conventional design without integrated magnetic materials.

  1. Annealing effects on magnetic properties of silicone-coated iron-based soft magnetic composites

    International Nuclear Information System (INIS)

    Wu Shen; Sun Aizhi; Zhai Fuqiang; Wang Jin; Zhang Qian; Xu Wenhuan; Logan, Philip; Volinsky, Alex A.

    2012-01-01

    This paper focuses on novel iron-based soft magnetic composites synthesis utilizing high thermal stability silicone resin to coat iron powder. The effect of an annealing treatment on the magnetic properties of synthesized magnets was investigated. The coated silicone insulating layer was characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Silicone uniformly coated the powder surface, resulting in a reduction of the imaginary part of the permeability, thereby increasing the electrical resistivity and the operating frequency of the synthesized magnets. The annealing treatment increased the initial permeability, the maximum permeability, and the magnetic induction, and decreased the coercivity. Annealing at 580 °C increased the maximum permeability by 72.5%. The result of annealing at 580 °C shows that the ferromagnetic resonance frequency increased from 2 kHz for conventional epoxy resin coated samples to 80 kHz for the silicone resin insulated composites. - Highlights: ► Silicone uniformly coated the powder, increased the operating frequency of SMCs. ► The annealing treatment increased the DC properties of SMCs. ► Annealing at 580 °C increased the maximum permeability by 72.5%. ► Compared with epoxy coated, the SMCs had higher resistivity annealing at 580 °C.

  2. Influence of thermal debinding on the final properties of Fe–Si soft magnetic alloys for metal injection molding (MIM)

    Energy Technology Data Exchange (ETDEWEB)

    Páez-Pavón, A.; Jiménez-Morales, A. [Dpto. Ciencia e Ing. de materiales e Ing. Química, Universidad Carlos III de Madrid, 28911 Leganés, Madrid (Spain); Santos, T.G. [UNIDEMI, Departamento de Engenharia Mecânica e Industrial, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Quintino, L. [Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal); Torralba, J.M. [Dpto. Ciencia e Ing. de materiales e Ing. Química, Universidad Carlos III de Madrid, 28911 Leganés, Madrid (Spain)

    2016-10-15

    Metal injection molding (MIM) may be used to produce soft magnetic materials with optimal mechanical and magnetic properties. Unlike other techniques, MIM enables the production of complex and small Fe–Si alloy parts with silicon contents greater than 3% by weight. In MIM process development, it is critical to design a proper debinding cycle not only to ensure complete removal of the binder system but also to obtain improved properties in the final part. This work is a preliminary study on the production of Fe-3.8Si soft magnetic parts by MIM using pre-alloyed powders and a non-industrialized binder. Two different heating rates during thermal debinding were used to study their effect on the final properties of the part. The final properties of the sintered parts are related to thermal debinding. It has been demonstrated that the heating rate during thermal debinding has a strong influence on the final properties of Fe–Si soft magnetic alloys. - Highlights: • The properties of MIM Fe-Si alloy are influenced by the debinding heating rate. • The slow debinding led to a lower porosity, lower oxygen content and grain growth. • The magnetization of the sintered samples improved after a slow thermal debinding.

  3. Study on magnetic property and fracture behavior of magnetic materials

    International Nuclear Information System (INIS)

    Miya, Kenzo; Demachi, Kazuyuki; Aoto, Kazumi; Nagae, Yuji

    2002-04-01

    Establishment of evaluation methods of material degradation before crack initiation is needed very much to enhance the reliability of structural components. We remark magnetic methods in this report. Our objectives are to reveal the relation between degradation and magnetic property and to develop evaluation methods of material degradation, especially plastic deformation and stress corrosion cracking (SCC). In the former part of this report, evaluation methods for plastic deformation are discussed. At first, the study that shows the relation between the magnetic flux leakage and plastic deformation is reviewed. We developed the inverse analysis method of magnetization to specify the degradation distribution. Moreover, we propose inverse analysis of magnetic susceptibility for quantitative evaluation. In the latter part, the topic is SCC. We measured the magnetic flux leakage from the sample induced a SCC crack (Inconel 600). Inconel 600 is a paramagnetic material at room temperature but the sample shows ferromagnetic and the magnetic flux leakage was changed near the SCC crack. The possibility of detection of a SCC crack is shown by the inverse analysis result from the magnetic flux leakage. Finally, it is recognized by observation of the micro magnetic distributions by using a magnetic force microscope that the magnetization has relation with chromium depletion near grain boundaries and it is weak near the SCC crack. From these results, the magnetic method is very effective for evaluation of degradation. (author)

  4. Magnetism and Structure in Functional Materials

    CERN Document Server

    Planes, Antoni; Saxena, Avadh

    2005-01-01

    Magnetism and Structure in Functional Materials addresses three distinct but related topics: (i) magnetoelastic materials such as magnetic martensites and magnetic shape memory alloys, (ii) the magnetocaloric effect related to magnetostructural transitions, and (iii) colossal magnetoresistance (CMR) and related magnanites. The goal is to identify common underlying principles in these classes of materials that are relevant for optimizing various functionalities. The emergence of apparently different magnetic/structural phenomena in disparate classes of materials clearly points to a need for common concepts in order to achieve a broader understanding of the interplay between magnetism and structure in this general class of new functional materials exhibiting ever more complex microstructure and function. The topic is interdisciplinary in nature and the contributors correspondingly include physicists, materials scientists and engineers. Likewise the book will appeal to scientists from all these areas.

  5. A general perspective on the magnetization reversal in cylindrical soft magnetic nanowires with dominant shape anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Kuncser, A. [National Institute of Materials Physics, PO Box MG-7, 077125 Bucharest-Magurele (Romania); University of Bucharest, Faculty of Physics, PO Box MG-11, 077125 Bucharest-Magurele (Romania); Antohe, S. [University of Bucharest, Faculty of Physics, PO Box MG-11, 077125 Bucharest-Magurele (Romania); Kuncser, V., E-mail: kuncser@infim.ro [National Institute of Materials Physics, PO Box MG-7, 077125 Bucharest-Magurele (Romania)

    2017-02-01

    Peculiarities of the magnetization reversal process in cylindrical Ni-Cu soft magnetic nanowires with dominant shape anisotropy are analyzed via both static and time dependent micromagnetic simulations. A reversible process involving a coherent-like spin rotation is always observed for magnetic fields applied perpendicularly to the easy axis whereas nucleation of domain walls is introduced for fields applied along the easy axis. Simple criteria for making distinction between a Stoner-Wohlfarth type rotation and a nucleation mechanism in systems with uniaxial magnetic anisotropy are discussed. Superposed reversal mechanisms can be in action for magnetic fields applied at arbitrary angles with respect to the easy axis within the condition of an enough strong axial component required by the nucleation. The dynamics of the domain wall, involving two different stages (nucleation and propagation), is discussed with respect to initial computing conditions and orientations of the magnetic field. A nucleation time of about 3 ns and corkscrew domain walls propagating with a constant velocity of about 150 m/s are obtained in case of Ni-Cu alloy (Ni rich side) NWs with diameters of 40 nm and high aspect ratio. - Highlights: • The formation and the dynamics of the domain walls in magnetic nanowires have been studied by micromagnetic simulations. • Simple criteria for making distinction between Stoner-Wohlfarth type and nucleation mechanisms in nanowires were discussed. • Corkscrew domain walls or quasi-coherent spin rotation may be induced depending on the field orientation. • The nucleation time was estimated at 3 ns and the wall velocity at 150 m/s. • A simple way for tuning the wall velocity in such systems was mentioned.

  6. Controlling the competing magnetic anisotropy energies in FineMET amorphous thin films with ultra-soft magnetic properties

    Directory of Open Access Journals (Sweden)

    Ansar Masood

    2017-05-01

    Full Text Available Thickness dependent competing magnetic anisotropy energies were investigated to explore the global magnetic behaviours of FineMET amorphous thin films. A dominant perpendicular magnetization component in the as-deposited state of thinner films was observed due to high magnetoelastic anisotropy energy which arises from stresses induced at the substrate-film interface. This perpendicular magnetization component decreases with increasing film thickness. Thermal annealing at elevated temperature revealed a significant influence on the magnetization state of the FineMET thin films and controlled annealing steps leads to ultra-soft magnetic properties, making these thin films alloys ideal for a wide range of applications.

  7. Modern permanent magnetic materials - preparation and properties

    International Nuclear Information System (INIS)

    Rodewald, W.

    1989-01-01

    First of all, the basic properties of the classical (steel, AlNiCo) permanent magnetic materials and the modern rare-earth (RE) permanent magnetic materials are compared. Since the properties of RE permanent magnets depend on the particular production process, the fundamentals of the main industrial processes (powder metallurgy, rapid-solidification technique) are described and the typical properties are explained. Furthermore the production processes in development such as mechanical alloying, melt spinning technique and extrusion upsetting are briefly outlined. For applying the permanent magnets, they have to be completely magnetized. The magnetization behaviour of the various RE permanent magnets is discussed by means of the internal demagnetization curve. Finally the various influences on the temperature stability of RE permanent magnets are compiled. (orig./MM) [de

  8. Soft magnetic characteristics of laminated magnetic block cores assembled with a high Bs nanocrystalline alloy

    Directory of Open Access Journals (Sweden)

    Atsushi Yao

    2018-05-01

    Full Text Available This paper focuses on an evaluation of core losses in laminated magnetic block cores assembled with a high Bs nanocrystalline alloy in high magnetic flux density region. To discuss the soft magnetic properties of the high Bs block cores, the comparison with amorphous (SA1 block cores is also performed. In the high Bs block core, both low core losses and high saturation flux densities Bs are satisfied in the low frequency region. Furthermore, in the laminated block core made of the high Bs alloy, the rate of increase of iron losses as a function of the magnetic flux density remains small up to around 1.6 T, which cannot be realized in conventional laminated block cores based on amorphous alloy. The block core made of the high Bs alloy exhibits comparable core loss with that of amorphous alloy core in the high-frequency region. Thus, it is expected that this laminated high Bs block core can achieve low core losses and high saturation flux densities in the high-frequency region.

  9. Permanent magnet materials and their application

    International Nuclear Information System (INIS)

    Campbell, P.

    1994-01-01

    Permanent magnets are of great industrial importance in industrial drives, consumer products, computers, and automobiles. Since 1970, new classes of magnet materials have been developed. This book reviews the older and newer materials and is presented as a comprehensive design text for permanent magnets and their applications. After an initial chapter on the fundamentals of magnetism, the author discusses magnetic physics considerations specific to permanent magnets and describes the fabrications and characteristics of commercial materials: alnico, samarium-cobalt, ferrite, and neodymium-iron-boron. Thermal stability, magnet design procedures, magnetic field analysis methods, and measurement methods are discussed in subsequent chapters, followed by a concluding chapter reviewing commercial and industrial products that use permanent magnets. The chapter on thermal properties of magnet materials is of particular interest, bringing together information not readily found elsewhere. The review of applications is also deserving of attention, specifically the sections on motors and actuators. Although particle accelerator applications are discussed, the use of permanent magnet sextuples in modern ECR ion sources is not mentioned

  10. INTEGRATED DEVELOPMENT OF CHEMICAL TEACHING MATERIALS ON MATERIAL BASED THERMOCHEMICAL SOFT SKILLS FOR VOCATIONAL STUDENTS

    Directory of Open Access Journals (Sweden)

    S. D. Purnawan

    2015-11-01

    Full Text Available Business and industrial field need workers who have not only good academic achievement but also the ability of hard skills and soft skills.  In order to prepare students who have a good academic skills, hard skills, soft skills it has to be done in all subjects including chemistry expertise to integrate the competencies of Motorcycle Engineering.  The research design uses One Group Pretest Posttest Design imposed on students in class XI SMK 1 Kedung TSM. Validator assessment results indicate that teaching materials developed very feasible for use in learning chemistry.  The result show that the learning device by using the integrated chemistry materials can increase students understanding of the thermo chemistry material with the acquisition of N-gain is at 0.63 or in the medium category.  Group of high-achieving students have the score of N-gain of 0.65, while the medium-achieving students get 0.63 and low-achieving students get 0.61, all have medium category.  Percentage  of students who passes the mastery learning  if mastery learning (KKM > 75 or reach 87 %.  The percentage of students’ soft skills in at least good criteria is at 87.10 %.  Students gave positive responses  90.71 % towards the learning material that is developed.

  11. Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials

    International Nuclear Information System (INIS)

    Moore, Lee R.; Williams, P. Stephen; Chalmers, Jeffrey J.; Zborowski, Maciej

    2017-01-01

    Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour. - Highlights: • Simple geometry of commercial, off-the-shelf NdFeB magnet blocks is amenable to generate high fields and open gradients. • Periodic pattern of permanent magnet blocks (tessellation) reduces the number of blocks per separation channel and improves the efficiency of separator design. • Split-flow lateral transport thin (SPLITT) fractionation model predicts 100-fold reduction of red blood cells from 1 mL whole blood sample in 1 h, suitable for laboratory medicine applications.

  12. Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Lee R. [Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Ave., Cleveland OH 44195 (United States); Williams, P. Stephen [Cambrian Technologies, Inc., Cleveland, OH (United States); Chalmers, Jeffrey J. [William G. Lowrie Department of Chemical and Biomedical Engineering, The Ohio State University, Columbus 151 W. Woodruff Avenue, OH 43210 (United States); Zborowski, Maciej, E-mail: zborowm@ccf.org [Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Ave., Cleveland OH 44195 (United States)

    2017-04-01

    Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour. - Highlights: • Simple geometry of commercial, off-the-shelf NdFeB magnet blocks is amenable to generate high fields and open gradients. • Periodic pattern of permanent magnet blocks (tessellation) reduces the number of blocks per separation channel and improves the efficiency of separator design. • Split-flow lateral transport thin (SPLITT) fractionation model predicts 100-fold reduction of red blood cells from 1 mL whole blood sample in 1 h, suitable for laboratory medicine applications.

  13. Tailoring the soft magnetic properties of sputtered multilayers by microstructure engineering for high frequency applications

    Directory of Open Access Journals (Sweden)

    Claudiu V. Falub

    2017-05-01

    Full Text Available Soft magnetic Ni78.5Fe21.5, Co91.5Ta4.5Zr4 and Fe52Co28B20 thin films laminated with SiO2, Al2O3, AlN, and Ta2O5 dielectric interlayers were deposited on 8” Si wafers using DC, pulsed DC and RF cathodes in the industrial, high-throughput Evatec LLS-EVO-II magnetron sputtering system. A typical multilayer consists of a bilayer stack up to 50 periods, with alternating (50-100 nm thick magnetic layers and (2-20 nm thick dielectric interlayers. We introduced the in-plane magnetic anisotropy in these films during sputtering by a combination of a linear magnetic field, seed layer texturing by means of linear collimators, and the oblique incidence inherent to the geometry of the sputter system. Depending on the magnetic material, the anisotropy field for these films was tuned in the range of ∼(7-120 Oe by choosing the appropriate interlayer thickness, the aspect ratios of the linear collimators in front of the targets, and the sputter process parameters (e.g. pressure, power, DC pulse frequency, while the coercivity was kept low, ∼(0.05-0.9 Oe. The alignment of the easy axis (EA on the 8” wafers was typically between ±1.5° and ±4°. We discuss the interdependence of structure and magnetic properties in these films, as revealed by atomic force microscopy (AFM, X-ray reflectivity (XRR with reciprocal space mapping (RSM and magneto-optical Kerr effect (MOKE measurements.

  14. Elastic Characterization of Transversely Isotropic Soft Materials by Dynamic Shear and Asymmetric Indentation

    OpenAIRE

    Namani, R.; Feng, Y.; Okamoto, R. J.; Jesuraj, N.; Sakiyama-Elbert, S. E.; Genin, G. M.; Bayly, P. V.

    2012-01-01

    The mechanical characterization of soft anisotropic materials is a fundamental challenge because of difficulties in applying mechanical loads to soft matter and the need to combine information from multiple tests. A method to characterize the linear elastic properties of transversely isotropic soft materials is proposed, based on the combination of dynamic shear testing (DST) and asymmetric indentation. The procedure was demonstrated by characterizing a nearly incompressible transversely isot...

  15. Magnetic susceptibility of MnZn and NiZn soft ferrites using Laplace transform and the Routh-Hurwitz criterion

    International Nuclear Information System (INIS)

    Fano, Walter Gustavo; Boggi, Silvina; Razzitte, Adrian Cesar

    2011-01-01

    This paper is devoted to study the Routh-Hurwitz stability criterion from the MnZn and NiZn soft ferrites using a phenomenological model with the gyromagnetic spin contribution and domain wall contribution. The magnetodynamic equation and the harmonic oscillator equation have been used to obtain the domain walls and the spin contribution of the magnetic susceptibility. The ferrite materials have been considered as linear, time invariant, isotropic and homogeneous, and the magnetization vector is proportional to the magnetic field vector. The resulting expression of the magnetization in time domain of both ferrites under study has been obtained by mean of the inverse Laplace transformation applying the residue method. The poles of the magnetic susceptibility have negative real parts, which ensures that the response decays exponentially to zero as the time increase. The degree of the numerator's polynomial of the magnetic susceptibility is less than the degree of denominator's polynomial in the magnetic susceptibility function: and the poles are located in the half left s-plane. Then the system is bounded-input, bounded-output (BIBO), and the results agree with the Routh-Hurwitz stability criterion for the MnZn and NiZn soft ferrites. - Research Highlights: → Laplace transform of the magnetic susceptibility of the MnZn and NiZn soft ferrites. → Routh-Hurwitz stability criterion of magnetic materials. → Bode plot of magnetic susceptibility. → Inverse Laplace transform using residue theorem.

  16. Losses Approximation for Soft Magnetic Composites Based on a Homogenized Equivalent Conductivity

    Directory of Open Access Journals (Sweden)

    X. Ren

    2016-09-01

    Full Text Available Soft magnetic composites (SMC are a promising alternative to laminated steel in many Electrical Engineering applications. This is largely owing to their low level of eddy current losses. The electromagnetic behavior of SMC in electromagnetic devices cannot be easily predicted using standard numerical techniques such as the finite element method, mostly due to the computational cost required to model the material microstructure. Another difficulty lies in the high property contrast between the matrix and the inclusions. In this paper we propose a homogenization strategy to define the equivalent electromagnetic properties of SMC. For components made of SMC, the equivalent conductivity and permeability can be determined. These equivalent properties can be used to calculate eddy current losses or introduced into structural analysis tools to design electromagnetic devices.

  17. Engineering Gilbert damping by dilute Gd doping in soft magnetic Fe thin Films

    NARCIS (Netherlands)

    Zhang, W.; Jiang, S.; Wong, P.K.J.; Sun, Li; Wang, Y.K.; Wang, Kai; de Jong, Machiel Pieter; van der Wiel, Wilfred Gerard; van der Laan, G.; Zhai, Y.

    2014-01-01

    By analyzing the ferromagnetic resonance linewidth, we show that the Gilbert damping constant in soft magnetic Fe thin films can be enhanced by ∼6 times with Gd doping of up to 20%. At the same time, the magnetic easy axis remains in the film plane while the coercivity is strongly reduced after Gd

  18. Controlling the induced anisotropy in soft magnetic films for high-frequency applications

    NARCIS (Netherlands)

    Chezan, A.R.; Craus, C.B.; Chechenin, N.G.; Vystavel, T.; Hosson, J.Th.M. De; Niesen, L.; Boerma, D.O.

    Nanocrystalline soft magnetic Fe–Zr–N films were successfully deposited by dc magnetron reactive sputtering. The nitrogen content was controlled by varying the Ar/N2 ratio and/or the substrate temperature. The films have saturation magnetization and induced uniaxial anisotropy values in the range

  19. Soft X-ray magnetic scattering study of rotational magnetisation processes in cobalt/copper multilayers

    International Nuclear Information System (INIS)

    Hase, T.P.A.; Fulthorpe, B.D.; Wilkins, S.B.; Tanner, B.K.; Marrows, C.H.; Hickey, B.J.

    2001-01-01

    We report the observation of magnetic viscosity in the intensity of resonant magnetic soft X-ray scattering during rotational magnetisation processes in antiferromagnetically coupled Co/Cu multilayers. The hysteretic time-dependent component of the signal can be fitted to a single-exponential function that varies as a function of magnetising field

  20. Magnetic properties of FeNi-based thin film materials with different additives

    KAUST Repository

    Liang, C.; Gooneratne, C.P.; Wang, Q.X.; Liu, Y.; Gianchandani, Y.; Kosel, Jü rgen

    2014-01-01

    This paper presents a study of FeNi-based thin film materials deposited with Mo, Al and B using a co-sputtering process. The existence of soft magnetic properties in combination with strong magneto-mechanical coupling makes these materials

  1. High-frequency electromagnetic properties of soft magnetic metal-polyimide hybrid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Woo [Nano-Materials Research Center, Korea Institute of Science and Technology, 39-1 Haweoulgog-dong, Sungbuk-gu, Seoul 136-791 (Korea, Republic of)]. E-mail: swkim@kist.re.kr; Yoon, Chong S. [Division of Advanced Materials Science, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2007-09-15

    Although there are a lot of demands for suppression of unwanted high-frequency electromagnetic noise in highly integrated electronic devices such as mobile phones and notebook computers, electromagnetic thin films that effectively work in the high-frequency range have still been underdeveloped. Soft magnetic metal-polyimide (PI) hybrid films with high electrical resistivity were prepared by thermal imidization and selective oxidation between the metal alloy layer and polyamic acid (PAA) layer. Electromagnetic properties of the hybrid thin films in the radio-frequency range were characterized by using the microstrip line method and were correlated with their material parameters. Although anisotropy field of the CoFe/NiFe hybrid film was two times lower than that of the NiFe hybrid film, the saturation magnetization of the CoFe/NiFe hybrid film was three times higher than that of the NiFe hybrid film. The CoFe/NiFe hybrid film showed higher power loss in the frequency range of 3-6 GHz compared to the NiFe hybrid film. The high power loss of the CoFe/NiFe hybrid film was caused by high relative permeability and high ferromagnetic resonance (FMR) frequency due to high saturation magnetization.

  2. High-frequency electromagnetic properties of soft magnetic metal-polyimide hybrid thin films

    International Nuclear Information System (INIS)

    Kim, Sang Woo; Yoon, Chong S.

    2007-01-01

    Although there are a lot of demands for suppression of unwanted high-frequency electromagnetic noise in highly integrated electronic devices such as mobile phones and notebook computers, electromagnetic thin films that effectively work in the high-frequency range have still been underdeveloped. Soft magnetic metal-polyimide (PI) hybrid films with high electrical resistivity were prepared by thermal imidization and selective oxidation between the metal alloy layer and polyamic acid (PAA) layer. Electromagnetic properties of the hybrid thin films in the radio-frequency range were characterized by using the microstrip line method and were correlated with their material parameters. Although anisotropy field of the CoFe/NiFe hybrid film was two times lower than that of the NiFe hybrid film, the saturation magnetization of the CoFe/NiFe hybrid film was three times higher than that of the NiFe hybrid film. The CoFe/NiFe hybrid film showed higher power loss in the frequency range of 3-6 GHz compared to the NiFe hybrid film. The high power loss of the CoFe/NiFe hybrid film was caused by high relative permeability and high ferromagnetic resonance (FMR) frequency due to high saturation magnetization

  3. Soft mode and magnetic phase transition in PrNi

    International Nuclear Information System (INIS)

    Alekseev, P.A.; Lazukov, V.N.; Sadikov, I.P.; Klement'ev, E.S.; Allenspach, P.; Chumlyakov, Yu.I.

    2002-01-01

    The spectrum of the magnetic excitation of the PrNi intermetallic compound monocrystal is studied through the neutrons inelastic scattering. Essential softening of certain collective modes of the magnetic excitation near the temperature of the ferromagnetic ordering T c ∼ 20 K is identified. The above result is analyzed from the viewpoint of the model, describing the magnetic phase transition in the systems with the directed magnetic moment [ru

  4. Materials with low DC magnetic susceptibility for sensitive magnetic measurements

    International Nuclear Information System (INIS)

    Khatiwada, R; Kendrick, R; Khosravi, M; Peters, M; Smith, E; Snow, W M; Dennis, L

    2016-01-01

    Materials with very low DC magnetic susceptibility have many scientific applications. To our knowledge however, relatively little research has been conducted with the goal to produce a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic volumes, it possesses an average zero DC magnetic susceptibility. We report measurements of the DC magnetic susceptibility of three different types of nonmagnetic materials at room temperature: (I) solutions of paramagnetic salts and diamagnetic liquids, (II) liquid gallium–indium alloys and (III) pressed powder mixtures of tungsten and bismuth. The lowest measured magnetic susceptibility among these candidate materials is in the order of 10 −9 cgs volume susceptibility units, about two orders of magnitude smaller than distilled water. In all cases, the measured concentration dependence of the magnetic susceptibility is consistent with that expected for the weighted sum of the susceptibilities of the separate components within experimental error. These results verify the well-known Wiedemann additivity law for the magnetic susceptibility of inert mixtures of materials and thereby realize the ability to produce materials with small but tunable magnetic susceptibility. For our particular scientific application, we are also looking for materials with the largest possible number of neutrons and protons per unit volume. The gallium–indium alloys fabricated and measured in this work possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature liquid, and the tungsten-bismuth pressed powder mixtures possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature solid. This ratio is a figure of merit for a certain class of precision experiments that search for possible exotic spin-dependent forces of Nature. (paper)

  5. Magnetic resonance imaging of peripheral soft tissue hemangiomas

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, M C; Stull, M A; Patt, R H; Freedman, M T [Georgetown Univ., Washington, DC (USA). Dept. of Radiology; Teitelbaum, G P [Georgetown Univ., Washington, DC (USA). Dept. of Radiology University of Southern California, Los Angeles (USA). Dept. of Radiology; Lack, E E [Georgetown Univ., Washington, DC (USA). Dept. of Pathology; Bogumill, G P [Georgetown Univ., Washington, DC (USA). Dept. of Orthopedic Surgery

    1990-10-01

    Ten patients with soft tissue hemangiomas outside the central nervous system were studied with MR imaging. Eight patients were studied at 1.5 Tesla (T) with T{sub 1}-weighted and triple echo T{sub 2}-weighted sequences. Two additional patients were imaged on a 0.5-T system. The MR images were correlated with images from other modalities. It was found that prolonged T{sub 2}-weighted imaging together with standard spin echo T{sub 1} and T{sub 2} pulse sequences is a good substitute for contrast-enhanced CT and arteriographic evaluation of soft tissue hemangiomas. (orig./DG).

  6. Nanolaminated FeCoB/FeCo and FeCoB/NiFe soft magnetic thin films with tailored magnetic properties deposited by magnetron sputtering

    Science.gov (United States)

    Hida, Rachid; Falub, Claudiu V.; Perraudeau, Sandrine; Morin, Christine; Favier, Sylvie; Mazel, Yann; Saghi, Zineb; Michel, Jean-Philippe

    2018-05-01

    Thin films based on layers of Fe52Co28B20 (at%), Fe65Co35 (at%), and Ni80Fe20 (at%) were deposited by sputtering on 8″ bare Si and Si/200 nm-thermal-SiO2 wafers by simultaneous use of two or more cathodes. Due to the continuous rotation of the substrate cage, such that the substrates faced different targets alternately, the multilayers consisted of stacks of alternating, nanometer-thick regular layers. The composition of the films was determined by Rutherford Backscattering Spectrometry (RBS) and Nuclear Reactive Analysis (NRA), whereas Plasma Profiling Time of Flight Mass Spectrometry (PP-TOFMS) analysis gave depth profile information about the chemical elements. The structural and magnetic properties of the films were investigated by X-ray Diffraction and by TEM analysis, B-H loop tracer and high frequency single coil technique permeametry, respectively. The linear dependence of the coercivity of these thin films versus the grain size can be explained by the random anisotropy model. These novel, composite soft magnetic multilayers, with tunable in-plane anisotropy, allow operation at tunable frequencies, as shown by broadband (between 100 MHz and 10 GHz) RF measurements that exhibit a classical Landau-Lifschitz-Gilbert (LLG) behavior and, combine the magnetic properties of the individual materials in an advantageous way. This article presents a method to produce nanostructured soft magnetic multilayers, the properties of which can easily be tuned by choosing the ratio of the individual nanolayers. In this way it's possible to combine soft magnetic materials with complementary properties, e.g. high saturation magnetization, low coercivity, high specific resistivity and low magnetostriction

  7. Hemorrhagic lesions in soft tissue: utility and limitations of magnetic resonance

    International Nuclear Information System (INIS)

    Legorburu, A.; Oleaga, L.; Ibarra, V.; Grande, D.

    1998-01-01

    We present four patients with hemorrhagic soft tissue tumors. The diagnosis was malignant fibrous histiocytoma in three of the patients and hematoma in the fourth. We show the magnetic resonance findings in these four cases, stressing the value of this technique in the assessment of the extension of soft tissue tumors. The difficulty in differentiating tumors with bleeding, as often occurs with malignant fibrous histiocytoma, from true hematomas. (Author) 8 refs

  8. Magnetic materials research with polarized neutrons

    International Nuclear Information System (INIS)

    Hammer, J.; Rauch, H.; Badurek, G.

    1980-01-01

    In order to study the mechanisms of time dependent effects in magnetic materials with superparamagnetic or spinglass behaviour as well as in ferromagnetic materials a 'dynamic neutron depolarization' system has been developed as a beam hole experiment at the TRIGA Mark II Reactor in Vienna. In the course of this experiment an increasing or decreasing polarization can be observed as a consequence of the interaction between spins of the polarized neutron beam and the magnetic structure if the magnetic clusters in the sample are stimulated by a short magnetic pulse, lasting up to a few seconds. In accordance with numerical calculations and theoretical considerations we can draw conclusions from dynamics in the range of 10 ms to 1 h within magnetic materials which give us additional information that cannot be obtained from experiments used so far

  9. Casimir stress in materials: Hard divergency at soft walls

    Science.gov (United States)

    Griniasty, Itay; Leonhardt, Ulf

    2017-11-01

    The Casimir force between macroscopic bodies is well understood, but not the Casimir stress inside bodies. Suppose empty space or a uniform medium meets a soft wall where the refractive index is continuous but its derivative jumps. For this situation we predict a characteristic power law for the stress inside the soft wall and close to its edges. Our result shows that such edges are not tolerated in the aggregation of liquids at surfaces, regardless whether the liquid is attracted or repelled.

  10. Magnetically responsive biological materials and their applications

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Pospíšková, K.; Baldíková, E.; Šafaříková, Miroslava

    2016-01-01

    Roč. 7, č. 4 (2016), s. 254-261 ISSN 0976-3961 Institutional support: RVO:60077344 Keywords : adsorbents * biological materials * carriers * magnetic modification * whole-cell biocatalyst Subject RIV: EI - Biotechnology ; Bionics

  11. Giant magnetoimpedance in composite wires with insulator layer between non-magnetic core and soft magnetic shell

    International Nuclear Information System (INIS)

    Buznikov, N.A.; Antonov, A.S.; Granovsky, A.B.; Kim, C.G.; Kim, C.O.; Li, X.P.; Yoon, S.S.

    2006-01-01

    A method for calculation of the magnetoimpedance in composite wires having an insulator layer between non-magnetic core and soft magnetic shell is described. It is assumed that the magnetic shell has a helical anisotropy and the driving current flows through the core only. The distribution of eddy currents and expressions for the impedance are found by means of a solution of Maxwell equations taking into account the magnetization dynamics within the shell governed by the Landau-Lifshitz equation. The effect of the insulator layer on the magnetoimpedance is analyzed

  12. Giant magnetoimpedance in composite wires with insulator layer between non-magnetic core and soft magnetic shell

    Energy Technology Data Exchange (ETDEWEB)

    Buznikov, N.A. [Research Center for Advanced Magnetic Materials, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Antonov, A.S. [Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Granovsky, A.B. [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Kim, C.G. [Research Center for Advanced Magnetic Materials, Chungnam National University, Daejeon 305-764 (Korea, Republic of)]. E-mail: cgkim@cnu.ac.kr; Kim, C.O. [Research Center for Advanced Magnetic Materials, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Li, X.P. [Department of Mechanical Engineering and Division of Bioengineering, National University of Singapore, Singapore 119260 (Singapore); Yoon, S.S. [Department of Physics, Andong National University, Andong 760-749 (Korea, Republic of)

    2006-05-15

    A method for calculation of the magnetoimpedance in composite wires having an insulator layer between non-magnetic core and soft magnetic shell is described. It is assumed that the magnetic shell has a helical anisotropy and the driving current flows through the core only. The distribution of eddy currents and expressions for the impedance are found by means of a solution of Maxwell equations taking into account the magnetization dynamics within the shell governed by the Landau-Lifshitz equation. The effect of the insulator layer on the magnetoimpedance is analyzed.

  13. Recent developments in hard magnetic materials

    International Nuclear Information System (INIS)

    Asti, G.

    1989-01-01

    Hard magnetic materials find ever-increasing uses in modern technology. Their importance is mainly in the domain of permanent magnets, but a variety of other applications is being offered to this class of materials, especially for what regards the areas of information storage, telecommunications and special electronic devices. These developments are connected to the emphasis that is more and more given to thin films having high magnetic anisotropy. The recent advancement in the field of hard magnetic materials is among the best examples where technology depends to a great extent upon the continuous progress in the scientific knowledge. The research activity is characterized by the introduction of new classes of materials and continuous improvements in the preparation techniques both for what regards industrial processing and method for obtaining high quality materials in form of crystals, films or amorphous specimens. In this respect a special place must be reserved to rare earth transition metal compounds, a class of materials that attracted enormeous attention after the discovery by Hoffer and Strnat in 1966 of the large uniaxial magnetocrystalline anisotropy of the compound YCo 5 . Beside the so called 1:5 phase, other compositions of technical importance are the 2:17 and the recently discovered Nd 2 Fe 14 B, which is a real new ternary phase having tetragonal crystal structure. Great efforts have been done to gain a better understanding of the magnetic anisotropy and its relationship to the coercivity is of leading importance for a further development in this important area of magnetism. (orig.)

  14. Crystallographic aspects of L10 magnetic materials

    International Nuclear Information System (INIS)

    Laughlin, David E.; Srinivasan, Kumar; Tanase, Mihaela; Wang, Lisha

    2005-01-01

    In this paper we present an overview of various features of the structure of L1 0 magnetic phase. We discuss the various microstructural features which occur in these materials due to the changes in symmetry (translational and orientational domains) as well as the relationship between the crystal symmetry and features such as the thermodynamic order of the disorder to order phase transition. We also show the various ways that the magnetic moments of the elements align themselves in these alloys producing ferromagnetic and antiferromagnetic materials. Finally we discuss the way that the atomic order, composition and magnetic order affect the Curie temperatures of the FePd L1 0 alloys

  15. From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

    Directory of Open Access Journals (Sweden)

    Maria Helena Godinho

    2014-06-01

    Full Text Available Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR, Rheology coupled with NMR (Rheo-NMR, rheology, optical methods, Magnetic Resonance Imaging (MRI, Wide Angle X-rays Scattering (WAXS, were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

  16. Soft tissue augmentation techniques and materials used in the oral cavity : an overview

    NARCIS (Netherlands)

    Wolff, J.; Farré-Guasch, E.; Sándor, G.K.; Gibbs, S.; Jager, D.J.; Forouzanfar, T.

    2016-01-01

    Purpose: Oral soft tissue augmentation or grafting procedures are often necessary to achieve proper wound closure after deficits resulting from tumor excision, clefts, trauma, dental implants, and tooth recessions. Materials and Methods: Autologous soft tissue grafts still remain the gold standard

  17. Peptide-based soft materials as potential drug delivery vehicles.

    Science.gov (United States)

    Verma, Sandeep; Joshi, K B; Ghosh, Surajit

    2007-11-01

    Emerging concepts in the construction of nanostructures hold immense potential in the areas of drug delivery and targeting. Such nanoscopic assemblies/structures, similar to natural proteins and self-associating systems, may lead to the formation of programmable soft structures with expanded drug delivery options and the capability to circumvent first-pass metabolism. This article aims to illustrate key recent developments and innovative bioinspired design paradigms pertaining to peptide-containing self-assembled tubular and vesicular soft structures. Soft structures are composed of components that self-assemble to reveal diverse morphologies stabilized by weak, noncovalent interactions. Morphological properties of such structures and their ability to encapsulate drugs, biologicals and bioactive small molecules, with the promise of targeted delivery, are discussed.

  18. Passive microrheology of soft materials with atomic force microscopy: A wavelet-based spectral analysis

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Torres, C.; Streppa, L. [CNRS, UMR5672, Laboratoire de Physique, Ecole Normale Supérieure de Lyon, 46 Allée d' Italie, Université de Lyon, 69007 Lyon (France); Arneodo, A.; Argoul, F. [CNRS, UMR5672, Laboratoire de Physique, Ecole Normale Supérieure de Lyon, 46 Allée d' Italie, Université de Lyon, 69007 Lyon (France); CNRS, UMR5798, Laboratoire Ondes et Matière d' Aquitaine, Université de Bordeaux, 351 Cours de la Libération, 33405 Talence (France); Argoul, P. [Université Paris-Est, Ecole des Ponts ParisTech, SDOA, MAST, IFSTTAR, 14-20 Bd Newton, Cité Descartes, 77420 Champs sur Marne (France)

    2016-01-18

    Compared to active microrheology where a known force or modulation is periodically imposed to a soft material, passive microrheology relies on the spectral analysis of the spontaneous motion of tracers inherent or external to the material. Passive microrheology studies of soft or living materials with atomic force microscopy (AFM) cantilever tips are rather rare because, in the spectral densities, the rheological response of the materials is hardly distinguishable from other sources of random or periodic perturbations. To circumvent this difficulty, we propose here a wavelet-based decomposition of AFM cantilever tip fluctuations and we show that when applying this multi-scale method to soft polymer layers and to living myoblasts, the structural damping exponents of these soft materials can be retrieved.

  19. Multiscale modeling of emergent materials: biological and soft matter

    DEFF Research Database (Denmark)

    Murtola, Teemu; Bunker, Alex; Vattulainen, Ilpo

    2009-01-01

    In this review, we focus on four current related issues in multiscale modeling of soft and biological matter. First, we discuss how to use structural information from detailed models (or experiments) to construct coarse-grained ones in a hierarchical and systematic way. This is discussed in the c......In this review, we focus on four current related issues in multiscale modeling of soft and biological matter. First, we discuss how to use structural information from detailed models (or experiments) to construct coarse-grained ones in a hierarchical and systematic way. This is discussed...

  20. Soft silicone based interpenetrating networks as materials for actuators

    DEFF Research Database (Denmark)

    Yu, Liyun; Gonzalez, Lidia; Hvilsted, Søren

    2014-01-01

    A new approach based on silicone interpenetrating networks with orthogonal chemistries has been investigated with focus on developing soft and flexible elastomers with high energy densities and small viscous losses. The interpenetrating networks are made as simple two pot mixtures...... as for the commercial available silylation based elastomers such as Elastosil RT625. The resulting interpenetrating networks are formulated to be softer than RT625 to increase the actuation caused when applying a voltage due to their softness combined with the significantly higher permittivity than the pure silicone...

