Fabrication, characterization and comparison of composite magnetic materials for high efficiency integrated voltage regulators with embedded magnetic core micro-inductors

International Nuclear Information System (INIS)

Bellaredj, Mohamed L F; Mueller, Sebastian; Davis, Anto K; Swaminathan, Madhavan; Mano, Yasuhiko; Kohl, Paul A

2017-01-01

High-efficiency integrated voltage regulators (IVRs) require the integration of power inductors, which have low loss and reduced size at very high frequency. The use of a magnetic material core can reduce significantly the inductor area and simultaneously increase the inductance. This paper focuses on the fabrication, characterization and modeling of nickel zinc (NiZn) ferrite and carbonyl iron powder (CIP)-epoxy magnetic composite materials, which are used as the magnetic core materials of embedded inductors in a printed wiring board (PWB) for a system in package (SIP) based buck type IVR. The fabricated composite materials and process are fully compatible with FR4 epoxy resin prepreg and laminate. For 85% weight loading of the magnetic powder (around 100 MHz at room temperature), the composite materials show a relative permeability of 7.5–8.1 for the NiZn ferrite composite and 5.2–5.6 for the CIP composite and a loss tangent value of 0.24–0.28 for the NiZn ferrite composite and 0.09–0.1 for the CIP-composite. The room temperature saturation flux density values are 0.1351 T and 0.5280 T for the NiZn ferrite and the CIP composites, respectively. The frequency dispersion parameters of the magnetic composites are modeled using a simplified Lorentz and Landau–Lifshitz–Gilbert equation for a Debye type relaxation. Embedded magnetic core solenoid inductors were designed based on the composite materials for the output filter of a high-efficiency SIP based buck type IVR. Evaluation of a SIP based buck type IVR with the designed inductors shows that it can reach peak efficiencies of 91.7% at 11 MHz for the NiZn ferrite-composite, 91.6% at 14 MHz for CIP-composite and 87.5% (NiZn ferrite-composite) and 87.3% (CIP-composite) efficiency at 100 MHz for a 1.7 V:1.05 V conversion. For a direct 5 V:1 V conversion using a stacked topology, a peak efficiency of 82% at 10 MHz and 72% efficiency at 100 MHz can be achieved for both materials. (paper)

Fabrication, characterization and comparison of composite magnetic materials for high efficiency integrated voltage regulators with embedded magnetic core micro-inductors

Science.gov (United States)

Bellaredj, Mohamed L. F.; Mueller, Sebastian; Davis, Anto K.; Mano, Yasuhiko; Kohl, Paul A.; Swaminathan, Madhavan

2017-11-01

High-efficiency integrated voltage regulators (IVRs) require the integration of power inductors, which have low loss and reduced size at very high frequency. The use of a magnetic material core can reduce significantly the inductor area and simultaneously increase the inductance. This paper focuses on the fabrication, characterization and modeling of nickel zinc (NiZn) ferrite and carbonyl iron powder (CIP)-epoxy magnetic composite materials, which are used as the magnetic core materials of embedded inductors in a printed wiring board (PWB) for a system in package (SIP) based buck type IVR. The fabricated composite materials and process are fully compatible with FR4 epoxy resin prepreg and laminate. For 85% weight loading of the magnetic powder (around 100 MHz at room temperature), the composite materials show a relative permeability of 7.5-8.1 for the NiZn ferrite composite and 5.2-5.6 for the CIP composite and a loss tangent value of 0.24-0.28 for the NiZn ferrite composite and 0.09-0.1 for the CIP-composite. The room temperature saturation flux density values are 0.1351 T and 0.5280 T for the NiZn ferrite and the CIP composites, respectively. The frequency dispersion parameters of the magnetic composites are modeled using a simplified Lorentz and Landau-Lifshitz-Gilbert equation for a Debye type relaxation. Embedded magnetic core solenoid inductors were designed based on the composite materials for the output filter of a high-efficiency SIP based buck type IVR. Evaluation of a SIP based buck type IVR with the designed inductors shows that it can reach peak efficiencies of 91.7% at 11 MHz for the NiZn ferrite-composite, 91.6% at 14 MHz for CIP-composite and 87.5% (NiZn ferrite-composite) and 87.3% (CIP-composite) efficiency at 100 MHz for a 1.7 V:1.05 V conversion. For a direct 5 V:1 V conversion using a stacked topology, a peak efficiency of 82% at 10 MHz and 72% efficiency at 100 MHz can be achieved for both materials.

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).

Characterization of steel grit recovered from ornamental rocks waste by magnetic separation

International Nuclear Information System (INIS)

Junca, E.; Telles, V.B.; Rodrigues, G.F.; Oliveira, J.R. de; Tenorio, J.A.S.

2010-01-01

The aim of this work is characterization of steel grit recovered from ornamental rock waste by magnetic separation. The magnetic separation was realized in three steps: first, using a high intensity wet magnetic separator, which used only the remaining magnetic field of equipment. In the second step, the magnetic material obtained in the first phase was subjected to a new manual magnetic separation using rare earth magnets. In a third step, magnetic material obtained with rare earth magnets was subjected to manual magnetic separation using ferrite magnets. After the magnetic separation, the material was sent to characterization which was obtained by chemical analysis, scanning electron microscopy, X-ray diffraction and size analysis. The size analysis showed that the concentrate range from 0,5 to 563,67 μm with 4 wt.% over 100 μm and content metallic iron of 93 wt%. (author)

Characterization of Nanophase Materials

Science.gov (United States)

Wang, Zhong Lin

2000-01-01

Engineering of nanophase materials and devices is of vital interest in electronics, semiconductors and optics, catalysis, ceramics and magnetism. Research associated with nanoparticles has widely spread and diffused into every field of scientific research, forming a trend of nanocrystal engineered materials. The unique properties of nanophase materials are entirely determined by their atomic scale structures, particularly the structures of interfaces and surfaces. Development of nanotechnology involves several steps, of which characterization of nanoparticles is indespensable to understand the behavior and properties of nanoparticles, aiming at implementing nanotechnolgy, controlling their behavior and designing new nanomaterials systems with super performance. The book will focus on structural and property characterization of nanocrystals and their assemblies, with an emphasis on basic physical approach, detailed techniques, data interpretation and applications. Intended readers of this comprehensive reference work are advanced graduate students and researchers in the field, who are specialized in materials chemistry, materials physics and materials science.

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.)

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)

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.

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)

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.

Electronic, electrical and magnetic ceramics synthesis and characterization

International Nuclear Information System (INIS)

Calix, V.S.; Saligan, P.P.; Naval, P.C.

1989-01-01

This paper describes the research and development activities of the Philippine Nuclear Research Institute (PNRI) on the synthesis and characterization of soft and hard ferrites and some beta alumina type superionic conductor materials. XRD, XRF and Moessbauer effect spectrometry are used to determine the structure phases, compositions and some magnetic properties of the materials. Effects of composition and preparation methods on the bulk electronic and magnetic properties are also discussed. (Auth.). 6 figs.; 3 tabs

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.

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.)

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

Magnetic structures synthesized by controlled oxidative etching: Structural characterization and magnetic behavior

Directory of Open Access Journals (Sweden)

Álvaro de Jesús Ruíz-Baltazar

Full Text Available A facile strategy for the fabrication Fe3O4 nanostructures at room temperature and with well-defined morphology is proposed. In this methodology, the iron precursors were reduced by sodium borohydride. Subsequently an oxidative etching process promotes the formation of Fe2O3 nanostructures. Magnetic measurements revealed a well-defined superparamagnetic behavior for the material. The Zero-Field-Cooled (ZFC and Field-Cooled (FC magnetization curves reveals that critical and blocking temperature were 24 and 350 °C respectively. The Fe3O4 nanostructures were characterized using aberration-corrected (Cs scanning transmission electron microscopy (STEM and energy dispersive spectroscopy (EDS. Additionally, Raman spectra support the Fe3O4 presence and corroborate the efficiency of the synthesis process to obtain magnetite. Keywords: Chemical synthesis, Fe3O4 nanoparticles, Structural characterization, Magnetic properties

Rapid characterization of superconducting wires and tapes in strong pulsed magnetic fields

International Nuclear Information System (INIS)

Bockstal, L. van; Keyser, A. de; Deschagt, J.; Hopkins, S.C.; Glowacki, B.A.

2007-01-01

A new measurement system for rapid characterization of superconducting wires and tapes is developed. The CryoPulse-BI is a system to provide a direct measurement of critical material parameters for superconducting materials when high long pulsed magnetic fields and strong currents are applied. In the experiments, synchronized magnetic fields up to 30 T and current pulses up to 5 kA are generated with adjustable timing. Varying the magnetic field strength, the current through the sample and the BI timing allows for a thorough characterization of the sample and the determination of critical currents. The rapid cycle time of the experiments yields a rapid and thorough determination of the critical parameters. The method has been tested on low T c as well as high T c materials with the field parallel or perpendicular to the current. The discussion covers the current state of the art including a comparison of our results to classical DC characterization measurements

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.

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)

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.

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...

Synthesis and characterization of functional magnetic nanocomposites

Science.gov (United States)

Gass, J.; Sanders, J.; Srinath, S.; Srikanth, H.

2006-03-01

Magnetic nanoparticles and carbon nanotubes have been excellent functional materials that could be dispersed in polymer matrices for various applications. However, uniform dispersion of particles in polymers without agglomeration is quite challenging. We have fabricated PMMA/polypyrrole bilayer structures embedded with Fe3O4 magnetite nanoparticles synthesized using wet chemical synthesis. Agglomeration-free dispersion of nanoparticles was achieved by coating the particles with surfactants and by dissolving both the particles and PMMA in chlorobenzene. Structural characterization was done using XRD and TEM. Magnetic properties of the bilayer structures indicated superparamagnetic behavior that is desirable for RF applications as the magnetic losses are reduced. Our polymer nanocomposite bilayer films with conducting polymer coatings are potential candidates for tunable RF applications with integrated EMI suppression. We will also report on our studies of pumped ferrofluids flowing past carbon nanotubes that are arranged in microchannel arrays. Magnetization under various flow conditions is investigated and correlated with the hydrodynamic properties. This scheme provides a novel method of energy conversion and storage using nanocomposite materials.

Material properties and modeling characteristics for MnFeP1-xAsx materials for application in magnetic refrigeration

DEFF Research Database (Denmark)

Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Bahl, Christian R.H.

2013-01-01

and thermal hysteresis, and it is not well understood how the hysteresis will affect performance in a practical AMR device. The amount of hysteresis shown by a material can be controlled to an extent by tuning the processing conditions used during material synthesis; therefore, knowledge of the practical......Compounds of MnFeP1-xAsx have received attention recently for their use in active magnetic regenerators (AMR) because of their relatively high isothermal entropy change and adiabatic temperature change with magnetization. However, the materials also generally exhibit a significant magnetic...... impact of hysteresis is a key element to guide successful material development and synthesis. The properties of a magnetocaloric MnFeP1-xAsx compound are characterized as a function of temperature and applied magnetic field, and the results are used to assess the effects of hysteresis on magnetocaloric...

Synthesis, characterization and a.c. magnetic analysis of magnetite nanoparticles

International Nuclear Information System (INIS)

Riani, P.; Napoletano, M.; Canepa, F.

2011-01-01

In the last years, the study of Fe-based magnetic nanoparticles (MNP) has attracted increasing interest either for the physical properties shown by nanosized materials (electric and magnetic properties are strongly affected by dimension and surface effects) either for the different technological applications of these materials (catalysis, drug delivery, magnetic resonance imaging, contaminants removal from groundwater, new exchange coupled magnets, soft nanomagnets for high frequency applications, etc.). In this article, the results obtained in the synthesis and characterization of the Fe 3 O 4 MNP is reported. The magnetite nanoparticles were synthesized by a modified Massart method. Structural characterization was performed using X-ray diffraction analysis and a complete morphological and dimensional study was carried out by means of Transmission Electron Microscopy, and a.c. magnetic susceptibility measured as a function of the frequency of the applied magnetic field. Diameters of the superparamagnetic Fe 3 O 4 nanoparticles are ranging from 2 to 10 nm, as evidenced by all the techniques employed. The size distribution of the hydrated aggregates in solution has been obtained by quantitative analysis of the frequency dependence of the a.c. susceptibility. The mathematical approach adopted will be described and all the obtained results will be compared and discussed.

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

OBTAINING HYSTERESIS LOOPS AT LOW FREQUENCY FOR CHARACTERIZATION OF MATERIALS TO BE USED IN BIOMEDICAL APPLICATIONS

Directory of Open Access Journals (Sweden)

Atika Arshad

2015-05-01

Full Text Available The promising development of magnetic sensors in biomedical field demands an appropriate level of understanding of the magnetic properties of the materials used in their fabrication. To date only few of the types of magnetic materials are encountered where their magnetic properties, characterization techniques and magnetization behavior are yet to be explored more suitably in the light of their applications. This research work studies the characterization of materials by using a cost effective and simple circuit consisting of inductive transducer and an OP-AMP as a voltage integrator. In this approach the circuit was simulated using PSPICE and experiments have been conducted to achieve the desired results. The simulation and experimental results are obtained for three test materials namely iron, steel and plastic. The novelty lies in applying the simple circuit for material testing and characterization via obtaining simulation results and validating these results through experiment. The magnetic properties in low external magnetic field are studied with materials under test. The magnetization effect of a magneto-inductive sensor is detected in low frequency range for different magnetic core materials. The results have shown magnetization behaviour of magnetic materials due to the variation of permeability and magnetism. The resulted hysteresis loops appeared to have different shapes for different materials. The magnetic hysteresis loop found for iron core demonstrated a bigger coercive force and larger reversals of magnetism than these of steel core, thus obtaining its magnetic saturation at a larger magnetic field strength. The shape of the hysteresis loop itself is found to be varying upon the nature of the material in use. The resulted magnetization behaviors of the materials proved their possible applicability for use in sensing devices. The key concern of this work is found upon selecting the appropriate magnetic materials at the desired

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...

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...

VISCOSE BASED MAGNETIC YARNS – PHYSICAL AND MECHANICAL CHARACTERIZATION

Directory of Open Access Journals (Sweden)

GROSU Marian-Cătălin

2017-05-01

Full Text Available In the context of the rapid growth in the number of electrical and electronic devices and accessories that emit electromagnetic energy in different frequency bands we present and characterize here several magnetic functionalized viscose twisted yarns. A 100% viscose twisted staple yarn was covered through an in-house developed process with a polymeric solution containing micrometric sized barium hexaferrite magnetic powder. The in-house developed process allows deposition of micrometric thickness polymeric paste layer on the yarn surface. Barium hexaferrite is a hard magnetic material exhibiting high chemical stability and corrosion resistivity, relatively large saturation and residual magnetization and microwave absorbing properties. Five different percentages of the magnetic powder in the polymer solution were used, i.e. ranging from 15 wt% to 45 wt%. Physical characterization shows a very good adherence between the highly hygroscopic viscose staple fibers and the polymeric solution that contains polyvinyl acetate and polyurethane as binders. SEM images evidenced the fact that the polymeric solution penetrated more than 1/3 of the yarn diameter. The concentration of magnetic powder in the polymeric solution has a direct influence on the coating amount, diameter and density. The mechanical characterization of the coated yarns revealed that the breaking force is increasing with increasing magnetic powder content up to o certain value and then decreased because the magnetic layer became stiffer. At the same time, the elongation at brake is decreasing.

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...

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)

Composite particles formed by complexation of poly(methacrylic acid) - stabilized magnetic fluid with chitosan: Magnetic material for bioapplications.

Science.gov (United States)

Safarik, Ivo; Stepanek, Miroslav; Uchman, Mariusz; Slouf, Miroslav; Baldikova, Eva; Nydlova, Leona; Pospiskova, Kristyna; Safarikova, Mirka

2016-10-01

A simple procedure for the synthesis of magnetic fluid (ferrofluid) stabilized by poly(methacrylic acid) has been developed. This ferrofluid was used to prepare a novel type of magnetically responsive chitosan-based composite material. Both ferrofluid and magnetic chitosan composite were characterized by a combination of microscopy (optical microscopy, TEM, SEM), scattering (static and dynamic light scattering, SANS) and spectroscopy (FTIR) techniques. Magnetic chitosan was found to be a perspective material for various bioapplications, especially as a magnetic carrier for immobilization of enzymes and cells. Lipase from Candida rugosa was covalently attached after cross-linking and activation of chitosan using glutaraldehyde. Baker's yeast cells (Saccharomyces cerevisiae) were incorporated into the chitosan composite during its preparation; both biocatalysts were active after reaction with appropriate substrates. Copyright © 2016 Elsevier B.V. All rights reserved.

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

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.

Nanoscale magnetic characterization of tunneling magnetoresistance spin valve head by electron holography.

Science.gov (United States)

Park, Hyun Soon; Hirata, Kei; Yanagisawa, Keiichi; Ishida, Yoichi; Matsuda, Tsuyoshi; Shindo, Daisuke; Tonomura, Akira

2012-12-07

Nanostructured magnetic materials play an important role in increasing miniaturized devices. For the studies of their magnetic properties and behaviors, nanoscale imaging of magnetic field is indispensible. Here, using electron holography, the magnetization distribution of a TMR spin valve head of commercial design is investigated without and with a magnetic field applied. Characterized is the magnetic flux distribution in complex hetero-nanostructures by averaging the phase images and separating their component magnetic vectors and electric potentials. The magnetic flux densities of the NiFe (shield and 5 nm-free layers) and the CoPt (20 nm-bias layer) are estimated to be 1.0 T and 0.9 T, respectively. The changes in the magnetization distribution of the shield, bias, and free layers are visualized in situ for an applied field of 14 kOe. This study demonstrates the promise of electron holography for characterizing the magnetic properties of hetero-interfaces, nanostructures, and catalysts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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...

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, ...