  1. Magnetization of neutron star matter and implications in physics of soft gamma repeaters

    Energy Technology Data Exchange (ETDEWEB)

    Kondratyev, V N [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-01-01

    The magnetization of neutron star matter is considered within the thermodynamic formalism. The quantization effects are demonstrated to result in sharp abrupt magnetic field dependence of nuclide magnetic moments. Accounting for inter-nuclide magnetic coupling we show that such anomalies give rise to erratic jumps in magnetotransport of neutron star crusts. The properties of such a noise are favorably compared with burst statistics of Soft Gamma Repeaters. PACS: 97.60.Jd, 21.10.Dr, 26.60.+c, 95.30.Ky. (author)

  2. Magnetization and magnetostriction in highly magnetostrictive materials

    Energy Technology Data Exchange (ETDEWEB)

    Thoelke, Jennifer Beth [Iowa State Univ., Ames, IA (United States)

    1993-05-26

    The majority of this research has been in developing a model to describe the magnetostrictive properties of Terfenol-D, Tbsub>1-xDyxFey (x = 0.7-0.75 and y = 1.8--2.0), a rare earth-iron alloy which displays much promise for use in device applications. In the first chapter an introduction is given to the phenomena of magnetization and magnetostriction. The magnetic processes responsible for the observed magnetic properties of materials are explained. An overview is presented of the magnetic properties of rare earths, and more specifically the magnetic properties of Terfenol-D. In the second chapter, experimental results are presented on three composition of Tb< with x = 0.7, y= 1.9, 1.95, and x= 0.73, y= 1.95. The data were taken for various levels of prestress to show the effects of composition and microstructure on the magnetic and magnetostrictive properties of Terfenol-D. In the third chapter, a theoretical model is developed based on the rotation of magnetic domains. The model is used to explain the magnetic and magnetostrictive properties of Terfenol-D, including the observed negative strictions and large change in strain. The fourth chapter goes on to examine the magnetic properties of Terfenol-D along different crystallographic orientations. In the fifth chapter initial data are presented on the time dependence of magnetization in nickel.

  3. Magnetization and magnetostriction in highly magnetostrictive materials

    International Nuclear Information System (INIS)

    Thoelke, J.B.

    1993-01-01

    The majority of this research has been in developing a model to describe the magnetostrictive properties of Terfenol-D, Tb 1-x Dy x Fe y (x = 0.7-0.75 and y = 1.8--2.0), a rare earth-iron alloy which displays much promise for use in device applications. In the first chapter an introduction is given to the phenomena of magnetization and magnetostriction. The magnetic processes responsible for the observed magnetic properties of materials are explained. An overview is presented of the magnetic properties of rare earths, and more specifically the magnetic properties of Terfenol-D. In the second chapter, experimental results are presented on three composition of Tb 1-x Dy x Fe y with x = 0.7, y= 1.9, 1.95, and x= 0.73, y= 1.95. The data were taken for various levels of prestress to show the effects of composition and microstructure on the magnetic and magnetostrictive properties of Terfenol-D. In the third chapter, a theoretical model is developed based on the rotation of magnetic domains. The model is used to explain the magnetic and magnetostrictive properties of Terfenol-D, including the observed negative strictions and large change in strain. The fourth chapter goes on to examine the magnetic properties of Terfenol-D along different crystallographic orientations. In the fifth chapter initial data are presented on the time dependence of magnetization in nickel

  4. Designing magnetic composite materials using aqueous magnetic fluids

    CERN Document Server

    Galicia, J A; Cousin, F; Guemghar, D; Menager, C; Cabuil, V

    2003-01-01

    In this paper, we report on how to take advantage of good knowledge of both the chemistry and the stability of an aqueous magnetic colloidal suspension to realize different magnetic composites. The osmotic pressure of the magnetic nanoparticles is set prior to the realization of the composite to a given value specially designed for the purpose for each hybrid material: magnetic particles in polymer networks, particles as probes for studying the structure of clay suspensions and shape modification of giant liposomes. First, we show that the introduction of magnetic particles in polyacrylamide gels enhances their Young modulus and reduces the swelling caused by water. The particles cause both a mechanical and an osmotic effect. The latter is strongly dependent on the ionic strength and is attributed to an attraction between particles and the polymeric matrix. In the second part, we determine the microscopic structure of suspensions of laponite as a function of concentration, by combining SANS and magneto-optica...

  5. Levitating a Magnet Using a Superconductive Material.

    Science.gov (United States)

    Juergens, Frederick H.; And Others

    1987-01-01

    Presented are the materials and a procedure for demonstrating the levitation of a magnet above a superconducting material. The demonstration can be projected with an overhead projector for a large group of students. Kits to simplify the demonstration can be purchased from the Institute for Chemical Education of the University of Wisconsin-Madison.…

  6. Superconductivity and magnetism: Materials properties and developments

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, N H; Bay, N; Grivel, J C [and others

    2003-07-01

    The 24th Risoe International Symposium on Materials Science focuses on development of new materials, devices and applications, as well as experimental and theoretical studies of novel and unexplained phenomena in superconductivity and magnetism, e.g. within high.T{sub c} superconductivity, magnetic superconductors, MgB{sub 2}, CMR materials, nanomagnetism and spin-tronics. The aim is to stimulate exchange of ideas and establish new collaborations between leading Danish and international scientists. The topics are addressed by presentations from 24 invited speakers and by 41 contributed papers. (ln)

  7. Superconductivity and magnetism: Materials properties and developments

    International Nuclear Information System (INIS)

    Andersen, N.H.; Bay, N.; Grivel, J.C.

    2003-01-01

    The 24th Risoe International Symposium on Materials Science focuses on development of new materials, devices and applications, as well as experimental and theoretical studies of novel and unexplained phenomena in superconductivity and magnetism, e.g. within high.T c superconductivity, magnetic superconductors, MgB 2 , CMR materials, nanomagnetism and spin-tronics. The aim is to stimulate exchange of ideas and establish new collaborations between leading Danish and international scientists. The topics are addressed by presentations from 24 invited speakers and by 41 contributed papers. (ln)

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

    Science.gov (United States)

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

    2018-05-01

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

  9. Soft X-ray magnetic circular dichroism study of UFe2

    International Nuclear Information System (INIS)

    Okane, T.; Takeda, Y.; Fujimori, S.-I.; Terai, K.; Saitoh, Y.; Muramatsu, Y.; Fujimori, A.; Haga, Y.; Yamamoto, E.; Onuki, Y.

    2006-01-01

    Soft X-ray magnetic circular dichroism has been measured at the U N 4,5 and Fe L 2,3 absorption edges of ferromagnetic UFe 2 . The orbital and spin magnetic moments of U 5f and Fe 3d electrons are evaluated by a sum-rule analysis of the XMCD data. It is confirmed that the U 5f orbital moment is parallel to the Fe 3d spin moment

  10. Small angle neutron scattering investigations of spin disorder in nanocomposite soft magnets

    International Nuclear Information System (INIS)

    Vecchini, C.; Moze, O.; Suzuki, K.; Cadogan, J.M.; Pranzas, K.; Michels, A.; Weissmueller, J.

    2006-01-01

    The technique of SANS (small angle neutron scattering) furnishes unique information on the characteristic magnetic length scales and local magnetic anisotropies at the nanoscale in nanocomposite ferromagnets. Such information is not presently available using any other microscopic technique. The basic principles and results of the technique will be presented with regard to a unique and unexpected observation of a dipole field controlled spin disorder in a prototypical soft nanocomposite ferromagnet of the Nanoperm type

  11. Bragg diffraction from magnetic materials

    DEFF Research Database (Denmark)

    Lebech, B.

    2002-01-01

    Neutrons form a penetrating neutral probe, which makes it possible to use neutrons scattering techniques to study bulk materials, localise both light and heavy atoms and to distinguish between isotopes (e.g. hydrogen and deuterium). These properties make neutron scattering complementary to X-ray ...

  12. Materials program for magnetic fusion energy

    International Nuclear Information System (INIS)

    Zwilsky, K.M.; Cohen, M.M.; Finfgeld, C.R.; Reuther, T.C.

    1978-01-01

    The Magnetic Fusion Reactor Materials Program is currently operating at a level of $7.8M. The program is divided into four technical areas which cover both short and long term problems. These are: Alloy Development for Irradiation Performance, Damage Analysis and Fundamental Studies, Plasma-Materials Interaction, and Special Purpose Materials. A description of the program planning process, the continuing management structure, and the resulting documents is presented

  13. Structure and soft magnetic properties of sputter deposited MnZn-ferrite films

    NARCIS (Netherlands)

    Gillies, M.F.; Coehoorn, R.; van Zon, J.B.A.D.; Alders, D.

    1998-01-01

    In this paper we report the soft magnetic properties of thin films of sputtered MnZn ferrite deposited on thermally oxidized Si substrates. A high deposition temperature, 600¿°C, together with the addition of water vapor to the sputtering gas was found to improve the initial ac permeability, µ. The

  14. Influence of stresses and magnetostriction on the soft magnetic behavior of metallic films

    NARCIS (Netherlands)

    Chezan, AR; Craus, CB; Chechenin, NG; Vystavel, T; Niesen, L; De Hosson, JTM; Boerma, DO

    Nanocrystalline soft magnetic Fe-Zr-N films have been successfully deposited by DC magnetron reactive sputtering. For thick films (>200 nm), the compressive stress in the as-deposited films and the positive matgnetostriction produce perpendicular anisotropy. The magnitude of this effect is smaller

  15. Computerized J-H loop tracer for soft magnetic thick films in the audio frequency range

    Directory of Open Access Journals (Sweden)

    Loizos G.

    2014-07-01

    Full Text Available A computerized J-H loop tracer for soft magnetic thick films in the audio frequency range is described. It is a system built on a PXI platform combining PXI modules for control signal generation and data acquisition. The physiscal signals are digitized and the respective data strems are processed, presented and recorded in LabVIEW 7.0.

  16. Structural Changes in Deformed Soft Magnetic Ni-Based Metallic Glass

    NARCIS (Netherlands)

    Jurikova, A.; Csach, K.; Miskuf, J.; Ocelik, V.

    The effects of intensive plastic deformation of the soft magnetic metallic glass Ni Si 13 on the structural relaxation were examined. The enthalpy changes studied by differential scanning calorimetry revealed that the intensive plastic deformation was associated with the partial structural

  17. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

    2015-03-24

    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  18. Effect of thickness on structure, microstructure, residual stress and soft magnetic properties of DC sputtered Fe65Co35 soft magnetic thin films

    International Nuclear Information System (INIS)

    Prasanna Kumari, T.; Manivel Raja, M.; Kumar, Atul; Srinath, S.; Kamat, S.V.

    2014-01-01

    The effect of film thickness on structure, microstructure, residual stress and soft magnetic properties of Fe 65 Co 35 thin films deposited on Si(001) and MgO(001) substrates was investigated by varying film thickness from 30 to 600 nm. X-ray diffraction studies showed that the FeCo films are polycrystalline in the as-deposited condition irrespective of deposition on Si or MgO substrate. The microstructure of films consisted of spherical grains for 30 nm film thickness and columnar grains for all other film thicknesses. The grain size for the films was found to increase from 15 to 50 nm with increasing film thickness. The sputtered films also exhibited tensile residual stresses with the magnitude of stress decreasing with increasing film thickness. The Fe 65 Co 35 films deposited on both substrates also exhibited very good in-plane soft magnetic properties with a saturation magnetization 4πM s of ∼23.6–23.8 kG and coercivity of ∼27–30 Oe without any under-layer only for films with thickness of 30 nm. For all other thicknesses, these films exhibited a significantly higher coercivity. The observed variations in soft magnetic properties with film thickness were explained in terms of residual stress and microstructure of the films. - Highlights: • Spherical grain morphology transformed to columnar above 30 nm film thickness. • Sputtered films exhibited tensile residual stresses decreasing with film thickness. • An in-plane coercivity of ∼27–30 Oe was achieved without any under-layer

  19. The history of permanent magnet materials

    International Nuclear Information System (INIS)

    Livingston, J.D.

    1990-01-01

    Permanent-magnet materials play a large and growing, but largely unseen, role in today's technology. Many common devices in the home and elsewhere, including appliances, computers and printers, contain permanent-magnet motors and actuators. The growth of applications for permanent magnets results in large part from the improvements in magnetic properties, which allow the engineer to design smaller, lighter and more efficient devices. The properties of the greatest technological interest are remanence, coercivity and maximum energy product. All are non-equilibrium and high structure-sensitive. Coercivity is particularly sensitive to microstructure, while remanence is sensitive to texture (crystallographic alignment). The energy product depends on both coercivity and remanence. The more than one hundredfold increase in the available energy product in this century, and the corresponding amount of magnet required for a specific application, are shown

  20. Magnetic resonance tomography in skeletal and soft tissue traumas

    International Nuclear Information System (INIS)

    Stiris, Morten G.

    2000-01-01

    MRI has revolutionised the diagnostic yield in musculo-skeletal trauma. Studies have documented that MRI can be an accurate, cost-effective means of assessing injuries in the knee, the foot and the ankle and it may also be cost-effective in other anatomic locations. MRTI may have a significant impact on decision-making in relation to these patients and on the follow-up. The patient does not need to be moved for evaluation in all the anatomical planes. Each study can also be post-processes if necessary. MRI may be used in patients with fractures for evaluation of complications. The fracture lines as well as accompanying soft tissue damage are well documented

  1. Soft Magnetic Properties of High-Entropy Fe-Co-Ni-Cr-Al-Si Thin Films

    Directory of Open Access Journals (Sweden)

    Pei-Chung Lin

    2016-08-01

    Full Text Available Soft magnetic properties of Fe-Co-Ni-Al-Cr-Si thin films were studied. As-deposited Fe-Co-Ni-Al-Cr-Si nano-grained thin films showing no magnetic anisotropy were subjected to field-annealing at different temperatures to induce magnetic anisotropy. Optimized magnetic and electrical properties of Fe-Co-Ni-Al-Cr-Si films annealed at 200 °C are saturation magnetization 9.13 × 105 A/m, coercivity 79.6 A/m, out-of-plane uniaxial anisotropy field 1.59 × 103 A/m, and electrical resistivity 3.75 μΩ·m. Based on these excellent properties, we employed such films to fabricate magnetic thin film inductor. The performance of the high entropy alloy thin film inductors is superior to that of air core inductor.

  2. How to obtain a magnetic hard-soft architecture by pulsed laser deposition

    International Nuclear Information System (INIS)

    Fix, T; Trassin, M; Hassan, R Sayed; Schmerber, G; Viart, N; Meny, C; Colis, S; Dinia, A

    2007-01-01

    In spin valve type systems, one ferromagnetic electrode must be magnetically hard to act as a reference layer while the other electrode must be magnetically soft to act as a sensor or storage layer. This magnetic hard-soft architecture can usually be obtained by four different methods: the use of two ferromagnets with different coercive fields (here CoFe 2 and Ni 80 Fe 20 ), the use of an underlayer enhancing the coercive field of one of the two ferromagnets (here Ta and Ru), the use of a ferromagnet coupled to a ferrimagnet or antiferromagnet (here NiO/CoFe 2 and CoFe 2 O 4 /CoFe 2 ), or the use of an artificial antiferromagnet (here CoFe 2 /Ru/CoFe 2 ). We show that at least the first and the third methods seem to work with pulsed laser deposition in the thermodynamic conditions used

  3. Soft magnetism, magnetostriction, and microwave properties of FeGaB thin films

    International Nuclear Information System (INIS)

    Lou, J.; Insignares, R. E.; Cai, Z.; Ziemer, K. S.; Liu, M.; Sun, N. X.

    2007-01-01

    A series of (Fe 100-y Ga y ) 1-x B x (x=0-21 and y=9-17) films were deposited; their microstructure, soft magnetism, magnetostrictive behavior, and microwave properties were investigated. The addition of B changes the FeGaB films from polycrystalline to amorphous phase and leads to excellent magnetic softness with coercivity s , self-biased ferromagnetic resonance (FMR) frequency of 1.85 GHz, narrow FMR linewidth (X band) of 16-20 Oe, and a high saturation magnetostriction constant of 70 ppm. The combination of these properties makes the FeGaB films potential candidates for tunable magnetoelectric microwave devices and other rf/microwave magnetic device applications

  4. A 3D-Printable Polymer-Metal Soft-Magnetic Functional Composite—Development and Characterization

    Directory of Open Access Journals (Sweden)

    Bilal Khatri

    2018-01-01

    Full Text Available In this work, a 3D printed polymer–metal soft-magnetic composite was developed and characterized for its material, structural, and functional properties. The material comprises acrylonitrile butadiene styrene (ABS as the polymer matrix, with up to 40 vol. % stainless steel micropowder as the filler. The composites were rheologically analyzed and 3D printed into tensile and flexural test specimens using a commercial desktop 3D printer. Mechanical characterization revealed a linearly decreasing trend of the ultimate tensile strength (UTS and a sharp decrease in Young’s modulus with increasing filler content. Four-point bending analysis showed a decrease of up to 70% in the flexural strength of the composite and up to a two-factor increase in the secant modulus of elasticity. Magnetic hysteresis characterization revealed retentivities of up to 15.6 mT and coercive forces of up to 4.31 kA/m at an applied magnetic field of 485 kA/m. The composite shows promise as a material for the additive manufacturing of passive magnetic sensors and/or actuators.

  5. Ultra-soft magnetic Co-Fe-B-Si-Nb amorphous alloys for high frequency power applications

    Science.gov (United States)

    Ackland, Karl; Masood, Ansar; Kulkarni, Santosh; Stamenov, Plamen

    2018-05-01

    With the continuous shrinkage of the footprint of inductors and transformers in modern power supplies, higher flux, while still low-loss metallic replacements of traditional ferrite materials are becoming an intriguing alternative. One candidate replacement strategy is based on amorphous CoFeBSi soft-magnetic alloys, in their metallic glass form. Here the structural and magnetic properties of two different families of CoFeBSi-based soft magnetic alloys, prepared by arc-melting and subsequent melt spinning (rapid quenching) are presented, targeting potential applications at effective frequencies of 100 kHz and beyond. The nominal alloy compositions are Co67Fe4B11Si16Mo2 representing commercial Vitrovac and Co72-xFexB28-y (where B includes non-magnetic elements such as Boron, Silicon etc. x varies between 4 and 5 % and y is varied from 0 to 2 %) denoted Alloy #1 and prepared as a possible higher performance alternative, i.e. lower power loss and lower coercivity, to commercial Vitrovac. Room temperature magnetization measurements of the arc-melted alloys reveal that compared to Vitrovac, Alloy #1 already presents a ten-fold decrease in coercivity, with Hc ˜ 1.4 Am-1 and highest figure of merit of (Ms/Hc > 96). Upon melt-spinning the alloys into thin (< 30 μm) ribbons, the alloys are essentially amorphous when analyzed by XRD. Magnetization measurements of the melt-spun ribbons demonstrate that Alloy #1 possesses a coercivity of just 2 Am-1, which represents a significant improvement compared to melt-spun ribbons of Vitrovac (17 Am-1). A set of prototype transformers of approximately 10 turns of Alloy #1 ribbon exhibits systematically Hc < 10 Am-1 at 100 kHz, without a noticeable decrease in coupled flux and saturation.

  6. Study on soft magnetic properties of Finemet-type nanocrystalline alloys with Mo substituting for Nb

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Dehui; Zhou, Bingwen; Jiang, Boyu; Ya, Bin; Zhang, Xingguo [School of Materials Science and Engineering, Dalian University of Technology, Dalian (China)

    2017-10-15

    The thermal stability, microstructure, and soft magnetic properties as a function of annealing time were studied for Fe{sub 73.5}Si{sub 13.5}B{sub 9}Cu{sub 1}Nb{sub 3-x}Mo{sub x} (x = 0, 1, 2, 3) (atom percent, at.%,) ribbons. It was found that substituting Nb by Mo reduced the thermal stability. After 15 min short time vacuum annealing, Fe{sub 73.5}Si{sub 13.5}B{sub 9}Cu{sub 1}Nb{sub 2}Mo{sub 1} and Fe{sub 73.5}Si{sub 13.5}B{sub 9}Cu{sub 1}Nb{sub 1}Mo{sub 2} samples obtained higher permeability and similar coercivity compared to the original Finemet alloy (Fe{sub 73.5}Si{sub 13.5}B{sub 9}Cu{sub 1}Nb{sub 3}), Mo substituting Nb reduced the optimum annealing time in Finemet-type alloys, and meanwhile marginally increased the saturation magnetization. Substituting all Nb by Mo led to the earlier formation of non-soft magnetic phase, thus deteriorated the soft magnetic properties. XRD and TEM structural analysis showed that in Fe{sub 73.5}Si{sub 13.5}B{sub 9}Cu{sub 1}Nb{sub 2}Mo{sub 1} and Fe{sub 73.5}Si{sub 13.5}B{sub 9}Cu{sub 1}Nb{sub 1}Mo{sub 2} samples (annealed for 15 min), nanocrystals ∝10 nm in size were obtained, and the good soft magnetic properties of these alloys could be attributed to the small grain size. The relationship between annealing time, soft magnetic properties, and microstructure was established. Reducing annealing time and temperature to obtain best soft magnetic properties could cut down the production costs of Finemet-type alloys. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Computed Tomography and Magnetic Resonance Imaging of Myoepitheliloma in the Soft Palate: A Case Report

    International Nuclear Information System (INIS)

    Lim, Hun Cheol; Yu, In Kyu; Park, Mi Ja; Jang, Dong Sik

    2011-01-01

    We report the appearance of myoepithelioma arising from minor salivary glands in the soft palate observed on computed tomography (CT) and magnetic resonance imaging (MRI). CT, the tumor was round with a smooth and partial lobulating contour, and slightly marginal contrast enhancement. On T1-weighted images, the mass had heterogeneous iso-signal intensity compared to the pharyngeal muscle. Additionally, the tumor had heterogeneously high T2 signal intensity with heterogeneously strong enhancement on the Gd-enhanced T1-weighted image. Radiologists should consider myoepithelioma in the radiological differential diagnosis of soft palate tumors.

  8. Soft magnetic properties of bulk amorphous Co-based samples

    International Nuclear Information System (INIS)

    Fuezer, J.; Bednarcik, J.; Kollar, P.

    2006-01-01

    Ball milling of melt-spun ribbons and subsequent compaction of the resulting powders in the supercooled liquid region were used to prepare disc shaped bulk amorphous Co-based samples. The several bulk samples have been prepared by hot compaction with subsequent heat treatment (500 deg C - 575 deg C). The influence of the consolidation temperature and follow-up heat treatment on the magnetic properties of bulk samples was investigated. The final heat treatment leads to decrease of the coercivity to the value between the 7.5 to 9 A/m (Authors)

  9. Diamond Beamline I16 (Materials and Magnetism)

    International Nuclear Information System (INIS)

    Collins, S. P.; Bombardi, A.; Marshall, A. R.; Williams, J. H.; Barlow, G.; Day, A. G.; Pearson, M. R.; Woolliscroft, R. J.; Walton, R. D.; Beutier, G.; Nisbet, G.

    2010-01-01

    We describe the key features and performance specifications of a facility for high-resolution single-crystal x-ray diffraction at Diamond Light Source. The scientific emphasis of the beamline is materials- and x-ray-physics, including resonant and magnetic scattering. We highlight some of the more novel aspects of the beamline design.

  10. Thermoinduced magnetization in nanoparticles of antiferromagnetic materials

    DEFF Research Database (Denmark)

    Mørup, Steen; Frandsen, Cathrine

    2004-01-01

    We show that there is a thermoinduced contribution to the magnetic moment of nanoparticles of antiferromagnetic materials. It arises from thermal excitations of the uniform spin-precession mode, and it has the unusual property that its magnitude increases with increasing temperature. This has...

  11. Lower activation materials and magnetic fusion reactors

    International Nuclear Information System (INIS)

    Conn, R.W.; Bloom, E.E.; Davis, J.W.; Gold, R.E.; Little, R.; Schultz, K.R.; Smith, D.L.; Wiffen, F.W.

    1984-01-01

    Radioactivity in fusion reactors can be effectively controlled by materials selection. The detailed relationship between the use of a material for construction of a magnetic fusion reactor and the material's characteristics important to waste disposal, safety, and system maintainability has been studied. The quantitative levels of radioactivation are presented for many materials and alloys, including the role of impurities, and for various design alternatives. A major outcome has been the development of quantitative definitions to characterize materials based on their radioactivation properties. Another key result is a four-level classification scheme to categorize fusion reactors based on quantitative criteria for waste management, system maintenance, and safety. A recommended minimum goal for fusion reactor development is a reference reactor that (a) meets the requirements for Class C shallow land burial of waste materials, (b) permits limited hands-on maintenance outside the magnet's shield within 2 days of a shutdown, and (c) meets all requirements for engineered safety. The achievement of a fusion reactor with at least the characteristics of the reference reactor is a realistic goal. Therefore, in making design choices or in developing particular materials or alloys for fusion reactor applications, consideration must be given to both the activation characteristics of a material and its engineering practicality for a given application

  12. Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces

    Science.gov (United States)

    Herbert, Robert; Kim, Jong-Hoon; Kim, Yun Soung; Lee, Hye Moon

    2018-01-01

    Flexible hybrid electronics (FHE), designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas. PMID:29364861

  13. Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces

    Directory of Open Access Journals (Sweden)

    Robert Herbert

    2018-01-01

    Full Text Available Flexible hybrid electronics (FHE, designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas.

  14. Soft Material-Enabled, Flexible Hybrid Electronics for Medicine, Healthcare, and Human-Machine Interfaces.

    Science.gov (United States)

    Herbert, Robert; Kim, Jong-Hoon; Kim, Yun Soung; Lee, Hye Moon; Yeo, Woon-Hong

    2018-01-24

    Flexible hybrid electronics (FHE), designed in wearable and implantable configurations, have enormous applications in advanced healthcare, rapid disease diagnostics, and persistent human-machine interfaces. Soft, contoured geometries and time-dynamic deformation of the targeted tissues require high flexibility and stretchability of the integrated bioelectronics. Recent progress in developing and engineering soft materials has provided a unique opportunity to design various types of mechanically compliant and deformable systems. Here, we summarize the required properties of soft materials and their characteristics for configuring sensing and substrate components in wearable and implantable devices and systems. Details of functionality and sensitivity of the recently developed FHE are discussed with the application areas in medicine, healthcare, and machine interactions. This review concludes with a discussion on limitations of current materials, key requirements for next generation materials, and new application areas.

  15. Problems in physical modeling of magnetic materials

    International Nuclear Information System (INIS)

    Della Torre, E.

    2004-01-01

    Physical modeling of magnetic materials should give insights into the basic processes involved and should be able to extrapolate results to new situations that the models were not necessarily intended to solve. Thus, for example, if a model is designed to describe a static magnetization curve, it should also be able to describe aspects of magnetization dynamics. Both micromagnetic modeling and Preisach modeling, the two most popular magnetic models, fulfill this requirement, but in the process of fulfilling this requirement, they both had to be modified in some ways. Hence, we should view physical modeling as an iterative process whereby we start with some simple assumptions and refine them as reality requires. In the process of refining these assumptions, we should try to appeal to physical arguments for the modifications, if we are to come up with good models. If we consider phenomenological models, on the other hand, that is as axiomatic models requiring no physical justification, we can follow them logically to see the end and examine the consequences of their assumptions. In this way, we can learn the properties, limitations and achievements of the particular model. Physical and phenomenological models complement each other in furthering our understanding of the behavior of magnetic materials

  16. Magnetic properties and loss separation in FeSi/MnZnFe2O4 soft magnetic composites

    International Nuclear Information System (INIS)

    Lauda, M.; Füzer, J.; Kollár, P.; Strečková, M.; Bureš, R.; Kováč, J.; Baťková, M.; Baťko, I.

    2016-01-01

    We investigated composites that have been prepared from FeSi powders covered with MnZnFe 2 O 4 (MnZn ferrite), which was prepared by sol–gel synthesis accompanied with the auto-combustion process. The aim of this paper is to analyze the complex permeability and core losses of prepared samples with different amount of MnZn ferrite. The microstructure and the powder morphology were examined by scanning electron microscopy. Magnetic measurements on bulk samples were carried out using a vibrating sample magnetometer, an impedance analyzer and hysteresisgraphs. The results indicate that the composites with 2.6 wt% MnZn ferrite show better soft magnetic properties than the composites with about 6 wt% MnZn ferrite. - Highlights: • Successful preparation of soft magnetic composite FeSi/MnZnFe 2 O 4 . • Study of the complex magnetic permeability. • Comparison of different compositions of prepared SMC's. • Determination of parts of magnetic losses.

  17. De Magnete et Meteorite: Cosmically Motivated Materials

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, LH; Pinkerton, FE; Bordeaux, N; Mubarok, A; Poirier, E; Goldstein, JI; Skomski, R; Barmak, K

    2014-01-01

    Meteorites, likely the oldest source of magnetic material known to mankind, are attracting renewed interest in the science and engineering community. Worldwide focus is on tetrataenite, a uniaxial ferromagnetic compound with the tetragonal L1(0) crystal structure comprised of nominally equiatomic Fe-Ni that is found naturally in meteorites subjected to extraordinarily slow cooling rates, as low as 0.3 K per million years. Here, the favorable permanent magnetic properties of bulk tetrataenite derived from the meteorite NWA 6259 are quantified. The measured magnetization approaches that of Nd-Fe-B (1.42 T) and is coupled with substantial anisotropy (1.0-1.3 MJ/m(3)) that implies the prospect for realization of technologically useful coercivity. A highly robust temperature dependence of the technical magnetic properties at an elevated temperature (20-200 degrees C) is confirmed, with a measured temperature coefficient of coercivity of -0.005%/ K, over one hundred times smaller than that of Nd-Fe-B in the same temperature range. These results quantify the extrinsic magnetic behavior of chemically ordered tetrataenite and are technologically and industrially significant in the current context of global supply chain limitations of rare-earth metals required for present-day high-performance permanent magnets that enable operation of a myriad of advanced devices and machines.

  18. Sub-50 nm Scale to Micrometer Scale Soft Lithographic Patterning of Functional Materials

    NARCIS (Netherlands)

    George, A.

    2011-01-01

    This PhD thesis addresses two major issues: 1) Fabricating nanometer-scale patterns of functional materials, 2) Extending the applicability of soft lithographic processes to a wide range of functional materials on conventional silicon substrates and flexible plastic substrates. This thesis describes

  19. Out-of-equilibrium self-assembly approaches for new soft materials

    NARCIS (Netherlands)

    Hendriksen, W.E.

    2015-01-01

    Living creatures exists for an important part out of soft material, such as skin, organs and cells, that are out-of-equilibrium formed by the self-assembly of molecular building blocks. Natural materials are continuously active with dynamic processes occurring, such as growth, shrinkage and

  20. Earthquake statistics inferred from plastic events in soft-glassy materials

    NARCIS (Netherlands)

    Benzi, Roberto; Toschi, Federico; Trampert, Jeannot

    2016-01-01

    We propose a new approach for generating synthetic earthquake catalogues based on the physics of soft glasses. The continuum approach produces yield-stress materials based on Lattice-Boltzmann simulations. We show that, if the material is stimulated below yield stress, plastic events occur, which

  1. Iron-borosilicate soft magnetic composites: The correlation between processing parameters and magnetic properties for high frequency applications

    Energy Technology Data Exchange (ETDEWEB)

    Gheiratmand, T., E-mail: t.gheiratmand@yahoo.com; Madaah Hosseini, H.R., E-mail: Madaah@sharif.edu; Seyed Reihani, S.M.

    2017-05-01

    Iron-borosilicate soft magnetic composites are suitable magnetic materials for high temperature and high frequency applications. In this research two different techniques have been applied to fabricate these composites: uniaxial pressing following by sintering and spark plasma sintering. Different processing parameters including the content of borosilicate, the amount of compaction pressure and the size of iron particles have been evaluated through the study of microstructure and magnetic properties. The microstructural observations showed that the borosilicate is distributed on the iron grain boundaries enhancing the resistivity and causing the loss of eddy currents. Increasing the compaction pressure was led to the decrease of electrical resistivity. By increasing the frequency both real and imaginary parts of permeability decreased. The use of higher content of borosilicate resulted in the lower decreasing slop of permeability. Best combination of density, permeability and electrical resistivity was obtained in the sample with 2 wt% of borosilicate. In addition, the densification of powders with fine particles was more difficult than coarse particles due to the inter particles friction and bridging effects. Furthermore, as the particles size increases the size of open porosities before sintering where the borosilicate could aggregate enhances. This could yields to the increase in the electrical resistivity. The high ratio of surface to the volume in the powders with fine particles results in the developing the demagnetizing fields and subsequently, decreasing the permeability. The highest relative density (99.99% of theoretical density) with best distribution of borosilicate was achieved in the composites produced by spark plasma sintering (SPS). The relaxation frequency, obtained from imaginary part of permeability, was found as 340 Hz in the composites made by SPS. - Highlights: • Iron-borosilicate SMC was produced for high temperature and frequency

  2. Soft x-ray resonant magnetic powder diffraction on PrNiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Staub, U [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); GarcIa-Fernandez, M [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Mulders, A M [Department of Applied Physics, Curtin University of Technology, GPO Box U1987, Perth WA 6845 (Australia); Bodenthin, Y [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); MartInez-Lope, M J [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Alonso, J A [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)

    2007-03-07

    We report on the first soft x-ray resonant powder diffraction experiments performed at the Ni L{sub 2,3} edges of PrNiO{sub 3}. The temperature, polarization and energy dependence of the (1/2 0 1/2) reflection indicates a magnetic origin for the signal. This experiment demonstrates that x-ray resonant magnetic powder diffraction can be relatively easily performed in the soft x-ray regime due to the very large enhancement factors at the absorption edges. Such experiments allow us to extract important information on the electronic states of the d shell. Similar results can be anticipated from orbital reflections measured in a powder. (fast track communication)

  3. Magnetic resonance imaging of local soft tissue inflammation using gadolinium-DTPA

    International Nuclear Information System (INIS)

    Paajanen, H.; Brasch, R.C.; Schmiedl, U.; Ogan, M.

    1987-01-01

    Chemical inflammation was induced subcutaneously in 10 rats using carrageenan mucopolysaccharide. Dual spin echo (SE) imaging of inflammatory loci was performed employing a 0.35 tesla resistive magnet. In addition, gadolinium-DTPA was administrated intravenously into 5 rats to evaluate the potential benefits of paramagnetic contrast medium for the detection and characterization of inflammatory loci. T2 weighted SE images demonstrated the edematous lesions as zones of high intensity. This was attributed to the increased relaxation times of lesions when compared to the adjacent soft tissue. The inflammation was also delineated on T1 weighted SE images, but only after injection of paramagnetic Gd-DTPA. Carrageenan mucopolysaccharide-induced lesions provide a useful experimental model for in viva evaluation of soft tissue inflammation using magnetic resonance imaging. No special benefit of paramagnetic contrast enhancement was demonstrated in this model of local edema. (orig.)

  4. Preparation of Fe–Si–Ni soft magnetic composites with excellent high-frequency properties

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Wu, Chen, E-mail: chen_wu@zju.edu.cn; Yan, Mi, E-mail: mse_yanmi@zju.edu.cn

    2015-05-01

    Fe–Si–Ni powders were firstly prepared into soft magnetic composites (SMCs) by ball milling, surface passivation and subsequent compaction. The morphology, phase composition, and magnetic properties of the Fe–Si–Ni powders and their high-frequency performance as SMCs were investigated. The Fe–Si–Ni powders, with saturation magnetization (M{sub s}) of 254.40 emu/g after annealing, were milled down to particle sizes ranging from 40 μm to 150 μm. Surface passivation of the powders was carried out with 0.2–1.0 wt% phosphoric acid solution prior to compaction. Evolution of the high-frequency properties for the Fe–Si–Ni SMCs with the passivator concentration and the molding pressure was studied. With optimized preparation parameters, high saturation flux density (B{sub s}) of 1.23 T, stable permeability, and superior dc-bias property with a percentage permeability above 70% while H=50 Oe were achieved for the Fe–Si–Ni SMC. Minimum core loss (285 mW/cm{sup 3}) was also measured at 50 kHz for B{sub m}=50 mT. - Highlights: • Fe–Si–Ni as a new type of magnetic powder has been prepared into soft magnetic composites. • Effective surface passivation of the Fe–Si–Ni powders can be achieved by phosphate treatment. • Influence of the passivator concentration and molding pressure has been investigated. • The obtained Fe–Si–Ni soft magnetic composites exhibit excellent high-frequency performance.

  5. Hard and soft supersymmetry breaking for ‘graphinos’ in uniform magnetic fields

    International Nuclear Information System (INIS)

    Hernández-Ortíz, S; Raya, A; Murguía, G

    2012-01-01

    Using irreducible and reducible representations of the Dirac matrices, we study the two- and four-component quantum mechanical supersymmetric (SUSY) theories for ultrarelativistic fermions in (2 + 1) dimensions (‘graphinos’) in a background uniform magnetic field perpendicular to their plane of motion. We then consider ordinary and parity-violating mass terms and identify the former as a soft SUSY breaking term and the latter as the hard SUSY breaking one. (paper)

  6. Axial Magneto-Inductive Effect in Soft Magnetic Microfibers, Test Methodology, and Experiments

    Science.gov (United States)

    2016-03-24

    Nickle nT Nano- Tesla Si Silicon V Volts w Exchange Energy W Watts Zm Coil Impedance, measured  Circumferential Field Direction T Micro... Tesla  Ratio of Coil Length to Diameter  Ohm ° Degrees 1 (2 blank) 1. INTRODUCTION Magneto-induction (MI) effects in soft...axial magnetic field is utilized to excite the fiber. Previous investigators have demonstrated this effect with small coils applied directly to the

  7. Optimizing Energy Conversion: Magnetic Nano-materials

    Science.gov (United States)

    McIntyre, Dylan; Dann, Martin; Ilie, Carolina C.

    2015-03-01

    We present herein the work started at SUNY Oswego as a part of a SUNY 4E grant. The SUNY 4E Network of Excellence has awarded SUNY Oswego and collaborators a grant to carry out extensive studies on magnetic nanoparticles. The focus of the study is to develop cost effective rare-earth-free magnetic materials that will enhance energy transmission performance of various electrical devices (solar cells, electric cars, hard drives, etc.). The SUNY Oswego team has started the preliminary work for the project and graduate students from the rest of the SUNY 4E team (UB, Alfred College, Albany) will continue the project. The preliminary work concentrates on analyzing the properties of magnetic nanoparticle candidates, calculating molecular orbitals and band gap, and the fabrication of thin films. SUNY 4E Network of Excellence Grant.

  8. Contactless remote induction of shear waves in soft tissues using a transcranial magnetic stimulation device

    International Nuclear Information System (INIS)

    Grasland-Mongrain, Pol; Miller-Jolicoeur, Erika; Cloutier, Guy; Tang, An; Catheline, Stefan

    2016-01-01

    This study presents the first observation of shear waves induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel phantom and a chicken breast sample. Using an ultrafast ultrasound scanner, shear waves of respective amplitudes of 5 and 0.5 μm were observed. Experimental and numerical results were in good agreement. This study constitutes the framework of an alternative shear wave elastography method. (paper)

  9. Contactless remote induction of shear waves in soft tissues using a transcranial magnetic stimulation device

    Science.gov (United States)

    Grasland-Mongrain, Pol; Miller-Jolicoeur, Erika; Tang, An; Catheline, Stefan; Cloutier, Guy

    2016-03-01

    This study presents the first observation of shear waves induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel phantom and a chicken breast sample. Using an ultrafast ultrasound scanner, shear waves of respective amplitudes of 5 and 0.5 μm were observed. Experimental and numerical results were in good agreement. This study constitutes the framework of an alternative shear wave elastography method.

  10. Design Methodology for Magnetic Field-Based Soft Tri-Axis Tactile Sensors.

    Science.gov (United States)

    Wang, Hongbo; de Boer, Greg; Kow, Junwai; Alazmani, Ali; Ghajari, Mazdak; Hewson, Robert; Culmer, Peter

    2016-08-24

    Tactile sensors are essential if robots are to safely interact with the external world and to dexterously manipulate objects. Current tactile sensors have limitations restricting their use, notably being too fragile or having limited performance. Magnetic field-based soft tactile sensors offer a potential improvement, being durable, low cost, accurate and high bandwidth, but they are relatively undeveloped because of the complexities involved in design and calibration. This paper presents a general design methodology for magnetic field-based three-axis soft tactile sensors, enabling researchers to easily develop specific tactile sensors for a variety of applications. All aspects (design, fabrication, calibration and evaluation) of the development of tri-axis soft tactile sensors are presented and discussed. A moving least square approach is used to decouple and convert the magnetic field signal to force output to eliminate non-linearity and cross-talk effects. A case study of a tactile sensor prototype, MagOne, was developed. This achieved a resolution of 1.42 mN in normal force measurement (0.71 mN in shear force), good output repeatability and has a maximum hysteresis error of 3.4%. These results outperform comparable sensors reported previously, highlighting the efficacy of our methodology for sensor design.