The relationship between microstructure and magnetic properties in high-energy permanent magnets characterized by polytwinned structures

Science.gov (United States)

This report summarizes the results of a study of the relationship between microstructure and magnetic properties in a unique genre of ferromagnetic material characterized by a polysynthetically twinned structure which arises during solid state transformation. These results stem from the work over a period of approximately 27 months of a nominal 3 year grant period. The report also contains a proposal to extend the research project for an additional 3 years. The polytwinned structures produce an inhomogeneous magnetic medium in which the easy axis of magnetization varies quasi-periodically giving rise to special domain configurations which are expected to markedly influence the mechanism of magnetization reversal and hysteresis behavior of these materials in bulk or thin films. The extraordinary permanent magnet properties exhibited by the well-known Co-Pt alloys as well as the Fe-Pt and Fe-Pd systems near the equiatomic composition derive from the formation of a polytwinned microstructure.

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

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

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.

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.

Optical fiber magnetic field sensors with TbDyFe magnetostrictive thin films as sensing materials.

Science.gov (United States)

Yang, Minghong; Dai, Jixiang; Zhou, Ciming; Jiang, Desheng

2009-11-09

Different from usually-used bulk magnetostrictive materials, magnetostrictive TbDyFe thin films were firstly proposed as sensing materials for fiber-optic magnetic field sensing characterization. By magnetron sputtering process, TbDyFe thin films were deposited on etched side circle of a fiber Bragg Grating (FBG) as sensing element. There exists more than 45pm change of FBG wavelength when magnet field increase up to 50 mT. The response to magnetic field is reversible, and could be applicable for magnetic and current sensing.

Polydimethylsiloxane films doped with NdFeB powder: magnetic characterization and potential applications in biomedical engineering and microrobotics.

Science.gov (United States)

Iacovacci, V; Lucarini, G; Innocenti, C; Comisso, N; Dario, P; Ricotti, L; Menciassi, A

2015-12-01

This work reports the fabrication, magnetic characterization and controlled navigation of film-shaped microrobots consisting of a polydimethylsiloxane-NdFeB powder composite material. The fabrication process relies on spin-coating deposition, powder orientation and permanent magnetization. Films with different powder concentrations (10 %, 30 %, 50 % and 70 % w/w) were fabricated and characterized in terms of magnetic properties and magnetic navigation performances (by exploiting an electromagnet-based platform). Standardized data are provided, thus enabling the exploitation of these composite materials in a wide range of applications, from MEMS/microrobot development to biomedical systems. Finally, the possibility to microfabricate free-standing polymeric structures and the biocompatibility of the proposed composite materials is demonstrated.

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)

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)

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)

Synthesis and characterization of montmorillonite clay intercalated with molecular magnetic compounds

Energy Technology Data Exchange (ETDEWEB)

Martins, Marcel G.; Martins, Daniel O.T.A.; Carvalho, Beatriz L.C. de [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Mercante, Luiza A. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação, São Carlos, SP 13560 970 (Brazil); Soriano, Stéphane [Instituto de Física, Universidade Federal Fluminense, Niterói, RJ 24.210 346 (Brazil); Andruh, Marius [Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Str. Dumbrava Rosie nr. 23, Bucharest (Romania); Vieira, Méri D., E-mail: gqimeri@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Vaz, Maria G.F., E-mail: mariavaz@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil)

2015-08-15

In this work montmorillonite (MMT) clay, whose matrix was modified with an ammonium salt (hexadecyltrimethylammonium bromide – CTAB), was employed as an inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange: a nitronyl nitroxide derivative 2-[4-(N-ethyl)-pyridinium]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (p-EtRad{sup +}) and two binuclear coordination compounds, [Ni(valpn)Ln]{sup 3+}, where H{sub 2}valpn stands for 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol), and Ln=Gd{sup III}; Dy{sup III}. The pristine MMT and the intercalated materials were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and magnetic measurements. The X-ray diffraction data analysis showed an increase of the interlamellar space of the intercalated MMT, indicating the intercalation of the magnetic compounds. Furthermore, the magnetic properties of the hybrid compounds were investigated, showing similar behavior as the pure magnetic guest species. - Graphical abstract: Montmorillonite clay was employed as inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange - Highlights: • Montmorillonite was employed as a host material. • Three molecular magnetic compounds were intercalated through ion exchange. • The compounds were successful intercalated maintaining the layered structure. • The hybrid materials exhibited similar magnetic behavior as the pure magnetic guest.

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.

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

Anisotropic characterization of magnetorheological materials

Energy Technology Data Exchange (ETDEWEB)

Dohmen, E., E-mail: eike.dohmen@tu-dresden.de; Modler, N.; Gude, M.

2017-06-01

For the development of energy efficient lightweight parts novel function integrating materials are needed. Concerning this field of application magnetorheological (MR) fluids, MR elastomers and MR composites are promising materials allowing the adjustment of mechanical properties by an external magnetic field. A key issue for operating such structures in praxis is the magneto-mechanical description. Most rheological properties are gathered at laboratory conditions for high magnetic flux densities and a single field direction, which does not correspond to real praxis conditions. Although anisotropic formation of superstructures can be observed in MR suspensions (Fig. 1) or experimenters intentionally polymerize MR elastomers with anisotropic superstructures these MR materials are usually described in an external magnetic field as uniform, isotropic materials. This is due to missing possibilities for experimentally measuring field angle dependent properties and ways of distinguishing between material properties and frictional effects. Just a few scientific works experimentally investigated the influence of different field angles (Ambacher et al., 1992; Grants et al., 1990; Kuzhir et al., 2003) or the influence of surface roughness on the shear behaviour of magnetic fluids (Tang and Conrad, 1996) . The aim of this work is the introduction of a novel field angle cell allowing the determination of anisotropic mechanical properties for various MR materials depending on the applied magnetic field angle. - Highlights: • Novel magnetic field angle testing device (MFATD) presented. • Determination of magnetic field dependent anisotropic mechanical properties. • Experimental data for different field directions shown for a commercial MR fluid. • Material description of MR fluids as transversal-isotropic solids. • Magnetic field angle dependent variations in shear stresses experimentally measured. • Determination of frictional coefficients between the MR fluid and

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.

Synthesis and characterization of magnetic cobalt ferrite nanoparticles covered with 3-aminopropyltriethoxysilane for use as hybrid material in nano technology

International Nuclear Information System (INIS)

Camilo, Ruth Luqueze

2006-01-01

Nowadays with the appear of nano science and nano technology, magnetic nanoparticles have been finding a variety of applications in the fields of biomedicine, diagnosis, molecular biology, biochemistry, catalysis, etc. The magnetic functionalized nanoparticles are constituted of a magnetic nucleus, involved by a polymeric layer with active sites, which ones could anchor metals or selective organic compounds. These nanoparticles are considered organic inorganic hybrid materials and have great interest as materials for commercial applications due to the specific properties. Among the important applications it can be mentioned: magneto hyperthermia treatment, drugs delivery in specific local of the body, molecular recognition, biosensors, enhancement of nuclear magnetic resonance images quality, etc. This work was developed in two parts: 1) the synthesis of the nucleus composed by superparamagnetic nanoparticles of cobalt ferrite and, 2) the recovering of nucleus by a polymeric bifunctional 3-aminopropyltriethoxysilane. The parameters studied in the first part of the research were: pH, hydroxide molar concentration, hydroxide type, reagent order of addition, reagent way of addition, speed of shake, metals initial concentrations, molar fraction of cobalt and thermal treatment. In the second part it was studied: pH, temperature, catalyst type, catalyst concentration, time of reaction, relation ratios of H 2 O/silane, type of medium and the efficiency of the recovering regarding to pH. The products obtained were characterized using the following techniques X-ray powder diffraction (DRX), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), spectroscopy of scatterbrained energy spectroscopy (DES), atomic emission spectroscopy (ICP-AES), thermogravimetric analysis (TGA/DTGA), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and magnetization curves (VSM). (author)

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)

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

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

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.

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.

Practical materials characterization

CERN Document Server

2014-01-01

Presents cross-comparison between materials characterization techniquesIncludes clear specifications of strengths and limitations of each technique for specific materials characterization problemFocuses on applications and clear data interpretation without extensive mathematics

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...

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.

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.

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

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...

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.

Structural and magnetic characterization of the new GdMn1-xFexO3 perovskite material

International Nuclear Information System (INIS)

Vasquez, J A Cardona; Téllez, D A Landínez; Rojas, J Roa; Collazos, C A

2016-01-01

In this paper we presents the synthesis process of the GdMn 1-x Fe x O 3 perovskite material by conventional solid state reaction method. Crystalline phase evolution during the synthesis was studied by X-ray Diffraction (XRD) in powder of the materials, observing that the chemical reaction of the precursor oxides was significant above 1000°C. Rietveld refinement of DRX patterns shows a perovskite structure with octahedral distortions (space group Pbnm, # 62) for studied values of x (0, 0.1 and 0.2). The degree of substitution generates an increasing tendency on lattice parameters a and c, while for b is decreasing just as for the volume of the unit cell. The effect of the change in the lattice parameters directly affects the octahedral distortions, ie, with increasing degree of substitution (increased parameter c) octahedra tend to arrange one above the other aligned with the c axis. Magnetization measurements as a function of temperature were performed above room temperature between 300K and 860K with an applied field of 20Oe and below room temperature in Field Cooling (FC) and Zero Field Cooling modes (ZFC) between 4.2K and 300K with an applied field of 200Oe. Magnetic behavior above room temperature is paramagnetic for used values of x, on the other hand at low temperatures (T<30K) magnetic phase transitions associated to the apparition of an antiferromagnetic phase are observed. In addition for x=0.1 the derivative of magnetization shows a peak around 31K, associated to the ferrimagnetic transition for this material. Curie-Weiss fit reveals the antiferromagnetic (ferrimagnetic) behavior of the materials, also shows that the configurations with x=0 and x=0.2 have an effective magnetic moment very similar to the reported value of undoped material, while for x=0.1 a higher value is observed confirming the ferrimagnetic behavior of this configuration. (paper)

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

Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction

International Nuclear Information System (INIS)

Silva, Amanda Luzia da; Oliveira, Arno Heeren de; Fernandes, Maria Lourdes Souza

2013-01-01

The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Silva, Amanda Luzia da; Oliveira, Arno Heeren de; Fernandes, Maria Lourdes Souza, E-mail: amanda@igc.ufmg.br, E-mail: heeren@nuclear.ufmg.br, E-mail: amanda@igc.ufmg.br, E-mail: lurdesfernandes@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horionte, MG (Brazil)

2013-07-01

The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

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

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.

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.

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

Single step synthesis, characterization and applications of curcumin functionalized iron oxide magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Bhandari, Rohit; Gupta, Prachi; Dziubla, Thomas; Hilt, J. Zach, E-mail: zach.hilt@uky.edu

2016-10-01

Magnetic iron oxide nanoparticles have been well known for their applications in magnetic resonance imaging (MRI), hyperthermia, targeted drug delivery, etc. The surface modification of these magnetic nanoparticles has been explored extensively to achieve functionalized materials with potential application in biomedical, environmental and catalysis field. Herein, we report a novel and versatile single step methodology for developing curcumin functionalized magnetic Fe{sub 3}O{sub 4} nanoparticles without any additional linkers, using a simple coprecipitation technique. The magnetic nanoparticles (MNPs) were characterized using transmission electron microscopy, X-ray diffraction, fourier transform infrared spectroscopy and thermogravimetric analysis. The developed MNPs were employed in a cellular application for protection against an inflammatory agent, a polychlorinated biphenyl (PCB) molecule. - Graphical abstract: Novel single step curcumin coated magnetic Fe{sub 3}O{sub 4} nanoparticles without any additional linkers for medical, environmental, and other applications. Display Omitted - Highlights: • A novel and versatile single step methodology for developing curcumin functionalized magnetic Fe{sub 3}O{sub 4} nanoparticles is reported. • The magnetic nanoparticles (MNPs) were characterized using TEM, XRD, FTIR and TGA. • The developed MNPs were employed in a cellular application for protection against an inflammatory agent, a polychlorinated biphenyl (PCB).

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...

Characterization of nanocomposite NdFeB permanent magnetic materials

International Nuclear Information System (INIS)

Mat Husin Salleh; Hussain, P.; Mohammad, M.; Abd Aziz Mohamed

2005-01-01

The following topics were discussed: Introduction to NdFeB magnet, grain size measurement using XRD (X-ray diffraction), FESEM , TEM (Transmission Electron Microscopy) and SANS (Small-angle Neutron Scattering). The objective of the project are to analyze the structure of nano-crystallite formed in the melt spun ribbons after annealing by XRD, FESEM,TEM and SANS, to study the magnetic properties of nano-composite NdFeB melt spun ribbons and their bonded magnet and possible usage in small motor to replace the conventional NdFeB bonded magnet

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

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

Low dimensional magnetism and nanograined materials - magnetometry, magnetooptics and laser-ultrasound

International Nuclear Information System (INIS)

Krenn, H.; Paltauf, G.; Rumpf, K.; Granitzer, P.; Kozhushko, V.; Nadeem, K.; Hofmayer, M.

2008-01-01

of the magnetism of porous FePd and FePt is investigated in collaboration with the TU Graz (Institute of Materials' Science). The electric charging of the compacted powder is performed by loading with an electrolyte and measuring the magnetic response by SQUID-magnetometry. Simulations of magneto-optic Kerr spectra are performed by M. Hofmayer (PhD) for InMnAs-, InMnSb- ferromagnetic semiconductors in quantizing magnetic fields in close cooperation with Univ. Bayreuth (H. Pascher) and Univ. of Notre Dame, USA (J. Furdyna). This modelling project is supported by the NAWI Graz cooperation with TU Graz. The available equipment at the location of the group consists of cryogenic facilities (cryostats, temperature controller), fiber optic sample holder, Nd:Yag solid state laser, time-resolving ultrasound prober, electrochemical cells for deposition using pulsed charging, potentiostat, SQUID-magnetometry, FTIR-spectrometry, time-resolved luminescence in VIS, MOKE-, Faraday-rotation, ESR-spectroscopy, detection and analysis of Barkhausen noise, versatile semiconductor probing device for magnetoresistance and Hall-effect, and Rapid Thermal Annealing (RTA) facility for 6'' silicon wafers. Furthermore structural characterizations are carried out in close collaboration with the TUG (Institute for Electron Microscopy, FELMI). The personnel consists of 2 permanent staff members (incl. the head), 3 Postdocs, 7 PhD's and 1 diploma student. Current projects are: FWF P18593: Ir/Regular magnetic nanowires in porous silicon; NFN-network S10407-N16: bulk-nanostructured materials: nondestructuve testing of nancrystalline materials by Barkhausen noise, ultrasound and magneto-optic Kerr effect; NAWI Graz cooperation project: magnetic and optic properties of nanocrystalline materials applied projects: Doktorats-Kolleg C53 nanostructured systems: self-assembly, hierarchical ordering and materials foundations, Sub-Projekt: C53.3 (H. Krenn): fabrication of self assembled ferromagnet

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

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

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,...

Structural, morphological and magnetic characterization of electrodeposited Co–Fe–W alloys

Energy Technology Data Exchange (ETDEWEB)

Noce, R. Della, E-mail: rodrnoce@iq.unesp.br [Instituto de Química, Universidade Estadual Paulista, UNESP, 14800-900 Araraquara, SP (Brazil); Benedetti, A.V.; Magnani, M. [Instituto de Química, Universidade Estadual Paulista, UNESP, 14800-900 Araraquara, SP (Brazil); Passamani, E.C. [Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória, ES (Brazil); Kumar, H.; Cornejo, D.R. [Instituto de Física, Universidade de São Paulo, USP, 05508-090 São Paulo, SP (Brazil); Ospina, C.A. [Electron Microscopy Laboratory, Brazilian Nanotechnology National Laboratory, 13083-970 Campinas, SP (Brazil)

2014-10-25

Highlights: • Small W additions (up to 9 at.%) to the Co{sub 35}Fe{sub 65} binary system. • Electrodeposited Co–Fe–W alloys characterization by XRD, SEM, TEM, Mössbauer spectroscopy and magnetic measurements. • Production of Co–Fe–W alloys with low values of coercivity and high saturation magnetization. • Potential materials for applications in magnetic devices such as read/write heads and hard disks. - Abstract: Structural, morphological and magnetic characterization of electrodeposited Co–Fe–W alloys, containing small amounts of W (up to 9 at.%), were performed using X-ray diffractometry, scanning (SEM) and transmission (TEM) electron microscopy, Mössbauer spectroscopy and magnetization measurements. Electrodeposited (Co{sub 100−x}Fe{sub x}){sub 100−y}W{sub y} films (x = 63–72 at.% Fe, y = 4–9 at.% W) were successfully produced varying the applied cathodic current density (i{sub c}) between 0.5 and 10 mA cm{sup −2}. X-ray diffraction results revealed a bcc-like structure for all studied compositions with average crystallite size ranging from 16 to 35 nm, as also confirmed by TEM results. SEM images indicated that needle-type morphology is dominant for the deposits containing lower W content (up to 4.5 at.%.), while a cauliflower-type behavior is observed for higher W content deposits. Room temperature Mössbauer spectra indicate the presence of two magnetic species for all samples; one component associated with an ordered Co–Fe–W fraction (crystalline grain core) and a magnetic disordered Co–Fe–W contribution, which can be attributed to the grain boundaries/grain surfaces. Magnetization was observed to be in the film plane along the film direction, except the sample prepared at i{sub c} = 10 mA cm{sup −2} that is slightly canted from in- to out-of-plane geometry. Magnetic measurements show high saturation magnetization values accompanied by low coercivity ones for the electrodeposited Co–Fe–W alloys, making these

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

Characterization of steel grit recovered from ornamental rocks waste by magnetic separation; Caracterizacao da granalha de aco recuperada do residuo de rochas ornamentais por separacao magnetica

Energy Technology Data Exchange (ETDEWEB)

Junca, E.; Telles, V.B.; Rodrigues, G.F.; Oliveira, J.R. de; Tenorio, J.A.S., E-mail: eduardojunca@gmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Metalurgica e de Materiais; Instituto Federal de Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil)