  11. A facile way to realize exchange coupling interaction in hard/soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dongyun, E-mail: lidongyun@cjlu.edu.cn [College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Wang, Fan [College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Xia, Ailin, E-mail: alxia@126.com [Anhui Key Laboratory of Metal Materials and Processing, School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243032 (China); Zhang, Lijiao [School of Science, Hebei University of Science and Technology, Shijiazhuang 050018 (China); Li, Tingting; Jin, Chuangui; Liu, Xianguo [Anhui Key Laboratory of Metal Materials and Processing, School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243032 (China)

    2016-11-01

    SrFe{sub 12}O{sub 19}/CoFe{sub 2}O{sub 4} and SrFe{sub 12}O{sub 19}/Fe–B hard/soft magnetic composites were obtained by using powders synthesized via a hydrothermal and a molten salt method, respectively. The exchange coupling interaction was found to exist in the composites after a facile grinding according to the results of magnetic hysteresis loops and irreversible sloping recoil loops. It can be found that different grinding time affects their magnetic properties slightly. Our study proves that the conditions of realizing exchange coupling interaction may not be so stringent. - Highlights: • SrM/CFO and SrM/Fe–B with exchange coupling were obtained via a grinding way. • Different grinding time affects their magnetic properties slightly. • The conditions of realizing exchange coupling may not be so stringent.

  12. Magnetic and electronic properties of RNiO{sub 3} (R = Pr, Nd, Eu, Ho and Y) perovskites studied by resonant soft x-ray magnetic powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Bodenthin, Y; Staub, U; Piamonteze, C; Garcia-Fernandez, M [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Martinez-Lope, M J; Alonso, J A, E-mail: urs.staub@psi.ch [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)

    2011-01-26

    Soft x-ray resonant magnetic powder diffraction of the (1/2 0 1/2) reflection at the Ni L{sub 2,3} edges is used to study the magnetic and electronic properties of a series of RNiO{sub 3} materials (with R = Pr, Nd, Eu, Ho and Y) below the metal-insulator transition. The polarization and energy dependence of the reflection gives further support for a non-collinear magnetic structure and charge disproportionation in the whole RNiO{sub 3} series. Only small changes in the spectra of the magnetic (1/2 0 1/2) reflection and in the absorption spectra could be detected. The results are discussed with comparison to charge transfer multiplet calculations. Our results emphasize that the lighter and heavier RNiO{sub 3} compounds are very similar from the point of view of their local electronic and magnetic state despite the strong change of the metal-to-insulator transition temperature.

  13. Modification of structural and magnetic properties of soft magnetic multi-component metallic glass by 80 MeV {sup 16}O{sup 6+} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kane, S.N., E-mail: kane_sn@yahoo.com [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Shah, M.; Satalkar, M.; Gehlot, K. [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Kulriya, P.K.; Avasthi, D.K. [Inter-University Accelerator Centre, P.O. Box No. 10502, Aruna Asaf Ali Marg, New Delhi 110067 (India); Sinha, A.K. [Raja Ramanna Centre for Advanced Technology, P.O. CAT, Indore 452013 (India); Modak, S.S. [Physics Department, Jaypee University of Eng. & Tech., A-B Road, Raghogarh, Guna 473226 (India); Ghodke, N.L.; Reddy, V.R. [UGC-DAE CSR, University Campus, Khandwa Road, Indore 452001 (India); Varga, L.K. [RISSPO, Hungarian Academy of Sciences, P.O. Box 49, 1525 Budapest (Hungary)

    2016-07-15

    Effect of 80 MeV {sup 16}O{sup 6+} ion irradiation in amorphous Fe{sub 77}P{sub 8}Si{sub 3}C{sub 5}Al{sub 2}Ga{sub 1}B{sub 4} alloy is reported. Electronic energy loss induced modifications in the structural and, magnetic properties were monitored by synchrotron X-ray diffraction (SXRD), Mössbauer and, magnetic measurements. Broad amorphous hump seen in SXRD patterns reveals the amorphous nature of the studied specimens. Mössbauer measurements suggest that: (a) alignment of atomic spins within ribbon plane, (b) changes in average hyperfine field suggests radiation-induced decrease in the inter atomic distance around Mössbauer (Fe) atom, (c) hyperfine field distribution confirms the presence of non-magnetic elements (e.g. – B, P, C) in the first near-neighbor shell of the Fe atom, thus reducing its magnetic moment, and (d) changes in isomer shift suggests variation in average number of the metalloid near neighbors and their distances. Minor changes in soft magnetic behavior – watt loss and, coercivity after an irradiation dose of 2 × 10{sup 13} ions/cm{sup 2} suggests prospective application of Fe{sub 77}P{sub 8}Si{sub 3}C{sub 5}Al{sub 2}Ga{sub 1}B{sub 4} alloy as core material in accelerators (radio frequency cavities).

  14. High performance of low cost soft magnetic materials

    Indian Academy of Sciences (India)

    Author Affiliations. Josefina M Silveyra1 Emília Illeková2 Marco Coïsson3 Federica Celegato3 Franco Vinai3 Paola Tiberto3 Javier A Moya1 Victoria J Cremaschi1. Lab. de Sólidos Amorfos, INTECIN, FIUBA-CONICET, Paseo Colón 850, (C1063ACV) Buenos Aires, Argentina; Institute of Physics SAS, Dúbravská cesta 9, 845 ...

  15. Hybrid nanostructured materials with tunable magnetic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Martínez, Nubia E.; Garza-Navarro, M. A., E-mail: marco.garzanr@uanl.edu.mx; García-Gutiérrez, Domingo; González-González, Virgilio A.; Torres-Castro, Alejandro; Ortiz-Méndez, U. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica (Mexico)

    2014-12-15

    We report on the development of hybrid nanostructured materials (HNM) based on spinel-metal-oxide nanoparticles (SMON) stabilized in carboxymethyl-cellulose (CMC)/cetyltrimethyl-ammonium-bromide (CTAB) templates, with tunable magnetic characteristics. These HNM were synthesized using a one-pot chemical approach to obtain CMC/CTAB templates with controllable size and morphology, where the SMON could be densely arranged. The synthesized HNM were characterized by transmission electron microscopy and its related techniques, such as bright field (BF) and Z-contrast (HAADF-STEM) imaging, and selected area electron diffraction, as well as static magnetic measuring. Experimental evidence suggests that the morphology and size of the CMC/CTAB templates are highly dependent on the weight ratio of CTAB:SMON, as well as the hydration days of the CMC that is used for the synthesis of the HNM. Controlling these parameters allows modifying the density of the SMON arrangement in the CMC/CTAB templates. Moreover, magnetic features such as remanence, coercivity, and blocking/de-blocking processes of the particles’ magnetic moments are highly dependent on the interactions among the SMON assembled in the templates. Hence, the magnetic characteristics of HNM can be modulated or tuned by controlling the manner the SMON are arranged within the CMC/CTAB templates.

  16. Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics.

    Science.gov (United States)

    Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Jaung, Jae Yun; Kim, Yong-Hoon; Park, Sung Kyu

    2015-09-28

    The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

  17. Fe-based soft magnetic composites coated with NiZn ferrite prepared by a co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Yuandong; Yi, Yi; Li, Liya; Ai, Hengyu; Wang, Xiaoxu [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Chen, Lulu [Jiangsu Eagle-globe Group Co., Ltd., Nantong 226600 (China)

    2017-04-15

    Fe powder was coated with NiZn ferrite by a co-precipitation method using chlorate as the raw material. Soft magnetic composites were manufactured via compaction and heat treatment of the coated powder. The coated powder and heat treated powder were analysed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy. Their magnetic properties were determined using a Quantum Design-Vibrating Sample Magnetometer (QD-VSM). The composites were analysed with SEM and EDS. The permeability and magnetic loss of the composites were measured with a B-H curve analyzer. The results show that, using the co-precipitation method, the raw precipitate was successfully prepared and coated the pure Fe powder and turned into spinel NiZn ferrite treated at 600 ℃ for 1 h. After heat treatment at 500 ℃ under air, the insulation coating layer of soft magnetic composite (SMC) was not destroyed and containing Fe, Ni, Zn and oxygen. The permeabilities of the SMC are stable at edge of the 2–200 kHz frequency range and the total loss was lower. - Graphical abstract: Scanning electron microscopy (SEM) images of Fe/(NiZn)Fe{sub 2}O{sub 4} composite powder heated at 600 ℃ for 1 h. - Highlights: • Fe particles were coated with (NiZn)Fe{sub 2}O{sub 4} via a co-precipitation and calcined method. • Coating layers were uniform and dense. • The permeabilities of the SMC are stable at edge of the 2–200 kHz frequency range.

  18. A Biogeotechnical approach to Stabilize Soft Marine Soil with a Microbial Organic Material called Biopolymer

    Science.gov (United States)

    Chang, I.; Cho, G. C.; Kwon, Y. M.; Im, J.

    2017-12-01

    The importance and demands of offshore and coastal area development are increasing due to shortage of usable land and to have access to valuable marine resources. However, most coastal soils are soft sediments, mainly composed with fines (silt and clay) and having high water and organic contents, which induce complicated mechanical- and geochemical- behaviors and even be insufficient in Geotechnical engineering aspects. At least, soil stabilization procedures are required for those soft sediments, regardless of the purpose of usage on the site. One of the most common soft soil stabilization method is using ordinary cement as a soil strengthening binder. However, the use of cement in marine environments is reported to occur environmental concerns such as pH increase and accompanying marine ecosystem disturbance. Therefore, a new environmentally-friendly treatment material for coastal and offshore soils. In this study, a biopolymer material produced by microbes is introduced to enhance the physical behavior of a soft tidal flat sediment by considering the biopolymer rheology, soil mineralogy, and chemical properties of marine water. Biopolymer material used in this study forms inter-particle bonds between particles which is promoted through cation-bridges where the cations are provided from marine water. Moreover, biopolymer treatment renders unique stress-strain relationship of soft soils. The mechanical stiffness (M) instantly increase with the presence of biopolymer, while time-dependent settlement behavior (consolidation) shows a big delay due to the viscous biopolymer hydrogels in pore spaces.

  19. Key electronic states in lithium battery materials probed by soft X-ray spectroscopy

    International Nuclear Information System (INIS)

    Yang, Wanli; Liu, Xiaosong; Qiao, Ruimin; Olalde-Velasco, Paul; Spear, Jonathan D.; Roseguo, Louis; Pepper, John X.; Chuang, Yi-de; Denlinger, Jonathan D.; Hussain, Zahid

    2013-01-01

    Highlights: •Key electronic states in battery materials revealed by soft X-ray spectroscopy. •Soft X-ray absorption consistently probes Mn oxidation states in different systems. •Soft X-ray absorption and emission fingerprint battery operations in LiFePO 4 . •Spectroscopic guidelines for selecting/optimizing polymer materials for batteries. •Distinct SEI formation on same electrode material with different crystal orientations. -- Abstract: The formidable challenges for developing a safe, low-cost, high-capacity, and high-power battery necessitate employing advanced tools that are capable of directly probing the key electronic states relevant to battery performance. Synchrotron based soft X-ray spectroscopy directly measures both the occupied and unoccupied states in the vicinity of the Fermi level, including transition-metal-3d and anion-p states. This article presents the basic concepts on how fundamental physics in electronic structure could provide valuable information for lithium-ion battery applications. We then discuss some of our recent studies on transition-metal oxide based cathodes, silicon based anode, and solid-electrolyte-interphase through soft X-ray absorption and emission spectroscopy. We argue that spectroscopic results reveal the evolution of electronic states for fingerprinting, understanding, and optimizing lithium-ion battery operations

  20. Influence of soft ferromagnetic sections on the magnetic flux density profile of a large grain, bulk Y–Ba–Cu–O superconductor

    International Nuclear Information System (INIS)

    Philippe, M P; Wéra, L; Fagnard, J-F; Vanderheyden, B; Vanderbemden, P; Ainslie, M D; Dennis, A R; Shi, Y-H; Cardwell, D A

    2015-01-01

    Bulk, high temperature superconductors have significant potential for use as powerful permanent magnets in a variety of practical applications due to their ability to trap record magnetic fields. In this paper, soft ferromagnetic sections are combined with a bulk, large grain Y–Ba–Cu–O high temperature superconductor to form superconductor/ferromagnet hybrid structures. We study how the ferromagnetic sections influence the shape of the profile of the trapped magnetic induction at the surface of each structure and report the surface magnetic flux density measured by Hall probe mapping. These configurations have been modelled using a 2D axisymmetric finite element method based on the H-formulation and the results show excellent qualitative and quantitative agreement with the experimental measurements. The model has also been used to study the magnetic flux distribution and predict the behaviour for other constitutive laws and geometries. The results show that the ferromagnetic material acts as a magnetic shield, but the flux density and its gradient are enhanced on the face opposite to the ferromagnet. The thickness and saturation magnetization of the ferromagnetic material are important and a characteristic ferromagnet thickness d* is derived: below d*, saturation of the ferromagnet occurs, and above d*, a weak thickness-dependence is observed. The influence of the ferromagnet is observed even if its saturation magnetization is lower than the trapped flux density of the superconductor. Conversely, thin ferromagnetic discs can be driven to full saturation even though the outer magnetic field is much smaller than their saturation magnetization. (paper)

  1. Innovative soft magnetic multilayers with enhanced in-plane anisotropy and ferromagnetic resonance frequency for integrated RF passive devices

    Science.gov (United States)

    Falub, Claudiu V.; Bless, Martin; Hida, Rachid; MeduÅa, Mojmír; Ammann, Arnold

    2018-04-01

    We present an innovative, economical method for manufacturing soft magnetic materials that may pave the way for integrated thin film magnetic cores with dramatically improved properties. Soft magnetic multilayered thin films based on the Fe-28%Co20%B (at.%) and Co-4.5%Ta4%Zr (at.%) amorphous alloys are deposited on 8" bare Si and Si/200nm-thermal-SiO2 wafers in an industrial, high-throughput Evatec LLS EVO II magnetron sputtering system. The multilayers consist of stacks of alternating 80-nm-thick ferromagnetic layers and 4-nm-thick Al2O3 dielectric interlayers. Since in our dynamic sputter system the substrate cage rotates continuously, such that the substrates face different targets alternatively, each ferromagnetic sublayer in the multilayer consists of a fine structure comprising alternating CoTaZr and FeCoB nanolayers with very sharp interfaces. We adjust the thickness of these individual nanolayers between 0.5 and 1.5 nm by changing the cage rotation speed and the power of each gun, which is an excellent mode to engineer new, composite ferromagnetic materials. Using X-ray reflectometry (XRR) we reveal that the interfaces between the FeCoB and CoTaZr nanolayers are perfectly smooth with roughness of 0.2-0.3 nm. Kerr magnetometry and B-H looper measurements for the as-deposited samples show that the coercivity of these thin films is very low, 0.2-0.3 Oe, and gradually scales up with the thickness of FeCoB nanolayers, i.e. with the increase of the overall Fe content from 0 % (e.g. CoTaZr-based multilayers) to 52 % (e.g. FeCoB-based multilayers). We explain this trend in the random anisotropy model, based on considerations of grain size growth, as revealed by glancing angle X-ray diffraction (GAXRD), but also because of the increase of magnetostriction with the increase of Fe content as shown by B-H looper measurements performed on strained wafers. The unexpected enhancement of the in-plane anisotropy field from 18.3 Oe and 25.8 Oe for the conventional Co

  2. Interference between magnetism and surface roughness in coherent soft X-ray scattering

    International Nuclear Information System (INIS)

    Rahmim, A.; Tixier, S.; Tiedje, T.; Eisebitt, S.; Lorgen, M.; Scherer, R.; Eberhardt, W.; Luning, J.; Scholl, A.

    2002-01-01

    In coherent soft x-ray scattering from magnetically ordered surfaces there are contributions to the scattering from the magnetic domains, from the surface roughness, and from the diffraction associated with the pinhole aperture used as a coherence filter. In the present work, we explore the interplay between these contributions by analyzing speckle patterns in diffusely scattered x rays from the surface of magnetic thin films. Magnetic contrast from the surface of anti ferro magnetically ordered LaFeO3 films is caused by magnetic linear dichroism in resonant x-ray scattering. The samples studied possess two types of domains with their magnetic orientations perpendicular to each other. By tuning the x-ray energy from one of the two Fe-L3 resonant absorption peaks to the other, the relative amplitudes of the x-ray scattering from the two domains is inverted which results in speckle pattern changes. A theoretical expression is derived for the intensity correlation between the speckle patterns with the magnetic contrast inverted and not inverted. The model is found to be in good agreement with the x-ray-scattering observations and independent measurements of the surface roughness. An analytical expression for the correlation function gives an explicit relation between the change in the speckle pattern and the roughness, and magnetic and aperture scattering. Changes in the speckle pattern are shown to arise from beating of magnetic scattering with the roughness scattering and diffraction from the aperture. The largest effect is found when the surface roughness scatter is comparable in intensity to the magnetic scatter

  3. Improving soft magnetic properties of Mn-Zn ferrite by rare earth ions doping

    Science.gov (United States)

    Zhong, X. C.; Guo, X. J.; Zou, S. Y.; Yu, H. Y.; Liu, Z. W.; Zhang, Y. F.; Wang, K. X.

    2018-04-01

    Mn-Zn ferrites doped with different Sm2O3, Gd2O3, Ce2O3 or Y2O3 were prepared by traditional ceramic technology using industrial pre-sintered powders. A small amount of Sm2O3, Gd2O3, Ce2O3 or Y2O3 can significantly improve the microstructure and magnetic properties. The single spinel phase structure can be maintained with the doping amount up to 0.07 wt.%. A refined grain structure and uniform grain size distribution can be obtained by doping. For all rare earth oxides, a small amount of doping can significantly increase the permeability and reduce the coercivity and magnetic core loss. The optimized doping amount for Sm2O3 or Gd2O3 is 0.01 wt.%, while for Ce2O3 or Y2O3 is 0.03 wt.%. A further increase of the doping content will lead to reduced soft magnetic properties. The ferrite sample with 0.01 wt.% Sm2O3 exhibits the good magnetic properties with permeability, loss, and coercivity of 2586, 316 W/kg, and 24A/m, respectively, at 200 mT and 100 kHz. The present results indicate that rare earth doping can be suggested to be one of the effective ways to improve the performance of soft ferrites.

  4. Improving soft magnetic properties of Mn-Zn ferrite by rare earth ions doping

    Directory of Open Access Journals (Sweden)

    X. C. Zhong

    2018-04-01

    Full Text Available Mn-Zn ferrites doped with different Sm2O3, Gd2O3, Ce2O3 or Y2O3 were prepared by traditional ceramic technology using industrial pre-sintered powders. A small amount of Sm2O3, Gd2O3, Ce2O3 or Y2O3 can significantly improve the microstructure and magnetic properties. The single spinel phase structure can be maintained with the doping amount up to 0.07 wt.%. A refined grain structure and uniform grain size distribution can be obtained by doping. For all rare earth oxides, a small amount of doping can significantly increase the permeability and reduce the coercivity and magnetic core loss. The optimized doping amount for Sm2O3 or Gd2O3 is 0.01 wt.%, while for Ce2O3 or Y2O3 is 0.03 wt.%. A further increase of the doping content will lead to reduced soft magnetic properties. The ferrite sample with 0.01 wt.% Sm2O3 exhibits the good magnetic properties with permeability, loss, and coercivity of 2586, 316 W/kg, and 24A/m, respectively, at 200 mT and 100 kHz. The present results indicate that rare earth doping can be suggested to be one of the effective ways to improve the performance of soft ferrites.

  5. Conducting single-molecule magnet materials.

    Science.gov (United States)

    Cosquer, Goulven; Shen, Yongbing; Almeida, Manuel; Yamashita, Masahiro

    2018-05-11

    Multifunctional molecular materials exhibiting electrical conductivity and single-molecule magnet (SMM) behaviour are particularly attractive for electronic devices and related applications owing to the interaction between electronic conduction and magnetization of unimolecular units. The preparation of such materials remains a challenge that has been pursued by a bi-component approach of combination of SMM cationic (or anionic) units with conducting networks made of partially oxidized (or reduced) donor (or acceptor) molecules. The present status of the research concerning the preparation of molecular materials exhibiting SMM behaviour and electrical conductivity is reviewed, describing the few molecular compounds where both SMM properties and electrical conductivity have been observed. The evolution of this research field through the years is discussed. The first reported compounds are semiconductors in spite being able to present relatively high electrical conductivity, and the SMM behaviour is observed at low temperatures where the electrical conductivity of the materials is similar to that of an insulator. During the recent years, a breakthrough has been achieved with the coexistence of high electrical conductivity and SMM behaviour in a molecular compound at the same temperature range, but so far without evidence of a synergy between these properties. The combination of high electrical conductivity with SMM behaviour requires not only SMM units but also the regular and as far as possible uniform packing of partially oxidized molecules, which are able to provide a conducting network.

  6. Novel trends in the study of magnetically soft Co-based amorphous glass-coated wires

    International Nuclear Information System (INIS)

    Chiriac, H.; Ovari, T.-A.

    2011-01-01

    An overview of the recent progress and state-of-the-art results in the investigation of the amorphous glass-coated wires with nearly zero magnetostriction is presented. These versatile microwires display enhanced soft magnetic properties, which make them suitable as sensing elements in various sensors for biomedical and automotive applications. Current results on their magnetic characteristics refer to a major refinement of their core-shell magnetic structure by taking into account the interdomain wall and to the thorough analysis of the magnetization within the outer shell. Experimental techniques such as giant magneto-impedance, magneto-resistance, and magneto-optical Kerr effect measurements are employed to prove the outcome of the theoretical calculations. The impact of the magnetic structure of the outer shell on the propagation of domain walls in bistable amorphous wires is analyzed. Very recent results on the magnetization process in nearly zero magnetostrictive amorphous glass-coated wires with submicron dimensions are also reviewed. - Highlights: → The most recent advances in the study of amorphous glass-coated wires with nearly zero magnetostriction are surveyed. → Major progress in the study of their domain structure: the wide interdomain wall, which affects high frequency phenomena. → The magnetization of the outer shell depends on wire diameter and affects the wall propagation in bistable samples. → These novel results are important for future sensor applications of nearly zero magnetostrictive amorphous microwires.

  7. Tests on irradiated magnet-insulator materials

    International Nuclear Information System (INIS)

    Schmunk, R.E.; Miller, L.G.; Becker, H.

    1983-01-01

    Fusion-reactor coils, located in areas where they will be only partially shielded, must be fabricated from materials which are as resistant to radiation as possible. They will probably incorporate resistive conductors with either water or cryogenic cooling. Inorganic insulators have been recommended for these situations, but the possibility exists that some organic insulators may be usuable as well. Results were previously reported for irradiation and testing of three glass reinforced epoxies: G-7, G-10, and G-11. Thin disks of these materials, nominally 0.5 mm thick by 11.1 mm diameter, were tested in compressive fatigue, a configuration and loading which represents reasonably well the magnet environment. In that work G-10 was shown to withstand repeated loading to moderately high stress levels without failure, and the material survived better at liquid nitrogen temperature than at room temperature

  8. Analytical TEM investigations of nanoscale magnetic materials

    International Nuclear Information System (INIS)

    Meingast, A.

    2015-01-01

    Analytical transmission electron microscopy has been applied within this thesis to investigate several novel approaches to design and fabricate nanoscale magnetic materials. As the size of the features of interest rank in the sub-nanometer range, it is necessary to employ techniques with a resolution – both spatial and analytical – well below this magnitude. Only at this performance level it is possible to examine material properties, necessary for the further tailoring of materials. Within this work two key aspects have been covered: First, analytical TEM (transmission electron microscopy) investigations were carried out to get insight into novel magnetic materials with high detail. Second, new analytical and imaging possibilities enabled with the commissioning of the new ASTEM (Austrian scanning transmission electron microscope) were explored. The aberration corrected TITAN® microscope (© FEI Company) allows resolving features in scanning transmission mode (STEM) with 70 pm distance. Thereby, direct imaging of light elements in STEM mode by using the annular bright field method becomes possible. Facilitated through high beam currents within the electron probe, an increased acquisition speed of analytical signals is possible. For energy dispersive X-ray spectroscopy (EDXS) a new four detector disc geometry around the specimen was implemented, which increases the accessible collection angle. With the integration of the latest generation of image filter and electron spectrometer (GIF QuantumERS), electron energy loss spectroscopy (EELS) is boosted through the high acquisition speed and the dual spectroscopy mode. The high acquisition speed allows to record up to 1000 spectra per second and the possibility to record atomically resolved EELS maps is at hand. Hereby it is important to avoid beam damage and alteration of the material during imaging and analysis. With the simultaneous acquisition of the low and the high loss spectral region, an extended range for

  9. Thickness measurement of soft thin films on periodically patterned magnetic substrates by phase difference magnetic force microscopy.

    Science.gov (United States)

    Passeri, D; Dong, C; Angeloni, L; Pantanella, F; Natalizi, T; Berlutti, F; Marianecci, C; Ciccarello, F; Rossi, M

    2014-01-01

    The need for accurate measurement of the thickness of soft thin films is continuously encouraging the development of techniques suitable for this purpose. We propose a method through which the thickness of the film is deduced from the quantitative measurement of the contrast in the phase images of the sample surface acquired by magnetic force microscopy, provided that the film is deposited on a periodically patterned magnetic substrate. The technique is demonstrated by means of magnetic substrates obtained from standard floppy disks. Colonies of Staphylococcus aureus adherent to such substrates were used to obtain soft layers with limited lateral (a few microns) and vertical (hundreds of nanometers) size. The technique is described and its specific merits, limitations and potentialities in terms of accuracy and measurable thickness range are discussed. These parameters depend on the characteristics of the sensing tip/cantilever as well as of the substrates, the latter in terms of spatial period and homogeneity of the magnetic domains. In particular, with the substrates used in this work we evaluated an uncertainty of about 10%, a limit of detection of 50-100 nm and an upper detection limit (maximum measurable thickness) of 1 μm, all obtained with standard lift height values (50-100 nm). Nonetheless, these parameters can be easily optimized by selecting/realizing substrates with suitable spacing and homogeneity of the magnetic domains. For example, the upper detection limit can be increased up to 25-50 μm while the limit of detection can be reduced to a few tens of nanometers or a few nanometers. © 2013 Elsevier B.V. All rights reserved.

  10. Comparison of the fractional power motor with cores made of various magnetic materials

    Directory of Open Access Journals (Sweden)

    Gmyrek Zbigniew

    2017-12-01

    Full Text Available The optimization of the motor cores, coupled with new core shapes as well as powering the motor at high frequency are the primary reasons for the use of new materials. The utilization of new materials, like SMC (soft magnetic composite, reduce the core loss and/or provide quasi-isotropic core’s properties in any magnetization direction. Moreover, the use of SMC materials allows for avoiding degradation of the material portions, resulting from punching process, thereby preventing the deterioration of operating parameters of the motor. The authors examine the impact of technological parameters on the properties of a new type of SMC material and analyze the possibility of its use as the core of the fractional power motor. The result of the work is an indication of the shape of the rotor core made of a new SMC material to achieve operational parameters similar to those that have a motor with a core made of laminations.

  11. Comparison of the fractional power motor with cores made of various magnetic materials

    Science.gov (United States)

    Gmyrek, Zbigniew; Lefik, Marcin; Cavagnino, Andrea; Ferraris, Luca

    2017-12-01

    The optimization of the motor cores, coupled with new core shapes as well as powering the motor at high frequency are the primary reasons for the use of new materials. The utilization of new materials, like SMC (soft magnetic composite), reduce the core loss and/or provide quasi-isotropic core's properties in any magnetization direction. Moreover, the use of SMC materials allows for avoiding degradation of the material portions, resulting from punching process, thereby preventing the deterioration of operating parameters of the motor. The authors examine the impact of technological parameters on the properties of a new type of SMC material and analyze the possibility of its use as the core of the fractional power motor. The result of the work is an indication of the shape of the rotor core made of a new SMC material to achieve operational parameters similar to those that have a motor with a core made of laminations.

  12. Electromagnetic shielding mechanisms using soft magnetic stainless steel fiber enabled polyester textiles

    Science.gov (United States)

    Shyr, Tien-Wei; Shie, Jing-Wen

    2012-11-01

    This work studied the effects of conductivity, magnetic loss, and complex permittivity when using blended textiles (SSF/PET) of polyester fibers (PET) with stainless steel fibers (SSF) on electromagnetic wave shielding mechanisms at electromagnetic wave frequencies ranging from 30 MHz to 1500 MHz. The 316L stainless steel fiber used in this study had 38 vol% γ austenite and 62 vol% α' martensite crystalline phases, which was characterized by an x-ray diffractometer. Due to the magnetic and dielectric loss of soft metallic magnetic stainless steel fiber enabled polyester textiles, the relationship between the reflection/absorption/transmission behaviors of the electromagnetic wave and the electrical/magnetic/dielectric properties of the SSF and SSF/PET fabrics was analyzed. Our results showed that the electromagnetic interference shielding of the SSF/PET textiles show an absorption-dominant mechanism, which attributed to the dielectric loss and the magnetic loss at a lower frequency and attributed to the magnetic loss at a higher frequency, respectively.

  13. Study of AC Magnetic Properties and Core Losses of Fe/Fe3O4-epoxy Resin Soft Magnetic Composite

    Science.gov (United States)

    Laxminarayana, T. A.; Manna, Subhendu Kumar; Fernandes, B. G.; Venkataramani, N.

    Soft Magnetic Composites (SMC) were prepared by coating of nanocrystalline Fe3O4 particles, synthesized by co-precipitation method, on atomized iron powder of particle size less than 53 μm in size using epoxy resin as a binder between iron and Fe3O4. Fe3O4 was chosen, for its high electric resistivity and suitable magnetic properties, to keep the coating layer magnetic and seek improvement to the magnetic properties of SMC. SEM images and XRD patterns were recorded in order to investigate the coatings on the surface of iron powder. A toroid was prepared by cold compaction of coated iron powder at 1050 MPa and subsequently cured at 150˚C for 1 hr in argon atmosphere. For comparison of properties, a toroid of uncoated iron powder was also compacted at 1050 MPa and annealed at 600˚C for 2 hr in argon atmosphere. The coated iron powder composite has a resistivity of greater than 200 μΩm, measured by four probe method. A comparison of Magnetic Hysteresis loops and core losses using B-H Loop tracer in the frequency range 0 to 1500 Hz on the coated and uncoated iron powder is reported.

  14. Effects of annealing and pulse plating on soft magnetic properties of electroplated Fe-Ni films

    Directory of Open Access Journals (Sweden)

    T. Yanai

    2016-05-01

    Full Text Available We have already reported that Fe-Ni films prepared in citric-acid-based plating baths show good soft magnetic properties. In this paper, we investigated the effect of the grain size of the Fe-Ni crystalline phase in the films on magnetic properties, and employed an annealing and a pulse plating method in order to vary the grain size. The coercivity of the annealed Fe-Ni films at 600 °C shows large value, and good correlation between the grain growth and the coercivity was observed. The pulse plating enables us to reduce the grain size of the as-plated Fe-Ni films compared with the DC plating method, and we realized smooth surface and low coercivity of the Fe-Ni films using the pulse plating method. From these results, we confirmed the importance of the reduction in the grain size, and concluded that a pulse plating is an effective method to improve the good soft magnetic properties for our previously-reported Fe-Ni films.

  15. Probing buried solid-solid interfaces in magnetic multilayer structures and other nanostructures using spectroscopy excited by soft x-ray standing waves

    International Nuclear Information System (INIS)

    Yang, S.-H.; Mun, B.S.; Mannella, N.; Sell, B.; Ritchey, S.B.; Fadley, C.S.; Pham, L.; Nambu, A.; Watanabe, M.

    2004-01-01

    Full text: Buried solid-solid interfaces are becoming increasingly more important in all aspects of nanoscience, and we here dis- cuss the st applications of a new method for selectively studying them with the vuv/soft x-ray spectroscopies. As specific examples, magnetic multilayer structures represent key elements of current developments in spintronics, including giant magnetoresistance, exchange bias, and magnetic tunnel resistance. The buried interfaces in such structures are of key importance to their performance, but have up to now been difficult to study selectively with these spectroscopies. This novel method involves excitation of photoelectrons or fluorescent x-rays with soft x-ray standing waves created by Bragg reflection from a multilayer mirror substrate on which the sample is grown. We will discuss core and valence photoemission, as well soft x-ray emission, results from applying this method to multilayer structures relevant to both giant magnetoresistance (Fe/Cr-[2]) and magnetic tunnel junctions (Al 2 O 3 /FeCo) , including magnetic dichroism measurements. Work supported by the Director, Of e of Science, Of e of Basic Energy Sciences, Materials Science and Engineering Division, U.S. Department of Energy, Contract No. DE-AC03-76SF000

  16. The percolation effect and optimization of soft magnetic properties of FeSiAl magnetic powder cores

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Ruru [College of Material Science and Engineering, Nanchang University, Nanchang 330031, Jiangxi (China); Zhu, Zhenghou, E-mail: z00708@sina.com [College of Material Science and Engineering, Nanchang University, Nanchang 330031, Jiangxi (China); Zhao, Hui, E-mail: candyzhaohui@126.com [College of Material Science and Engineering, Nanchang University, Nanchang 330031, Jiangxi (China); Institute of Space Science and Technology, Nanchang University, Nanchang 330031, Jiangxi (China); Mao, Shenghua [Jiangxi Aite magnetic materials Co. Ltd., Yichun 336000, Jiangxi (China); Zhong, Qi [College of Material Science and Engineering, Nanchang University, Nanchang 330031, Jiangxi (China)

    2017-07-01

    Highlights: • A new magnetic percolation phenomenon of ρ-μe in MPCs was discovered. • The soft magnetic properties of FeSiAl MPCs were studied. • The comprehensive magnetic properties of MPCs were optimized. • The formation mechanism of magnetic conductive path was explained. - Abstract: In this paper, a new magnetic percolation phenomenon between the green compact density ρ and effective permeability μe in FeSi{sub 9.6}Al{sub 6.5} magnetic powder cores, was discovered. The Magnetic Percolation Area of ρ is the range of 5.6 g/cm{sup 3} ∼ 5.78 g/cm{sup 3}, and the percolation threshold is 5.78 g/cm{sup 3}. As a result of the guidance of the percolation theory, the best comprehensive magnetic properties have been optimized through adjusting the distribution of powders. The special distribution of the magnetic powder cores with the best comprehensive magnetic properties was as follows: the content 60% with the particle size distribution of 100–200 mesh, the content 20% with the particle size distribution of 200–325 mesh and the content 20% with the particle size distribution of ≥400 mesh. When the green compact density ρ of cores was 5.79 g/cm{sup 3}, and the frequency was in the range of 1 kHz ∼ 100 kHz, the best comprehensive magnetic properties were as follows: μe = 91, ∆μ = 0.61%, μe(H80 Oe) = 43, μe(H100 Oe) = 33, μe(H120 Oe) = 26, Pc(50 mT/20 kHz) = 30.58 kW/m{sup 3}, Pc(50 mT/50 kHz) = 76.85 kW/m{sup 3}, Pc(50 mT/100 kHz) = 178 kW/m{sup 3}. Not only have those cores the excellent constant magnetic properties with frequency, the excellent DC superposition characteristic and the lower loss at high frequency, but also the effective permeability outstandingly goes up, which has important significance for the miniaturization of inductance components.

  17. Laser Additive Manufacturing of Magnetic Materials

    Science.gov (United States)

    Mikler, C. V.; Chaudhary, V.; Borkar, T.; Soni, V.; Jaeger, D.; Chen, X.; Contieri, R.; Ramanujan, R. V.; Banerjee, R.

    2017-03-01

    While laser additive manufacturing is becoming increasingly important in the context of next-generation manufacturing technologies, most current research efforts focus on optimizing process parameters for the processing of mature alloys for structural applications (primarily stainless steels, titanium base, and nickel base alloys) from pre-alloyed powder feedstocks to achieve properties superior to conventionally processed counterparts. However, laser additive manufacturing or processing can also be applied to functional materials. This article focuses on the use of directed energy deposition-based additive manufacturing technologies, such as the laser engineered net shaping (LENS™) process, to deposit magnetic alloys. Three case studies are presented: Fe-30 at.%Ni, permalloys of the type Ni-Fe-V and Ni-Fe-Mo, and Fe-Si-B-Cu-Nb (derived from Finemet) alloys. All these alloys have been processed from a blend of elemental powders used as the feedstock, and their resultant microstructures, phase formation, and magnetic properties are discussed in this paper. Although these alloys were produced from a blend of elemental powders, they exhibited relatively uniform microstructures and comparable magnetic properties to those of their conventionally processed counterparts.

  18. Positive muon studies of magnetic materials

    International Nuclear Information System (INIS)

    Patterson, B.D.

    1975-01-01

    Polarized positive muons (μ + ) are stopped in magnetic materials, and the μ + precession is observed via the muons's asymmetric decay to a positron. The precession frequency is a measure of the local magnetic field at the μ + . Relaxation of the μ + spin is caused by spatially or time-varying local fields. The local field at a stopped μ + in ferromagnetic nickel is measured. From this measurement, the hyperfine field seen by an interstitial μ + due to its contact interaction with polarized screening electrons is inferred to be -0.66kG. A discussion of this value in terms of a simple model for the screening configuration is presented. Critical spin fluctuations in Ni at temperatures just above the Curie point rapidly relax the μ + spin. The temperature and external magnetic field dependence of the relaxation rate is determined experimentally. A theory for the relaxation rate is presented which demonstrates the importance of the hyperfine and dipolar interactions of the μ + with its Ni host. Preliminary results on μ + studies in ferromagnetic iron and cobalt are also discussed. (U.S.)

  19. Improved soft magnetic properties in nanocrystalline FeCuNbSiB Nanophy{sup ®} cores by intense magnetic field annealing

    Energy Technology Data Exchange (ETDEWEB)

    Madugundo, Rajasekhar; Geoffroy, Olivier [Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble (France); CNRS, Inst NEEL, F-38000 Grenoble (France); Grenoble Electrical Engineering Laboratory (G2Elab), Bâtiment GreEn-ER, 21 avenue des martyrs, 38031 Grenoble (France); Waeckerle, Thierry [Aperam Research Center, 58160 Imphy (France); Frincu, Bianca; Kodjikian, Stéphanie [Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble (France); CNRS, Inst NEEL, F-38000 Grenoble (France); Rivoirard, Sophie, E-mail: sophie.rivoirard@neel.cnrs.fr [Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble (France); CNRS, Inst NEEL, F-38000 Grenoble (France)

    2017-01-15

    The effect of high external magnetic field (up to 7 T) on soft magnetic properties in nanocrystalline Fe{sub 74.1}Si{sub 15.7}Nb{sub 3.1}B{sub 6.1}Cu{sub 1} Nanophy{sup ®} cores has been investigated. The as-quenched amorphous ribbons were nanocrystallized by annealing between 540 and 620 °C in transverse magnetic field. By varying annealing field from 0 to 7 T, induced anisotropy ranging from as low as 4 J/m{sup 3} to as high as 41 J/m{sup 3} is obtained. It is responsible for an increase in the cut-off frequency up to 300 kHz when the material is submitted to dynamic magnetic excitations. A minimum coercivity of 0.74 A/m is observed in the core annealed in 1 T associated to low losses. The relative permeability decreases on increasing the annealing field intensity with a minimum value of 13,654 at 7 T. Such permeability level opens the way to new applications of the Nanophy{sup ®} alloys. - Highlights: • Effect of magnetic field (0–7 T) in nanocrystalline Nanophy{sup ®} cores was investigated. • Amorphous ribbons were annealing between 540 and 620 °C in transverse magnetic field. • Induced anisotropy ranging from 4 to 41 J/m{sup 3} was obtained by annealing in field 0−7 T. • Permeability ranging between 135,122 and 13,654 was obtained. • A minimum coercivity of 0.74 A/m was observed.