2010-07-01

The aim of this work is characterization of steel grit recovered from ornamental rock waste by magnetic separation. The magnetic separation was realized in three steps: first, using a high intensity wet magnetic separator, which used only the remaining magnetic field of equipment. In the second step, the magnetic material obtained in the first phase was subjected to a new manual magnetic separation using rare earth magnets. In a third step, magnetic material obtained with rare earth magnets was subjected to manual magnetic separation using ferrite magnets. After the magnetic separation, the material was sent to characterization which was obtained by chemical analysis, scanning electron microscopy, X-ray diffraction and size analysis. The size analysis showed that the concentrate range from 0,5 to 563,67 {mu}m with 4 wt.% over 100 {mu}m and content metallic iron of 93 wt%. (author)

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

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

Percolation Phenomena For New Magnetic Composites And Tim Nanocomposites Materials

Directory of Open Access Journals (Sweden)

Ahmed Thabet Mohamed

2015-01-01

Full Text Available This paper presents a theoretical investigation in order to obtain new composite and nanocomposite magnetic industrial materials. The effective conductivity and thermal effective conductivity have been predicted by adding various types and percentages of conductive particles (Al2O3, MgO, ZnO, Graphite etc. to the main matrices of Epoxy, Iron and Silicon for formulating new composite and nanocomposite industrial materials. The characterization of effective conductivity of new polymeric composites has been investigated with various applied forces, inclusion types and their concentrations. In addition, the effect of inclusion types and their concentrations on the effective thermal conductivities of thermal interface nanocomposite industrial materials has been explained and discussed.

Magnetic Levitation To Characterize the Kinetics of Free-Radical Polymerization.

Science.gov (United States)

Ge, Shencheng; Semenov, Sergey N; Nagarkar, Amit A; Milette, Jonathan; Christodouleas, Dionysios C; Yuan, Li; Whitesides, George M

2017-12-27

This work describes the development of magnetic levitation (MagLev) to characterize the kinetics of free-radical polymerization of water-insoluble, low-molecular-weight monomers that show a large change in density upon polymerization. Maglev measures density, and certain classes of monomers show a large change in density when monomers covalently join in polymer chains. MagLev characterized both the thermal polymerization of methacrylate-based monomers and the photopolymerization of methyl methacrylate and made it possible to determine the orders of reaction and the Arrhenius activation energy of polymerization. MagLev also made it possible to monitor polymerization in the presence of solids (aramid fibers, and carbon fibers, and glass fibers). MagLev offers a new analytical technique to materials and polymer scientists that complements other methods (even those based on density, such as dilatometry), and will be useful in investigating polymerizations, evaluating inhibition of polymerizations, and studying polymerization in the presence of included solid materials (e.g., for composite materials).

Study and Characterization of Magnetic Materials for Beam Intensity Monitors at CERN

CERN Document Server

AUTHOR|(CDS)2082768; Jones, Owain Rhodri

The number of particles in the beams used at CERN is measured by a family of devices called the Beam Current Transformers (BCTs). One of such devices is the DC Current Transformer (DCCT) measuring the total number of particles in an accelerator. The DCCT is built around a magnetic core made of a soft magnetic material. Currently, the DCCT cores are purchased from one of a few industrial partners. This situation might result in some significant issues with development of the DCCTs. Firstly, the choice of the core can be made only among the already developed and manufactured cores. Secondly, the industrial partners do not normally guarantee long-term availability of their products which could manifest itself as future maintenance problems. Thirdly, the cores available on the market have not been developed with CERN's intended application in mind and, hence, might be non-optimal for the DCCTs. These three factors, among others, led to a decision to investigate a possibility of in-house core manufacturing. BCT co...

Magnetically recoverable nanocatalysts

KAUST Repository

Polshettiwar, Vivek

2011-05-11

A broad overview on magnetically recoverable nanocatalysts is presented and the use of magnetic nanomaterials as catalysts is discussed. Magnetic materials are used as organocatalysts and their applications range to challenging reactions, such as hydroformylation and olefin metathesis. Magnetic nanomaterials are also being used in environmental applications, such as for photo- and biocatalysis and for the adsorption and removal of pollutants from air and water. These materials show great promise as enantioselective catalysts, which are used extensively for the synthesis of medicines, drugs, and other bioactive molecules. By functionalizing these materials using chiral ligands, a series of chiral nanocatalysts can be designed, offering great potential to reuse these otherwise expensive catalyst systems. Characterization of magnetic catalysts is often a challenging task, and NMR characterization of these catalysts is difficult because the magnetic nature of the materials interferes with the magnetic field of the spectrometer.

Magnetically recoverable nanocatalysts

KAUST Repository

Polshettiwar, Vivek; Luque, Rafael L.; Fihri, Aziz; Zhu, Haibo; Bouhrara, Mohamed; Basset, Jean-Marie

2011-01-01

A broad overview on magnetically recoverable nanocatalysts is presented and the use of magnetic nanomaterials as catalysts is discussed. Magnetic materials are used as organocatalysts and their applications range to challenging reactions, such as hydroformylation and olefin metathesis. Magnetic nanomaterials are also being used in environmental applications, such as for photo- and biocatalysis and for the adsorption and removal of pollutants from air and water. These materials show great promise as enantioselective catalysts, which are used extensively for the synthesis of medicines, drugs, and other bioactive molecules. By functionalizing these materials using chiral ligands, a series of chiral nanocatalysts can be designed, offering great potential to reuse these otherwise expensive catalyst systems. Characterization of magnetic catalysts is often a challenging task, and NMR characterization of these catalysts is difficult because the magnetic nature of the materials interferes with the magnetic field of the spectrometer.

Materials characterization techniques

National Research Council Canada - National Science Library

Zhang, Sam; Li, L; Kumar, Ashok

2009-01-01

"With an emphasis on practical applications and real-world case studies, Materials Characterization Techniques presents the principles of widely used advanced surface and structural characterization...

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

Synthesis and characterization of luminescence magnetic nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Kiplagat, Ayabei [DST/Mintek Nanotechnology Innovation Centre, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville (South Africa); Onani, Martin O., E-mail: monani@uwc.ac.za [DST/Mintek Nanotechnology Innovation Centre, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville (South Africa); Meyer, Mervin [DST/Mintek Nanotechnology Innovation Centre, Department of Biotechnology, University of the Western Cape, Private Bag X17, Bellville (South Africa); Akenga, Teresa A. [Department of Chemistry, University of Eldoret, P.O. Box 1125, Eldoret (Kenya); Dejene, Francis B. [Department of Physics, University of the Free State, QwaQwa Campus, Private Bag X13, Phuthadithaba 9866 (South Africa)

2016-01-01

We report a new type of indium based quantum dots which were conjugated to the magnetic Fe{sub 2}O{sub 3} nanoparticles. They were characterized by photoluminescence (PL), high resolution transmission electron microscopy (HRTEM), superconducting quantum interference device (SQUID) and fourier transform infra-red (FTIR). The photoluminescence characteristics of the coupled and uncoupled indium based quantum dots were investigated to determine whether the fluorescing property could be retained in the bifunctional system. Generally, the PL intensity of the quantum dots was observed to reduce significantly and with huge red shift most probably due to quenching effects for the MNPs. The average size of the coupled nanoparticles were found to range between 4 and 5 nm for the quantum dots and range of 6–13 nm for the Fe{sub 2}O{sub 3} magnetic nanoparticles as revealed by both HRTEM and XRD. The highest magnetic saturation reached for both bare and functionalized magnetic nanoparticles was 68.58 emu/g. The FTIR data revealed that the postulated functional groups were actually present in both the bare and functionalized nanoparticles. For instance, Fe–O was observed at around 580 cm{sup −1}, O–H at 3432 cm{sup −1} and thiol group at 2929 cm{sup −1} for meso-2,3-dimercaptosuccinic acid capped Fe{sub 2}O{sub 3} magnetic nanoparticles. The energy dispersive spectroscopy (EDS) also confirmed that all the elements of the nanocomposite were actually present in the designed material.

R and D of low activated Fe-Mn-Cr high strength non-magnetic steel, (I). Screening test for constituent optimization and fundamental characterization test

Energy Technology Data Exchange (ETDEWEB)

Ishiyama, Shintaro; Fukaya, Kiyoshi; Eto, Motokuni; Kikuchi, Mituru [Japan Atomic Energy Research Inst., Tokyo (Japan); Sato, Ikuo; Kusuhashi, Mikio; Hatakeyama, Tuyoshi [Japan Steel Works Ltd., Tokyo (Japan); Takahashi, Heishitiro [Center for Advanced Research of Energy Technology, Hokkaido Univ., Sapporo (Japan)

2000-02-01

It is very important to develop low activated/non-magnetic materials as large scale structural materials for fusion reactors. In the structural design of JT-60SU, low activated/non-magnetic materials with high specific strength and low decay heat characterizations are required. In the present paper, a new low activated/non-magnetic material (15.5 Mn-16Cr-0.2N-0.3Si-0.2C (wt%)) based on the conventional high manganese steel with lower Ni, CO, C, N and Mn contents for the purpose of lower activation and decay heat was developed and the mass production conditions of the material were optimized. Fundamental material characterization tests of the new material developed in present study were carried out, and the following conclusions are derived ; (1) Lower activation characterizations with the new materials in the order of 1/10 of that of SUS316L steel, (2) Higher strength of the material in the order of 2{approx}3 of SUS316L steel and (3) Lower decay heat with higher thermal conductivity with comparison of SUS316L steel. (author)

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.

X-ray Characterization of Materials

Science.gov (United States)

Lifshin, Eric

1999-09-01

Linking of materials properties with microstructures is a fundamental theme in materials science, for which a detailed knowledge of the modern characterization techniques is essential. Since modern materials such as high-temperature alloys, engineering thermoplastics and multilayer semiconductor films have many elemental constituents distributed in more than one phase, characterization is essential to the systematic development of such new materials and understanding how they behave in practical applications. X-ray techniques play a major role in providing information on the elemental composition and crystal and grain structures of all types of materials. The challenge to the materials characterization expert is to understand how specific instruments and analytical techniques can provide detailed information about what makes each material unique. The challenge to the materials scientist, chemist, or engineer is to know what information is needed to fully characterize each material and how to use this information to explain its behavior, develop new and improved properties, reduce costs, or ensure compliance with regulatory requirements. This comprehensive handbook presents all the necessary background to understand the applications of X-ray analysis to materials characterization with particular attention to the modern approach to these methods.

Far-infrared spectroscopy of lanthanide-based molecular magnetic materials

Energy Technology Data Exchange (ETDEWEB)

Haas, Sabrina

2015-05-13

This thesis demonstrates the applicability of far-infrared spectroscopy for the study of the crystal-field splitting of lanthanides in single-molecular magnetic materials. The far-infrared studies of three different kinds of single-molecular-magnetic materials, a single-ion magnet, a single-chain magnet and an exchange-coupled cluster, yielded a deeper understanding of the crystal-field splitting of the lanthanides in these materials. In addition, our results offered the opportunity to gain a deeper insight into the relaxation processes of these materials.

Design and characterization of a device to quantify the magnetic drug targeting efficiency of magnetic nanoparticles in a tube flow phantom by magnetic particle spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Radon, Patricia, E-mail: patricia.radon@ptb.de; Löwa, Norbert; Gutkelch, Dirk; Wiekhorst, Frank

2017-04-01

The aim of magnetic drug targeting (MDT) is to transfer a therapeutic drug coupled to magnetic nanoparticles (MNP) to desired disease locations (e.g. tumor region) with the help of magnetic field gradients. To transfer the MDT approach into clinical practice a number of important issues remain to be solved. We developed and characterized an in-vitro flow phantom to provide a defined and reproducible MDT environment. The tube system of the flow phantom is directed through the detection coil of a magnetic particle spectroscopy (MPS) device to determine the targeting efficiency. MPS offers an excellent temporal resolution of seconds and an outstanding specific sensitivity of some nanograms of iron. In the flow phantom different MNP types, magnet geometries and tube materials can be employed to vary physical parameters like diameter, flow rate, magnetic targeting gradient, and MNP properties. - Highlights: • Flow phantom for magnetic targeting. • MPS for quantitative MNP detection. • ng detection limit for MNP.

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

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

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)

Evaluation of airborne thermal, magnetic, and electromagnetic characterization technologies

Energy Technology Data Exchange (ETDEWEB)

Josten, N.E.

1992-03-01

The identification of Buried Structures (IBS) or Aerial Surveillance Project was initiated by the US Department of Energy (DOE) Office of Technology Development to demonstrate airborne methods for locating and identifying buried waste and ordnance at the Idaho National Engineering Laboratory (INEL). Two technologies were demonstrated: (a) a thermal infrared imaging system built by Martin Marietta Missile Systems and (b) a magnetic and electromagnetic (EM) geophysical surveying system operated by EBASCO Environmental. The thermal system detects small differences in ground temperature caused by uneven heating and cooling of the ground by the sun. Waste materials on the ground can be detected when the temperature of the waste is different than the background temperature. The geophysical system uses conventional magnetic and EM sensors. These sensors detect disturbances caused by magnetic or conductive waste and naturally occurring magnetic or conductive features of subsurface soils and rock. Both systems are deployed by helicopter. Data were collected at four INEL sites. Tests at the Naval Ordnance Disposal Area (NODA) were made to evaluate capabilities for detecting ordnance on the ground surface. Tests at the Cold Simulated Waste Demonstration Pit were made to evaluate capabilities for detecting buried waste at a controlled site, where the location and depth of buried materials are known. Tests at the Subsurface Disposal Area and Stationary Low-Power Reactor-1 burial area were made to evaluate capabilities for characterizing hazardous waste at sites that are typical of DOE buried waste sites nationwide.

Evaluation of airborne thermal, magnetic, and electromagnetic characterization technologies

International Nuclear Information System (INIS)

Josten, N.E.

1992-03-01

The identification of Buried Structures (IBS) or Aerial Surveillance Project was initiated by the US Department of Energy (DOE) Office of Technology Development to demonstrate airborne methods for locating and identifying buried waste and ordnance at the Idaho National Engineering Laboratory (INEL). Two technologies were demonstrated: (a) a thermal infrared imaging system built by Martin Marietta Missile Systems and (b) a magnetic and electromagnetic (EM) geophysical surveying system operated by EBASCO Environmental. The thermal system detects small differences in ground temperature caused by uneven heating and cooling of the ground by the sun. Waste materials on the ground can be detected when the temperature of the waste is different than the background temperature. The geophysical system uses conventional magnetic and EM sensors. These sensors detect disturbances caused by magnetic or conductive waste and naturally occurring magnetic or conductive features of subsurface soils and rock. Both systems are deployed by helicopter. Data were collected at four INEL sites. Tests at the Naval Ordnance Disposal Area (NODA) were made to evaluate capabilities for detecting ordnance on the ground surface. Tests at the Cold Simulated Waste Demonstration Pit were made to evaluate capabilities for detecting buried waste at a controlled site, where the location and depth of buried materials are known. Tests at the Subsurface Disposal Area and Stationary Low-Power Reactor-1 burial area were made to evaluate capabilities for characterizing hazardous waste at sites that are typical of DOE buried waste sites nationwide

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.

Surface, interface and bulk materials characterization using Indus synchrotron sources

International Nuclear Information System (INIS)

Phase, Deodatta M.

2014-01-01

Synchrotron radiation sources, providing intense, polarized and stable beams of ultra violet, soft and hard x-ray photons, are having great impact on physics, chemistry, biology, materials science and other areas research. In particular synchrotron radiation has revolutionized materials characterization techniques by enhancing its capabilities for investigating the structural, electronic and magnetic properties of solids. The availability of synchrotron sources and necessary instrumentation has led to considerable improvements in spectral resolution and intensities. As a result, application scope of different materials characterization techniques has tremendously increased particularly in the analysis of solid surfaces, interfaces and bulk materials. The Indian synchrotron storage ring, Indus-1 and Indus-2 are in operation at RRCAT, Indore. The UGC-DAE CSR with the help of university scientist had designed and developed an angle integrated photoelectron spectroscopy (AlPES) beam line on Indus-1 storage ring of 450 MeV and polarized light beam line for soft x-ray absorption spectroscopy (SXAS) on Indus-2 storage ring of 2.5 GeV. (author)

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

Magnetic domains the analysis of magnetic microstructures

CERN Document Server

Hubert, Alex

1998-01-01

The book gives a systematic and comprehensive survey of the complete area of magnetic microstructures. It reaches from micromagnetism of nanoparticles to complex structures of extended magnetic materials. The book starts with a comprehensive evaluation of traditional and modern experimental methods for the observation of magnetic domains and continues with the treatment of important methods for the theoretical analysis of magnetic microcstructures. A survey of the necessary techniques in materials characterization is given. The book offers an observation and analysis of magnetic domains in all

Characterization of minerals, metals and materials

CERN Document Server

Hwang, Jiann-Yang; Bai, Chengguang; Carpenter, John; Cai, Mingdong; Firrao, Donato; Kim, Byoung-Gon

2012-01-01

This state-of-the-art reference contains chapters on all aspects of the characterization of minerals, metals, and materials. The title presents papers from one of the largest yearly gatherings of materials scientists in the world and thoroughly discusses the characterization of minerals, metals, and materials The scope includes current industrial applications and research and developments in the following areas:  Characterization of Ferrous Metals Characterization of Non-Ferrous Materials Characterization of Minerals and Ceramics Character

Structural and magnetic domains characterization of magnetite nanoparticles

International Nuclear Information System (INIS)

Santoyo-Salazar, J.; Castellanos-Roman, M.A.; Beatriz Gomez, L.