  20. Exploring the Hard and Soft X-ray Emission of Magnetic Cataclysmic Variables

    Science.gov (United States)

    de Martino, D.; Anzolin, G.; Bonnet-Bidaud, J.-M.; Falanga, M.; Matt, G.; Mouchet, M.; Mukai, K.; Masetti, N.

    2009-05-01

    A non-negligible fraction of galactic hard (>20 keV) X-ray sources were identified as CVs of the magnetic Intermediate Polar type in INTEGRAL, SWIFT and RXTE surveys, that suggests a still hidden but potentially important population of faint hard X-ray sources. Simbol-X has the unique potential to simultaneously characterize their variable and complex soft and hard X-ray emission thus allowing to understand their putative role in galactic populations of X-ray sources.

  1. Soft x-ray spectroscopy for probing electronic and chemical states of battery materials

    International Nuclear Information System (INIS)

    Yang Wanli; Qiao Ruimin

    2016-01-01

    The formidable challenge of developing high-performance battery system stems from the complication of battery operations, both mechanically and electronically. In the electrodes and at the electrode–electrolyte interfaces, chemical reactions take place with evolving electron states. In addition to the extensive studies of material synthesis, electrochemical, structural, and mechanical properties, soft x-ray spectroscopy provides unique opportunities for revealing the critical electron states in batteries. This review discusses some of the recent soft x-ray spectroscopic results on battery binder, transition-metal based positive electrodes, and the solid-electrolyte-interphase. By virtue of soft x-ray’s sensitivity to electron states, the electronic property, the redox during electrochemical operations, and the chemical species of the interphases could be fingerprinted by soft x-ray spectroscopy. Understanding and innovating battery technologies need a multimodal approach, and soft x-ray spectroscopy is one of the incisive tools to probe the chemical and physical evolutions in batteries. (topical review)

  2. Superconducting materials for particle accelerator magnets

    International Nuclear Information System (INIS)

    Larbalestier, D.C.

    1983-01-01

    Present accelerator designs are clustered around a field of 5 Tesla with several future studies looking at the 8-to-10 Tesla range. There has also been some recent interest in low-field iron-dominated dipoles in which the superconductor will see a field of about 2 Tesla. The demands of this present range of interest can still be met, with the upper limit at about 10 Tesla, by the use of Nb-Ti (or Nb-Ti-Ta) or Nb 3 Sn. Both of these conductors are available in multifilamentary form from industrial sources and are suitable for accelerator magnets. The upper critical field and transition temperature of both types of composite cover the foreseeable range of demand for such magnets. There is no magical new composite on the horizon that is likely to replace Nb-Ti or Nb 3 Sn. One class of materials which has a potentially exciting prospect is that of the ternary molybdenum sulfides. These can have an upper critical field of greater than 50 T, which extends their superconductivity into field ranges unattainable with A15 compounds; the two drawbacks to such materials, however, are the amount of development needed to produce superconductors from them with useful current densities and the fact that it does not appear that they would offer any features not already possessed by Nb-Ti or Nb 3 Sn in the field range presently of interest to accelerator designers. Using this pragmatic approach, this paper addresses these and other superconducting composites in terms of their fabrication, their testing, the measurement aspects of their critical current densities, and other properties which are pertinent to their selection for particle accelerator magnet use

  3. Tailoring of magnetoimpedance effect and magnetic softness of Fe-rich glass-coated microwires by stress- annealing.

    Science.gov (United States)

    Zhukova, V; Blanco, J M; Ipatov, M; Churyukanova, M; Taskaev, S; Zhukov, A

    2018-02-16

    There is a pressing need for improving of the high-frequency magneto-impedance effect of cost-effective soft magnetic materials for use in high-performance sensing devices. The impact of the stress-annealing on magnetic properties and high frequency impedance of Fe-rich glass-coated microwires was studied. Hysteresis loops of Fe-rich microwires have been considerably affected by stress- annealing. In stress-annealed Fe- rich microwire we obtained drastic decreasing of coercivity and change of character of hysteresis loop from rectangular to linear. By controlling stress-annealing conditions (temperature and time) we achieved drastic increasing (by order of magnitude) of giant magnetoimpedance ratio. Coercivity, remanent magnetization, diagonal and of-diagonal magnetoimpedance effect of Fe-rich microwires can be tuned by stress-annealing conditions: annealing temperature and time. Observed experimental results are discussed considering relaxation of internal stresses, compressive "back-stresses" arising after stress annealing and topological short range ordering.

  4. Effect of cohesion on local compaction and granulation of sheared soft granular materials

    Directory of Open Access Journals (Sweden)

    Roy Sudeshna

    2017-01-01

    Full Text Available This paper results from an ongoing investigation of the effect of cohesion on the compaction of sheared soft wet granular materials. We compare dry non-cohesive and wet moderately-to-strongly cohesive soft almost frictionless granular materials and report the effect of cohesion between the grains on the local volume fraction. We study this in a three dimensional, unconfined, slowly sheared split-bottom ring shear cell, where materials while sheared are subject to compression under the confining weight of the material above. Our results show that inter-particle cohesion has a considerable impact on the compaction of soft materials. Cohesion causes additional stresses, due to capillary forces between particles, leading to an increase in volume fraction due to higher compaction. This effect is not visible in a system of infinitely stiff particles. In addition, acting oppositely, we observe a general decrease in volume fraction due to increased cohesion for frictional particle, which we attribute to the role of contact friction that enhances dilation.

  5. New Soft Magnetic Composites for electromagnetic applications with improved mechanical properties

    Science.gov (United States)

    Ferraris, Luca; Pošković, Emir; Franchini, Fausto

    2016-05-01

    The chance to move from 2D to 3D approach in the design of the electrical machines is made possible by the availability of Soft Magnetic Composites (SMC), iron based powders, insulated and pressed to realize shapes otherwise impossible with the traditional lamination sheets technology. Some commercial products are available on the market as "ready to press" powders, which presents good magnetic and energetic properties but are sometimes weak under the mechanical point of view; other products aim at improving this aspect but with considerable process complications and relative cost. The experience of the Authors in the realization of bonded magnets with the adoption of selected organic resins has been partly transferred in the research field of the SMC in order to investigate the possibility to obtain good mechanical properties maintaining the magnetic characteristics of the Insulated Iron Powder Compounds (I.I.P.C.) taken as reference. The paper presents the activity that has been carried out in the realization of SMC mixing iron powders and phenolic resin, in different weight percentages and mold pressures. The obtained results are considered satisfactory under the point of view of the compromise between magnetic and mechanical properties, considering also that the required productive process is simpler. The comparison of the obtained results with those related to commercial products encourages to carry on the research, also because of the reduced cost of the proposed SMC at parity (or better) performance.

  6. Magnetic modification of diamagnetic agglomerate forming powder materials

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Baldíková, Eva; Pospíšková, K.; Šafaříková, Miroslava

    2016-01-01

    Roč. 29, December (2016), s. 169-171 ISSN 1674-2001 Institutional support: RVO:60077344 Keywords : magnetic modification * magnetic separation * powdered material * magnetic iron oxide * microwave assisted synthesis Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.621, year: 2016

  7. Soft tissue masses with myxoid stroma: Can conventional magnetic resonance imaging differentiate benign from malignant tumors?

    Energy Technology Data Exchange (ETDEWEB)

    Crombe, A., E-mail: amandine.crombe@ens-lyon.fr [Department of Radiology, Institut Bergonié, 229 cours de l’Argonne, 33076 Bordeaux Cedex (France); Alberti, N. [Department of Radiology, Institut Bergonié, 229 cours de l’Argonne, 33076 Bordeaux Cedex (France); Stoeckle, E. [Department of Surgery, Institut Bergonié, 229 cours de l’Argonne, 33076 Bordeaux Cedex (France); Brouste, V. [Clinical and Epidemiological Research Unit, Institut Bergonié, 33000 Bordeaux (France); Buy, X. [Department of Radiology, Institut Bergonié, 229 cours de l’Argonne, 33076 Bordeaux Cedex (France); Coindre, J-M. [Department of Pathology, Institut Bergonié, 229 cours de l’Argonne, 33076 Bordeaux Cedex (France); Kind, M. [Department of Radiology, Institut Bergonié, 229 cours de l’Argonne, 33076 Bordeaux Cedex (France)

    2016-10-15

    Objectives: To retrospectively evaluate the diagnostic performance of morphological signs observed on conventional magnetic resonance (MR) imaging to differentiate benign from malignant peripheral solid tumors of soft tissue with myxoid stroma. Methods: MR images from 95 consecutive histopathologically proven tumors (26 benign and 69 malignant) of soft tissues with myxoid components were evaluated in our tertiary referral center. Two radiologists, blind to pathology results, independently reviewed conventional MR sequences including at least a) one T2-weighted sequence with or without fat suppression; b) one T1-weighted sequence without fat suppression; and c) one T1-weighted sequence with gadolinium-complex contrast enhancement and fat suppression. Multiple criteria were defined to analyze morphology, margins, architecture and tumor periphery and evaluated for each lesion. Intra- and inter-observer reproducibility and Odds ratios were calculated for each criterion. Results: The most relevant and reproducible criteria to significantly predict malignancy were: (1) ill-defined tumor margins, (2) a hemorrhagic component, (3) intra-tumoral fat, (4) fibrosis and (5) the “tail sign”. A lesion is classified as malignant if any of these 5 criteria is present, and benign if none of them are observed. Therefore, this combination provides a sensitivity of 92.9% and a specificity of 93.3%. Conclusion: Conventional MR imaging provides reproducible criteria that can be combined to differentiate between benign and malignant solid tumors of soft tissue with myxoid stroma.

  8. Synthesis and magnetic properties of cobalt-iron/cobalt-ferrite soft/hard magnetic core/shell nanowires

    Science.gov (United States)

    Leandro Londoño-Calderón, César; Moscoso-Londoño, Oscar; Muraca, Diego; Arzuza, Luis; Carvalho, Peterson; Pirota, Kleber Roberto; Knobel, Marcelo; Pampillo, Laura Gabriela; Martínez-García, Ricardo

    2017-06-01

    A straightforward method for the synthesis of CoFe2.7/CoFe2O4 core/shell nanowires is described. The proposed method starts with a conventional pulsed electrodeposition procedure on alumina nanoporous template. The obtained CoFe2.7 nanowires are released from the template and allowed to oxidize at room conditions over several weeks. The effects of partial oxidation on the structural and magnetic properties were studied by x-ray spectrometry, magnetometry, and scanning and transmission electron microscopy. The results indicate that the final nanowires are composed of 5 nm iron-cobalt alloy nanoparticles. Releasing the nanowires at room conditions promoted surface oxidation of the nanoparticles and created a CoFe2O4 shell spinel-like structure. The shell avoids internal oxidation and promotes the formation of bi-magnetic soft/hard magnetic core/shell nanowires. The magnetic properties of both the initial single-phase CoFe2.7 nanowires and the final core/shell nanowires, reveal that the changes in the properties from the array are due to the oxidation more than effects associated with released processes (disorder and agglomeration).

  9. Genetic resources as initial material for developing new soft winter wheat varieties

    Directory of Open Access Journals (Sweden)

    В. М. Кір’ян

    2016-12-01

    Full Text Available Purpose. To estimate genetic resources collection of soft winter wheat plants (new collection accessions of Ustymivka Experimental Station for Plant Production and select initial material for breeding of adaptive, productive and qualitative soft winter wheat varieties. Methods. Field experiment, laboratory testing. Results. The authors pre- sented results of study of over 1000 samples of gene pool of soft winter wheat from 25 countries during 2001–2005 in Ustymivka Experimental Station for Plant Production of Plant Production Institute nd. a. V. Ya. Yuriev, NAAS of Ukraine for a complex of economic traits. More than 400 new sources with high adaptive properties were selected that combine traits of high productivity and high quality of grain, early ripening, resistance to biotic and abiotic fac- tors (the assessment of samples for 16 valuable traits is given. The selected material comes from various agro-cli- matic zones, including zones of unsustainable agriculture. Conclusions. Recommended sources of traits that have breeding value will allow to enrich high-quality assortment of wheat and considerably accelerate breeding process du- ring development of new soft winter wheat varieties.

  10. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with L-ascorbic acid, as materials for soft tissue regeneration

    International Nuclear Information System (INIS)

    Kucinska-Lipka, J.; Gubanska, I.; Strankowski, M.; Cieśliński, H.; Filipowicz, N.; Janik, H.

    2017-01-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4′-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with L-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ( 1 HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test with

  11. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with L-ascorbic acid, as materials for soft tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kucinska-Lipka, J., E-mail: juskucin@pg.gda.pl [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Gubanska, I.; Strankowski, M. [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Cieśliński, H.; Filipowicz, N. [Gdansk University of Technology, Faculty of Chemistry, Department of Microbiology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Janik, H. [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland)

    2017-06-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4′-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with L-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ({sup 1}HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test

  12. Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism.

    Science.gov (United States)

    Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J; Mancuso, Christopher A; Hogle, Craig W; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L; Dorney, Kevin M; Chen, Cong; Shpyrko, Oleg G; Fullerton, Eric E; Cohen, Oren; Oppeneer, Peter M; Milošević, Dejan B; Becker, Andreas; Jaroń-Becker, Agnieszka A; Popmintchev, Tenio; Murnane, Margaret M; Kapteyn, Henry C

    2015-11-17

    We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

  13. Magnetic properties of frictional volcanic materials

    Science.gov (United States)

    Kendrick, Jackie E.; Lavallée, Yan; Biggin, Andrew; Ferk, Annika; Leonhardt, Roman

    2015-04-01

    During dome-building volcanic eruptions, highly viscous magma extends through the upper conduit in a solid-like state. The outer margins of the magma column accommodate the majority of the strain, while the bulk of the magma is able to extrude, largely undeformed, to produce magma spines. Spine extrusion is often characterised by the emission of repetitive seismicity, produced in the upper <1 km by magma failure and slip at the conduit margins. The rheology of the magma controls the depth at which fracture can occur, while the frictional properties of the magma are important in controlling subsequent marginal slip processes. Upon extrusion, spines are coated by a carapace of volcanic fault rocks which provide insights into the deeper conduit processes. Frictional samples from magma spines at Mount St. Helens (USA), Soufriere Hills (Montserrat) and Mount Unzen (Japan) have been examined using structural, thermal and magnetic analyses to reveal a history of comminution, frictional heating, melting and cooling to form volcanic pseudotachylyte. Pseudotachylyte has rarely been noted in volcanic materials, and the recent observation of its syn-eruptive formation in dome-building volcanoes was unprecedented. The uniquely high thermal conditions of volcanic environments means that frictional melt remains at elevated temperatures for longer than usual, causing slow crystallisation, preventing the development of some signature "quench" characteristics. As such, rock-magnetic tests have proven to be some of the most useful tools in distinguishing pseudotachylytes from their andesite/ dacite hosts. In volcanic pseudotachylyte the mass normalised natural remanent magnetisation (NRM) when further normalised with the concentration dependent saturation remanence (Mrs) was found to be higher than the host rock. Remanence carriers are defined as low coercive materials across all samples, and while the remanence of the host rock displays similarities to an anhysteretic remanent

  14. Effect of P addition on glass forming ability and soft magnetic properties of melt-spun FeSiBCuC alloy ribbons

    International Nuclear Information System (INIS)

    Xu, J.; Yang, Y.Z.; Li, W.; Chen, X.C.; Xie, Z.W.

    2016-01-01

    The dependency of phosphorous content on the glass forming ability, thermal stability and soft magnetic properties of Fe 83.4 Si 2 B 14−x P x Cu 0.5 C 0.1 (x=0,1,2,3,4) alloys was investigated. The experimental results showed that the substitution of B by P increased the glass forming ability in this alloy system. The Fe 83.4 Si 2 B 10 P 4 Cu 0.5 C 0.1 alloy shows a fully amorphous character. Thermal stability of melt-spun ribbons increases and temperature interval between the first and second crystallization peaks enlarges with the increase of P content. And the saturation magnetic flux density (Bs) shows a slight increase with the increase of P content. The Fe 83.4 Si 2 B 11 P 3 Cu 0.5 C 0.1 nanocrystalline alloy exhibits a high Bs about 200.6 emu/g. The Bs of fully amorphous alloy Fe 83.4 Si 2 B 10 P 4 Cu 0.5 C 0.1 drops dramatically to 172.1 emu/g, which is lower than that of other nanocrystallines. Low material cost and excellent soft magnetic properties make the FeSiBPCuC alloys promise soft magnetic materials for industrial applications. - Highlights: • Partial substituting B by P helps to improve the glass forming ability of the alloy. • The addition of P content reduces the thermal stability and improves heat treatment temperature region for these alloys. • The Fe 83.4 Si 2 B 11 P 3 Cu 0.5 C 0.1 nanocrystalline alloy exhibits a high saturation magnetic density of 200.6 emu/g.

  15. Fabrication and properties of submicrometer structures of magnetic materials

    International Nuclear Information System (INIS)

    Martin, J.I.; Velez, M.; Nogues, J.; Schuller, I.K.

    1998-01-01

    The method of electron beam lithography is described. This technique allows to fabricate well defined submicrometer structures of magnetic materials, that are suitable to show and study interesting physical properties by transport measurements either in Superconductivity or in Magnetism. In particular, using these structures, we have analyzed pinning effects of the vortex lattice in superconductors and magnetization reversal processes in magnetic materials. (Author) 15 refs

  16. Soft magnetic properties and damping parameter of (FeCo-Al alloy thin films

    Directory of Open Access Journals (Sweden)

    Isao Kanada

    2017-05-01

    Full Text Available For high frequency device applications, a systematic study of the soft magnetic properties and magnetization dynamics of (FeCo-Al alloy thin films has been carried out. A low effective damping parameter αeff of 0.002 and a high saturation magnetization of about 1,800 emu/cc are obtained at y=0.2∼0.3 for (Fe1-yCoy98Al2 alloy thin films deposited onto fused silica and MgO(100 at an ambient temperature during deposition. Those films are of the bcc structure with the orientation normal to the film plane. They possess a columnar structure, grown along the film normal. The column width is found to be about 20 nm for y=0.25. It is concluded that the (FeCo-Al thin films with a damping parameter as low as 0.002 and high saturation magnetization of about 1,800 emu/cc have been successfully fabricated, and that they are potential for future high frequency device applications.

  17. The diagnostic value of diffusion-weighted magnetic resonance imaging in soft tissue abscesses

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Ozkan; Koparan, Halil Ibrahim [Yuezuencue Yil University, Department of Radiology, Van (Turkey); Avcu, Serhat, E-mail: serhatavcu@hotmail.com [Yuezuencue Yil University, Department of Radiology, Van (Turkey); Kalender, Ali Murat [Yuezuencue Yil University, Department of Orthopaedics, General Surgery, Van (Turkey); Kisli, Erol [Yuezuencue Yil University, Department of General Surgery, Van (Turkey)

    2011-03-15

    Purpose: To study the diagnostic value of diffusion-weighted imaging (DWI) in soft tissue abscesses. Materials and methods: Fifty patients were included in this study who were thought to have soft tissue abscess or cystic lesion as a result of clinical and radiological examinations. Localisations of the lesions were: 1 periorbital, 3 breast, 14 intraabdominal, and 32 intramuscular lesions. After other radiological examinations, DWI was performed. The signal intensity values of the lesions were evaluated qualitatively according to the hyperintensity on b-1000 DWI, using 1.5 T MR system. All of the lesions were aspirated after DWI, and detection of pus in the aspiration material was accepted as gold standard for the diagnosis of abscess. Results: In 38 of the 50 patients, hyperintensity was obtained on diffusion-weighted images. False-positive results were maintained in 2 of these patients, and true-positive results were maintained in 36 of them. In 11 of the 50 patients, hypointensity was visualised on diffusion-weighted images. False-negative results were maintained in 3 of these patients, and true-negative results were maintained in 8 of them. An abscess which was seen on post-contrast conventional MRI could not be seen on DWI, and this was regarded as false-negative. Conclusion: The sensitivity and specificity of diffusion-weighted images for detecting soft tissue abscesses were found to be 92% and 80%, respectively. DWI has a high diagnostic value in soft tissue abscesses, and is an important imaging modality that may be used for the differentiation of cysts and abscesses.

  18. The diagnostic value of diffusion-weighted magnetic resonance imaging in soft tissue abscesses

    International Nuclear Information System (INIS)

    Unal, Ozkan; Koparan, Halil Ibrahim; Avcu, Serhat; Kalender, Ali Murat; Kisli, Erol

    2011-01-01

    Purpose: To study the diagnostic value of diffusion-weighted imaging (DWI) in soft tissue abscesses. Materials and methods: Fifty patients were included in this study who were thought to have soft tissue abscess or cystic lesion as a result of clinical and radiological examinations. Localisations of the lesions were: 1 periorbital, 3 breast, 14 intraabdominal, and 32 intramuscular lesions. After other radiological examinations, DWI was performed. The signal intensity values of the lesions were evaluated qualitatively according to the hyperintensity on b-1000 DWI, using 1.5 T MR system. All of the lesions were aspirated after DWI, and detection of pus in the aspiration material was accepted as gold standard for the diagnosis of abscess. Results: In 38 of the 50 patients, hyperintensity was obtained on diffusion-weighted images. False-positive results were maintained in 2 of these patients, and true-positive results were maintained in 36 of them. In 11 of the 50 patients, hypointensity was visualised on diffusion-weighted images. False-negative results were maintained in 3 of these patients, and true-negative results were maintained in 8 of them. An abscess which was seen on post-contrast conventional MRI could not be seen on DWI, and this was regarded as false-negative. Conclusion: The sensitivity and specificity of diffusion-weighted images for detecting soft tissue abscesses were found to be 92% and 80%, respectively. DWI has a high diagnostic value in soft tissue abscesses, and is an important imaging modality that may be used for the differentiation of cysts and abscesses.

  19. Determination of Residual Monomers Released from Soft Lining Materials with the use of HPLC

    Directory of Open Access Journals (Sweden)

    Afrodite Sofou

    2007-12-01

    Full Text Available A study was carried out to examine the post polymerized leachability of three non phthalic and four phthalic residual monomers, from twelve commercially available soft lining materials, using HPLC. Specimens of equal dimensions were constructed from each brand of material following a standardized procedure and were stored in three different conditions of storage i.e. distilled water, artificial saliva and a binary mixture of ethanol-water, with the resulting liquids providing samples for analysis in the HPLC apparatus. Three different experiments were performed for each brand of material and each condition of storage, in order to examine the parameters time and temperature. The results obtained from this study suggest that a wide spectrum of residues is diffusing out of the twelve examined soft lining materials. The non phthalic compounds were leaching at high concentrations while all the phthalates examined exhibited different degrees of elusion commensurate with the storage condition, brand of material and type of experiment. The main non phthalic component extracted from all the materials was methyl methacrylate, while the mainly extracted phthalic compound was different from each material. The level of elusion seems to be increasing dependent on time, medium of storage, and temperature as well.

  20. Determination of residual monomers released from soft lining materials with the use of HPLC

    International Nuclear Information System (INIS)

    Sofou, A.; Tsoupi, I.; Karayannia, M.

    2007-01-01

    A study was carried out to examine the post polymerized leachability of three non phthalic and four phthalic residual monomers, from twelve commercially available soft lining materials, using HPLC. Specimens of equal: dimensions were constructed from each brand of material following a standardized procedure and were stored in three different conditions of storage i.e. distilled water, artificial saliva and a binary mixture of ethanol-water with the resulting liquids providing samples for analysis in the HPLC apparatus. Three different experiments were performed for each brand of material and each condition of storage, in order to examine the parameters time and temperature. The results obtained from this study suggest that a wide spectrum of residues is diffusing out of the twelve examined soft lining materials. The non phthalic compounds were leaching at high concentrations while all the phthalates examined exhibited different degrees of elusion commensurate with the storage condition, brand of material and type of experiment. The main non phthalic component extracted from all the materials was methyl methacrylate, while the mainly extracted phthalic compound was different from each material. The level of elusion seems to be increasing dependent on time, medium of storage and temperature as well. (author)

  1. Recording soft-X-ray images with photographic materials at large gamma background

    International Nuclear Information System (INIS)

    Izrailev, I.M.

    1993-01-01

    The sensitivity of photographic materials to soft X-rays and 60 Co γ-quanta when developed by visible light and a chemical developer is investigated. When the photographic paper is developed by visible light, its sensitivity is reduced by 200-300 times independent of the quantum energy. This method allows an X-ray image to be recorded even when there is γ-background of 10 5 R. 2 refs., 1 tab

  2. SYNTHESIS of MOLECULE/POLYMER-BASED MAGNETIC MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Joel S. [Univ. of Utah, Salt Lake City, UT (United States)

    2016-02-01

    We have synthesized and characterized several families of organic-based magnets, a new area showing that organic species can exhibit the technologically important property of magnetic ordering. Thin film magnets with ordering temperatures exceeding room temperature have been exceeded. Hence, organic-based magnets represent a new class of materials that exhibit magnetic ordering and do not require energy-intensive metallurgical processing and are based upon Earth-abundant elements.

  3. Effect of non-magnetic intermediate layer on film structure, magnetic properties, and noise characteristics of FeCSi soft magnetic multilayers

    International Nuclear Information System (INIS)

    Kawano, Hiroyasu; Morikawa, Takeshi; Matsumoto, Koji; Shono, Keiji

    2004-01-01

    The film structures, magnetic properties, and noise characteristics of soft magnetic multilayers with alternately stacked FeCSi soft magnetic layers and non-magnetic intermediate layers were investigated. The FeCSi layers in an as-deposited multilayer with C or Ta intermediate layers had the same nano-sized fine crystalline grains and low media noise as an as-deposited FeCSi monolayer. Amorphous C intermediate layers suppressed the amplitude of spike noise especially well. In contrast, FeCSi layers in an as-deposited multilayer with Cr or Ti intermediate layers were composed of coarse crystalline grains, which increased the media noise. The crystallographic match at the interface between the layers in a multilayer could explain these phenomena. The similarity of the atomic arrangement at the interface between layers and the crystallographic match of less than a few percent for the distance between atoms crystallized FeCSi layers with nano-sized fine crystalline grains into ones with coarse crystalline grains during deposition

  4. Minor-Cu doped soft magnetic Fe-based FeCoBCSiCu amorphous alloys with high saturation magnetization

    Science.gov (United States)

    Li, Yanhui; Wang, Zhenmin; Zhang, Wei

    2018-05-01

    The effects of Cu alloying on the amorphous-forming ability (AFA) and magnetic properties of the P-free Fe81Co5B11C2Si1 amorphous alloy were investigated. Addition of ≤ 1.0 at.% Cu enhances the AFA of the base alloy without significant deterioration of the soft magnetic properties. The Fe80.5Co5B11C2Si1Cu0.5 alloy with the largest critical thickness for amorphous formation of ˜35 μm possesses a high saturation magnetization (Bs) of ˜1.78 T, low coercivity of ˜14.6 A/m, and good bending ductility upon annealing in a wide temperature range of 513-553 K with maintaining the amorphous state. The fabrication of the new high-Fe-content Fe-Co-B-C-Si-Cu amorphous alloys by minor doping of Cu gives a guideline to developing high Bs amorphous alloys with excellent AFA.

  5. Magnetic properties of Cobalt thin films deposited on soft organic layers

    Energy Technology Data Exchange (ETDEWEB)

    Bergenti, I. [ISMN-CNR via P. Gobetti 101, Bologna 40129 (Italy)]. E-mail: i.bergenti@bo.ismn.cnr.it; Riminucci, A. [ISMN-CNR via P. Gobetti 101, Bologna 40129 (Italy); Arisi, E. [ISMN-CNR via P. Gobetti 101, Bologna 40129 (Italy); Murgia, M. [ISMN-CNR via P. Gobetti 101, Bologna 40129 (Italy); Cavallini, M. [ISMN-CNR via P. Gobetti 101, Bologna 40129 (Italy); Solzi, M. [Dipartimento di Fisica dell' Universita di Parma and CNISM, Parco Area delle Scienze 7/A, Parma 43100 (Italy); Casoli, F. [IMEM-CNR Parco Area delle Scienze 37/A, Parma 43100 (Italy); Dediu, V. [ISMN-CNR via P. Gobetti 101, Bologna 40129 (Italy)

    2007-09-15

    Magnetic and morphological properties of Cobalt thin films grown by RF sputtering on organic Alq3 layers were investigated by magneto-optical Kerr effect (MOKE) technique and atomic force microscopy (AFM). The AFM images indicate a template growth of Co layers on top of Alq3, the magnetic film 'decorates' the surface of organic material. This peculiar morphology induces a strong uniaxial magnetic anisotropy in the Co films, as detected by MOKE measurements. Results are important for the operation of a new class of devices-vertical organic spin valves.

  6. Magnetization measurement of niobium for superconducting cavity material evaluation

    International Nuclear Information System (INIS)

    Wake, Masayoshi; Saito, Kenji.

    1995-05-01

    A series of magnetization measurements on niobium materials for superconducting cavities was performed, and the method was found to be very useful for material evaluation. The effects of annealing, chemical polishing and machining were clearly observed by this method. The material quality and the processing of the material can be properly evaluated by measuring the magnetization. An observation of the Q-disease effect indicates the possibility of using this method for the studies beyond material evaluation. (J.P.N)

  7. Evaluation of local muscle soreness treatment with anterior bite splint made of soft putty impression material

    Directory of Open Access Journals (Sweden)

    Harry Laksono

    2013-03-01

    Full Text Available Background: Local muscle soreness is the most common temporomandibular disorders complaint of patients seeking treatment in the dental clinics. The emergency treatment that can be done in the clinics to manage this disorder is by making anterior bite splint. Anterior bite splint is usually made of acrylic, but currently there is a soft putty impression material that can also be used for making anterior bite splint. The effectiveness of soft putty anterior bite splint in local muscle soreness treatment still has not clear. Purpose: To determine the effectiveness of the soft putty impression material as a material used for making anterior bite splint in the treatment of local muscle soreness. Case: Six patients was reported five female patients aged 20-40 years old and one male patient aged 37 years old with local muscle soreness. Four female patients with a “click” sound on TMJ. Case management: Make differential diagnosis with screening history (anamnesis, clinical examination consists of extra oral examination such as muscle and temporomandibular joint palpation, measure the mandibular movement, end-feel, load test, intra oral examination and radiographic evaluation. Record the results and make the diagnosis. Make a soft putty anterior bite splint, adjusted and inserted in the maxillary anterior teeth. Record the results based on signs and symptoms. Conclusion: It can be concluded that anterior bite splint made of soft putty impression material is effective for treatment the local muscle soreness.Latar belakang: Salah satu tipe temporomandibular disorders yang paling sering dijumpai di klinik dokter gigi adalah local muscle soreness. Perawatan yang dapat dengan segera dilakukan di klinik untuk mengelola gangguan tersebut adalah dengan pembuatan anterior bite splint. Biasanya anterior bite splint terbuat dari akrilik, namun saat ini telah ada bahan cetak soft putty yang memungkinkan untuk dipakai sebagai bahan pembuatan anterior bite splint

  8. A novel hyperthermia treatment for bone metastases using magnetic materials

    International Nuclear Information System (INIS)

    Matsumine, Akihiko; Asanuma, Kunihiro; Matsubara, Takao; Nakamura, Tomoki; Uchida, Atsumasa; Sudo, Akihiro; Takegami, Kenji

    2011-01-01

    Patients with bone metastases in the extremities sometimes require surgical intervention to prevent deterioration of quality of life due to a pathological fracture. The use of localized radiotherapy combined with surgical reinforcement has been a gold standard for the treatment of bone metastases. However, radiotherapy sometimes induces soft tissue damage, including muscle induration and joint contracture. Moreover, cancer cells are not always radiosensitive. Hyperthermia has been studied since the 1940s using an experimental animal model to treat various types of advanced cancer, and studies have now reached the stage of clinical application, especially in conjunction with radiotherapy or chemotherapy. Nevertheless, bone metastases have several special properties which discourage oncologists from developing hyperthermic therapeutic strategies. First, the bone is located deep in the body, and has low thermal conductivity due to the thickness of cortical bone and the highly vascularized medulla. To address these issues, we developed new hyperthermic strategies which generate heat using magnetic materials under an alternating electromagnetic field, and started clinical application of this treatment modality. The purpose of this review is to summarize the latest studies on hyperthermic treatment in the field of musculoskeletal tumors, and to introduce the treatment strategy employing our novel hyperthermia approach. (author)

  9. Measuring spectroscopy and magnetism of extracted and intracellular magnetosomes using soft X-ray ptychography.

    Science.gov (United States)

    Zhu, Xiaohui; Hitchcock, Adam P; Bazylinski, Dennis A; Denes, Peter; Joseph, John; Lins, Ulysses; Marchesini, Stefano; Shiu, Hung-Wei; Tyliszczak, Tolek; Shapiro, David A

    2016-12-20

    Characterizing the chemistry and magnetism of magnetotactic bacteria (MTB) is an important aspect of understanding the biomineralization mechanism and function of the chains of magnetosomes (Fe 3 O 4 nanoparticles) found in such species. Images and X-ray absorption spectra (XAS) of magnetosomes extracted from, and magnetosomes in, whole Magnetovibrio blakemorei strain MV-1 cells have been recorded using soft X-ray ptychography at the Fe 2p edge. A spatial resolution of 7 nm is demonstrated. Precursor-like and immature magnetosome phases in a whole MV-1 cell were visualized, and their Fe 2p spectra were measured. Based on these results, a model for the pathway of magnetosome biomineralization for MV-1 is proposed. Fe 2p X-ray magnetic circular dichroism (XMCD) spectra have been derived from ptychography image sequences recorded using left and right circular polarization. The shape of the XAS and XMCD signals in the ptychographic absorption spectra of both sample types is identical to the shape and signals measured with conventional bright-field scanning transmission X-ray microscope. A weaker and inverted XMCD signal was observed in the ptychographic phase spectra of the extracted magnetosomes. The XMCD ptychographic phase spectrum of the intracellular magnetosomes differed from the ptychographic phase spectrum of the extracted magnetosomes. These results demonstrate that spectro-ptychography offers a superior means of characterizing the chemical and magnetic properties of MTB at the individual magnetosome level.

  10. Magnetization reversal and exchange bias effects in hard/soft ferromagnetic bilayers with orthogonal anisotropies

    International Nuclear Information System (INIS)

    Navas, D; Ross, C A; Torrejon, J; Béron, F; Pirota, K R; Redondo, C; Sierra, B; Castaño, F; Batallan, F; Toperverg, B P; Devishvili, A

    2012-01-01

    The magnetization reversal processes are discussed for exchange-coupled ferromagnetic hard/soft bilayers made from Co 0.66 Cr 0.22 Pt 0.12 (10 and 20 nm)/Ni (from 0 to 40 nm) films with out-of-plane and in-plane magnetic easy axes respectively, based on room temperature hysteresis loops and first-order reversal curve analysis. On increasing the Ni layer thicknesses, the easy axis of the bilayer reorients from out-of-plane to in-plane. An exchange bias effect, consisting of a shift of the in-plane minor hysteresis loops along the field axis, was observed at room temperature after in-plane saturation. This effect was associated with specific ferromagnetic domain configurations experimentally determined by polarized neutron reflectivity. On the other hand, perpendicular exchange bias effect was revealed from the out-of-plane hysteresis loops and it was attributed to residual domains in the magnetically hard layer. (paper)

  11. Histopathological changes by the use of soft reline materials: a rat model study.

    Science.gov (United States)

    Bail, Michele; Meister, Lissandra Matos Brol; Campagnoli, Eduardo Bauml; Jorge, Janaina Habib; Ban, Manuella de Cassia Iglesias; Sanchez-Ayala, Alfonso; Campanha, Nara Hellen

    2014-01-01

    To assess the histopathological changes of rat palatal mucosa exposed to soft reline materials. Forty-five adult female Wistar rats with controlled living conditions and fed ad libitum were employed. Palatal appliances of heat-polymerized acrylic resin Lucitone 550 were manufactured and worn by forty animals during 14 days. Five animals did not use the appliances (G1) and were used to control the appliance influence. One experimental group (n = 10) used the appliances without any relining material (G2) to control the material effect. Three experimental groups (n = 10) received the following soft reline materials below appliances: Dentusoft (G3), Dentuflex (G4), and Trusoft (G5). Appliances from half of each experimental group(n = 5) was immersed in water bath at 55°C for 10 min before use. Animals were slaughtered and the palates were fixed in 10% buffered formalin. Hematoxylin and eosin stained sections of 5 µm were analyzed by computerized planimetry. Cellular compartment, keratin and total epithelial thickness, and basement membrane length were measured to histopathological description.Analysis of variance and Tukey post-hoc test were used to data examination(α = 0.05). For heat-treatment groups, G4 showed less elongated ridges at the basal layer interface (p = 0.037) than G2. When comparing the conditions with and without heat-treatment, only G2 showed a significant decrease in the cellular compartment, keratin layer and total epithelium thickness (p<0.05). The post-polymerization for Lucitone 550 was an effective method to reduce the changes in the rat palatal mucosa. The soft reline materials tested did not cause significant histopathological changes in the rat palatal mucosa.

  12. Focus on Materials Analysis and Processing in Magnetic Fields

    Directory of Open Access Journals (Sweden)

    Yoshio Sakka, Noriyuki Hirota, Shigeru Horii and Tsutomu Ando

    2009-01-01

    Full Text Available Recently, interest in the applications of feeble (diamagnetic and paramagnetic magnetic materials has grown, whereas the popularity of ferromagnetic materials remains steady and high. This trend is due to the progress of superconducting magnet technology, particularly liquid-helium-free superconducting magnets that can generate magnetic fields of 10 T and higher. As the magnetic energy is proportional to the square of the applied magnetic field, the magnetic energy of such 10 T magnets is in excess of 10 000 times that of conventional 0.1 T permanent magnets. Consequently, many interesting phenomena have been observed over the last decade, such as the Moses effect, magnetic levitation and the alignment of feeble magnetic materials. Researchers in this area are widely spread around the world, but their number in Japan is relatively high, which might explain the success of magnetic field science and technology in Japan.Processing in magnetic fields is a rapidly expanding research area with a wide range of promising applications in materials science. The 3rd International Workshop on Materials Analysis and Processing in Magnetic Fields (MAP3, which was held on 14–16 May 2008 at the University of Tokyo, Japan, focused on various topics including magnetic field effects on chemical, physical, biological, electrochemical, thermodynamic and hydrodynamic phenomena; magnetic field effects on the crystal growth and processing of materials; diamagnetic levitation, the magneto-Archimedes effect, spin chemistry, magnetic orientation, control of structure by magnetic fields, magnetic separation and purification, magnetic-field-induced phase transitions, properties of materials in high magnetic fields, the development of NMR and MRI, medical applications of magnetic fields, novel magnetic phenomena, physical property measurement by magnetic fields, and the generation of high magnetic fields.This focus issue compiles 13 key papers selected from the proceedings

  13. Transient finite element magnetic field calculation method in the anisotropic magnetic material based on the measured magnetization curves

    International Nuclear Information System (INIS)

    Jesenik, M.; Gorican, V.; Trlep, M.; Hamler, A.; Stumberger, B.