2007-01-01

Recently, important advances have been achieved in application, reproducibility and response ability of magnetic materials due to the relationships among processing, structure and nanometric size particle. Features like homogeneity of compounds and nanoparticle-sizing have improved some magnetic properties of materials and their field application. Of particular interest is the study of magnetic materials at the atomic and microstuctural level because the orientation and magnetic domains (large numbers of atoms moments coupled together in a preferential direction) can be observed. In this work, magnetite (Fe 3 O 4 ) powders which were obtained by precipitation route in alkaline medium are analyzed to identify the structure and mechanism formation of domains over the core and border of nanoparticles. Results obtained by XRD, atomic force microscopy (AFM) and magnetic force microscopy (MFM) showed a structural phase corresponding to Fe 3 O 4 and nanoparticles in a range of 20-40 nm. Samples scanned by MFM in nanometric resolution and profile images showed orientation of magnetic domains in the border and cores of the material. Finally, an analysis of repulsion and attraction in magnetic field and direction changes of domains formed by magnetite (Fe 3 O 4 ) powders were done

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

Synthesis and characterization of anisotropic magnetic hydrogels

Energy Technology Data Exchange (ETDEWEB)

Hinrichs, Stephan, E-mail: stephan.hinrichs@chemie.uni-hamburg.de; Nun, Nils; Fischer, Birgit, E-mail: birgit.fischer@chemie.uni-hamburg.de

2017-06-01

Multiresponsive hydrogels are an interesting new class of materials. They offer the advantage, that they respond to different stimuli like temperature, pH and magnetic fields. By this they can change their properties which makes the hydrogels ideal candidates for many applications in the technical as well as medical field. Here we present the synthesis and characterization of hydrogels - micro- as well as macrogels - which consist of an iron oxide core, varying in phase and morphology, embedded in a thermoresponsive polymer, consisting of poly N-isopropylacrylamide. By using dynamic light scattering we investigated the thermoresponsive properties. In addition we were able to follow the formation of the macrogel by monitoring the shear viscosity.

Computational methods for 2D materials: discovery, property characterization, and application design.

Science.gov (United States)

Paul, J T; Singh, A K; Dong, Z; Zhuang, H; Revard, B C; Rijal, B; Ashton, M; Linscheid, A; Blonsky, M; Gluhovic, D; Guo, J; Hennig, R G

2017-11-29

The discovery of two-dimensional (2D) materials comes at a time when computational methods are mature and can predict novel 2D materials, characterize their properties, and guide the design of 2D materials for applications. This article reviews the recent progress in computational approaches for 2D materials research. We discuss the computational techniques and provide an overview of the ongoing research in the field. We begin with an overview of known 2D materials, common computational methods, and available cyber infrastructures. We then move onto the discovery of novel 2D materials, discussing the stability criteria for 2D materials, computational methods for structure prediction, and interactions of monolayers with electrochemical and gaseous environments. Next, we describe the computational characterization of the 2D materials' electronic, optical, magnetic, and superconducting properties and the response of the properties under applied mechanical strain and electrical fields. From there, we move on to discuss the structure and properties of defects in 2D materials, and describe methods for 2D materials device simulations. We conclude by providing an outlook on the needs and challenges for future developments in the field of computational research for 2D materials.

Synthesis and Characterization of Novel Magnetic Nano-Materials and Studying Their Potential Application in Recovery of Metal Ions

International Nuclear Information System (INIS)

Moussa, S.I.M.

2013-01-01

The release of hazardous pollutants and their dispersion in the environment can cause adverse impacts on both environment and public health. These pollutants are more easily controlled when they are generated than after they are dispersed. Therefore, it is necessity of prime to design treatment processes can remove the contaminants at their source. Recently, many industrial and nuclear activities produce large amounts of wastewaters that contains a variety of contaminants. These contaminants may include toxic metals or radioactive isotopes. The efforts in this work are firstly directed to prepare some materials to be used as sorbents for removal of Sr(II), Cd(II) and Eu(III) radionuclide from waste solutions. The study concerned with the characterization of the prepared sorbents using surface area (BET), FTIR, X-Ray, TG/DTA, SEM and magnetic properties to throw light on its sense when practically used as a decontaminating material in aqueous systems. Also, the work involves the sorption of Sr(II), Cd(II) and Eu(III) ions from aqueous solutions under different experimental conditions to clarify the affinity of these sorbents and to assess main factors affecting the sorption behavior of these species. This is to evaluate the efficiency of these sorbents to be used as decontaminating materials for treatment of hazard wastes and finally to judge the criteria of sorbents selectivity towards the studies solutes.

One-pot synthesis of magnetic hybrid materials based on ovoid-like carboxymethyl-cellulose/cetyltrimethylammonium-bromide templates

Energy Technology Data Exchange (ETDEWEB)

Torres-Martínez, Nubia E. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, 66450 Nuevo León (Mexico); Garza-Navarro, M.A., E-mail: marco.garzanr@uanl.edu.mx [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, 66450 Nuevo León (Mexico); Universidad Autónoma de Nuevo León, Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología, Apodaca, 66600 Nuevo León (Mexico); Lucio-Porto, Raúl [Université de Nantes, CNRS, Institut des Matériaux Jean Rouxel (IMN), 2 rue de la Houssinière, BP32229, 44322 Nantes Cedex 3 (France); and others

2013-09-16

A novel one-pot synthetic procedure to obtain magnetic hybrid nanostructured materials (HNM), based on magnetic spinel-metal-oxide (SMO) nanoparticles stabilized in ovoid-like carboxymethyl-cellulose (CMC)/cetyltrimethylammonium-bromide (CTAB) templates, is reported. The HNM were synthesized from the controlled hydrolysis of inorganic salts of Fe (II) and Fe (III) into aqueous dissolutions of CMC and CTAB. The synthesized HNM were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and static magnetic measurements. The experimental evidence suggests that, due to the competition between CTAB molecules and SMO nanoparticles to occupy CMC intermolecular sites nearby to its carboxylate functional groups, the size of both, SMO nanoparticles and ovoid-like CMC/CTAB templates can be tuned, varying the CTAB:SMO weight ratio. Moreover, it was found that the magnetic response of the HNM depends on the confinement degree of the SMO nanoparticles into the CMC/CTAB template. Hence, their magnetic characteristics can be adjusted controlling the size of the template, the quantity and distribution of the SMO nanoparticles within the template and their size. - Graphical abstract: Display Omitted - Highlights: • The synthesis of magnetic hybrid materials is reported. • The hybrid materials were synthesized following a novel one-pot procedure. • The magnetic nanoparticles were stabilized in ovoid-like templates. • The size of the templates was tuned adjusting nanoparticles weight content. • The magnetic properties of hybrid materials depend on the size of the template.

Spin and Charge Transport in 2D Materials and Magnetic Insulator/Metal Heterostructures

Science.gov (United States)

Amamou, Walid

Spintronic devices are very promising for future information storage, logic operations and computation and have the potential to replace current CMOS technology approaching the scaling limit. In particular, the generation and manipulation of spin current enables the integration of storage and logic within the same circuit for more powerful computing architectures. In this thesis, we examine the manipulation of spins in 2D materials such as graphene and metal/magnetic insulator heterostructures. In particular, we investigate the feasibility for achieving magnetization switching of a nanomagnet using graphene as a nonmagnetic channel material for All Spin Logic Device applications. Using in-situ MBE deposition of nanomagnet on graphene spin valve, we demonstrate the presence of an interfacial spin dephasing at the interface between the graphene and the nanomagnet. By introducing a Cu spacer between the nanomagnet and graphene, we demonstrate that this interfacial effect is related to an exchange interaction between the spin current and the disordered magnetic moment of the nanomagnet in the first monolayer. In addition to the newly discovered interfacial spin relaxation effect, the extracted contact resistance area product of the nanomagnet/graphene interface is relatively high on the order of 1Omicrom2. In practice, reducing the contact resistance will be as important as eliminating the interfacial relaxation in order to achieve magnetization switching. Furthermore, we examine spin manipulation in a nonmagnetic Pt using an internal magnetic exchange field produced by the adjacent magnetic insulator CoFe2O4 grown by MBE. Here, we report the observation of a strong magnetic proximity effect of Pt deposited on top of a perpendicular magnetic anisotropy (PMA) inverse spinel material Cobalt Ferrite (CFO, CoFe 2O4). The CFO was grown by MBE and its magnetization was characterized by Vibrating Sample Magnetometry (VSM) demonstrating the strong out of plane magnetic

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

Electroplating and characterization of cobalt-nickel-iron and nickel-iron for magnetic microsystems applications

DEFF Research Database (Denmark)

Rasmussen, Frank Engel; Ravnkilde, Jan Tue; Tang, Peter Torben

2001-01-01

The magnetic properties of pulse reverse (PR) electroplated CoNiFe and DC electroplated NiTe are presented. CoNiFe is a very promising material for magnetic microsystems due to the possibility of achieving a high saturation flux density (B-s) and a low coercivity (H-c). A new bath formulation has...... been developed, which by means of PR electroplating makes it possible to deposit high B-s CoNiFe with a low residual stress level. The magnetic properties have been determined using a new simple measurement setup that allows for wafer level characterization. The results have been validated...

Neutron and gamma irradiation effects on organic insulating materials for fusion magnets

International Nuclear Information System (INIS)

Maurer, W.

1985-10-01

Available low-temperature neutron and gamma irradiation data for organic insulating materials are collected and compared with room temperature data. Only the most promising polymers in terms of mechanical strength for magnet insulation are taken into account. For characterization and comparison of different materials the 75% dose is used, i.e. the dose, where the mechanical strength is reduced by 25%, and 75% is retained. For room temperature special prepared polyimide and epoxy materials reinforced with glass fibre retained 75% of the mechanical strength up to a dose of 7x10 7 Gy. For 5 K irradiation the best epoxy material retained the 75% dose up to 1x10 7 Gy, the best polyimide material up to 1x10 8 Gy. (orig.) [de

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...