    2006-01-01

    A lot of magnetic materials are anisotropic. In the 3D finite element method calculation, anisotropy of the material is taken into account. Anisotropic magnetic material is described with magnetization curves for different magnetization directions. The 3D transient calculation of the rotational magnetic field in the sample of the round rotational single sheet tester with circular sample considering eddy currents is made and compared with the measurement to verify the correctness of the method and to analyze the magnetic field in the sample

  14. Preparation of Magnetic Composite Materials: Experiments for Secondary School Students

    Czech Academy of Sciences Publication Activity Database

    Baldíková, Eva; Pospíšková, K.; Maděrová, Zdeňka; Šafaříková, Miroslava; Šafařík, Ivo

    2016-01-01

    Roč. 110, č. 1 (2016), s. 64-68 ISSN 0009-2770 Keywords : dyes removal * nanoparticles * mechanochemistry * technology * adsorbent * fe3o4 * magnetic modification * magnetic composite materials * magnetic separation * microwave-assisted synthesis * mechanochemical synthesis Impact factor: 0.387, year: 2016

  15. Microwave assisted synthesis of Magnetically responsive composite materials

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Horská, Kateřina; Pospíšková, K.; Maděrová, Zdeňka; Šafaříková, Miroslava

    2013-01-01

    Roč. 49, č. 1 (2013), s. 213-218 ISSN 0018-9464 R&D Projects: GA ČR(CZ) GAP503/11/2263; GA MŠk LH12190 Institutional support: RVO:67179843 Keywords : magnetic materials * magnetic modification * magnetic separation * microwaves Subject RIV: EH - Ecology, Behaviour Impact factor: 1.213, year: 2013

  16. 'Optical' soft x-ray arrays for fluctuation diagnostics in magnetic fusion energy experiments

    International Nuclear Information System (INIS)

    Delgado-Aparicio, L.F.; Stutman, D.; Tritz, K.; Finkenthal, M.; Kaita, R.; Roquemore, L.; Johnson, D.; Majeski, R.

    2004-01-01

    We are developing large pixel count, fast (≥100 kHz) and continuously sampling soft x-ray (SXR) array for the diagnosis of magnetohydrodynamics (MHD) and turbulent fluctuations in magnetic fusion energy plasmas. The arrays are based on efficient scintillators, high thoughput multiclad fiber optics, and multichannel light amplification and integration. Compared to conventional x-ray diode arrays, such systems can provide vastly increased spatial coverage, and access to difficult locations with small neutron noise and damage. An eight-channel array has been built using columnar CsI:Tl as an SXR converter and a multianode photomultiplier tube as photoamplifier. The overall system efficiency is measured using laboratory SXR sources, while the time response and signal-to-noise performance have been evaluated by recording MHD activity from the spherical tori (ST) Current Drive Experiment-Upgrade and National Spherical Torus Experiment, both at Princeton Plasma Physics Laboratory

  17. Innovative soft magnetic multilayers with enhanced in-plane anisotropy and ferromagnetic resonance frequency for integrated RF passive devices

    Directory of Open Access Journals (Sweden)

    Claudiu V. Falub

    2018-04-01

    Full Text Available We present an innovative, economical method for manufacturing soft magnetic materials that may pave the way for integrated thin film magnetic cores with dramatically improved properties. Soft magnetic multilayered thin films based on the Fe-28%Co20%B (at.% and Co-4.5%Ta4%Zr (at.% amorphous alloys are deposited on 8” bare Si and Si/200nm-thermal-SiO2 wafers in an industrial, high-throughput Evatec LLS EVO II magnetron sputtering system. The multilayers consist of stacks of alternating 80-nm-thick ferromagnetic layers and 4-nm-thick Al2O3 dielectric interlayers. Since in our dynamic sputter system the substrate cage rotates continuously, such that the substrates face different targets alternatively, each ferromagnetic sublayer in the multilayer consists of a fine structure comprising alternating CoTaZr and FeCoB nanolayers with very sharp interfaces. We adjust the thickness of these individual nanolayers between 0.5 and 1.5 nm by changing the cage rotation speed and the power of each gun, which is an excellent mode to engineer new, composite ferromagnetic materials. Using X-ray reflectometry (XRR we reveal that the interfaces between the FeCoB and CoTaZr nanolayers are perfectly smooth with roughness of 0.2-0.3 nm. Kerr magnetometry and B-H looper measurements for the as-deposited samples show that the coercivity of these thin films is very low, 0.2-0.3 Oe, and gradually scales up with the thickness of FeCoB nanolayers, i.e. with the increase of the overall Fe content from 0 % (e.g. CoTaZr-based multilayers to 52 % (e.g. FeCoB-based multilayers. We explain this trend in the random anisotropy model, based on considerations of grain size growth, as revealed by glancing angle X-ray diffraction (GAXRD, but also because of the increase of magnetostriction with the increase of Fe content as shown by B-H looper measurements performed on strained wafers. The unexpected enhancement of the in-plane anisotropy field from 18.3 Oe and 25.8 Oe for the

  18. 3D printing of concentrated emulsions into multiphase biocompatible soft materials.

    Science.gov (United States)

    Sommer, Marianne R; Alison, Lauriane; Minas, Clara; Tervoort, Elena; Rühs, Patrick A; Studart, André R

    2017-03-01

    3D printing via direct ink writing (DIW) is a versatile additive manufacturing approach applicable to a variety of materials ranging from ceramics over composites to hydrogels. Due to the mild processing conditions compared to other additive manufacturing methods, DIW enables the incorporation of sensitive compounds such as proteins or drugs into the printed structure. Although emulsified oil-in-water systems are commonly used vehicles for such compounds in biomedical, pharmaceutical, and cosmetic applications, printing of such emulsions into architectured soft materials has not been fully exploited and would open new possibilities for the controlled delivery of sensitive compounds. Here, we 3D print concentrated emulsions into soft materials, whose multiphase architecture allows for site-specific incorporation of both hydrophobic and hydrophilic compounds into the same structure. As a model ink, concentrated emulsions stabilized by chitosan-modified silica nanoparticles are studied, because they are sufficiently stable against coalescence during the centrifugation step needed to create a bridging network of droplets. The resulting ink is ideal for 3D printing as it displays high yield stress, storage modulus and elastic recovery, through the formation of networks of droplets as well as of gelled silica nanoparticles in the presence of chitosan. To demonstrate possible architectures, we print biocompatible soft materials with tunable hierarchical porosity containing an encapsulated hydrophobic compound positioned in specific locations of the structure. The proposed emulsion-based ink system offers great flexibility in terms of 3D shaping and local compositional control, and can potentially help address current challenges involving the delivery of incompatible compounds in biomedical applications.

  19. FOREWORD: Focus on Materials Analysis and Processing in Magnetic Fields Focus on Materials Analysis and Processing in Magnetic Fields

    Science.gov (United States)

    Sakka, Yoshio; Hirota, Noriyuki; Horii, Shigeru; Ando, Tsutomu

    2009-03-01

    Recently, interest in the applications of feeble (diamagnetic and paramagnetic) magnetic materials has grown, whereas the popularity of ferromagnetic materials remains steady and high. This trend is due to the progress of superconducting magnet technology, particularly liquid-helium-free superconducting magnets that can generate magnetic fields of 10 T and higher. As the magnetic energy is proportional to the square of the applied magnetic field, the magnetic energy of such 10 T magnets is in excess of 10 000 times that of conventional 0.1 T permanent magnets. Consequently, many interesting phenomena have been observed over the last decade, such as the Moses effect, magnetic levitation and the alignment of feeble magnetic materials. Researchers in this area are widely spread around the world, but their number in Japan is relatively high, which might explain the success of magnetic field science and technology in Japan. Processing in magnetic fields is a rapidly expanding research area with a wide range of promising applications in materials science. The 3rd International Workshop on Materials Analysis and Processing in Magnetic Fields (MAP3), which was held on 14-16 May 2008 at the University of Tokyo, Japan, focused on various topics including magnetic field effects on chemical, physical, biological, electrochemical, thermodynamic and hydrodynamic phenomena; magnetic field effects on the crystal growth and processing of materials; diamagnetic levitation, the magneto-Archimedes effect, spin chemistry, magnetic orientation, control of structure by magnetic fields, magnetic separation and purification, magnetic-field-induced phase transitions, properties of materials in high magnetic fields, the development of NMR and MRI, medical applications of magnetic fields, novel magnetic phenomena, physical property measurement by magnetic fields, and the generation of high magnetic fields. This focus issue compiles 13 key papers selected from the proceedings of MAP3. Other

  20. Time of isothermal holding in the course of in-air heat treatment of soft magnetic Fe-based amorphous alloys and their magnetic properties

    Science.gov (United States)

    Skulkina, N. A.; Ivanov, O. A.; Pavlova, I. O.; Minina, O. A.

    2011-12-01

    On the example of soft magnetic Fe81B13Si4C2 and Fe77Ni1Si9B13 amorphous alloys, the relation between the level of magnetic properties and duration of isothermal holding in the course of heat treatment in air has been studied. The optimum temperature-dependent time τ of isothermal holding has been shown to be related to the volume fraction of domains ( V orth) with orthogonal magnetization in the initial (quenched) ribbon by equation V orth = ττ1/3. A temperature dependence of the proportionality coefficient α, which determines the degree of diffusion-process activity, has been determined. The results obtained allow us to substantially simplify the choice of optimum conditions of atmospheric heat treatment of soft magnetic Fe-based amorphous ribbons.

  1. Project for a beam line consecrated to soft condensed matter, common heterogeneous materials and non-crystalline materials on soleil

    International Nuclear Information System (INIS)

    Ne, F.; Zemb, T.

    1998-01-01

    This project is a part of the 'SOLEIL' synchrotron project. The camera proposed is optimized for small angle x-ray scattering in the domain of soft condensed matter, common heterogeneous materials such as wood, cements, glass, and more generally non-crystalline materials. The beam line is designed to allow a quick succession of different users without time consuming adjustments. Therefore, optical settings are minimized, taking into account the pluri-disciplinary nature of the analysis possibilities. To this end, the technical requirements are as follows. First and essentially, the wave-length has to be fixed and set around 12 keV. Focusing mirrors, optics to sample and sample to detector distances, and the size of the detector allow for a wide range of wave vector to be used. Rejection rate will be lower, and angular dynamical range will be larger than any of the current synchrotron lines. We want this line to be, and to stay, complementary to more specific systems, such as reflectivity experiments or grazing angle scattering experiments. However, we are thinking of an adaptation to ultra small angle scattering mode, based on the Bonse and Hart camera. Such equipment, actually a kind of 'Instamatic' of the reciprocal space, will fulfill to the need of chemical engineers, biophysicists or material scientists interested in hard as well as soft condensed matter. It will allow a large amount of experiments per time unit. (author)

  2. Evaluation of bionanocomposites as packaging material on properties of soft white cheese during storage period.

    Science.gov (United States)

    Youssef, Ahmed M; El-Sayed, Samah M; Salama, Heba H; El-Sayed, Hoda S; Dufresne, A

    2015-11-05

    Novel bionanocomposites based on chitosan/poly(vinyl alcohol)/titanium nanoparticles (CS/PVA/TiO2 nanocomposite) were prepared and used as packaging materials for soft white cheese. The prepared bionanocomposites were characterized using XRD, SEM, TEM and FT-IR. The CS/PVA/TiO2 bionanocomposites exhibited good mechanical properties. Furthermore, the obtained bionanocomposites exhibited superior antibacterial activity against gram positive (Staphylococcus aureus), gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria and fungi (Candidia albicans). The soft white cheese was manufactured and packaged within the CS/PVA/TiO2 nanocomposite films and stored at 7 °C for 30 days. The color, rheological and chemical properties of cheese were evaluated, also the influence of CS/PVA/TiO2 bionanocomposites on microbiological analysis of soft white cheese was assessed, the results indicated that the total bacterial counts, mold & yeast and coliform decreased with the increasing storage period and disappeared at the end of storage period compared with control. Consequently, CS/PVA/TiO2 bionanocomposite can be used in food packaging applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Real-time soft x-ray imaging on composite materials

    International Nuclear Information System (INIS)

    Polichar, R.

    1985-01-01

    The increased use of composite materials in aircraft structures has emphasized many of the unique and difficult aspects of the inspection of such components. Ultrasound has been extensively applied to certain configurations since it is relatively sensitive to laminar discontinuities in structure. Conversely, the use of conventional x-ray examination has been severely hampered by the fact that these composite materials are virtually transparent to the x-ray energies commonly encountered in industrial radiography (25 kv and above). To produce images with contrast approaching conventional radiography, one must use x-ray beams with average energies below 10 KEV where the absorption coefficients begin to rise rapidly for these low atomic number materials. This new regime of soft x-rays presents a major challenge to real-time imaging components. Special screen and window technology is required if these lower energy x-rays are to be effectively detected. Moreover, conventional x-ray tubes become very inefficient for generating the required x-ray flux at potentials much below 29 kv and the increased operating currents put significant limitations on conventional power sources. The purpose of this paper is to explore these special problems related to soft x-ray real-time imaging and to define the optimal technologies. Practical results obtained with the latest commerical and developmental instruments for real-time imaging will be shown. These instruments include recently developed imaging systems, new x-ray tubes and various approaches to generator design. The measured results convincingly demonstrate the effectiveness practicality of real-time soft x-ray imaging. They also indicate the major changes in technology and approach that must be taken for practical systems to be truly effective

  4. Development of a high gradient rf system using a nanocrystalline soft magnetic alloy

    Directory of Open Access Journals (Sweden)

    Chihiro Ohmori

    2013-11-01

    Full Text Available The future high intensity upgrade project of the J-PARC (Japan Proton Accelerator Research Complex MR (Main Ring includes developments of high gradient rf cavities and magnet power supplies for high repetition rate. The scenario describing the cavity replacements is reported. By the replacement plan, the total acceleration voltage will be almost doubled, while the number of rf stations remains the same. The key issue is the development of a high gradient rf system using high impedance magnetic alloy, FT3L. The FT3L is produced by the transverse magnetic field annealing although the present cavity for the J-PARC adopts the magnetic alloy, FT3M, which is annealed without magnetic field. After the test production using a large spectrometer magnet in 2011, a dedicated production system for the FT3L cores was assembled in 2012. This setup demonstrated that we can produce material with 2 times higher μ_{p}^{′}Qf product compared to the cores used for present cavities. In this summer, the production system was moved to the company from J-PARC and is used for mass production of 280 FT3L cores for the J-PARC MR. The cores produced in the first test production are already used for standard machine operation. The operation experience shows that the power loss in the cores was reduced significantly as expected.

  5. Temperature dependence of microwave absorption phenomena in single and biphase soft magnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    El Kammouni, Rhimou, E-mail: elkammounirhimou@gmail.com [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Vázquez, Manuel [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Lezama, Luis [Depto. Química Inorgánica, Universidad País Vasco, UPV/EHU, Bilbao (Spain); Kurlyandskaya, Galina [Depto. Electricidad y Electrónica, Universidad País Vasco, UPV/EHU, Bilbao (Spain); Dept. Magnetism and Magnetic Nanomaterials, Ural Federal University, Ekaterinburg (Russian Federation); Kraus, Ludek [Institute of Physics, Academy of Sciences of the Czech Republic, Prague (Czech Republic)

    2014-11-15

    The microwave absorption phenomena of single and biphase magnetic microwires with soft magnetic behavior have been investigated as a function of DC applied magnetic field using two alternative techniques: (i) absorption measurements in the temperature range of 4–300 K using a spectrometer operating at X-band frequency, at 9.5 GHz, and (ii) room-temperature, RT, ferromagnetic resonance measurements in a network analyzer in the frequency range up to 20 GHz. Complementary low-frequency magnetic characterization was performed in a Vibrating Sample Magnetometer. Studies have been performed for 8 μm diameter small-magnetostriction amorphous CoFeSiB single-phase microwire, coated by micrometric Pyrex layer, and after electroplating an external shell, 2 µm or 4 µm thick, of FeNi alloys. For single phase CoFeSiB microwire, a single absorption is observed, whose DC field dependence of resonance frequency at RT fits to a Kittel-law behavior for in-plane magnetized thin film. The temperature dependence behavior shows a monotonic increase in the resonance field, H{sub r}, with temperature. A parallel reduction of the circular anisotropy field, H{sub K}, is deduced from the temperature dependence of hysteresis loops. For biphase, CoFeSiB/FeNi, microwires, the absorption phenomena at RT also follow the Kittel condition. The observed opposite evolution with temperature of resonance field, H{sub r}, in 2 and 4 µm thick FeNi samples is interpreted considering the opposite sign of magnetostriction of the respective FeNi layers. The stress-induced magnetic anisotropy field, H{sub K}, in the FeNi shell is deduced to change sign at around 130 K. - Highlights: • A single absorption phenomenon is observed for single phase CoFeSiB. • The T dependence of the microwave behavior shows a monotonic increase of H{sub r} with T. • The absorption at RT follows the Kittel condition for biphase CoFe/FeNi microwires. • The T dependence of resonant field of CoFe/FeNi is interpreted to be

  6. Fabrication and Properties of Iron-based Soft Magnetic Composites Coated with NiZnFe2O4

    Directory of Open Access Journals (Sweden)

    WU Shen

    2017-07-01

    Full Text Available This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing the sol-gel method prepared Ni-Zn ferrite particles as insulating compound to coat iron powder, and the influence of NiZnFe2O4 content and molding pressure on the magnetic properties was studied. The morphology, magnetic properties and density of Ni-Zn ferrite insulated compacts were investigated. Scanning electron microscope,line-scan EDX analysis and distribution maps show that the iron particle surface is covered with a thin layer of uniform Ni-Zn ferrites. The existing of the insulating layer can effectively improve the electrical resistivity of soft magnetic composites. Magnetic measurements show that the real part of permeability decreases with the increase of the Ni-Zn ferrite content, and the sample with 3%(mass fraction, the same below Ni-Zn ferrite has an acceptable real part and minimum imaginary part of permeability in comparison with other samples. Results show that the addition of NiZnFe2O4 can dramatically decrease the internal magnetic loss, the magnetic loss of coated samples decreases by 83.8% as compared with that of uncoated samples at 100kHz. The density of the Fe-3%NiZnFe2O4 compacts reaches 7.14g/cm3 and the saturation magnetization is 1.47T when the molding pressure is 1000MPa.

  7. Enthalpy-based equation of state for highly porous materials employing modified soft sphere fluid model

    Science.gov (United States)

    Nayak, Bishnupriya; Menon, S. V. G.

    2018-01-01

    Enthalpy-based equation of state based on a modified soft sphere model for the fluid phase, which includes vaporization and ionization effects, is formulated for highly porous materials. Earlier developments and applications of enthalpy-based approach had not accounted for the fact that shocked states of materials with high porosity (e.g., porosity more than two for Cu) are in the expanded fluid region. We supplement the well known soft sphere model with a generalized Lennard-Jones formula for the zero temperature isotherm, with parameters determined from cohesive energy, specific volume and bulk modulus of the solid at normal condition. Specific heats at constant pressure, ionic and electronic enthalpy parameters and thermal excitation effects are calculated using the modified approach and used in the enthalpy-based equation of state. We also incorporate energy loss from the shock due to expansion of shocked material in calculating porous Hugoniot. Results obtained for Cu, even up to initial porosities ten, show good agreement with experimental data.

  8. A novel method for the accurate evaluation of Poisson's ratio of soft polymer materials.

    Science.gov (United States)

    Lee, Jae-Hoon; Lee, Sang-Soo; Chang, Jun-Dong; Thompson, Mark S; Kang, Dong-Joong; Park, Sungchan; Park, Seonghun

    2013-01-01

    A new method with a simple algorithm was developed to accurately measure Poisson's ratio of soft materials such as polyvinyl alcohol hydrogel (PVA-H) with a custom experimental apparatus consisting of a tension device, a micro X-Y stage, an optical microscope, and a charge-coupled device camera. In the proposed method, the initial positions of the four vertices of an arbitrarily selected quadrilateral from the sample surface were first measured to generate a 2D 1st-order 4-node quadrilateral element for finite element numerical analysis. Next, minimum and maximum principal strains were calculated from differences between the initial and deformed shapes of the quadrilateral under tension. Finally, Poisson's ratio of PVA-H was determined by the ratio of minimum principal strain to maximum principal strain. This novel method has an advantage in the accurate evaluation of Poisson's ratio despite misalignment between specimens and experimental devices. In this study, Poisson's ratio of PVA-H was 0.44 ± 0.025 (n = 6) for 2.6-47.0% elongations with a tendency to decrease with increasing elongation. The current evaluation method of Poisson's ratio with a simple measurement system can be employed to a real-time automated vision-tracking system which is used to accurately evaluate the material properties of various soft materials.

  9. A Novel Method for the Accurate Evaluation of Poisson’s Ratio of Soft Polymer Materials

    Directory of Open Access Journals (Sweden)

    Jae-Hoon Lee

    2013-01-01

    Full Text Available A new method with a simple algorithm was developed to accurately measure Poisson’s ratio of soft materials such as polyvinyl alcohol hydrogel (PVA-H with a custom experimental apparatus consisting of a tension device, a micro X-Y stage, an optical microscope, and a charge-coupled device camera. In the proposed method, the initial positions of the four vertices of an arbitrarily selected quadrilateral from the sample surface were first measured to generate a 2D 1st-order 4-node quadrilateral element for finite element numerical analysis. Next, minimum and maximum principal strains were calculated from differences between the initial and deformed shapes of the quadrilateral under tension. Finally, Poisson’s ratio of PVA-H was determined by the ratio of minimum principal strain to maximum principal strain. This novel method has an advantage in the accurate evaluation of Poisson’s ratio despite misalignment between specimens and experimental devices. In this study, Poisson’s ratio of PVA-H was 0.44 ± 0.025 (n=6 for 2.6–47.0% elongations with a tendency to decrease with increasing elongation. The current evaluation method of Poisson’s ratio with a simple measurement system can be employed to a real-time automated vision-tracking system which is used to accurately evaluate the material properties of various soft materials.

  10. Controlled molecular self-assembly of complex three-dimensional structures in soft materials.

    Science.gov (United States)

    Huang, Changjin; Quinn, David; Suresh, Subra; Hsia, K Jimmy

    2018-01-02

    Many applications in tissue engineering, flexible electronics, and soft robotics call for approaches that are capable of producing complex 3D architectures in soft materials. Here we present a method using molecular self-assembly to generate hydrogel-based 3D architectures that resembles the appealing features of the bottom-up process in morphogenesis of living tissues. Our strategy effectively utilizes the three essential components dictating living tissue morphogenesis to produce complex 3D architectures: modulation of local chemistry, material transport, and mechanics, which can be engineered by controlling the local distribution of polymerization inhibitor (i.e., oxygen), diffusion of monomers/cross-linkers through the porous structures of cross-linked polymer network, and mechanical constraints, respectively. We show that oxygen plays a role in hydrogel polymerization which is mechanistically similar to the role of growth factors in tissue growth, and the continued growth of hydrogel enabled by diffusion of monomers/cross-linkers into the porous hydrogel similar to the mechanisms of tissue growth enabled by material transport. The capability and versatility of our strategy are demonstrated through biomimetics of tissue morphogenesis for both plants and animals, and its application to generate other complex 3D architectures. Our technique opens avenues to studying many growth phenomena found in nature and generating complex 3D structures to benefit diverse applications. Copyright © 2017 the Author(s). Published by PNAS.

  11. Visible-Light Modulation on Lattice Dielectric Responses of a Piezo-Phototronic Soft Material.

    Science.gov (United States)

    Huang, E-Wen; Hsu, Yu-Hsiang; Chuang, Wei-Tsung; Ko, Wen-Ching; Chang, Chung-Kai; Lee, Chih-Kung; Chang, Wen-Chi; Liao, Tzu-Kang; Thong, Hao Cheng

    2015-12-16

    In situ synchrotron X-ray diffraction is used to investigate a three-way piezo-phototronic soft material. This new system is composed of a semi-crystalline poly(vinylidene fluoride-co-trifluoroethylene) piezoelectric polymer and titanium oxide nanoparticles. Under light illumination, photon-induced piezoelectric responses are nearly two times higher at both the lattice-structure and the macroscopic level than under conditions without light illumination. A mechanistic model is proposed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Tracking the harmonic response of magnetically-soft sensors for wireless temperature, stress, and corrosive monitoring

    Science.gov (United States)

    Ong, Keat G.; Grimes, Craig A.

    2002-01-01

    This paper describes the application of magnetically-soft ribbon-like sensors for measurement of temperature and stress, as well as corrosive monitoring, based upon changes in the amplitudes of the higher-order harmonics generated by the sensors in response to a magnetic interrogation signal. The sensors operate independently of mass loading, and so can be placed or rigidly embedded inside nonmetallic, opaque structures such as concrete or plastic. The passive harmonic-based sensor is remotely monitored through a single coplanar interrogation and detection coil. Effects due to the relative location of the sensor are eliminated by tracking harmonic amplitude ratios, thereby, enabling wide area monitoring. The wireless, passive, mass loading independent nature of the described sensor platform makes it ideally suited for long-term structural monitoring applications, such as measurement of temperature and stress inside concrete structures. A theoretical model is presented to explain the origin and behavior of the higher-order harmonics in response to temperature and stress. c2002 Elsevier Science B.V. All rights reserved.

  13. Neutron scattering—The key characterization tool for nanostructured magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Fitzsimmons, M.R., E-mail: fitz@lanl.gov [Los Alamos National Laboratory (United States); Schuller, Ivan K. [University of California, San Diego (United States)

    2014-01-15

    The novel properties of materials produced using nanoscale manufacturing processes often arise from interactions across interfaces between dissimilar materials. Thus, to characterize the structure and magnetism of nanoscale materials demands tools with interface specificity. Neutron scattering has long been known to provide unique and quantitative information about nuclear and magnetic structures of bulk materials. Moreover, the specialty techniques of polarized neutron reflectometry and small angle neutron scattering (SANS) with polarized neutron beams and polarization analysis, are ideally and often uniquely suited to studies of nanostructured magnetic materials. Since neutron scattering is a weakly interacting probe, it gives quantifiable and easily-interpreted information on properties of statistically representative quantities of bulk, thin film and interfacial materials. In addition, neutron scattering can provide information to complement that obtained with bulk probes (magnetization, Kerr effect) or surface measurements obtained with scanning probe microscopy or resonant soft x-ray scattering. The straightforward interpretation and the simultaneous availability of structural information, make neutron scattering the technique of choice for the structural and physical characterization of many novel materials, especially those with buried interfaces, ones allowing for isotopic substitutions to decorate buried interfaces, or cases where the magnetic response to an external stimulus can be measured. We describe recent applications of neutron scattering to important thin film materials systems and future opportunities. Unquestionably, neutron scattering has played a decisive role in the development and study of new emergent phenomena. We argue with the advent of new techniques in neutron scattering and sample environment, neutron scattering's role in such studies will become even more dominant. In particular, neutron scattering will clarify and distinguish

  14. Structural materials for large superconducting magnets for tokamaks

    International Nuclear Information System (INIS)

    Long, C.J.

    1976-12-01

    The selection of structural materials for large superconducting magnets for tokamak-type fusion reactors is considered. The important criteria are working stress, radiation resistance, electromagnetic interaction, and general feasibility. The most advantageous materials appear to be face-centered-cubic alloys in the Fe-Ni-Cr system, but high-modulus composites may be necessary where severe pulsed magnetic fields are present. Special-purpose structural materials are considered briefly

  15. Study of soft magnetic iron cobalt based alloys processed by powder injection molding

    International Nuclear Information System (INIS)

    Silva, Aline; Lozano, Jaime A.; Machado, Ricardo; Escobar, Jairo A.; Wendhausen, Paulo A.P.

    2008-01-01

    As a near net shape process, powder injection molding (PIM) opens new possibilities to process Fe-Co alloys for magnetic applications. Due to the fact that PIM does not involve plastic deformation of the material during processing, we envisioned the possibility of eliminating vanadium (V), which is generally added to Fe-Co alloys to improve the ductility in order to enable its further shaping by conventional processes such as forging and cold rolling. In our investigation we have found out two main futures related to the elimination of V, which lead to a cost-benefit gain in manufacturing small magnetic components where high-saturation induction is needed at low frequencies. Firstly, the elimination of V enables the achievement of much better magnetic properties when alloys are processed by PIM. Secondly, a lower sintering temperature can be used when the alloy is processed starting with elemental Fe and Co powders without the addition of V

  16. Bioinspired fabrication and characterization of a synthetic fish skin for the protection of soft materials.

    Science.gov (United States)

    Funk, Natasha; Vera, Marc; Szewciw, Lawrence J; Barthelat, Francois; Stoykovich, Mark P; Vernerey, Franck J

    2015-03-18

    The scaled skin of fish is a high-performance natural armor that represents a source of inspiration for novel engineering designs. In this paper, we present a biomimetic fish skin material, fabricated with a design and components that are simple, that achieves many of the advantageous attributes of natural materials, including the unique combination of flexibility and mechanical robustness. The bioinspired fish skin material is designed to replicate the structural, mechanical, and functional aspects of a natural teleost fish skin comprised of leptoid-like scales, similar to that of the striped red mullet Mullus surmuletus. The man-made fish skin material consists of a low-modulus elastic mesh or "dermis" layer that holds rigid, plastic scales. The mechanics of the synthetic material is characterized under in-plane, bending, and indentation modes of deformation and is successfully described by theoretical deformation models that have been developed. This combined experimental and modeling approach elucidates the critical mechanisms by which the composite material achieves its unique properties and provides design rules that allow for the engineering of scaled skins. Such artificial scaled skins that are flexible, lightweight, transparent, and robust under mechanical deformation may thus have potential as thin protective coatings for soft materials.

  17. Magnetic Properties of FeNi-Based Thin Film Materials with Different Additives

    Directory of Open Access Journals (Sweden)

    Cai Liang

    2014-07-01

    Full Text Available This paper presents a study of FeNi-based thin film materials deposited with Mo, Al and B using a co-sputtering process. The existence of soft magnetic properties in combination with strong magneto-mechanical coupling makes these materials attractive for sensor applications. Our findings show that FeNi deposited with Mo or Al yields magnetically soft materials and that depositing with B further increases the softness. The out-of-plane magnetic anisotropy of FeNi thin films is reduced by depositing with Al and completely removed by depositing with B. The effect of depositing with Mo is dependent on the Mo concentration. The coercivity of FeNiMo and FeNiAl is reduced to less than a half of that of FeNi, and a value as low as 40 A/m is obtained for FeNiB. The surfaces of the obtained FeNiMo, FeNiAl and FeNiB thin films reveal very different morphologies. The surface of FeNiMo shows nano-cracks, while the FeNiAl films show large clusters and fewer nano-cracks. When FeNi is deposited with B, a very smooth morphology is obtained. The crystal structure of FeNiMo strongly depends on the depositant concentration and changes into an amorphous structure at a higher Mo level. FeNiAl thin films remain polycrystalline, even at a very high concentration of Al, and FeNiB films are amorphous, even at a very low concentration of B.

  18. Magnetic properties of FeNi-based thin film materials with different additives

    KAUST Repository

    Liang, C.

    2014-07-04

    This paper presents a study of FeNi-based thin film materials deposited with Mo, Al and B using a co-sputtering process. The existence of soft magnetic properties in combination with strong magneto-mechanical coupling makes these materials attractive for sensor applications. Our findings show that FeNi deposited with Mo or Al yields magnetically soft materials and that depositing with B further increases the softness. The out-of-plane magnetic anisotropy of FeNi thin films is reduced by depositing with Al and completely removed by depositing with B. The effect of depositing with Mo is dependent on the Mo concentration. The coercivity of FeNiMo and FeNiAl is reduced to less than a half of that of FeNi, and a value as low as 40 A/m is obtained for FeNiB. The surfaces of the obtained FeNiMo, FeNiAl and FeNiB thin films reveal very different morphologies. The surface of FeNiMo shows nano-cracks, while the FeNiAl films show large clusters and fewer nano-cracks. When FeNi is deposited with B, a very smooth morphology is obtained. The crystal structure of FeNiMo strongly depends on the depositant concentration and changes into an amorphous structure at a higher Mo level. FeNiAl thin films remain polycrystalline, even at a very high concentration of Al, and FeNiB films are amorphous, even at a very low concentration of B. 2014 by the authors.

  19. Transition from reversible to irreversible magnetic exchange-spring processes in antiferromagnetically exchange-coupled hard/soft/hard trilayer structures

    International Nuclear Information System (INIS)

    Wang Xiguang; Guo Guanghua; Zhang Guangfu

    2011-01-01

    The demagnetization processes of antiferromagnetically exchange-coupled hard/soft/hard trilayer structures have been studied based on the discrete one-dimensional atomic chain model and the linear partial domain-wall model. It is found that, when the magnetic anisotropy of soft layer is taken into account, the changes of the soft layer thickness and the interfacial exchange coupling strength may lead a transition of demagnetization process in soft layer from the reversible to the irreversible magnetic exchange-spring process. For the trilayer structures with very thin soft layer, the demagnetization process exhibits typical reversible exchange-spring behavior. However, as the thickness of soft layer is increased, there is a crossover point t c , after which the process becomes irreversible. Similarly, there is also a critical interfacial exchange coupling constant A sh c , above which the exchange-spring process is reversible. When A sh sh c , the irreversible exchange-spring process is achieved. The phase diagram of reversible and irreversible exchange-spring processes is mapped in the plane of the interfacial exchange coupling A sh and soft layer thickness N s . - Research highlights: → A differing magnetic exchange-spring process is found in antiferromagnetically exchange-coupled hard/soft/hard trilayers if the magnetic anisotropy of the soft layers is taken into account. → The change of the soft layer thickness may lead to a transition of demagnetization process in soft layer from the reversible to the irreversible exchange-spring process. → The change of the soft-hard interfacial exchange coupling strength may lead a transition of demagnetization process in soft layer from the reversible to the irreversible exchange-spring process. → The phase diagram of reversible and irreversible exchange-spring processes is mapped in the plane of the interfacial exchange coupling and soft layer thickness.

  20. Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

    Science.gov (United States)

    Barclay, John A.; Stewart, Walter F.; Henke, Michael D.; Kalash, Kenneth E.

    1987-01-01

    A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

  1. Extended Jiles-Atherton model for modelling the magnetic characteristics of isotropic materials

    International Nuclear Information System (INIS)

    Szewczyk, Roman; Bienkowski, Adam; Salach, Jacek

    2008-01-01

    This paper presents the idea of the extension of the Jiles-Atherton model applied for modelling of the magnetic characteristics of Mn-Zn, as well as Ni-Zn ferrites. The presented extension of the model takes into account changes of the parameter k during the magnetisation process, what is physically judged. The extended Jiles-Atherton model gives novel possibility of modelling the hysteresis loops of isotropic materials. For one set of the extended model parameters, a good agreement between experimental data and modelled hysteresis loops is observed, for different values of maximal magnetising field. As a result, the extended Jiles-Atherton model presented in the paper may be applied for both technical applications and fundamental research, focused on understanding the physical aspects of the magnetisation process of anisotropic soft magnetic materials

  2. A comparative study between magnetic resonance imaging and histological findings of bone and soft tissue tumors

    International Nuclear Information System (INIS)

    Itoh, Koichi

    1995-01-01

    Diagnostic methodology for bone and soft tissue tumors has made great strides recently through the development of magnetic resonance imaging (MRI). Here we report a comparative assessment of the histological findings of bone and soft tissue tumors with MRI from 212 cases. The accuracy of a qualitative diagnosis was observed in a solitary bone cyst, enchondroma, giant cell tumor, chondrosarcoma, lipoma, hemangioma, neurinoma, and in a synovial cyst. However, the qualitative diagnosis of a malignant tumor was difficult because of the variety of the intratumoral histological changes. An enhanced-image using Gd-DTPA was useful for differentiation of the viable region in the internal area of a tumor, discrimination of the reactive zone of an edema or assessing vascularity, and for discrimination between a cyst and a solid tumor. Based on comparison with findings from the excised specimen, it was found that histological changes such as calcification, fibrosis, hemorrhaging and necrosis, and the presence or absence of a tumor capsule had been reflected accurately on MR images. However, infiltration of the tumor into the bone cortex and into the articular cartilage were found frequently to be false-positive on MRI. Although problems remained to be solved regarding the evaluation of the presence or absence of tumor infiltration into adjacent tissue, the depiction of periosteal reaction, and regarding differentiation from inflammatory disease, MRI was a very useful information source for operative planning because it could evaluate the relationship between the tumor and adjacent blood vessels or nerves, the effect of preoperative therapy, and effectively discriminate between benign and malignant tumors. (author)

  3. Magnetic Resonance Imaging of Surgical Implants Made from Weak Magnetic Materials

    Science.gov (United States)

    Gogola, D.; Krafčík, A.; Štrbák, O.; Frollo, I.

    2013-08-01

    Materials with high magnetic susceptibility cause local inhomogeneities in the main field of the magnetic resonance (MR) tomograph. These inhomogeneities lead to loss of phase coherence, and thus to a rapid loss of signal in the image. In our research we investigated inhomogeneous field of magnetic implants such as magnetic fibers, designed for inner suture during surgery. The magnetic field inhomogeneities were studied at low magnetic planar phantom, which was made from four thin strips of magnetic tape, arranged grid-wise. We optimized the properties of imaging sequences with the aim to find the best setup for magnetic fiber visualization. These fibers can be potentially exploited in surgery for internal stitches. Stitches can be visualized by the magnetic resonance imaging (MRI) method after surgery. This study shows that the imaging of magnetic implants is possible by using the low field MRI systems, without the use of complicated post processing techniques (e.g., IDEAL).

  4. Cryogenic magnet case and distributed structural materials for high-field superconducting magnets

    International Nuclear Information System (INIS)

    Summers, L.T.; Miller, J.R.; Kerns, J.A.; Myall, J.O.

    1987-01-01

    The superconducting magnets of the Tokamak Ignition/Burn Experimental Reactor (TIBER II) will generate high magnetic fields over large bores. The resulting electromagnetic forces require the use of large volumes of distributed steel and thick magnet case for structural support. Here we review the design allowables, calculated loads and forces, and structural materials selection for TIBER II. 7 refs., 2 figs., 3 tabs

  5. Deflection of weakly magnetic materials by superconducting OGMS

    International Nuclear Information System (INIS)

    Boehm, J.; Gerber, R.; Fletcher, D.; Parker, M.R.

    1988-01-01

    Applications of a superconducting Open Gradient Magnetic Separator to fractional separation in air of weakly magnetic materials are presented. The dependence of particle deflection of these materials on the magnetic field strength, release location, magnetic susceptibility, particle density and other properties is investigated. The aim is to maximise the deflection of the magnetically stronger component of the feed to facilitate its separation from the particle stream round the magnet. Materials (e.g. CuSO/sub 4/, MnO/sub 2/) with chi/rho- ratios of the order of 7 x 10/sup -8/ m/sup 3//kg have been deflected. The applicability of dry magnetic separation has thus been considerably extended since up to now the separation of such materials has been restricted to High Gradient Magnetic Separation. The dependence of the separation efficiency upon the method of feeding and the influence of the residence time are studied in order to establish the optimum parameters for the recovery of the desired fraction. The experimental results are compared with predictions of a theory that is based upon novel approximative calculations of magnetic fields in which the use of elliptic integrals is avoided

  6. Soft x-ray spectroscopy studies of novel electronic materials using synchrotron radiation

    Science.gov (United States)

    Newby, David, Jr.

    Soft x-ray spectroscopy can provide a wealth of information on the electronic structure of solids. In this work, a suite of soft x-ray spectroscopies is applied to organic and inorganic materials with potential applications in electronic and energy generation devices. Using the techniques of x-ray absorption (XAS), x-ray emission spectroscopy (XES), and x-ray photoemission spectroscopy (XPS), the fundamental properties of these different materials are explored. Cycloparaphenylenes (CPPs) are a recently synthesized family of cyclic hydrocarbons with very interesting properties and many potential applications. Unusual UV/Visible fluorescence trends have spurred a number of theoretical investigations into the electronic properties of the CPP family, but thus far no comprehensive electronic structure measurements have been conducted. XPS, XAS, and XES data for two varieties, [8]- and [10]-CPP, are presented here, and compared with the results of relevant DFT calculations. Turning towards more application-centered investigations, similar measurements are applied to two materials commonly used in solid oxide fuel cell (SOFC) cathodes: La1-xSrxMnO 3 (LSMO) and La1-xSr1- xCo1-yFe yO3 (LSCF). Both materials are structurally perovskites, but they exhibit strikingly different electronic properties. SOFC systems very efficiently produce electricity by catalyzing reactions between oxygen and petroleum-based hydrocarbons at high temperatures (> 800 C). Such systems are already utilized to great effect in many industries, but more widespread adoption could be had if the cells could operate at lower temperatures. Understanding the electronic structure and operational evolution of the cathode materials is essential for the development of better low-temperature fuel cells. LSCF is a mixed ion-electron conductor which holds promise for low-temperature SOFC applications. XPS spectra of LSCF thin films are collected as the films are heated and gas-dosed in a controlled environment. The

  7. MSWI boiler fly ashes: magnetic separation for material recovery.

    Science.gov (United States)

    De Boom, Aurore; Degrez, Marc; Hubaux, Paul; Lucion, Christian

    2011-07-01

    Nowadays, ferrous materials are usually recovered from Municipal Solid Waste Incineration (MSWI) bottom ash by magnetic separation. To our knowledge, such a physical technique has not been applied so far to other MSWI residues. This study focuses thus on the applicability of magnetic separation on boiler fly ashes (BFA). Different types of magnet are used to extract the magnetic particles. We investigate the magnetic particle composition, as well as their leaching behaviour (EN 12457-1 leaching test). The magnetic particles present higher Cr, Fe, Mn and Ni concentration than the non-magnetic (NM) fraction. Magnetic separation does not improve the leachability of the NM fraction. To approximate industrial conditions, magnetic separation is also applied to BFA mixed with water by using a pilot. BFA magnetic separation is economically evaluated. This study globally shows that it is possible to extract some magnetic particles from MSWI boiler fly ashes. However, the magnetic particles only represent from 23 to 120 g/kg of the BFA and, though they are enriched in Fe, are composed of similar elements to the raw ashes. The industrial application of magnetic separation would only be profitable if large amounts of ashes were treated (more than 15 kt/y), and the process should be ideally completed by other recovery methods or advanced treatments. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. A New Probe for Mechanical Testing of Nanostructures in Soft Materials

    International Nuclear Information System (INIS)

    Hough, L.A.; Ou-Yang, H.D.

    1999-01-01

    We report a new application of the optical tweezers, where a harmonically driven oscillating tweezer is combined with the forward light scattering and lock-in amplification techniques, for probing the mechanics of nanostructures in soft materials in a broad frequency range. Model independent dynamic moduli G' and G'' of the material at a localized, sub-micron area can be measured directly from the displacement and the phase shift of the particle in the oscillating trap. The probe particles can be as small as 200 nm and the displacement of the particle was in the range of a few nanometers. To illustrate the new methodology, we show the microscopic viscoelastic properties of a transient polymer network in the vicinity of a silica bead

  9. Magnetic materials and 3D finite element modeling

    CERN Document Server

    Bastos, Joao Pedro A

    2014-01-01

    Magnetic Materials and 3D Finite Element Modeling explores material characterization and finite element modeling (FEM) applications. This book relates to electromagnetic analysis based on Maxwell’s equations and application of the finite element (FE) method to low frequency devices. A great source for senior undergraduate and graduate students in electromagnetics, it also supports industry professionals working in magnetics, electromagnetics, ferromagnetic materials science and electrical engineering. The authors present current concepts on ferromagnetic material characterizations and losses. They provide introductory material; highlight basic electromagnetics, present experimental and numerical modeling related to losses and focus on FEM applied to 3D applications. They also explain various formulations, and discuss numerical codes.

  10. Effect of heat treatment in air on surface composition of iron-phosphate based soft magnetic composite components

    Energy Technology Data Exchange (ETDEWEB)

    Oikonomou, C., E-mail: christos.oikonomou@chalmers.se; Oro, R.; Hryha, E.; Nyborg, L.

    2014-11-15

    Highlights: • Surface morphological and chemical depth profiling analyses of SMC parts. • Effect of annealing at exterior/interior areas for different temperature regimes. • Difference in degree of oxidation/nature of bulk/coating with area and temperature. • Thermodynamic calculations/considerations on the thermal stability of the coating. • Incomplete delubrication and strong bulk oxidation of the samples under 500 °C. - Abstract: Soft magnetic composite materials (SMC) manufactured by conventional powder metallurgical techniques for electromagnetic applications constitute individually encapsulated ferromagnetic powder particles with an insulating surface layer, bonded together into 3D finished structures. The production procedure includes compaction of the SMC base powder mixed with a lubricant substance and a post-annealing treatment that aims to relieve the stresses induced in the component during pressing. In the present study, the effect of the heat treatment process to the nature of the insulating layer was investigated under different temperature regimes using analytical techniques. Its surface chemistry was determined based on the XPS depth profiling technique, and its morphology and structure were evaluated using HR-SEM and XRD. Differences between interior and exterior areas of the samples suggested the development of an oxide scale in the outer regions that prevents its further bulk oxidation at temperatures above 500 °C, while below that temperature incomplete de-lubrication takes place.

  11. Fast determination of seven synthetic pigments from wine and soft drinks using magnetic dispersive solid-phase extraction followed by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Chen, Xiao-Hong; Zhao, Yong-Gang; Shen, Hao-Yu; Zhou, Li-Xin; Pan, Sheng-Dong; Jin, Mi-Cong

    2014-06-13

    A novel, simple and sensitive method based on the use of magnetic dispersive solid-phase extraction (M-dSPE) procedure combined with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) was developed to determine seven synthetic pigments (tartrazine, amaranth, carmine, sunset yellow, allura red, brilliant blue and erythrosine) in wines and soft drinks. An amino-functionalized low degrees of cross-linking magnetic polymer (NH2-LDC-MP) was synthesized via suspension polymerization, and characterized by transmission electron microscopy (TEM). The NH2-LDC-MP was used as the M-dSPE sorbent to remove the matrix from the solution, and the main factors affecting the extraction were investigated in detail. The obtained results demonstrated the higher extraction capacity of NH2-LDC-MP with recoveries between 84.0 and 116.2%. The limits of quantification (LOQs) for the seven synthetic pigments were between 1.51 and 5.0μg/L in wines and soft drinks. The developed M-dSPE UFLC-MS/MS method had been successfully applied to the real wines and soft drinks for food-safety risk monitoring in Zhejiang Province, China. The results showed that sunset yellow was in three out of thirty soft drink samples (2.95-42.6μg/L), and erythrosine in one out of fifteen dry red wine samples (3.22μg/L), respectively. It was confirmed that the NH2-LDC-MP was a kind of highly effective M-dSPE materials for the pigments analyses. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Magnetic properties of nano-multiferroic materials

    Science.gov (United States)

    Ramam, Koduri; Diwakar, Bhagavathula S.; Varaprasad, Kokkarachedu; Swaminadham, Veluri; Reddy, Venu

    2017-11-01

    Latent magnetization in the multiferroics can be achieved via the structural distortion with respect to particle size and destroying the spiral spin structure, which plays the vital role in high-performance applications. In this investigation, multifunctional single phase Bi1-xLaxFe1-yCoyO3 nanomaterials were synthesized by co-precipitation technique. The chemical composition, phase genesis, morphology and thermal characteristics of the Bi1-xLaxFe1-yCoyO3 were studied by FTIR, XRD, SEM/EDS, TEM and TGA. XRD studies confirmed single phase distorted rhombohedral structure in Bi1-xLaxFe1-yCoyO3. The novelty in magnetic behavior of the Bi0.85La0.15Fe0.75Co0.25O3 multiferroic at room temperature showed both ferro and anti-ferromagnetic nature with higher order remanent magnetization among other nanocomposites in this study. This magnetic anomaly in Bi0.85La0.15Fe0.75Co0.25O3 is due to doping and size effects on the crystal structure that leads to spin-orbit interactions. Besides, Bi0.85La0.15Fe0.75Co0.25O3 integrated graphene oxide (GO) nanocomposite has shown the change in the magnetic hysteresis that indicates the effect of the semiconducting behavior of GO on the ordered magnetic moments in the multiferroic. This kind of magnetic anomaly could form advanced multiferroic devices.

  13. Steady-State Diffusion of Water through Soft-Contact LensMaterials

    Energy Technology Data Exchange (ETDEWEB)

    Fornasiero, Francesco; Krull, Florian; Radke, Clayton J.; Prausnitz, JohnM.

    2005-01-31

    Water transport through soft contact lenses (SCL) is important for acceptable performance on the human eye. Chemical-potential gradient-driven diffusion rates of water through soft-contact-lens materials are measured with an evaporation-cell technique. Water is evaporated from the bottom surface of a lens membrane by impinging air at controlled flow rate and humidity. The resulting weight loss of a water reservoir covering the top surface of the contact-lens material is recorded as a function of time. New results are reported for a conventional hydrogel material (SofLens{trademark} One Day, hilafilcon A, water content at saturation W{sub 10} = 70 weight %) and a silicone hydrogel material (PureVision{trademark}, balafilcon A, W{sub 10} = 36 %), with and without surface oxygen plasma treatment. Also, previously reported data for a conventional HEMA-SCL (W{sub 10} = 38 %) hydrogel are reexamined and compared with those for SofLens{trademark} One Day and PureVision{trademark} hydrogels. Measured steady-state water fluxes are largest for SofLens{trademark} One Day, followed by PureVision{trademark} and HEMA. In some cases, the measured steady-state water fluxes increase with rising relative air humidity. This increase, due to an apparent mass-transfer resistance at the surface (trapping skinning), is associated with formation of a glassy skin at the air/membrane interface when the relative humidity is below 55-75%. Steady-state water-fluxes are interpreted through an extended Maxwell-Stefan diffusion model for a mixture of species starkly different in size. Thermodynamic nonideality is considered through Flory-Rehner polymer-solution theory. Shrinking/swelling is self-consistently modeled by conservation of the total polymer mass. Fitted Maxwell-Stefan diffusivities increase significantly with water concentration in the contact lens.

  14. Abutment Material Effect on Peri-implant Soft Tissue Color and Perceived Esthetics.

    Science.gov (United States)

    Kim, Aram; Campbell, Stephen D; Viana, Marlos A G; Knoernschild, Kent L

    2016-12-01

    The purpose of this study was to evaluate the effect of implant abutment material on peri-implant soft tissue color using intraoral spectrophotometric analysis and to compare the clinical outcomes with patient and clinician perception and satisfaction. Thirty patients and four prosthodontic faculty members participated. Abutments were zirconia, gold-hued titanium, and titanium. Peri-implant mucosa color of a single anterior implant restoration was compared to the patient's control tooth. Spectrophotometric analysis using SpectroShade TM Micro data determined the color difference (ΔE, ΔL*, Δa*, Δb*) between the midfacial peri-implant soft tissue for each abutment material and the marginal gingiva of the control tooth. Color difference values of the abutment groups were compared using ANOVA (α = 0.05). Patient and clinician satisfaction surveys were also conducted using a color-correcting light source. The results of each patient and clinician survey question were compared using chi-square analysis (α = 0.05). Pearson correlation analyses identified the relationship between the total color difference (ΔE) and the patient/clinician perception and satisfaction, as well as between ΔE and tissue thickness. Zirconia abutments displayed significantly smaller spectrophotometric gingival color difference (ΔE) compared to titanium and gold-hued titanium abutments (respectively, 3.98 ± 0.99; 7.22 ± 3.31; 5.65 ± 2.11; p abutment materials, and no correlation between ΔE and the patient and clinician satisfaction. Patient satisfaction was significantly higher than clinician, and patient-perceived differences were lower than clinicians' (p abutments demonstrated significantly lower mean color difference compared to titanium or gold-hued titanium abutments as measured spectrophotometrically; however, no statistical difference in patient or clinician perception/satisfaction among abutment materials was demonstrated. Patients were significantly more satisfied than

  15. Brush-Like Polymers: New Design Platforms for Soft, Dry Materials with Unique Property Relations

    Science.gov (United States)

    Daniel, William Francis McKemie, Jr.

    Elastomers represent a unique class of engineering materials due to their light weight, low cost, and desirable combination of softness (105 -107 Pa) and large extensibilities (up to 1000%). Despite these advantages, there exist applications that require many times softer modulus, greater extensibility, and stronger strain hardening for the purpose of mimicking the mechanical properties of systems such as biological tissues. Until recently, only liquid-filled gels were suitable materials for such applications, including soft robotics and implants. A considerable amount of work has been done to create gels with superior properties, but despite unique strengths they also suffer from unique weaknesses. This class of material displays fundamental limitations in the form of heterogeneous structures, solvent loss and phase transitions at extreme temperatures, and loss of liquid fraction upon high deformations. In gels the solvent fraction also introduces a large solvent/polymer interaction parameter which must be carefully considered when designing the final mechanical properties. These energetic considerations further exaggerate the capacity for inconstant mechanical properties caused by fluctuations of the solvent fraction. In order to overcome these weaknesses, a new platform for single component materials with low modulus (Standard networks have one major control factor outside of chemistry, the network stand length. Brush-like architectures are created from long strands with regularly grafted side chains creating three characteristic length scales which may be independently manipulated. In collaboration with M. Rubinstein, we have utilized bottlebrush polymer architectures (a densely grafted brush-like polymer) to experimentally verify theoretical predictions of disentangled bottlebrush melts. By attaching well-defined side chains onto long polymer backbones, individual polymer strands are separated in space (similar to dilution with solvent) accompanied by a

  16. Magnetic flux dynamics in superconducting materials

    International Nuclear Information System (INIS)

    Hernandez Nieves, Alexander

    2004-01-01

    The magnetization curves, the Bean-Livingston barrier in type I and type II superconductors, the ac magnetic response, the effects of thermal fluctuations on the magnetic behavior and the different dissipation mechanism at microwave frequencies are investigated in mesoscopic superconductors.For small mesoscopic samples we study the peaks and discontinuous jumps found in the magnetization as a function of magnetic field.To interpret these jumps we consider that vortices located inside the sample induce a reinforcement of the Bean- Livingston surface barrier at fields greater than the first penetration field Hp1.This leads to multiple penetration fields Hpi Hp1;Hp2;Hp3;... for vortex entrance in mesoscopic samples.For low-T c mesoscopic superconductors we found that the meta-stable states due to the surface barrier have a large half-life time, which leads to the hysteresis in the magnetization curves as observed experimentally.A very different behavior appears for high-T c mesoscopic superconductors where thermally activated vortex entrance/exit through surface barriers is frequent.This leads to a reduction of the magnetization and a non-integer average number of flux quanta penetrating the superconductor.At microwave frequencies we found that each vortex penetration event produces a significant suppression of the ac losses since the imaginary part of the ac susceptibility X ( H d c) as a function of the magnetic field (Hdc) increases before the penetration of vortices and then it decreases abruptly after vortices have entered into the sample.We show that nascent vortices (vortices that are partly inside the sample and nucleated at the surface) play an important role in the dynamic behavior of mesoscopic samples. In type I macroscopic superconductors with first-principles simulations of the TDGL equations we have been able to reproduce several features of the intermediate state observed in experiments.Particularly, droplet and striped patterns are obtained depending

  17. Soft and hard natures of Nd2Fe14B permanent magnet explored by first-order-reversal-curves

    International Nuclear Information System (INIS)

    Chen, Po-An; Yang, Chao-Yao; Chang, Shu-Jui; Lee, Min-Han; Tang, Nai-Kuang; Yen, Sheng-Chan; Tseng, Yuan-Chieh

    2014-01-01

    Two commercial Nd 2 Fe 14 B samples, MQP-B and sintered-NdFeB were investigated using synchrotron-based x-ray diffraction and first-order-reversal-curves (FORCs). Despite differing in magnetic and structural properties, the two samples were found to comprise two major ferromagnetic components in FORCs. For the sintered-NdFeB case, the soft component may originate from the intrinsically soft Nd-f site which was coupled with its local Fe atomic environment that differs in magnetic anisotropy from the Nd-g site (intrinsically hard). It may directly originate from the Nd-rich phase or microstructural imperfection, while the former possibility (Nd-f site) appears greater than the latter. While for the MQP-B, the minor second phase resulting from high structural disorder was likely in charge of the presence of the soft component. Sophisticated FORCs analyses revealed the natures of the soft and hard components, soft–hard coupling and switching reversibility of the two cases, irrespective of the origins of their two components. This provides insights to the origin of magnetic stability and reversal dynamics of Nd 2 Fe 14 B that have not been fully understood by conventional magnetic analyses. The coexistence of the two components led to an incoherent reversal undermining the magnetic stability of Nd 2 Fe 14 B. This is a fundamental problem as to why the performance extremity can only be improved finitely through extrinsic tuning. From FORCs simulation we understand that the soft–hard coupling was moderate in a real Nd 2 Fe 14 B compound. A stronger soft–hard coupling is necessary to conquer the anisotropic competition to enable a coherent reversal that will promote the magnetic hardness. - Highlights: • We investigated two commercially available Nd 2 Fe 14 B compounds with FORCs. • The two compounds were found to comprise soft and hard natures. • The coupling between the soft and hard phases is moderate in a real Nd 2 Fe 14 B

  18. Neutron diffraction studies of magnetic materials

    International Nuclear Information System (INIS)

    James, W.J.

    1987-01-01

    The ability of neutron diffraction in determining the nature and extent of magnetic ordering is illustrated for the intermetallic compounds, Y/sub 6/(Fe,Mn)/sub 23/ and ErFe/sub 3/. Substitution with other 3d transition metals influences the Fe-Fe exchange forces such as to alter, sometimes considerably, the magnetic properties, e.g., local site magnetic anisotropies in Er)Fe,Ni)/sub 3/ and thermal expansion anomalies in the R/sub 2/)Fe,Co)/sub 14/B compounds. When the 3d atoms are near neighbors in the periodic chart, their nuclear scattering lengths for neutrons are sufficiently different to permit the detection of preferential occupation of the several nonequivalent crystallographic 3d metal sites, i.e., atomic ordering, present in the R/sub 6/M/sub 23/, and R/sub 2/Fe/sub 14/B structures

  19. Magnetic Nanostructures Patterned by Self-Organized Materials

    Science.gov (United States)

    2016-01-05

    Palma , J. Escrig, J. C. Denardin Angular dependence of the coercivity and remanence of ordered arrays of Co nanowires Journal of...J. L. Palma , C. Gallardo, L. Spinu, J. M. Vargas, L. S. Dorneles, J. C. Denardin, J. Escrig, Magnetic properties of Fe20 Ni80 antidots: Pore size and...array disorder, Journal of Magnetism and Magnetic Materials., 344, 2013, 8-13 7. E. Vargas, P. Toro, J.L. Palma , J. Escrig, C. Chaneac,

  20. Influence of Water-jet Nozzle Geometry on Cutting Ability of Soft Material

    Directory of Open Access Journals (Sweden)

    Irwansyah Irwansyah

    2012-06-01

    Full Text Available Hygiene is main reason for food processor to use waterjet cutting system. Traditionally food cutting process is low-quality, unsafe products, procedures and direct contact between product and labor. This paper introduced a low cost waterjet system for cutting soft material as identic food material. The low cost waterjet system has been developed by using a commercial pressure pump for cleaning purposes and modified nozzle. In order to enhance waterjet pressure for cutting products, a modified waterjet nozzle was designed. Paramater design of waterjet system was setup on nozzle orifice diameter 0.5 mm, standoff distance 15 mm, length of nozzle cylindrical tube 2.5 mm. Polycarbonate, polysterene, and polyethelene materials are used as sample product with thickness 2 mm, to represent similar properties with agriculture products. The experimental results indicate good possibilities of waterjet system to cut material in appropriate profile surface. The waterjet also can be used to improve cutting finished surface of food products. Therefore, utilizing a low cost commercial pump and modified nozzle for waterjet system reduces equipment price, operational cost and environmental hazards. It indicates viable technology applied to substitute traditional cutting technology in post harvest agriculture products. Keywords: cutting ability, modified nozzle, polymer material, water-jet system

  1. Replacing critical rare earth materials in high energy density magnets

    Science.gov (United States)

    McCallum, R. William

    2012-02-01

    High energy density permanent magnets are crucial to the design of internal permanent magnet motors (IPM) for hybride and electric vehicles and direct drive wind generators. Current motor designs use rare earth permanent magnets which easily meet the performance goals, however, the rising concerns over cost and foreign control of the current supply of rare earth resources has motivated a search for non-rare earth based permanent magnets alloys with performance metrics which allow the design of permanent magnet motors and generators without rare earth magnets. This talk will discuss the state of non-rare-earth permanent magnets and efforts to both improve the current materials and find new materials. These efforts combine first principles calculations and meso-scale magnetic modeling with advance characterization and synthesis techniques in order to advance the state of the art in non rare earth permanent magnets. The use of genetic algorithms in first principle structural calculations, combinatorial synthesis in the experimental search for materials, atom probe microscopy to characterize grain boundaries on the atomic level, and other state of the art techniques will be discussed. In addition the possibility of replacing critical rare earth elements with the most abundant rare earth Ce will be discussed.

  2. Inertial and magnetic sensing of human movement near ferromagnetic materials

    NARCIS (Netherlands)

    Roetenberg, D.; Luinge, Hendrik J.; Veltink, Petrus H.

    2003-01-01

    This paper describes a Kalman filter design to estimate orientation of human body segments by fusing gyroscope, accelerometer and magnetometer signals. Ferromagnetic materials near the sensor disturb the local magnetic field and therefore the orientation estimation. The magnetic disturbance can be

  3. A novel magnetic valve using room temperature magnetocaloric materials

    DEFF Research Database (Denmark)

    Eriksen, Dan; Bahl, Christian; Pryds, Nini

    2012-01-01

    changes. This is made possible by the strong temperature dependence of the magnetization close to the Curie temperature of the magnetocaloric materials. Different compositions of both La0.67(Ca,Sr)0.33MnO3 and La(Fe,Co,Si)13 have been considered for use in prototype valves. Based on measured magnetization...

  4. Numerical Modeling of Multi-Material Active Magnetic Regeneration

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Engelbrecht, Kurt; Bahl, Christian Robert Haffenden

    2009-01-01

    and the specific heat as a function of temperature at constant magnetic field. A 2.5-dimensional numerical model of an active magnetic regenerative (AMR) refrigerator device is presented. The experimental AMR located at Risø DTU has been equipped with a parallel-plate based regenerator made of the two materials...

  5. Glass interface effect on high-strain-rate tensile response of a soft polyurethane elastomeric polymer material

    NARCIS (Netherlands)

    Fan, J.T.; Weerheijm, J.; Sluys, L.J.

    2015-01-01

    The glass interface effect on dynamic tensile response of a soft polyurethane elastomeric polymer material has been investigated by subjecting a glass-polymer system of this polymer material matrix embedded a single 3 mm-diameter glass particle to impact loading in a split Hopkinson tension bar

  6. Advanced Electric and Magnetic Material Models for FDTD Electromagnetic Codes

    CERN Document Server

    Poole, Brian R; Nelson, Scott D

    2005-01-01

    The modeling of dielectric and magnetic materials in the time domain is required for pulse power applications, pulsed induction accelerators, and advanced transmission lines. For example, most induction accelerator modules require the use of magnetic materials to provide adequate Volt-sec during the acceleration pulse. These models require hysteresis and saturation to simulate the saturation wavefront in a multipulse environment. In high voltage transmission line applications such as shock or soliton lines the dielectric is operating in a highly nonlinear regime, which requires nonlinear models. Simple 1-D models are developed for fast parameterization of transmission line structures. In the case of nonlinear dielectrics, a simple analytic model describing the permittivity in terms of electric field is used in a 3-D finite difference time domain code (FDTD). In the case of magnetic materials, both rate independent and rate dependent Hodgdon magnetic material models have been implemented into 3-D FDTD codes an...

  7. FMR measurements in fire ants: evidence of magnetic material

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Darci M.S.; Acosta-Avalos, Daniel; El-Jaick, Lea J.; Cunha, Alexandra D.M.; Malheiros, Maria G.; Wajnberg, Eliane [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Linhares, Marilia P. [Centro de Ciencias do Estado, do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    1998-01-01

    Based on the behavioral and the localization of iron-containing tissue fire ants were examined by EPR for magnetic material. Results suggest the presence of magnetite particles. (author) 12 refs., 1 fig.

  8. ADVANCED ELECTRIC AND MAGNETIC MATERIAL MODELS FOR FDTD ELECTROMAGNETIC CODES

    Energy Technology Data Exchange (ETDEWEB)

    Poole, B R; Nelson, S D; Langdon, S

    2005-05-05

    The modeling of dielectric and magnetic materials in the time domain is required for pulse power applications, pulsed induction accelerators, and advanced transmission lines. For example, most induction accelerator modules require the use of magnetic materials to provide adequate Volt-sec during the acceleration pulse. These models require hysteresis and saturation to simulate the saturation wavefront in a multipulse environment. In high voltage transmission line applications such as shock or soliton lines the dielectric is operating in a highly nonlinear regime, which require nonlinear models. Simple 1-D models are developed for fast parameterization of transmission line structures. In the case of nonlinear dielectrics, a simple analytic model describing the permittivity in terms of electric field is used in a 3-D finite difference time domain code (FDTD). In the case of magnetic materials, both rate independent and rate dependent Hodgdon magnetic material models have been implemented into 3-D FDTD codes and 1-D codes.

  9. ADVANCED ELECTRIC AND MAGNETIC MATERIAL MODELS FOR FDTD ELECTROMAGNETIC CODES

    International Nuclear Information System (INIS)

    Poole, B R; Nelson, S D; Langdon, S

    2005-01-01

    The modeling of dielectric and magnetic materials in the time domain is required for pulse power applications, pulsed induction accelerators, and advanced transmission lines. For example, most induction accelerator modules require the use of magnetic materials to provide adequate Volt-sec during the acceleration pulse. These models require hysteresis and saturation to simulate the saturation wavefront in a multipulse environment. In high voltage transmission line applications such as shock or soliton lines the dielectric is operating in a highly nonlinear regime, which require nonlinear models. Simple 1-D models are developed for fast parameterization of transmission line structures. In the case of nonlinear dielectrics, a simple analytic model describing the permittivity in terms of electric field is used in a 3-D finite difference time domain code (FDTD). In the case of magnetic materials, both rate independent and rate dependent Hodgdon magnetic material models have been implemented into 3-D FDTD codes and 1-D codes

  10. Stored energy in fusion magnet materials irradiated at low temperatures

    International Nuclear Information System (INIS)

    Chaplin, R.L.; Kerchner, H.R.; Klabunde, C.E.; Coltman, R.R.

    1989-08-01

    During the power cycle of a fusion reactor, the radiation reaching the superconducting magnet system will produce an accumulation of immobile defects in the magnet materials. During a subsequent warm-up cycle of the magnet system, the defects will become mobile and interact to produce new defect configurations as well as some mutual defect annihilations which generate heat-the release of stored energy. This report presents a brief qualitative discussion of the mechanisms for the production and release of stored energy in irradiated materials, a theoretical analysis of the thermal response of irradiated materials, theoretical analysis of the thermal response of irradiated materials during warm-up, and a discussion of the possible impact of stored energy release on fusion magnet operation 20 refs

  11. A new approach for assessing the wear resistance of soft ductile materials

    International Nuclear Information System (INIS)

    Zaid, A.I.O.; Banna, M.A.E.

    2007-01-01

    Aluminum and its alloys are the most versatile and attractive metallic materials which have been used for many decades in many engineering applications specially in the automobile and airspace industries due to their high strength-to- weight ratio, thermal conductivity, electrical conductivity, corrosion and wear resistances. Wear is the loss of material from a surface caused by interaction with another material. The main mechanisms of interaction are applied loads and relative motion, which can cause adhesion or/and abrasion, all of which leads to material loss. Therefore, most of the suggested methods, theoretical and empirical, for estimating the wear resistance of material is based on the mass loss, irrespective of the material or type of existing wear. Experimental observations reveal that in some situations, especially for soft and ductile materials, the tested specimen showed little or no mass loss while its dimensions and shape have suffered from plastic deformation which causes more damage than mass loss. Similar phenomenon was observed during electric spot welding of aluminum and zinc coated steels at the area beneath the electrode where plastic deformation takes place, causing increase in area which reduces the current density, will be also discussed in the paper. The amount of the plastic deformation, even when mentioned in some publications, was neglected in assessing wear resistance. In this paper, a model based on the plastic deformation at the worn end together with the mass loss is forwarded and discussed. The model was tested qualitatively using commercially pure aluminum of 99.97% purity in the as supplied condition and in grain refined conditions by some rare earth materials e.g. titanium and titanium plus boron, which are normally used in industry for improving its hardness and mechanical behavior. The wear tests were carried out under different loads and speeds (the main parameters in assessing wear resistance) and the data was used for

  12. Current Profile and Magnetic Structure Measurements through Tangential Soft X-Ray Imaging in Compact Tori

    International Nuclear Information System (INIS)

    Fonck, Raymond J.

    2004-01-01

    This report describes the fabrication and tests of a tangentially imaging soft X-ray (SXR) camera diagnostic for fusion energy plasma research. It can be used for the determination of the current distribution in strongly shaped toroidal magnetically confined plasmas, such as those found in spherical tori or advanced tokamaks. It included the development of both an appropriate imaging SXR camera and image analysis techniques necessary to deduce the plasma shape and current distribution. The basic camera concept consists of a tangentially viewing pinhole imaging system with thin-film SXR filters, a scintillator screen to provide SXR to visible conversion, a fast shuttering system, and an sensitive visible camera imaging device. The analysis approach consists of integrating the 2-D SXR image data into a Grad-Shafranov toroidal equilibrium solver code to provide strong constraints on the deduced plasma current and pressure profiles. Acceptable sensitivity in the deduced current profile can be obtained if the relative noise in the measured image can be kept in the range of 1% or less. Tests on the Pegasus Toroidal Experiment indicate very flat safety factor profiles in the plasma interior

  13. Identification of exponent from load-deformation relation for soft materials from impact tests

    Science.gov (United States)

    Ciornei, F. C.; Alaci, S.; Romanu, I. C.; Ciornei, M. C.; Sopon, G.

    2018-01-01

    When two bodies are brought into contact, the magnitude of occurring reaction forces increase together with the amplitude of deformations. The load-deformation dependency of two contacting bodies is described by a function having the form F = Cxα . An accurate illustration of this relationship assumes finding the precise coefficient C and exponent α. This representation proved to be very useful in hardness tests, in dynamic systems modelling or in considerations upon the elastic-plastic ratio concerning a Hertzian contact. The classical method for identification of the exponent consists in finding it from quasi-static tests. The drawback of the method is the fact that the accurate estimation of the exponent supposes precise identification of the instant of contact initiation. To overcome this aspect, the following observation is exploited: during an impact process, the dissipated energy is converted into heat released by internal friction in the materials and energy for plastic deformations. The paper is based on the remark that for soft materials the hysteresis curves obtained for a static case are similar to the ones obtained for medium velocities. Furthermore, utilizing the fact that for the restitution phase the load-deformation dependency is elastic, a method for finding the α exponent for compression phase is proposed. The maximum depth of the plastic deformations obtained for a series of collisions, by launching, from different heights, a steel ball in free falling on an immobile prism made of soft material, is evaluated by laser profilometry method. The condition that the area of the hysteresis loop equals the variation of kinetical energy of the ball is imposed and two tests are required for finding the exponent. Five collisions from different launching heights of the ball were taken into account. For all the possible impact-pair cases, the values of the exponent were found and close values were obtained.

  14. Quantitative Rheometry of Thin Soft Materials Using the Quartz Crystal Microbalance with Dissipation.

    Science.gov (United States)

    Sadman, Kazi; Wiener, Clinton G; Weiss, R A; White, Christopher C; Shull, Kenneth R; Vogt, Bryan D

    2018-03-20

    In the inertial limit, the resonance frequency of the quartz crystal microbalance (QCM) is related to the coupled mass on the quartz sensor through the Sauerbrey expression that relates the mass to the change in resonance frequency. However, when the thickness of the film is sufficiently large, the relationship becomes more complicated and both the frequency and damping of the crystal resonance must be considered. In this regime, a rheological model of the material must be used to accurately extract the adhered film's thickness, shear modulus, and viscoelastic phase angle from the data. In the present work we examine the suitability of two viscoelastic models, a simple Voigt model ( Physica Scripta 1999, 59, 391-396) and a more realistic power-law model ( Langmuir 2015, 31, 4008-4017), to extract the rheological properties of a thermoresponsive hydrogel film. By changing temperature and initial dry film thickness of the gel, the operation of QCM was traversed from the Sauerbrey limit, where viscous losses do not impact the frequency, through the regime where the QCM response is sensitive to viscoelastic properties. The density-shear modulus and the viscoelastic phase angle from the two models are in good agreement when the shear wavelength ratio, d/λ n , is in the range of 0.05-0.20, where d is the film thickness and λ n is the wavelength of the mechanical shear wave at the n th harmonic. We further provide a framework for estimating the physical properties of soft materials in the megahertz regime by using the physical behavior of polyelectrolyte complexes. This provides the user with an approximate range of allowable film thicknesses for accurate viscoelastic analysis with either model, thus enabling better use of the QCM-D in soft materials research.

  15. Permanent magnet material and process for producing the same

    International Nuclear Information System (INIS)

    Yoneyama, T.; Hori, T.; Ohima, T.

    1978-01-01

    This invention relates to an improvement of a permanent magnet material consisting, apart from impurities, of intermetallic compounds of the general formula of R 2 Co 17 , wherein the R component is at least one rare earth metal excluding radioactive elements and the Co component is cobalt. A suitable process to produce the permanent magnet material according to the invention is described. (U.K.)

  16. Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials

    International Nuclear Information System (INIS)

    Zhang, Jianhua; Tao, Cuilian; Zhu, Yufang; Zhu, Min; Li, Jie; Hanagata, Nobutaka

    2013-01-01

    We have prepared multifunctional magnetic mesoporous Fe–CaSiO 3 materials using triblock copolymer (P123) as a structure-directing agent. The effects of Fe substitution on the mesoporous structure, in vitro bioactivity, magnetic heating ability and drug delivery property of mesoporous CaSiO 3 materials were investigated. Mesoporous Fe–CaSiO 3 materials had similar mesoporous channels (5–6 nm) with different Fe substitution. When 5 and 10% Fe were substituted for Ca in mesoporous CaSiO 3 materials, mesoporous Fe–CaSiO 3 materials still showed good apatite-formation ability and had no cytotoxic effect on osteoblast-like MC3T3-E1 cells evaluated by the elution cell culture assay. On the other hand, mesoporous Fe–CaSiO 3 materials could generate heat to raise the temperature of the surrounding environment in an alternating magnetic field due to their superparamagnetic property. When we use gentamicin (GS) as a model drug, mesoporous Fe–CaSiO 3 materials release GS in a sustained manner. Therefore, magnetic mesoporous Fe–CaSiO 3 materials would be a promising multifunctional platform with bone regeneration, local drug delivery and magnetic hyperthermia. (paper)

  17. Anomalous dimension, chiral phase transition and inverse magnetic catalysis in soft-wall AdS/QCD

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Zhen, E-mail: fangzhen@itp.ac.cn [Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Science, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing (China)

    2016-07-10

    A modified soft-wall AdS/QCD model with a z-dependent bulk scalar mass is proposed. We argue for the necessity of a modified bulk scalar mass from the quark mass anomalous dimension and carefully constrain the form of bulk mass by the corresponding UV and IR asymptotics. After fixing the form of bulk scalar mass, we calculate the mass spectra of (axial-)vector and pseudoscalar mesons, which have a good agreement with the experimental data. The behavior of chiral phase transition is also investigated, and the results are consistent with the standard scenario and lattice simulations. Finally, the issue of chiral magnetic effects is addressed. We find that the inverse magnetic catalysis emerges naturally from the modified soft-wall model, which is consistent with the recent lattice simulations.

  18. Solenopsis ant magnetic material: statistical and seasonal studies

    International Nuclear Information System (INIS)

    Abraçado, Leida G; Esquivel, Darci M S; Wajnberg, Eliane

    2009-01-01

    In this paper, we quantify the magnetic material amount in Solenopsis ants using ferromagnetic resonance (FMR) at room temperature. We sampled S. interrupta workers from several morphologically indistinguishable castes. Twenty-five oriented samples of each body part of S. interrupta (20 units each) showed that FMR line shapes are reproducible. The relative magnetic material amount was 31 ± 12% (mean ± SD) in the antennae, 27 ± 13% in the head, 21 ± 12% in the thorax and 20 ± 10% in the abdomen. In order to measure variation in the magnetic material from late summer to early winter, ants were collected each month between March and July. The amount of magnetic material was greatest in all four body parts in March and least in all four body parts in June. In addition, S. richteri majors presented more magnetic material than minor workers. Extending these findings to the genera Solenopsis, the reduction in magnetic material found in winter could be explained by our sampling fewer foraging major ants

  19. Digital lock-in detection of site-specific magnetism in magnetic materials

    Science.gov (United States)

    Haskel, Daniel [Naperville, IL; Lang, Jonathan C [Naperville, IL; Srajer, George [Oak Park, IL

    2008-07-22

    The polarization and diffraction characteristics of x-rays incident upon a magnetic material are manipulated to provide a desired magnetic sensitivity in the material. The contrast in diffracted intensity of opposite helicities of circularly polarized x-rays is measured to permit separation of magnetic signals by element type and by atomic environment. This allows for the direct probing of magnetic signals from elements of the same species in nonequivalent atomic environments to better understand the behavior and characteristics of permanent magnetic materials. By using known crystallographic information together with manipulation of the polarization of x-rays having energies tuned near element-specific electronic excitations and by detecting and comparing the incident and diffracted photons at the same frequency, more accurate magnetic measurements can be made over shorter observation periods.

  20. Soft network materials with isotropic negative Poisson's ratios over large strains.

    Science.gov (United States)

    Liu, Jianxing; Zhang, Yihui

    2018-01-31

    Auxetic materials with negative Poisson's ratios have important applications across a broad range of engineering areas, such as biomedical devices, aerospace engineering and automotive engineering. A variety of design strategies have been developed to achieve artificial auxetic materials with controllable responses in the Poisson's ratio. The development of designs that can offer isotropic negative Poisson's ratios over large strains can open up new opportunities in emerging biomedical applications, which, however, remains a challenge. Here, we introduce deterministic routes to soft architected materials that can be tailored precisely to yield the values of Poisson's ratio in the range from -1 to 1, in an isotropic manner, with a tunable strain range from 0% to ∼90%. The designs rely on a network construction in a periodic lattice topology, which incorporates zigzag microstructures as building blocks to connect lattice nodes. Combined experimental and theoretical studies on broad classes of network topologies illustrate the wide-ranging utility of these concepts. Quantitative mechanics modeling under both infinitesimal and finite deformations allows the development of a rigorous design algorithm that determines the necessary network geometries to yield target Poisson ratios over desired strain ranges. Demonstrative examples in artificial skin with both the negative Poisson's ratio and the nonlinear stress-strain curve precisely matching those of the cat's skin and in unusual cylindrical structures with engineered Poisson effect and shape memory effect suggest potential applications of these network materials.

  1. Chemical signal activation of an organocatalyst enables control over soft material formation.

    Science.gov (United States)

    Trausel, Fanny; Maity, Chandan; Poolman, Jos M; Kouwenberg, D S J; Versluis, Frank; van Esch, Jan H; Eelkema, Rienk

    2017-10-12

    Cells can react to their environment by changing the activity of enzymes in response to specific chemical signals. Artificial catalysts capable of being activated by chemical signals are rare, but of interest for creating autonomously responsive materials. We present an organocatalyst that is activated by a chemical signal, enabling temporal control over reaction rates and the formation of materials. Using self-immolative chemistry, we design a deactivated aniline organocatalyst that is activated by the chemical signal hydrogen peroxide and catalyses hydrazone formation. Upon activation of the catalyst, the rate of hydrazone formation increases 10-fold almost instantly. The responsive organocatalyst enables temporal control over the formation of gels featuring hydrazone bonds. The generic design should enable the use of a large range of triggers and organocatalysts, and appears a promising method for the introduction of signal response in materials, constituting a first step towards achieving communication between artificial chemical systems.Enzymes regulated by chemical signals are common in biology, but few such artificial catalysts exist. Here, the authors design an aniline catalyst that, when activated by a chemical trigger, catalyses formation of hydrazone-based gels, demonstrating signal response in a soft material.

  2. An equal force theory for network models of soft materials with arbitrary molecular weight distribution

    Science.gov (United States)

    Verron, E.; Gros, A.

    2017-09-01

    Most network models for soft materials, e.g. elastomers and gels, are dedicated to idealized materials: all chains admit the same number of Kuhn segments. Nevertheless, such standard models are not appropriate for materials involving multiple networks, and some specific constitutive equations devoted to these materials have been derived in the last few years. In nearly all cases, idealized networks of different chain lengths are assembled following an equal strain assumption; only few papers adopt an equal stress assumption, although some authors argue that such hypothesis would reflect the equilibrium of the different networks in contact. In this work, a full-network model with an arbitrary chain length distribution is derived by considering that chains of different lengths satisfy the equal force assumption in each direction of the unit sphere. The derivation is restricted to non-Gaussian freely jointed chains and to affine deformation of the sphere. Firstly, after a proper definition of the undeformed configuration of the network, we demonstrate that the equal force assumption leads to the equality of a normalized stretch in chains of different lengths. Secondly, we establish that the network with chain length distribution behaves as an idealized full-network of which both chain length and density of are provided by the chain length distribution. This approach is finally illustrated with two examples: the derivation of a new expression for the Young modulus of bimodal interpenetrated polymer networks, and the prediction of the change in fluorescence during deformation of mechanochemically responsive elastomers.

  3. Dual phase magnetic material component and method of forming

    Science.gov (United States)

    Dial, Laura Cerully; DiDomizio, Richard; Johnson, Francis

    2017-04-25

    A magnetic component having intermixed first and second regions, and a method of preparing that magnetic component are disclosed. The first region includes a magnetic phase and the second region includes a non-magnetic phase. The method includes mechanically masking pre-selected sections of a surface portion of the component by using a nitrogen stop-off material and heat-treating the component in a nitrogen-rich atmosphere at a temperature greater than about 900.degree. C. Both the first and second regions are substantially free of carbon, or contain only limited amounts of carbon; and the second region includes greater than about 0.1 weight % of nitrogen.

  4. Magnetic materials in Japan research, applications and potential

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This, the third report in Elsevier's Materials Technology in Japan series, concentrates on magnetic materials as a topic gaining worldwide attention, and each chapter looks not only at current research, but also describes the technology as it is being applied and its future potential. Magnetic-related research is the second largest field of research in Japan after semiconductors, with the estimated number of researchers and engineers engaged in magnetics-related activities currently at 20,000. This research report serves as both a review of

  5. Permanent-magnet material applications in particle accelerators

    International Nuclear Information System (INIS)

    Kraus, R.H. Jr.

    1992-01-01

    The modern charged particle accelerator has found application in a wide range of scientific research, industrial, medical, and defense fields. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, which showed that magnetic field could be used to control the transverse envelope of charged particle beams. The history of permanent-magnet use in accelerator physics and technology is outlined, current design methods and material properties of concern for particle accelerator applications are reviewed

  6. Pure-iron/iron-based-alloy hybrid soft magnetic powder cores compacted at ultra-high pressure

    Science.gov (United States)

    Saito, Tatsuya; Tsuruta, Hijiri; Watanabe, Asako; Ishimine, Tomoyuki; Ueno, Tomoyuki

    2018-04-01

    We developed Fe/FeSiAl soft magnetic powder cores (SMCs) for realizing the miniaturization and high efficiency of an electromagnetic conversion coil in the high-frequency range (˜20 kHz). We found that Fe/FeSiAl SMCs can be formed with a higher density under higher compaction pressure than pure-iron SMCs. These SMCs delivered a saturation magnetic flux density of 1.7 T and iron loss (W1/20k) of 158 kW/m3. The proposed SMCs exhibited similar excellent characteristics even in block shapes, which are closer to the product shapes.

  7. Pure-iron/iron-based-alloy hybrid soft magnetic powder cores compacted at ultra-high pressure

    Directory of Open Access Journals (Sweden)

    Tatsuya Saito

    2018-04-01

    Full Text Available We developed Fe/FeSiAl soft magnetic powder cores (SMCs for realizing the miniaturization and high efficiency of an electromagnetic conversion coil in the high-frequency range (∼20 kHz. We found that Fe/FeSiAl SMCs can be formed with a higher density under higher compaction pressure than pure-iron SMCs. These SMCs delivered a saturation magnetic flux density of 1.7 T and iron loss (W1/20k of 158 kW/m3. The proposed SMCs exhibited similar excellent characteristics even in block shapes, which are closer to the product shapes.

  8. Study of the temperature dependence of the uniaxial creep property of similar material of new soft rock

    Science.gov (United States)

    Wang, Y. Y.; Wu, Y.; Fan, X. Y.; Zhang, J. L.; Guo, P.; Li, J. G.

    2017-11-01

    Using the experimental method, the experimental research of creep properties were conducted under different temperature ranging from 10°C to 60°C. The similar material of new soft rock consists of paraffin, which can obtain that the deformation contains the instantaneous elastic deformation and creep deformation through the uniaxial creep experimental results. And thus the increase of temperature has great influence on the creep characteristics of similar soft rock according to the creep curve of similar soft rock at 10°C to 60°C. With the increase of temperature, the slope of the stress-strain curve of similar soft rock is increasing, while the average of the creep modulus is decreasing, which means that the capacity of resist deformation is reduced. Therefore, the creeps law of high-temperature and short-time can be shown the creep phenomenon of low-temperature and long-time, and further shorten the creep experimental cycle.

  9. Design of solar cell materials via soft X-ray spectroscopy

    DEFF Research Database (Denmark)

    Himpsel, F.J.; Cook, P.L.; de la Torre, G.

    2013-01-01

    This overview illustrates how spectroscopy with soft X-rays can assist the development of new materials and new designs for solar cells. The starting point is the general layout of a solar cell, which consists of a light absorber sandwiched between an electron donor and an electron acceptor....... There are four relevant energy levels that can be measured with a combination of X-ray absorption spectroscopy and photoelectron spectroscopy, as illustrated for an organic dye as absorber attached to a p-doped diamond film as donor. Systematic measurements of organometallic dyes (phthalocyanines and porphyrins......) as a function of the metal atom are presented for the metal 2p and N 1s absorption edges. In combination with density functional theory one can discern trends that are useful for tailoring absorber molecules. A customized porphyrin molecule is investigated that combines an absorber with a donor and a linker...

  10. Imaging of soft and hard materials using a Boersch phase plate in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Alloyeau, D., E-mail: alloyeau.damien@gmail.com [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Hsieh, W.K. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Anderson, E.H.; Hilken, L. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley CA 94720 (United States); Benner, G. [Carl Zeiss NTS GmbH, Oberkochen 73447 (Germany); Meng, X. [Electrical Engineering and Computer Sciences, UC Berkeley, Berkeley, CA 94720-1770 (United States); Chen, F.R. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan (China); Kisielowski, C. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States)

    2010-04-15

    Using two levels of electron beam lithography, vapor phase deposition techniques, and FIB etching, we have fabricated an electrostatic Boersch phase plate for contrast enhancement of weak phase objects in a transmission electron microscope. The phase plate has suitable dimensions for the imaging of small biological samples without compromising the high-resolution capabilities of the microscope. A micro-structured electrode allows for phase tuning of the unscattered electron beam, which enables the recording of contrast enhanced in-focus images and in-line holograms. We have demonstrated experimentally that our phase plate improves the contrast of carbon nanotubes while maintaining high-resolution imaging performance, which is demonstrated for the case of an AlGaAs heterostructure. The development opens a new way to study interfaces between soft and hard materials.

  11. Microstructure and soft magnetic properties of Finemet-type ribbons obtained by twin-roller melt-spinning

    International Nuclear Information System (INIS)

    Pozo Lopez, G.; Fabietti, L.M.; Condo, A.M.; Urreta, S.E.

    2010-01-01

    Soft magnetic ribbons of Finemet-type (Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ) alloys are synthesized by the twin-roller melt-spinning technique directly from the melt, at tangential wheel speeds of 15, 18, 19 and 20 m/s. The microstructure and the magnetic properties are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential thermal analysis (DTA), thermo-gravimetric analysis (TGA) and hysteresis loops measurements. Samples cooled at 20 m/s are amorphous, while those quenched at lower wheel speeds are partially crystalline. All samples studied present saturation magnetization values (150-160 A m 2 /kg) higher than the commercial Finemet alloys (∼135 A m 2 /kg), obtained by controlled crystallization of amorphous single-roller melt-spun alloys. Optimal soft magnetic properties - σ S =(154±8) A m 2 /kg and H C =(6.9±0.9) A/m - are found in samples quenched at 19 m/s, consisting of size-distributed bcc Fe-Si nanograins (∼18 nm in average) embedded in an amorphous residual matrix. A minority nanocrystalline magnetic phase (≤10 nm) is also detected.

  12. Magnetic and transport properties of Fe-based nanocrystalline materials

    Science.gov (United States)

    Barandiarán, J. M.

    1994-01-01

    Fe-rich amorphous alloys containing late transition metals like Nb, V, Zr,..., sometimes with the addition of Cu, can crystallize in ultrafine grains of a crystalline phase, a few nanometers in diameter, embedded in a disordered matrix. In such state they have shown excellent soft magnetic properties for technical applications, rising the interest for deep studies. In this paper, recent work on some Fe-Nb and Fe-Zr based alloys both in amorphous state and after several degrees of nanocrystallization is presented. The nanocrystallization process has been achieved by conventional heat treatments (about 1 h at temperatures around 400-500 °C in a controlled atmosphere furnance) as well as by Joule heating using an electrical current flowing through the sample. Magnetic measurements, electrical resistivity, x-rays diffraction and 57Fe Mössbauer spectroscopy were used in the study of the crystalline phases appearing after the thermal treatments. The basic magnetic and transport properties of the nanocrystals do not differ appreciably from their bulk values. The magnetic anisotropy, however, is very sensitive to grain size and to the intergranular magnetic coupling. The effect of such coupling is deduced from the coercivity changes at the Curie Temperature of the amorphous matrix remaining after nanocrystallization.

  13. Study on Buckling of Stiff Thin Films on Soft Substrates as Functional Materials

    Science.gov (United States)

    Ma, Teng

    In engineering, buckling is mechanical instability of walls or columns under compression and usually is a problem that engineers try to prevent. In everyday life buckles (wrinkles) on different substrates are ubiquitous -- from human skin to a rotten apple they are a commonly observed phenomenon. It seems that buckles with macroscopic wavelengths are not technologically useful; over the past decade or so, however, thanks to the widespread availability of soft polymers and silicone materials micro-buckles with wavelengths in submicron to micron scale have received increasing attention because it is useful for generating well-ordered periodic microstructures spontaneously without conventional lithographic techniques. This thesis investigates the buckling behavior of thin stiff films on soft polymeric substrates and explores a variety of applications, ranging from optical gratings, optical masks, energy harvest to energy storage. A laser scanning technique is proposed to detect micro-strain induced by thermomechanical loads and a periodic buckling microstructure is employed as a diffraction grating with broad wavelength tunability, which is spontaneously generated from a metallic thin film on polymer substrates. A mechanical strategy is also presented for quantitatively buckling nanoribbons of piezoelectric material on polymer substrates involving the combined use of lithographically patterning surface adhesion sites and transfer printing technique. The precisely engineered buckling configurations provide a route to energy harvesters with extremely high levels of stretchability. This stiff-thin-film/polymer hybrid structure is further employed into electrochemical field to circumvent the electrochemically-driven stress issue in silicon-anode-based lithium ion batteries. It shows that the initial flat silicon-nanoribbon-anode on a polymer substrate tends to buckle to mitigate the lithiation-induced stress so as to avoid the pulverization of silicon anode. Spontaneously

  14. Magnetic Sensors Based on Amorphous Ferromagnetic Materials: A Review

    Science.gov (United States)

    Morón, Carlos; Cabrera, Carolina; Morón, Alberto; García, Alfonso; González, Mercedes

    2015-01-01

    Currently there are many types of sensors that are used in lots of applications. Among these, magnetic sensors are a good alternative for the detection and measurement of different phenomena because they are a “simple” and readily available technology. For the construction of such devices there are many magnetic materials available, although amorphous ferromagnetic materials are the most suitable. The existence in the market of these materials allows the production of different kinds of sensors, without requiring expensive manufacture investments for the magnetic cores. Furthermore, these are not fragile materials that require special care, favouring the construction of solid and reliable devices. Another important feature is that these sensors can be developed without electric contact between the measuring device and the sensor, making them especially fit for use in harsh environments. In this review we will look at the main types of developed magnetic sensors. This work presents the state of the art of magnetic sensors based on amorphous ferromagnetic materials used in modern technology: security devices, weapon detection, magnetic maps, car industry, credit cards, etc. PMID:26569244

  15. Magnetic Sensors Based on Amorphous Ferromagnetic Materials: A Review.

    Science.gov (United States)

    Morón, Carlos; Cabrera, Carolina; Morón, Alberto; García, Alfonso; González, Mercedes

    2015-11-11

    Currently there are many types of sensors that are used in lots of applications. Among these, magnetic sensors are a good alternative for the detection and measurement of different phenomena because they are a "simple" and readily available technology. For the construction of such devices there are many magnetic materials available, although amorphous ferromagnetic materials are the most suitable. The existence in the market of these materials allows the production of different kinds of sensors, without requiring expensive manufacture investments for the magnetic cores. Furthermore, these are not fragile materials that require special care, favouring the construction of solid and reliable devices. Another important feature is that these sensors can be developed without electric contact between the measuring device and the sensor, making them especially fit for use in harsh environments. In this review we will look at the main types of developed magnetic sensors. This work presents the state of the art of magnetic sensors based on amorphous ferromagnetic materials used in modern technology: security devices, weapon detection, magnetic maps, car industry, credit cards, etc.

  16. Magnetic Sensors Based on Amorphous Ferromagnetic Materials: A Review

    Directory of Open Access Journals (Sweden)

    Carlos Morón

    2015-11-01

    Full Text Available Currently there are many types of sensors that are used in lots of applications. Among these, magnetic sensors are a good alternative for the detection and measurement of different phenomena because they are a “simple” and readily available technology. For the construction of such devices there are many magnetic materials available, although amorphous ferromagnetic materials are the most suitable. The existence in the market of these materials allows the production of different kinds of sensors, without requiring expensive manufacture investments for the magnetic cores. Furthermore, these are not fragile materials that require special care, favouring the construction of solid and reliable devices. Another important feature is that these sensors can be developed without electric contact between the measuring device and the sensor, making them especially fit for use in harsh environments. In this review we will look at the main types of developed magnetic sensors. This work presents the state of the art of magnetic sensors based on amorphous ferromagnetic materials used in modern technology: security devices, weapon detection, magnetic maps, car industry, credit cards, etc.

  17. Higher order structure analysis of nano-materials by spectral reflectance of laser-plasma soft x-ray

    International Nuclear Information System (INIS)

    Azuma, Hirozumi; Takeichi, Akihiro; Noda, Shoji

    1995-01-01

    We have proposed a new experimental arrangement to measure spectral reflectance of nano-materials for analyzing higher order structure with laser-plasma soft x-rays. Structure modification of annealed Mo/Si multilayers and a nylon-6/clay hybrid with poor periodicity was investigated. The measurement of the spectral reflectance of soft x-rays from laser-produced plasma was found to be a useful method for the structure analysis of nano-materials, especially those of rather poor periodicity

  18. A novel superconducting toroidal field magnetic concept using advanced materials

    International Nuclear Information System (INIS)

    Schwartz, J.

    1991-01-01

    The plasma physics database indicates that two distinct approaches to tokamak design may lead to commercial fusion reactors: Low Aspect ratio, high plasma current, relatively low magnetic field devices, and high Aspect ratio, high field devices. The former requires significant enhancements in plasma performance, while the latter depends primarily upon technology development. The key technology for the commercialization of the high-field approach is large, high magnetic field superconducting magnets. In this paper, the physics motivation for the high field approach and key superconducting magnet (SCM) development issues are reviewed. Improved SCM performance may be obtained from improved materials and/or improved engineering. Superconducting materials ranging from NbTi to high-T c oxides are reviewed, demonstrating the broad range of potential superconducting materials. Structural material options are discussed, including cryogenic steel alloys and fiber-reinforced composite materials. The potential for improved magnet engineering is quantified in terms of the Virial Theorem Limit, and two examples of approaches to highly optimized magnet configurations are discussed. The force-reduced concept, which is a finite application of the force-free solutions to Ampere's Law, appear promising for large SCMs but may be limited by the electromagnetics of a fusion plasma. The Solid Superconducting Cylinder (SSC) concept is proposed. This concept combines the unique properties of high-T c superconductors within a low-T c SCM to obtain (1) significant reductions in the structural material volume, (2) a decoupling of the tri-axial (compressive and tensile) stress rate, and (3) a demountable TF magnet system. The advantages of this approach are quantified in terms of a 24 T commercial reactor TF magnet system. Significant reductions in the mechanical stress and the TF radial build are demonstrated. 54 refs., 14 figs., 5 tabs

  19. Advanced materials: The key to attractive magnetic fusion power reactors

    International Nuclear Information System (INIS)

    Bloom, E.E.

    1992-01-01

    Fusion is one of the most attractive central station power sources from the viewpoint of potential safety and environmental impact characteristics. Studies also indicate that fusion can be economically competitive with other options such as fission reactors and fossil-fired power stations. However, to achieve this triad of characteristics we must develop advanced materials with properties tailored for performance in the various fusion reactor systems. This paper discusses the desired characteristics of materials and the status of materials technology in four critical areas: (1) structural material for the first wail and blanket (FWB), (2) plasma-facing materials, (3) materials for superconducting magnets, and (4) ceramics for electrical and structural applications

  20. Advanced materials - the key to attractive magnetic fusion power reactors

    International Nuclear Information System (INIS)

    Bloom, E.E.

    1992-01-01

    Fusion is one of the most attractive central station power sources from the viewpoint of potential safety and environmental impact characteristics. Studies also indicate that fusion can be economically competitive with other options such as fission reactors and fossil-fired power stations. However, to achieve this triad of characteristics we must develop advanced materials with properties tailored for performance in the various fusion reactor systems. This paper discusses the desired characteristics of materials and the status of materials technology in four critical areas: (1) structural materials for the first wall and blanket (FWB), (2) plasmafacing materials, (3) materials for superconducting magnets, and (4) ceramics for electrical and structural applications. (author)

  1. High strain rate characterization of soft materials: past, present and possible futures

    Science.gov (United States)

    Siviour, Clive

    2015-06-01

    The high strain rate properties of low impedance materials have long been of interest to the community: the very first paper by Kolsky on his eponymous bars included data from man-made polymers and natural rubber. However, it has also long been recognized that characterizing soft or low impedance specimens under dynamic loading presents a number of challenges, mainly owing to the low sound speed in, and low stresses supported by, these materials. Over the past 20 years, significant progress has been made in high rate testing techniques, including better experimental design, more sensitive data acquisition and better understanding of specimen behavior. Further, a new generation of techniques, in which materials are characterized using travelling waves, rather than in a state of static equilibrium, promise to turn those properties that were previously a drawback into an advantage. This paper will give an overview of the history of high rate characterization, the current state of the art after an exciting couple of decades and some of the techniques currently being developed that have the potential to offer increased quality data in the future.

  2. Sensor calibration of polymeric Hopkinson bars for dynamic testing of soft materials

    Science.gov (United States)

    Martarelli, Milena; Mancini, Edoardo; Lonzi, Barbara; Sasso, Marco

    2018-02-01

    Split Hopkinson pressure bar (SHPB) testing is one of the most common techniques for the estimation of the constitutive behaviour of metallic materials. In this paper, the characterisation of soft rubber-like materials has been addressed by means of polymeric bars thanks to their reduced mechanical impedance. Due to their visco-elastic nature, polymeric bars are more sensitive to temperature changes than metallic bars, and due to their low conductance, the strain gauges used to measure the propagating wave in an SHPB may be exposed to significant heating. Consequently, a calibration procedure has been proposed to estimate quantitatively the temperature influence on strain gauge output. Furthermore, the calibration is used to determine the elastic modulus of the polymeric bars, which is an important parameter for the synchronisation of the propagation waves measured in the input and output bar strain gate stations, and for the correct determination of stress and strain evolution within the specimen. An example of the application has been reported in order to demonstrate the effectiveness of the technique. Different tests at different strain rates have been carried out on samples made of nytrile butadyene rubber (NBR) from the same injection moulding batch. Thanks to the correct synchronisation of the measured propagation waves measured by the strain gauges and applying the calibrated coefficients, the mechanical behaviour of the NBR material is obtained in terms of strain-rate-strain and stress-strain engineering curves.

  3. Moessbauer spectroscopic studies of magnetically ordered biological materials

    International Nuclear Information System (INIS)

    Dickson, D.P.E.

    1987-01-01

    This paper discusses recent work showing the application of Moessbauer spectroscopy to the study of the properties of the magnetically ordered materials which occur in a variety of biological systems. These materials display a diversity of behaviour which provides good examples of the various possibilities which can arise with iron-containing particles of different compositions and sizes. (orig.)

  4. Carnot cycle for magnetic materials: The role of hysteresis

    International Nuclear Information System (INIS)

    Sasso, Carlo P.; Basso, Vittorio; LoBue, Martino; Bertotti, Giorgio

    2006-01-01

    The role of hysteresis in a refrigeration thermodynamic cycle involving ferromagnetic materials is discussed. A model allowing to calculate magnetization, entropy and entropy production in systems with hysteresis is used to compute a non-ideal Carnot cycle performed on a ferromagnetic material

  5. Enhancing the magnetic properties of magnetic nanoparticles

    DEFF Research Database (Denmark)

    Ahlburg, Jakob; Saura-Múzquiz, Matilde; Stingaciu, Marian

    with a similar magnetic performance. There are several different ways of enhancing magnetic properties of 3d magnetic compounds. This includes, size control, core-shell particles or mixing hard and soft magnetic materials together to achieve an exchange coupling between the compounds and enhancing the magnetic...... energy product. In order to control the particle size, a hydrothermal synthesis is preferred. This followed by reduction or the oxides into either core shell particles, or a mixture of magnetic oxides and a metallic phase....

  6. Nuclear magnetic resonance of randomly diluted magnetic materials

    International Nuclear Information System (INIS)

    Magon, C.J.

    1985-01-01

    The temperature dependence of the nuclear relaxation rates and line shapes of the F O resonance in the diluted antiferromagnet Fe x Zn 1-x F 2 and Mn x Zn 1-x F 2 are studied over a large temperature range T N 1 ) of the F O nuclei, which are not transfer hyperfine coupled to the Fe (or Mn) spins, have been measured and calculated as a function of the concentration x. Good agreement with experiment is found for the theoretical results, which have been obtained in the range 0.1 ≤ x ≤ 0.8. The temperature dependence of 1/T 1 for T N 1 data near T N was used to study Random Field Effects on the critical behavior of Mn .65 Zn . 3 5 F 2 , for fields applied parallel and perpendicular to the easy (C) axis. It was found that the transition temperature T N depressed substantially with field only for H o || C. The experimental results are in general accord with the theory for Random Field Effects in disordered, anisotropic antiferromagnets. The critical divergence of the inhomogeneously broadened F O NMR was studied in Fe .6 Zn .4 F 2 above T N . The experimental results agree with Heller's calculation of the NMR line broadening by Random Field Effects. With H o || C the line shape changes from Gaussian towards Lozentzian for t -2 and below T N its line width increase qualitatively following the increase in the sublattice magnetization. (author)

  7. Magnetic properties and loss separation in FeSi/MnZnFe{sub 2}O{sub 4} soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Lauda, M. [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik Univesity, Park Angelinum 9, 04154 Košice (Slovakia); Füzer, J., E-mail: jan.fuzer@upjs.sk [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik Univesity, Park Angelinum 9, 04154 Košice (Slovakia); Kollár, P. [Institute of Physics, Faculty of Science, Pavol Jozef Šafárik Univesity, Park Angelinum 9, 04154 Košice (Slovakia); Strečková, M.; Bureš, R. [Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice (Slovakia); Kováč, J.; Baťková, M.; Baťko, I. [Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001 Košice (Slovakia)

    2016-08-01

    We investigated composites that have been prepared from FeSi powders covered with MnZnFe{sub 2}O{sub 4} (MnZn ferrite), which was prepared by sol–gel synthesis accompanied with the auto-combustion process. The aim of this paper is to analyze the complex permeability and core losses of prepared samples with different amount of MnZn ferrite. The microstructure and the powder morphology were examined by scanning electron microscopy. Magnetic measurements on bulk samples were carried out using a vibrating sample magnetometer, an impedance analyzer and hysteresisgraphs. The results indicate that the composites with 2.6 wt% MnZn ferrite show better soft magnetic properties than the composites with about 6 wt% MnZn ferrite. - Highlights: • Successful preparation of soft magnetic composite FeSi/MnZnFe{sub 2}O{sub 4}. • Study of the complex magnetic permeability. • Comparison of different compositions of prepared SMC's. • Determination of parts of magnetic losses.

  8. Multimaterial magnetically assisted 3D printing of composite materials

    Science.gov (United States)

    Kokkinis, Dimitri; Schaffner, Manuel; Studart, André R.

    2015-10-01

    3D printing has become commonplace for the manufacturing of objects with unusual geometries. Recent developments that enabled printing of multiple materials indicate that the technology can potentially offer a much wider design space beyond unusual shaping. Here we show that a new dimension in this design space can be exploited through the control of the orientation of anisotropic particles used as building blocks during a direct ink-writing process. Particle orientation control is demonstrated by applying low magnetic fields on deposited inks pre-loaded with magnetized stiff platelets. Multimaterial dispensers and a two-component mixing unit provide additional control over the local composition of the printed material. The five-dimensional design space covered by the proposed multimaterial magnetically assisted 3D printing platform (MM-3D printing) opens the way towards the manufacturing of functional heterogeneous materials with exquisite microstructural features thus far only accessible by biological materials grown in nature.

  9. Models and materials for generalized Kitaev magnetism

    Science.gov (United States)

    Winter, Stephen M.; Tsirlin, Alexander A.; Daghofer, Maria; van den Brink, Jeroen; Singh, Yogesh; Gegenwart, Philipp; Valentí, Roser

    2017-12-01

    The exactly solvable Kitaev model on the honeycomb lattice has recently received enormous attention linked to the hope of achieving novel spin-liquid states with fractionalized Majorana-like excitations. In this review, we analyze the mechanism proposed by Jackeli and Khaliullin to identify Kitaev materials based on spin-orbital dependent bond interactions and provide a comprehensive overview of its implications in real materials. We set the focus on experimental results and current theoretical understanding of planar honeycomb systems (Na2IrO3, α-Li2IrO3, and α-RuCl3), three-dimensional Kitaev materials (β- and γ-Li2IrO3), and other potential candidates, completing the review with the list of open questions awaiting new insights.

  10. Scanning microwave microscopy technique for nanoscale characterization of magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, C.H., E-mail: hadlee.joseph@artov.imm.cnr.it [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Department of Electronics Engineering, University of Rome “Tor Vergata”, Via del Politecnico 1, 00133 Rome (Italy); Sardi, G.M. [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Tuca, S.S.; Gramse, G. [Johannes Kepler University, Institute for Biophysics, Gruberstrasse 40, A-4020 Linz (Austria); Lucibello, A.; Proietti, E. [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Kienberger, F. [Keysight Technologies Austria GmbH, Keysight Laboratories, Gruberstrasse 40, A-4020 Linz (Austria); Marcelli, R. [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy)

    2016-12-15

    In this work, microwave characterization of magnetic materials using the scanning microwave microscopy (SMM) technique is presented. The capabilities of the SMM are employed for analyzing and imaging local magnetic properties of the materials under test at the nanoscale. The analyses are performed by acquiring both amplitude and phase of the reflected microwave signal. The changes in the reflection coefficient S{sub 11} are related to the local properties of the material under investigation, and the changes in its magnetic properties have been studied as a function of an external DC magnetic bias. Yttrium iron garnet (YIG) films deposited by RF sputtering and grown by liquid phase epitaxial (LPE) on gadolinium gallium garnet (GGG) substrates and permalloy samples have been characterized. An equivalent electromagnetic transmission line model is discussed for the quantitative analysis of the local magnetic properties. We also observed the hysteretic behavior of the reflection coefficient S{sub 11} with an external bias field. The imaging and spectroscopy analysis on the experimental results are evidently indicating the possibilities of measuring local changes in the intrinsic magnetic properties on the surface of the material.

  11. Soft errors in 10-nm-scale magnetic tunnel junctions exposed to high-energy heavy-ion radiation

    Science.gov (United States)

    Kobayashi, Daisuke; Hirose, Kazuyuki; Makino, Takahiro; Onoda, Shinobu; Ohshima, Takeshi; Ikeda, Shoji; Sato, Hideo; Inocencio Enobio, Eli Christopher; Endoh, Tetsuo; Ohno, Hideo

    2017-08-01

    The influences of various types of high-energy heavy-ion radiation on 10-nm-scale CoFeB-MgO magnetic tunnel junctions with a perpendicular easy axis have been investigated. In addition to possible latent damage, which has already been pointed out in previous studies, high-energy heavy-ion bombardments demonstrated that the magnetic tunnel junctions may exhibit clear flips between their high- and low-resistance states designed for a digital bit 1 or 0. It was also demonstrated that flipped magnetic tunnel junctions still may provide proper memory functions such as read, write, and hold capabilities. These two findings proved that high-energy heavy ions can produce recoverable bit flips in magnetic tunnel junctions, i.e., soft errors. Data analyses suggested that the resistance flips stem from magnetization reversals of the ferromagnetic layers and that each of them is caused by a single strike of heavy ions. It was concurrently found that an ion strike does not always result in a flip, suggesting a stochastic process behind the flip. Experimental data also showed that the flip phenomenon is dependent on the device and heavy-ion characteristics. Among them, the diameter of the device and the linear energy transfer of the heavy ions were revealed as the key parameters. From their dependences, the physical mechanism behind the flip was discussed. It is likely that a 10-nm-scale ferromagnetic disk loses its magnetization due to a local temperature increase induced by a single strike of heavy ions; this demagnetization is followed by a cooling period associated with a possible stochastic recovery process. On the basis of this hypothesis, a simple analytical model was developed, and it was found that the model accounts for the results reasonably well. This model also predicted that magnetic tunnel junctions provide sufficiently high soft-error reliability for use in space, highlighting their advantage over their counterpart conventional semiconductor memories.

  12. Left-handed materials in metallic magnetic granular composites

    International Nuclear Information System (INIS)

    Chui, S.T.; Lin, Z.F.; Hu, L.-B.

    2003-01-01

    There is recently interests in the 'left-handed' materials. In these materials the direction of the wave vector of electromagnetic radiation is opposite to the direction of the energy flow. We present simple arguments that suggests that magnetic composites can also be left-handed materials. However, the physics involved seems to be different from the original argument. In our argument, the imaginary part of the dielectric constant is much larger than the real part, opposite to the original argument

  13. Outstanding efficiency in energy conversion for electric motors constructed by nanocrystalline soft magnetic alloy “NANOMET®” cores

    Directory of Open Access Journals (Sweden)

    N. Nishiyama

    2016-05-01

    Full Text Available Recently updated nanocrystalline soft magnetic Fe-Co-Si-B-P-Cu alloys “NANOMET®” exhibit high saturation magnetic flux density (Bs > 1.8 T, low coercivity (Hc < 10 A/m and low core loss (W1.7/50 ∼ 0.4 W/kg even in a ribbon form with a thickness of up to 40 μm. By utilize excellent magnetic softness, several products such as motors or transformers for electrical appliances are now under developing by industry-academia collaboration. In particular, it is found that a brushless DC motor using NANOMET® core exhibited remarkable improvement in energy consumption. The prototype motor with an outer core diameter of 70 mm and a core thickness of 50 mm was constructed using laminated nano-crystallized NANOMET® ribbons. Core-loss for the constructed motor was improved from 1.4 W to 0.4 W only by replacing the non-oriented Si-steel core with NANOMET® one. The overall motor efficiency is evaluated to be 3% improvement. In this work, the relation between processing and resulting magnetic properties will be presented. In addition, feasibility for commercialization will also be discussed.

  14. Structure and magnetism in novel group IV element-based magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Frank [Univ. of North Carolina, Chapel Hill, NC (United States)

    2013-08-14

    The project is to investigate structure, magnetism and spin dependent states of novel group IV element-based magnetic thin films and heterostructures as a function of composition and epitaxial constraints. The materials systems of interest are Si-compatible epitaxial films and heterostructures of Si/Ge-based magnetic ternary alloys grown by non-equilibrium molecular beam epitaxy (MBE) techniques, specifically doped magnetic semiconductors (DMS) and half-metallic Heusler alloys. Systematic structural, chemical, magnetic, and electrical measurements are carried out, using x-ray microbeam techniques, magnetotunneling spectroscopy and microscopy, and magnetotransport. The work is aimed at elucidating the nature and interplay between structure, chemical order, magnetism, and spin-dependent states in these novel materials, at developing materials and techniques to realize and control fully spin polarized states, and at exploring fundamental processes that stabilize the epitaxial magnetic nanostructures and control the electronic and magnetic states in these complex materials. Combinatorial approach provides the means for the systematic studies, and the complex nature of the work necessitates this approach.

  15. Computational alloy design of (Co1-xNix)88Zr7B4Cu1 nanocomposite soft magnets

    Science.gov (United States)

    Dong, B.; Healy, J.; Lan, S.; Daniil, M.; Willard, M. A.

    2018-05-01

    The dependence of coercivity on composition is an important factor for establishing optimized soft magnetic properties. In this study, we have used the random anisotropy and coherent rotation models to estimate the variation of coercivity with composition in (Co1-xNix)88Zr7B4Cu1 nanocomposite alloys. Our calculations that the magnetoelastic anisotropy contribution to coercivity dominates for Ni rich compositions (x > 0.5). A small range of compositions (0.65 < x < 0.75) is predicted to result in low values of coercivity (<10 A/m). To validate this prediction, (Co1-xNix)88Zr7B4Cu1 nanocomposites in this range were prepared by melt spinning followed by 3600 s isothermal annealing at the primary crystallization peak temperature (˜673 K). Hysteresis loops were measured using vibrating sample magnetometry at room temperature and saturation magnetostriction was measured using a strain gage based magnetostrictometer. Moderately small coercivities (30-40 A/m) and magnetostrictions (3-4 ppm) were measured at for samples with 0.685 < x < 0.725. Our measured coercivity had a minimum value of 32 A/m at x = 0.725, a shift in composition of about 5 at% in the direction of higher Ni content and without the anticipated low value of coercivity. Several reasons for the inaccuracy of this approach are described, including: ignored contributions from amorphous phase (especially in magnetoealstic anisotropy), composition segregation during crystallization leading to unpredictable compositional shifts in prediction, and the general observation that the predictability of minimum coercivity from minimal combined anisotropies has unexplained deviation even in far less complicated materials.

  16. A NEW PORTABLE INSTRUMENT TO EVALUATE SOFT FLOORING MATERIALS IN DAIRY COW HOUSING

    Directory of Open Access Journals (Sweden)

    Paolo Liberati

    2012-06-01

    Full Text Available The improvement of flooring materials performance on animal health and welfare requires the support of reliable testing techniques. This is particularly relevant with the synthetic soft coverings used for walking areas since the friction coefficient is not only dependent on the surface characteristics, but also on the penetration of the animal hoof into the material. The paper presents the functioning of a new instrument capable of reproducing more closely the real interaction between the floor surface and the animal foot. The instrument is simple and portable and is suitable both for laboratory measurements and real housing conditions. The measurement is made in two steps: first a probe, shaped as a cow hoof and contacting the testing floor surface, is loaded with a vertical force to obtain a pressure similar to that exerted by the animal; then a pushing force parallel to the floor is applied, at a constant speed, producing a displacement along the surface. The values of the vertical and horizontal strengths required for skidding and the angle of the instrument are continuously measured and by them various parameters can be calculated. The results of the tests carried out in the laboratory and in real dairy houses are presented and, through the analysis of various calculated physical parameters, the main floor properties – more suitable for a previous estimate of the effect on animal welfare – are determined and discussed. In particular, the IPF parameter has been the only one able to predict also the foot escape among all the considered parameters.

  17. Size-controlled soft-template synthesis of carbon nanodots toward versatile photoactive materials.

    Science.gov (United States)

    Kwon, Woosung; Lee, Gyeongjin; Do, Sungan; Joo, Taiha; Rhee, Shi-Woo

    2014-02-12

    Size-controlled soft-template synthesis of carbon nanodots (CNDs) as novel photoactive materials is reported. The size of the CNDs can be controlled by regulating the amount of an emulsifier. As the size increases, the CNDs exhibit blue-shifted photoluminescence (PL) or so-called an inverse PL shift. Using time-correlated single photon counting, ultraviolet photoelectron spectroscopy, and low-temperature PL measurements, it is revealed that the CNDs are composed of sp² clusters with certain energy gaps and their oleylamine ligands act as auxochromes to reduce the energy gaps. This insight can provide a plausible explanation on the origin of the inverse PL shift which has been debatable over a past decade. To explore the potential of the CNDs as photoactive materials, several prototypes of CND-based optoelectronic devices, including multicolored light-emitting diodes and air-stable organic solar cells, are demonstrated. This study could shed light on future applications of the CNDs and further expedite the development of other related fields. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Expert-guided optimization for 3D printing of soft and liquid materials

    Science.gov (United States)

    Abdollahi, Sara; Davis, Alexander; Miller, John H.

    2018-01-01

    Additive manufacturing (AM) has rapidly emerged as a disruptive technology to build mechanical parts, enabling increased design complexity, low-cost customization and an ever-increasing range of materials. Yet these capabilities have also created an immense challenge in optimizing the large number of process parameters in order achieve a high-performance part. This is especially true for AM of soft, deformable materials and for liquid-like resins that require experimental printing methods. Here, we developed an expert-guided optimization (EGO) strategy to provide structure in exploring and improving the 3D printing of liquid polydimethylsiloxane (PDMS) elastomer resin. EGO uses three steps, starting first with expert screening to select the parameter space, factors, and factor levels. Second is a hill-climbing algorithm to search the parameter space defined by the expert for the best set of parameters. Third is expert decision making to try new factors or a new parameter space to improve on the best current solution. We applied the algorithm to two calibration objects, a hollow cylinder and a five-sided hollow cube that were evaluated based on a multi-factor scoring system. The optimum print settings were then used to print complex PDMS and epoxy 3D objects, including a twisted vase, water drop, toe, and ear, at a level of detail and fidelity previously not obtained. PMID:29621286

  19. Expert-guided optimization for 3D printing of soft and liquid materials.

    Science.gov (United States)

    Abdollahi, Sara; Davis, Alexander; Miller, John H; Feinberg, Adam W

    2018-01-01

    Additive manufacturing (AM) has rapidly emerged as a disruptive technology to build mechanical parts, enabling increased design complexity, low-cost customization and an ever-increasing range of materials. Yet these capabilities have also created an immense challenge in optimizing the large number of process parameters in order achieve a high-performance part. This is especially true for AM of soft, deformable materials and for liquid-like resins that require experimental printing methods. Here, we developed an expert-guided optimization (EGO) strategy to provide structure in exploring and improving the 3D printing of liquid polydimethylsiloxane (PDMS) elastomer resin. EGO uses three steps, starting first with expert screening to select the parameter space, factors, and factor levels. Second is a hill-climbing algorithm to search the parameter space defined by the expert for the best set of parameters. Third is expert decision making to try new factors or a new parameter space to improve on the best current solution. We applied the algorithm to two calibration objects, a hollow cylinder and a five-sided hollow cube that were evaluated based on a multi-factor scoring system. The optimum print settings were then used to print complex PDMS and epoxy 3D objects, including a twisted vase, water drop, toe, and ear, at a level of detail and fidelity previously not obtained.

  20. Effects of Cu substitution for Fe on the glass-forming ability and soft magnetic properties for Fe-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Dou, Lintao; Liu, Haishun; Hou, Long; Xue, Lin; Yang, Weiming; Zhao, Yucheng; Chang, Chuntao

    2014-01-01

    The effects of Cu substitution for Fe on the glass-forming ability (GFA) and soft magnetic properties for Fe 72−x Cu x B 20 Si 4 Nb 4 (x=0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) bulk metallic glasses (BMGs) are investigated. It is found that the investigated BMGs exhibit large GFA as well as excellent soft magnetic properties, and proper substitution of Fe by Cu improves the saturation magnetization, coercive force, and effective permeability without obvious deterioration of the GFA. - Highlights: • Fully glassy rods of Fe 72−x Cu x B 20 Si 4 Nb 4 BMGs were produced above 1 mm in diameter. • Investigated BMGs exhibit large glass-forming ability and excellent soft magnetic properties. • Proper Cu substitution improves magnetic properties without obvious deterioration of glass-forming ability

  1. Magnetization reversal and 1/H law in highly anisotropic materials

    International Nuclear Information System (INIS)

    Barbara, B.; Uehara, M.

    1978-01-01

    A model has been developed for the coercive field, based on the concept of creation and annihilation of domain-wall kinks. This model accounts for the Barkhausen jumps and leads to a new process of magnetization reversal involving simultaneously the pinning and nucleation mechanisms. It is characterized by an activation energy proportional to the reciprocal magnetic field H -1 . Such dependence has been observed in different kinds of materials and therefore seems to be general. (author)

  2. Effect of annealing treatment on soft magnetic properties of Fe-6.5 wt% Si wide ribbons

    International Nuclear Information System (INIS)

    Roy, R.K.; Panda, A.K.; Ghosh, M.; Mitra, A.; Ghosh, R.N.

    2009-01-01

    The 25 mm wide ribbons of Fe-6.5 wt% Si alloy have been developed by melt spinning technique, showing sufficient ductility and white silver appearance. Two magnetic transitions take place at 676 and 760 deg. C due to the formation of B2 ordered phase and A2 disordered paramagnetic phase, respectively. The saturation magnetization of the ribbon is 17.5 kG under the applied field of 12 kG. The as-cast ribbons consist of disordered A2 structure with a low volume of B2 phases while the annealed microstructure comprises a dispersion of B2 domains in the disordered A2 matrix. The alloy shows the enhancement of the soft magnetic properties with a reduction in coercivity from 150 A/m in the as-cast state to 45 A/m in the annealed condition at 850 deg. C.

  3. An electromagnetically actuated fiber optic switch using magnetized ferromagnetic materials

    Science.gov (United States)

    Pandojirao-S, Praveen; Dhaubanjar, Naresh; Phuyal, Pratibha C.; Chiao, Mu; Chiao, J.-C.

    2008-03-01

    This paper presents the design, fabrication and testing of a fiber optic switch actuated electromagnetically. The ferromagnetic gel coated optical fiber is actuated using external electromagnetic fields. The ferromagnetic gel consists of ferromagnetic powders dispersed in epoxy. The fabrication utilizes a simple cost-effective coating setup. A direct fiberto-fiber alignment eliminates the need for complementary optical parts and the displacement of fiber switches the laser coupling. The magnetic characteristics of magnetized ferromagnetic materials are performed using alternating gradient magnetometer and the magnetic hysteresis curves are measured for different ferromagnetic materials including iron, cobalt, and nickel. Optical fiber switches with various fiber lengths are actuated and their static and dynamic responses for the same volume of ferromagnetic gel are summarized. The highest displacement is 1.345 mm with an input current of 260mA. In this paper, the performance of fiber switches with various coating materials is presented.

  4. Magnetic susceptibility and magnetic resonance measurements of the moisture content and hydration condition of a magnetic mixture material

    International Nuclear Information System (INIS)

    Tsukada, K.; Kusaka, T.; Saari, M. M.; Takagi, R.; Sakai, K.; Kiwa, T.; Bito, Y.

    2014-01-01

    We developed a magnetic measurement method to measure the moisture content and hydration condition of mortar as a magnetic mixture material. Mortar is a mixture of Portland cement, sand, and water, and these materials exhibit different magnetic properties. The magnetization–magnetic field curves of these components and of mortars with different moisture contents were measured, using a specially developed high-temperature-superconductor superconducting quantum interference device. Using the differences in magnetic characteristics, the moisture content of mortar was measured at the ferromagnetic saturation region over 250 mT. A correlation between magnetic susceptibility and moisture content was successfully established. After Portland cement and water are mixed, hydration begins. At the early stage of the hydration/gel, magnetization strength increased over time. To investigate the magnetization change, we measured the distribution between bound and free water in the mortar in the early stage by magnetic resonance imaging (MRI). The MRI results suggest that the amount of free water in mortar correlates with the change in magnetic susceptibility

  5. Soft X-ray emission spectroscopy of liquids and lithium battery materials

    International Nuclear Information System (INIS)

    Augustsson, Andreas

    2004-01-01

    Lithium ion insertion into electrode materials is commonly used in rechargeable battery technology. The insertion implies changes in both the crystal structure and the electronic structure of the electrode material. Side-reactions may occur on the surface of the electrode which is exposed to the electrolyte and form a solid electrolyte interface (SEI). The understanding of these processes is of great importance for improving battery performance. The chemical and physical properties of water and alcohols are complicated by the presence of strong hydrogen bonding. Various experimental techniques have been used to study geometrical structures and different models have been proposed to view the details of how these liquids are geometrically organized by hydrogen bonding. However, very little is known about the electronic structure of these liquids, mainly due to the lack of suitable experimental tools. In this thesis examples of studies of lithium battery electrodes and liquid systems using soft x-ray emission spectroscopy will be presented. Monochromatized synchrotron radiation has been used to accomplish selective excitation, in terms of energy and polarization. The electronic structure of graphite electrodes has been studied, before and after lithium intercalation. Changes in the electronic structure upon lithiation due to transfer of electrons into the graphite π-bands have been observed. Transfer of electrons in to the 3d states of transition metal oxides upon lithiation have been studied, through low energy excitations as dd- and charge transfer-excitations. A SEI was detected on cycled graphite electrodes. By the use of selective excitation different carbon sites were probed in the SEI. The local electronic structure of water, methanol and mixtures of the two have been examined using a special liquid cell, to separate the liquid from the vacuum in the experimental chamber. Results from the study of liquid water showed a strong influence on the 3a1 molecular

  6. Population inversion and gain measurements for soft x-ray-laser development in a magnetically confined plasma column

    International Nuclear Information System (INIS)

    Suckewer, S.; Skinner, C.H.; Voorhees, D.; Milchberg, H.; Keane, C.; Semet, A.

    1983-06-01

    We present population inversion and gain measurements from an experimental investigation of possibilities to obtain high gain and lasing action in the soft x-ray region. Our approach to soft x-ray-laser development is based on rapid plasma cooling after the laser pulse by radiation losses, leading to fast recombination and collisional cascade into upper excited levels of CVI, for example, while the lower excited levels depopulate rapidly by radiative transitions, thus creating population inversions and gain. A approx. = 0.5 kJ CO 2 laser was focused onto a target of solid carbon or teflon; or CO 2 , O 2 , Ne gas, and the resulting plasma confined in a 50 to 90 kG magnetic field. Spectroscopic diagnostics with absolute intensity calibration were used to measure level populations

  7. Magneto optical properties of silver doped magnetic nanocomposite material

    Directory of Open Access Journals (Sweden)

    N. Abirami

    2017-11-01

    Full Text Available Magnetic composite materials challenge traditional materials in broad applications such as transformer, sensors and electrical motors. In this work by studying the permittivity and permeability spectra of silver doped magnetic nanocomposite system, the variation of the effective refractive index with frequency is investigated for different filling factor. It is found that the value of resonance frequency decrease with filling factor. The polariton dispersion of the system is also studied. This study of the nanocomposite system can be exploited in designing modern optical devices.PACS: 75.50-y, 71.36.+c, 78.67.Sc, 78.20.Ci. Keywords: Permittivity, Permeability, Nanocomposite system, Polariton

  8. Investigation of (Fe,Co)NbB-Based Nanocrystalline Soft Magnetic Alloys by Lorentz Microscopy and Off-Axis Electron Holography.

    Science.gov (United States)

    Zheng, Changlin; Kirmse, Holm; Long, Jianguo; Laughlin, David E; McHenry, Michael E; Neumann, Wolfgang

    2015-04-01

    The relationship between microstructure and magnetic properties of a (Fe,Co)NbB-based nanocrystalline soft magnetic alloy was investigated by analytical transmission electron microscopy (TEM). The microstructures of (Fe0.5Co0.5)80Nb4B13Ge2Cu1 nanocrystalline alloys annealed at different temperatures were characterized by TEM and electron diffraction. The magnetic structures were analyzed by Lorentz microscopy and off-axis electron holography, including quantitative measurement of domain wall width, induction, and in situ magnetic domain imaging. The results indicate that the magnetic domain structure and particularly the dynamical magnetization behavior of the alloys strongly depend on the microstructure of the nanocrystalline alloys. Smaller grain size and random orientation of the fine particles decrease the magneto-crystalline anisotropy and suggests better soft magnetic properties which may be explained by the anisotropy model of Herzer.

  9. Substitution effects in magnetic and superconducting materials

    Directory of Open Access Journals (Sweden)

    Peña, O.

    1999-10-01

    Full Text Available Chemical substitutions at very low level have been proved to be a very effective tool to change important physical parameters in many kinds of materials. These modifications may be the result of, for instance, subtle variations of the position of the Fermi level with respect to the density of states, presence of additional electrons which may change the hole carrier concentration, steric effects which impose contraints in the crystallographic lattice, mixed-valence states resultating from the dismutation of chemical components, etc. We review herein three systems in which the substitution effects are at the origin of new physical states : the high-Tc superconductor bismuth cuprate of the 2212 family, the mixed-valence manganese perovskites representative of giant magneto-resistive compounds, and the Chevrel phase materials in which a structural transition may inhibit the superconducting state.

    Las substituciones químicas a un nivel muy pequeño se han probado como una importante herramienta para cambiar los parámetros físicos en una gran variedad de materiales. Estas modificaciones pueden ser el resultado de, por ejemplo, muy ligeras variaciones de la posición del nivel de Fermi con respecto a la densidad de estados, presencia de electrones adicionales que pueden cambiar la concentración de portadores tipo huecos, efectos estéricos que imponen restricciones en la red cristalográfica, estados de valencia mixtos resultantes de la dismutación de los componentes químicos, etc. Aquí se revisan tres sistemas donde los efectos de substitución son el origen de nuevos estados físicos: los superconductores de alta temperatura basados en cupratos de bismuto de la familia 2212, las perovskitas de manganeso de valencia mixta representantes de compuestos con magnetorresistencia gigante, y los materiales con fases de Chevrelt cuya transición estructural puede inhibir el estado superconductor.

  10. Hydrogenated arsenenes as planar magnet and Dirac material

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shengli; Cai, Bo; Zeng, Haibo, E-mail: Huziyu@csrc.ac.cn, E-mail: zeng.haibo@njust.edu.cn [Institute of Optoelectronics and Nanomaterials, Herbert Gleiter Institute of Nanoscience, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Hu, Yonghong [Institute of Optoelectronics and Nanomaterials, Herbert Gleiter Institute of Nanoscience, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Nuclear Technology and Chemistry and Biology, Hubei University of Science and Technology, Xianning 437100 (China); Hu, Ziyu, E-mail: Huziyu@csrc.ac.cn, E-mail: zeng.haibo@njust.edu.cn [Beijing Computational Science Research Center, Beijing 100084 (China)

    2015-07-13

    Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices.

  11. Hydrogenated arsenenes as planar magnet and Dirac material

    International Nuclear Information System (INIS)

    Zhang, Shengli; Cai, Bo; Zeng, Haibo; Hu, Yonghong; Hu, Ziyu

    2015-01-01

    Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices

  12. Hydrogenated arsenenes as planar magnet and Dirac material

    Science.gov (United States)

    Zhang, Shengli; Hu, Yonghong; Hu, Ziyu; Cai, Bo; Zeng, Haibo

    2015-07-01

    Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices.

  13. PERANGKAT PEMBELAJARAN PROBLEM BASED LEARNING BERORIENTASI GREEN CHEMISTRY MATERI HIDROLISIS GARAM UNTUK MENGEMBANGKAN SOFT SKILL KONSERVASI SISWA

    Directory of Open Access Journals (Sweden)

    A. Rosita

    2014-10-01

    Full Text Available Penelitian ini bertujuan untuk mengembangkan perangkat pembelajaran problem based learning berorientasi green chemistry pada materi hidrolisis garam untuk mengembangkan soft skill konservasi siswa SMA. Metode penelitian ini adalah research and development (R&D. Hasil penelitian menunjukkan LKS yang dikembangkan sangat layak untuk digunakan dalam pembelajaran kimia. Perangkat pembelajaran dapat meningkatkan pemahaman konsep siswa materi hidrolisis garam dengan N-gain sebesar 0,63 (sedang. Peningkatan soft skill konservasi siswa yang berkriteria tinggi sebanyak 35,48 % sedangkan yang berkriteria sedang 64,52 %. This research has aim to developt teaching and learning instrument application on problem based learning which oriented on green chemistry on salt hydrolisys for developing conservation soft skill for student. The method of this research is research and development (R&D. The results showed a very worthy worksheets developed for use in teaching chemistry. Teaching instrument can improve the understanding of student concept of salt hydrolysis matery can get N-gain 0,63 (medium. The improving soft skill of student conservation has high criteria 35,48%. For medium has 64,52%.

  14. Liquid metal MHD studies with non-magnetic and ferro-magnetic structural material

    Energy Technology Data Exchange (ETDEWEB)

    Patel, A., E-mail: anipatel2009@gmail.com [Institute of Plasma Research, Gandhinagar 382428, Gujarat (India); Bhattacharyay, R. [Institute of Plasma Research, Gandhinagar 382428, Gujarat (India); Swain, P.K.; Satyamurthy, P. [Bhabha Atomic Research Center, Mumbai 400085, Maharashtra (India); Sahu, S.; Rajendrakumar, E. [Institute of Plasma Research, Gandhinagar 382428, Gujarat (India); Ivanov, S.; Shishko, A.; Platacis, E.; Ziks, A. [Institute of Physics, University of Latvia, Salaspils 2169 (Latvia)

    2014-10-15

    Highlights: • Effect of structural material on liquid metal MHD phenomena is studied. • Two identical test sections, one made of SS316L (non-magnetic) and other made of SS430 (ferromagnetic) structural material, are considered. • Wall electric potential and liquid metal pressure drop are compared under various experimental conditions. • Experimental results suggest screening of external magnetic field for SS430 material below the saturation magnetic field. - Abstract: In most of the liquid metal MHD experiments reported in the literature to study liquid breeder blanket performance, SS316/SS304 grade steels are used as the structural material which is non-magnetic. On the other hand, the structural material for fusion blanket systems has been proposed to be ferritic martensitic grade steel (FMS) which is ferromagnetic in nature. In the recent experimental campaign, liquid metal MHD experiments have been carried out with two identical test sections: one made of SS316L (non-magnetic) and another with SS430 (ferromagnetic), to compare the effect of structural materials on MHD phenomena for various magnetic fields (up to 4 T). The maximum Hartmann number and interaction number are 1047 and 300, respectively. Each test section consists of square channel (25 mm × 25 mm) cross-section with two U bends, with inlet and outlet at the middle portion of two horizontal legs, respectively. Pb–Li enters into the test section through a square duct and distributed into two parallel paths through a partition plate. In each parallel path, it travels ∼0.28 m length in plane perpendicular to the magnetic field and faces two 90° bends before coming out of the test section through a single square duct. The wall electrical potential and MHD pressure drop across the test sections are compared under identical experimental conditions. Similar MHD behavior is observed with both the test section at higher value of the magnetic field (>2 T)

  15. CLINICAL APPLICABILITY OF HUMAN IN-VIVO LOCALIZED P-31 MAGNETIC-RESONANCE SPECTROSCOPY OF BONE AND SOFT-TISSUE TUMORS

    NARCIS (Netherlands)

    HOEKSTRA, HJ; BOEVE, WJ; KAMMAN, RL; MOOYAART, EL

    1994-01-01

    Background: Magnetic resonance imaging (MRI) is of restricted value for the in vivo characterization of tumor types. The applicability of phosphorus-31 (P-31) magnetic resonance spectroscopy (MRS) in the diagnosis of bone and soft tissue tumors is unknown. Methods: A total of 191 consecutive

  16. Evolution of real contact area under shear and the value of static friction of soft materials.

    Science.gov (United States)

    Sahli, R; Pallares, G; Ducottet, C; Ben Ali, I E; Al Akhrass, S; Guibert, M; Scheibert, J

    2018-01-16

    The frictional properties of a rough contact interface are controlled by its area of real contact, the dynamical variations of which underlie our modern understanding of the ubiquitous rate-and-state friction law. In particular, the real contact area is proportional to the normal load, slowly increases at rest through aging, and drops at slip inception. Here, through direct measurements on various contacts involving elastomers or human fingertips, we show that the real contact area also decreases under shear, with reductions as large as 30[Formula: see text], starting well before macroscopic sliding. All data are captured by a single reduction law enabling excellent predictions of the static friction force. In elastomers, the area-reduction rate of individual contacts obeys a scaling law valid from micrometer-sized junctions in rough contacts to millimeter-sized smooth sphere/plane contacts. For the class of soft materials used here, our results should motivate first-order improvements of current contact mechanics models and prompt reinterpretation of the rate-and-state parameters.

  17. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, A. P., E-mail: aph@mcmaster.ca; Lee, V.; Wu, J.; Cooper, G. [Chemistry & Chemical Biology, McMaster University, Hamilton, ON, L8S 4M1 (Canada); West, M. M.; Berejnov, V. [Faculty of Health Sciences Electron Microscopy, McMaster University, Hamilton, ON L8N 3Z5 (Canada); Soboleva, T.; Susac, D.; Stumper, J. [Automotive Fuel Cell Cooperation Corp., Burnaby BC V5J 5J8 (Canada)

    2016-01-28

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.

  18. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    International Nuclear Information System (INIS)

    Hitchcock, A. P.; Lee, V.; Wu, J.; Cooper, G.; West, M. M.; Berejnov, V.; Soboleva, T.; Susac, D.; Stumper, J.

    2016-01-01

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined

  19. Synthesizing and Playing with Magnetic Nanoparticles: A Comprehensive Approach to Amazing Magnetic Materials

    Science.gov (United States)

    Dalverny, Anne-Laure; Leyral, Géraldine; Rouessac, Florence; Bernaud, Laurent; Filhol, Jean-Sébastien

    2018-01-01

    Magnetic iron oxide nanoparticles were synthesized and stabilized using ammonium cations or poly(vinyl alcohol) to produce amazing materials such as safer aqueous ferrofluids, ferrogels, ferromagnetic inks, plastics, and nanopowders illustrating how versatile materials can be produced just by simple modifications. The synthesis is fast, reliable,…

  20. The emergence of complex behaviours in molecular magnetic materials.

    Science.gov (United States)

    Goss, Karin; Gatteschi, Dante; Bogani, Lapo

    2014-09-14

    Molecular magnetism is considered an area where magnetic phenomena that are usually difficult to demonstrate can emerge with particular clarity. Over the years, however, less understandable systems have appeared in the literature of molecular magnetic materials, in some cases showing features that hint at the spontaneous emergence of global structures out of local interactions. This ingredient is typical of a wider class of problems, called complex behaviours, where the theory of complexity is currently being developed. In this perspective we wish to focus our attention on these systems and the underlying problematic that they highlight. We particularly highlight the emergence of the signatures of complexity in several molecular magnetic systems, which may provide unexplored opportunities for physical and chemical investigations.

  1. Microstructure characterization and magnetic properties of nano structured materials

    International Nuclear Information System (INIS)

    Sun, X.C.

    2000-01-01

    The present thesis deals with the unique microstructural properties and their novel magnetic properties of core-shell Ni-Ce nano composite particles, carbon encapsulated Fe, Co, and Ni nanoparticles and the nano crystallization behavior of typical ferromagnetic Fe 78 Si 9 B 13 ribbons. These properties have intensively been investigated by high resolution transmission electron microscopy (HREM), X-ray diffraction (XRD), scanning electron microscopy (Sem), X-ray energy dispersive spectroscopy (Eds.); selected area electron diffraction pattern (SAED), Ft-IR, differential scanning calorimeter (DSC). In addition, magnetic moments measurements at different temperatures and applied fields have been performed by transmission Moessbauer spectroscopy, superconducting quantum interference device magnetometer (SQUID), and vibrating sample magnetometer (VSM). The present studies may provide the insights for the better understanding of the correlation between the unique microstructure and novel magnetic properties for several magnetic nano structured materials. (Author)

  2. Microstructure characterization and magnetic properties of nano structured materials

    Energy Technology Data Exchange (ETDEWEB)

    Sun, X.C

    2000-07-01

    The present thesis deals with the unique microstructural properties and their novel magnetic properties of core-shell Ni-Ce nano composite particles, carbon encapsulated Fe, Co, and Ni nanoparticles and the nano crystallization behavior of typical ferromagnetic Fe{sub 78}Si{sub 9}B{sub 13} ribbons. These properties have intensively been investigated by high resolution transmission electron microscopy (HREM), X-ray diffraction (XRD), scanning electron microscopy (Sem), X-ray energy dispersive spectroscopy [eds.]; selected area electron diffraction pattern (SAED), Ft-IR, differential scanning calorimeter (DSC). In addition, magnetic moments measurements at different temperatures and applied fields have been performed by transmission Moessbauer spectroscopy, superconducting quantum interference device magnetometer (SQUID), and vibrating sample magnetometer (VSM). The present studies may provide the insights for the better understanding of the correlation between the unique microstructure and novel magnetic properties for several magnetic nano structured materials. (Author)

  3. 2nd Latin American Workshop on Magnetism, Magnetic Materials, and Their Applications

    CERN Document Server

    Sanchez, J

    1994-01-01

    During August 24-27, 1993, approximately 60 scientists from the Americas, Europe and Japan, gathered in the city of Guanajuato, in the state of Guanajuato, Mexico, at the II Latin American Workshop on Magnetism, Magnetic Materials and their Applications. The group of scientists converging into the beautiful city of Guanajuato had come from Argentina, Chile, Brazil, Venezuela, Cuba, several places in Mexico, U. S. A. , Japan, Spain, France, Italy, Germany, Austria, Switzerland, and Denmark. The event attested to the success of the previous Workshop on Magnetism, Magnetic Materials and their Applications, held in Havana, Cuba, in 1991, as well as to the interest, level of activity and quality of the work being carried out in Latin America in the area of magnetism and magnetic materials. Equally important to everyone present was the fact that we had come to honor a friend, Professor L. M. Falicov, on his sixtieth birthday. The choice of a Latin American Workshop on magnetism as a Festschrift for Leo Falicov was,...

  4. Updated Lagrangian finite element formulations of various biological soft tissue non-linear material models: a comprehensive procedure and review.

    Science.gov (United States)

    Townsend, Molly T; Sarigul-Klijn, Nesrin

    2016-01-01

    Simplified material models are commonly used in computational simulation of biological soft tissue as an approximation of the complicated material response and to minimize computational resources. However, the simulation of complex loadings, such as long-duration tissue swelling, necessitates complex models that are not easy to formulate. This paper strives to offer the updated Lagrangian formulation comprehensive procedure of various non-linear material models for the application of finite element analysis of biological soft tissues including a definition of the Cauchy stress and the spatial tangential stiffness. The relationships between water content, osmotic pressure, ionic concentration and the pore pressure stress of the tissue are discussed with the merits of these models and their applications.

  5. Effects of the magnetic field on the structure of materials

    International Nuclear Information System (INIS)

    Nakajima, Tetsuo

    1984-02-01

    This is a report of the ''Meeting on the effects of a magnetic field on the structure of materials'' held at KEK, Japan. The purpose of the Meeting was to study the diffraction of SR X-ray in a magnetic field. It was found that the effects of a magnetic field have been seen in various substnaces. The effects are due to the Zeeman effect, the Lamor diamagnetism, the Landau diamagnetism, the Meissner effect and the polarization effect. The topics discussed at the Meeting were the structure study of biological specimens by field orientation, the study of cell structure by field orientation, the phase transition under a strong pulse field, the behavior of high molecular liquid crystal in a magnetic field, the change of the f-electron density of the Tb 3+ ions in Tb IG in a magnetic field at low temperature, an electromagnet loaded on a goniometer and an in-situ observation system for the structure of magnetic domain, the control of structural phase transition by a magnetic field, the use of synchrotron orbit radiation for the structural analysis of random systems, and the field effect on chemical reactions. (Kato, T.)

  6. Magnetic properties of iron-based soft magnetic composites with SiO{sub 2} coating obtained by reverse microemulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shen [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Sun, Aizhi, E-mail: sunaizhi@126.com [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Lu, Zhenwen; Cheng, Chuan [School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Gao, Xuexu [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-05-01

    In this work, iron-based soft magnetic composites coated with the amorphous SiO{sub 2} layer have been fabricated by utilizing tetraethoxysilane in the reverse microemulsion method, and then the effects of addition amount of SiO{sub 2} and annealing temperature on the magnetic properties were investigated. The results show that the surface of iron powders contains a thin amorphous SiO{sub 2} insulation layer, which effectively decreases the magnetic loss of synthesized magnets. The magnetic loss of coated samples decreased by 87.8% as compared with that of uncoated samples at 150 kHz. Magnetic measurements show that the sample with 1.25 wt% SiO{sub 2} has an acceptable real part and minimum imaginary part of permeability in comparison with other samples. Also, the annealing treatment increased the initial permeability, the maximum permeability and the magnetic induction and decreased the coercivity with increasing temperature in the range 300–600 °C. The results of the loss separation imply that the annealed SMCs have a higher hysteresis loss coefficient (k{sub 2}) and lower eddy current loss coefficient (k{sub 3}) as compared with the pure iron compacts after the same heat treatment due to the preservation of the SiO{sub 2} layer. - Highlights: • SiO{sub 2} coated the iron powder by reverse microemulsion method, decreased the magnetic loss of SMCs. • 25 wt% is the optimum coating amount to attain the desired permeability. • The influence of annealing temperature on the magnetic performance of the core was discussed. • Compare with the pure iron compacts, the annealed SMCs have lower value of eddy current coefficient.

  7. Static Magnetic Properties of AL800 Garnet Material

    Energy Technology Data Exchange (ETDEWEB)

    Kuharik, J. [Fermilab; Madrak, R. [Fermilab; Makarov, A. [Fermilab; Pellico, W. [Fermilab; Sun, S. [Fermilab; Tan, C. Y. [Fermilab; Terechkine, I. [Fermilab

    2017-05-17

    A second harmonic tunable RF cavity is being devel-oped for the Fermilab Booster. This device, which prom-ises reduction of the particle beam loss at the injection, transition, and extraction stages, employs perpendicularly biased garnet material for frequency tuning. The required range of the tuning is significantly wider than in previously built and tested tunable RF devices. As a result, the mag-netic field in the garnet comes fairly close to the gyromag-netic resonance line at the lower end of the frequency range. The chosen design concept of a tuner for the cavity cannot ensure uniform magnetic field in the garnet mate-rial; thus, it is important to know the static magnetic prop-erties of the material to avoid significant increase in the lo-cal RF loss power density. This report summarizes studies performed at Fermilab to understand variations in the mag-netic properties of the AL800 garnet material used to build the tuner of the cavity.

  8. Magnetic characterisation of recording materials: design, instrumentation and experimental methods

    NARCIS (Netherlands)

    Samwel, E.O.

    1995-01-01

    The progress being made in the field of magnetic recording is extremely fast. The need to keep this progress going, leads to new types of recording materials which require advanced measurement systems and measurement procedures. Furthermore, the existing measurement methods need to be reviewed as

  9. Iron-based soft magnetic composites with Mn-Zn ferrite nanoparticles coating obtained by sol-gel method

    Science.gov (United States)

    Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zhang, Qian; Zhai, Fuqiang; Logan, Philip; Volinsky, Alex A.

    2012-11-01

    This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing Mn-Zn ferrite nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm, were obtained via the sol-gel method. Scanning electron microscopy, energy dispersive X-ray spectroscopy and distribution maps show that the iron particle surface is covered with a thin layer of Mn-Zn ferrites. Mn-Zn ferrite uniformly coated the surface of the powder particles, resulting in a reduced imaginary permeability, increased electrical resistivity and a higher operating frequency of the synthesized magnets. Mn-Zn ferrite coated samples have higher permeability and lower magnetic loss when compared with the non-magnetic epoxy resin coated compacts. The real part of permeability increases by 33.5% when compared with the epoxy resin coated samples at 10 kHz. The effects of heat treatment temperature on crystalline phase formation and on the magnetic properties of the Mn-Zn ferrite were investigated via X-ray diffraction and a vibrating sample magnetometer. Ferrites decomposed to FeO and MnO after annealing above 400 °C in nitrogen; thus it is the optimum annealing temperature to attain the desired permeability.

  10. Failure processes in soft and quasi-brittle materials with nonhomogeneous microstructures

    Science.gov (United States)

    Spring, Daniel W.

    Material failure pervades the fields of materials science and engineering; it occurs at various scales and in various contexts. Understanding the mechanisms by which a material fails can lead to advancements in the way we design and build the world around us. For example, in structural engineering, understanding the fracture of concrete and steel can lead to improved structural systems and safer designs; in geological engineering, understanding the fracture of rock can lead to increased efficiency in oil and gas extraction; and in biological engineering, understanding the fracture of bone can lead to improvements in the design of bio-composites and medical implants. In this thesis, we numerically investigate a wide spectrum of failure behavior; in soft and quasi-brittle materials with nonhomogeneous microstructures considering a statistical distribution of material properties. The first topic we investigate considers the influence of interfacial interactions on the macroscopic constitutive response of particle reinforced elastomers. When a particle is embedded into an elastomer, the polymer chains in the elastomer tend to adsorb (or anchor) onto the surface of the particle; creating a region in the vicinity of each particle (often referred to as an interphase) with distinct properties from those in the bulk elastomer. This interphasial region has been known to exist for many decades, but is primarily omitted in computational investigations of such composites. In this thesis, we present an investigation into the influence of interphases on the macroscopic constitutive response of particle filled elastomers undergoing large deformations. In addition, at large deformations, a localized region of failure tends to accumulate around inclusions. To capture this localized region of failure (often referred to as interfacial debonding), we use cohesive zone elements which follow the Park-Paulino-Roesler traction-separation relation. To account for friction, we present a new

  11. Temperature dependence of microwave absorption phenomena in single and biphase soft magnetic microwires

    Czech Academy of Sciences Publication Activity Database

    El Kammouni, R.; Vázquez, M.; Lezama, L.; Kurlyandskaya, G.; Kraus, Luděk

    2014-01-01

    Roč. 368, Nov (2014), 126-132 ISSN 0304-8853 Institutional support: RVO:68378271 Keywords : magnetic microwire * ferromagnetic resonance * microwave absorption * biphase magnetic system Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.970, year: 2014

  12. Soft tissue segmentation and 3D display from computerized tomography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Fan, R.T.; Trivedi, S.S.; Fellingham, L.L.; Gamboa-Aldeco, A.; Hedgcock, M.W.

    1987-01-01

    Volume calculation and 3D display of human anatomy facilitate a physician's diagnosis, treatment, and evaluation. Accurate segmentation of soft tissue structures is a prerequisite for such volume calculations and 3D displays, but segmentation by hand-outlining structures is often tedious and time-consuming. In this paper, methods based on analysis of statistics of image gray level are applied to segmentation of soft tissue in medical images, with the goal of making segmentation automatic or semi-automatic. The resulting segmented images, volume calculations, and 3D displays are analyzed and compared with results based on physician-drawn outlines as well as actual volume measurements

  13. Science and technology of reduced-dimensional magnetic materials

    International Nuclear Information System (INIS)

    Heffner, R.H.; Bishop, A.R.; Hundley, M.F.; Jia, Q.; Neumeier, J.J.; Trugman, S.A.; Thompson, J.D.; Wu, X.D.; Zhang, J.

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This work involved the synthesis of single crystal and thin film samples of magnetoresistive manganites (LaMnO 3 doped with Ca and Sr) and the characterization of their electronic transport properties to understand the underlying physical mechanisms responsible for the colossal magnetoresistance (CMR) of these materials. The experimental program was supplemented by a modeling effort that sought to develop microscopic mathematical models of the observed phenomena. The authors succeeded in finding an important relation between the magnetization and resistivity in these materials, which helps to explain the importance of lattice distortions accompanied by clusters of ferromagnetic spins (called spin-lattice polarons) in the CMR phenomena. In addition, they developed rudimentary tunnel junctions of CMR-insulator-CMR multilayers that will lead to possible applications of these materials as magnetic sensors

  14. Nanomodified heat-accumulating materials controlled by a magnetic field

    Science.gov (United States)

    Shchegolkov, Alexander; Shchegolkov, Alexey; Dyachkova, Tatyana; Bodin, Nikolay; Semenov, Alexander

    2017-11-01

    The paper presents studies of nanomodified heat-accumulating materials controlled by a magnetic field. In order to obtain controlled heat-accumulating materials, synthetic motor oil CASTROL 0W30, ferromagnetic particles, CNTs and paraffin were used. Mechanically activated carbon nanotubes with ferromagnetic particles were used for the nanomodification of paraffin. Mechanoactivation ensured the production of ferromagnetic particles with an average particle size of 5 µm. Using an extrusion plant, a mixture of CNTs and ferromagnetic particles was introduced into the paraffin. Further, the nanomodified paraffin in a granular form was introduced into synthetic oil. To conduct experimental studies, a contactless method for measuring temperature was used. The thermal contact control with the help of the obtained nanomodified material is possible with a magnetic induction of 1250 mT, and a heat flux of about 74 kW/m2 is provided at the same time.

  15. Recovery of material parameters of soft hyperelastic tissue by an inverse spectral technique

    KAUST Repository

    Gou, Kun; Joshi, Sunnie; Walton, Jay R.

    2012-01-01

    An inverse spectral method is developed for recovering a spatially inhomogeneous shear modulus for soft tissue. The study is motivated by a novel use of the intravascular ultrasound technique to image arteries. The arterial wall is idealized as a

  16. High-throughput search for new permanent magnet materials.

    Science.gov (United States)

    Goll, D; Loeffler, R; Herbst, J; Karimi, R; Schneider, G

    2014-02-12

    The currently highest-performance Fe-Nd-B magnets show limited cost-effectiveness and lifetime due to their rare-earth (RE) content. The demand for novel hard magnetic phases with more widely available RE metals, reduced RE content or, even better, completely free of RE metals is therefore tremendous. The chances are that such materials still exist given the large number of as yet unexplored alloy systems. To discover such phases, an elaborate concept is necessary which can restrict and prioritize the search field while making use of efficient synthesis and analysis methods. It is shown that an efficient synthesis of new phases using heterogeneous non-equilibrium diffusion couples and reaction sintering is possible. Quantitative microstructure analysis of the domain pattern of the hard magnetic phases can be used to estimate the intrinsic magnetic parameters (saturation polarization from the domain contrast, anisotropy constant from the domain width, Curie temperature from the temperature dependence of the domain contrast). The probability of detecting TM-rich phases for a given system is high, therefore the approach enables one to scan through even higher component systems with one single sample. The visualization of newly occurring hard magnetic phases via their typical domain structure and the correlation existing between domain structure and intrinsic magnetic properties allows an evaluation of the industrial relevance of these novel phases.

  17. Magnetic and material limiter discharges in Tokapole II

    International Nuclear Information System (INIS)

    Moyer, R.A.

    1988-01-01

    Disruptive instabilities have been studied in Tokapole II, a small poloidal divertor tokamak, in magnetic and material limiter configurations. In the magnetic limiter configuration, the divertor separatrix defines the tokamak current channel boundary. Limiters or neutralizer plates are not used to remove plasma in the scrape-off region. The relatively hot, dense plasma in the scrape-off region carries 5--20% of the current. In the material limiter configuration, limiter plates are inserted to the separatrix to remove plasma and current in the scrape-off region. The plates vary the tokamak current channel boundary condition in a controlled manner, and provide a benchmark for comparison with other tokamaks. Internal and external disruptions have been studied, and several unique features in the magnetic limiter configuration have been identified. The magnitic limiter configuration enables routine passing of the stability barriers at q(a) = 2 and q(a) = 1, where q(a) is the the edge safety factor, without a close fitting wall, external windings, or detailed profile control techniques. Passing the q(a) = 1 barrier permits operation in the q < 1 regime where total reconnection of the sawtooth does not occur. Discharges with q < 1 are also obtained in the material limiter configuration, suggesting that partial reconnection is characteristic of the sawteeth, and not the magnetic limiter configuration. The magnetic limiter configuration suppresses current termination in a major disruption. Current termination occurs in material limiter discharges due to enhanced interaction with the inboard limiter following the post-disruptive shift in major radius

  18. Ni-based nanoalloys: Towards thermally stable highly magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Palagin, Dennis, E-mail: dennis.palagin@chem.ox.ac.uk; Doye, Jonathan P. K. [Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ (United Kingdom)

    2014-12-07

    Molecular dynamics simulations and density functional theory calculations have been used to demonstrate the possibility of preserving high spin states of the magnetic cores within Ni-based core-shell bimetallic nanoalloys over a wide range of temperatures. We show that, unlike the case of Ni–Al clusters, Ni–Ag clusters preserve high spin states (up to 8 μ{sub B} in case of Ni{sub 13}Ag{sub 32} cluster) due to small hybridization between the electronic levels of two species. Intriguingly, such clusters are also able to maintain geometrical and electronic integrity of their cores at temperatures up to 1000 K (e.g., for Ni{sub 7}Ag{sub 27} cluster). Furthermore, we also show the possibility of creating ordered arrays of such magnetic clusters on a suitable support by soft-landing pre-formed clusters on the surface, without introducing much disturbance in geometrical and electronic structure of the cluster. We illustrate this approach with the example of Ni{sub 13}Ag{sub 38} clusters adsorbed on the Si(111)–(7×7) surface, which, having two distinctive halves to the unit cell, acts as a selective template for cluster deposition.

  19. Soft X-ray imaging of thick carbon-based materials using the normal incidence multilayer optics.

    Science.gov (United States)

    Artyukov, I A; Feschenko, R M; Vinogradov, A V; Bugayev, Ye A; Devizenko, O Y; Kondratenko, V V; Kasyanov, Yu S; Hatano, T; Yamamoto, M; Saveliev, S V

    2010-10-01

    The high transparency of carbon-containing materials in the spectral region of "carbon window" (lambda approximately 4.5-5nm) introduces new opportunities for various soft X-ray microscopy applications. The development of efficient multilayer coated X-ray optics operating at the wavelengths of about 4.5nm has stimulated a series of our imaging experiments to study thick biological and synthetic objects. Our experimental set-up consisted of a laser plasma X-ray source generated with the 2nd harmonics of Nd-glass laser, scandium-based thin-film filters, Co/C multilayer mirror and X-ray film UF-4. All soft X-ray images were produced with a single nanosecond exposure and demonstrated appropriate absorption contrast and detector-limited spatial resolution. A special attention was paid to the 3D imaging of thick low-density foam materials to be used in design of laser fusion targets.

  20. Images of soft materials: a 3D visualization of interior of the sample in terms of attenuation coefficient

    International Nuclear Information System (INIS)

    Golosio, B.; Brunetti, A.; Cesareo, R.; Amendolia, S.R.; Rao, D.V.; Seltzer, S.M.

    2001-01-01

    Images of soft materials are obtained using image intensifier based X-ray system (Rao et al., Nucl. Instr. and Meth. A 437 (1999) 141). The interior of the soft material is visualized using the novel software in order to know the distribution of attenuation coefficient in terms of density. The novel software is based mainly on graphical library and applicable to several operating systems without any change. It can be applied to several applications starting from biomedical to industries, for example, quality control. The results for walnut and brew tooth are presented as a set of images from the internal parts of the sample. A description of the principal parameters required for tomographic visualization is given and some results based on this technique are reported and discussed