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

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.

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.

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

Synthesis, characterization and magnetic properties of selected Laves and MAX phases

International Nuclear Information System (INIS)

Hamm, Christin Maria

2017-01-01

In this work the rare-earth free Laves phases Ti 2 M 3 Si with M = Mn, Fe, Co, Ni were synthesized by microwave heating and were structurally and magnetically characterized. Furthermore, the solid solution Ti 2 (Co 1-x Fe x ) 3 Si was synthesized by arc melting and spark plasma sintering, as well as their magnetic behavior was studied. In addition to the Laves phases, the focus was on the synthesis and characterization of aluminum-based MAX phases. For the first time the ternary carbides were prepared by microwave heating. The phase-pure representation of MAX phases was particularly challenging for synthetic solid-state chemistry. The susceptor-assisted microwave heating allows the synthesis of high-quality samples, which was shown in this work on M 2 AlC (M = Ti, V, Cr) and V 4 AlC 3 . Furthermore, for the first time, the doping of these materials with Mn and Fe was successful. In addition to the structural characterization of the new phases, the microstructure and magnetic properties are discussed in this work. Using these doped compounds as well as the compound V 4 AlC 3 , it has been shown that field-activated synthesis, particularly susceptor-assisted microwave heating, are a very good synthesis method for compounds which are hard or sometimes not synthesized by conventional methods.

Characterization of magnetic labels for bioassays

International Nuclear Information System (INIS)

Lalatonne, Yoann; Benyettou, Farah; Bonnin, Dominique; Lievre, Nicole; Monod, Philippe; Lecouvey, Marc; Weinmann, Pierre; Motte, Laurence

2009-01-01

Magnetic nanoparticles differing by their size have been synthesized to use them for multiparametric testing, based on their differing magnetic properties. The nanoparticle has two essential roles: to act as a probe owing to its specific magnetic properties and to carry on its surface precursor groups for the covalent coupling of biological recognition molecules, such as antibodies, nucleic acids. A totally unique, newly patented, method has been used to characterize magnetic signatures using the MIAplex technology. The MIAplex reader, developed by Magnisense, measures the non-linear response of the magnetic labels when they are exposed to a multi-frequency alternating magnetic field. This specific signature based on d 2 B(H)/dH 2 was correlated to other more conventional magnetic detection methods (superconducting quantum interference devices (SQUID) and Moessbauer).

Quantitative magnetic-moment mapping of a permanent-magnet material by X-ray magnetic circular dichroism nano-spectroscopy

Directory of Open Access Journals (Sweden)

Tetsuro Ueno

2017-05-01

Full Text Available We demonstrate the quantitative mapping of magnetic moments in a permanent-magnet material by X-ray magnetic circular dichroism nano-spectroscopy. An SmCo5 specimen was prepared from the bulk material by using a micro-fabrication technique. Scanning transmission X-ray microscopy images were obtained around the Sm M4,5 absorption edges. By applying the magneto-optical sum rules to these images, we obtained quantitative maps of the orbital and spin magnetic moments as well as their ratio. We found that the magnitudes of the orbital and spin magnetic moments and their ratio do not depend on thickness of the specimen.

Advanced Magnetic Nanostructures

CERN Document Server

Sellmyer, David

2006-01-01

Advanced Magnetic Nanostructures is devoted to the fabrication, characterization, experimental investigation, theoretical understanding, and utilization of advanced magnetic nanostructures. Focus is on various types of 'bottom-up' and 'top-down' artificial nanostructures, as contrasted to naturally occurring magnetic nanostructures, such as iron-oxide inclusions in magnetic rocks, and to structures such as perfect thin films. Chapter 1 is an introduction into some basic concepts, such as the definitions of basic magnetic quantities. Chapters 2-4 are devoted to the theory of magnetic nanostructures, Chapter 5 deals with the characterization of the structures, and Chapters 6-10 are devoted to specific systems. Applications of advanced magnetic nanostructures are discussed in Chapters11-15 and, finally, the appendix lists and briefly discusses magnetic properties of typical starting materials. Industrial and academic researchers in magnetism and related areas such as nanotechnology, materials science, and theore...

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.

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

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)

Chitosan magnetic microspheres for technological applications: Preparation and characterization

International Nuclear Information System (INIS)

Podzus, P.E.; Daraio, M.E.; Jacobo, S.E.

2009-01-01

One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800-1100 μm. The adsorption of Cu(II) onto chitosan-magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.

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

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.

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

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.

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

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

Recent Advances in Two-Dimensional Materials with Charge Density Waves: Synthesis, Characterization and Applications

Directory of Open Access Journals (Sweden)

Mongur Hossain

2017-10-01

Full Text Available Recently, two-dimensional (2D charge density wave (CDW materials have attracted extensive interest due to potential applications as high performance functional nanomaterials. As other 2D materials, 2D CDW materials are layered materials with strong in-plane bonding and weak out-of-plane interactions enabling exfoliation into layers of single unit cell thickness. Although bulk CDW materials have been studied for decades, recent developments in nanoscale characterization and device fabrication have opened up new opportunities allowing applications such as oscillators, electrodes in supercapacitors, energy storage and conversion, sensors and spinelectronic devices. In this review, we first outline the synthesis techniques of 2D CDW materials including mechanical exfoliation, liquid exfoliation, chemical vapor transport (CVT, chemical vapor deposition (CVD, molecular beam epitaxy (MBE and electrochemical exfoliation. Then, the characterization procedure of the 2D CDW materials such as temperature-dependent Raman spectroscopy, temperature-dependent resistivity, magnetic susceptibility and scanning tunneling microscopy (STM are reviewed. Finally, applications of 2D CDW materials are reviewed.

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)

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.

Synthesis and characterization of cationic lipid coated magnetic nanoparticles using multiple emulsions as microreactors

Science.gov (United States)

Akbaba, Hasan; Karagöz, Uğur; Selamet, Yusuf; Kantarcı, A. Gülten

2017-03-01

The aim of this study was to develop a novel iron oxide nanoparticle synthesis method with in-situ surface coating. For this purpose multiple emulsions were used as microreactors for the first time and magnetic iron oxide particles synthesized in the core of cationic solid lipid nanoparticles. DLS, SEM, TEM, VSM, Raman Spectrometer, XRD, and XPS techniques were performed for characterization of the magnetic nanoparticles. Obtained magnetic nanoparticles are superparamagnetic and no additional process was needed for surface adjustments. They are positively charged as a result of cationic lipid coating and has appropriate particle size (<30 nm) for drug or nucleic acid delivery. Structure analysis showed that magnetic core material is in the form of magnetite. Saturation magnetization value was measured as 15-17 emu g-1 for lipid coated magnetic nanoparticles obtained by multiple emulsion method which is reasonably sufficient for magnetic targeting.

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)

Dynamics expansion of laser produced plasma with different materials in magnetic field

Energy Technology Data Exchange (ETDEWEB)

Rabia Qindeel; Noriah Bte Bidin; Yaacob Mat daud [Laser Technology Laboratory, Physics Department, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia)], E-mail: plasmaqindeel@yahoo.com

2008-12-01

The dynamics expansion of the plasma generated by laser ablation of different materials has been investigated. The dynamics and confinement of laser generated plasma plumes are expanding across variable magnetic fields. A Q-switched neodymium-doped yttrium aluminum garnet laser with 1064 nm, 8 ns pulse width and 0.125 J laser energy was used to generate plasma that was allowed to expand across variable magnetic within 0.1 - 0.8 T. The expansions of laser-produced plasma of different materials are characterized by using constant laser power. CCD video camera was used to visualize and record the activities in the focal region. The plasma plume length, width and area were measured by using Matrox Inpector 2.1 and video Test 0.5 software. Spectrums of plasma beam from different materials are studied via spectrometer. The results show that the plasma generated by aluminum target is the largest than Brass and copper. The optical radiation from laser generated plasma beam spectrums are obtained in the range of UV to visible light.

Passive characterization and active testing of epoxy bonded regenerators for room temperature magnetic refrigeration

DEFF Research Database (Denmark)

Lei, Tian; Navickaité, Kristina; Engelbrecht, Kurt

2017-01-01

-layer AMR based on spherical particles is tested actively in a small reciprocating magnetic refrigerator, achieving a no-load temperature span of 16.8 °C using about 143 g of epoxy-bonded La(Fe,Mn,Si)13Hy materials. Simulations based on a one-dimensional (1D) AMR model are also implemented to validate......Epoxy bonded regenerators of both spherical and irregular La(Fe,Mn,Si)13Hy particles have been developed aiming at increasing the mechanical strength of active magnetic regenerators (AMR) loaded with brittle magnetocaloric materials and improving the flexibility of shaping the regenerator geometry....... Although the magnetocaloric properties of these materials are well studied, the flow and heat transfer characteristics of the epoxy bonded regenerators have seldom been investigated. This paper presents a test apparatus that passively characterizes regenerators using a liquid heat transfer fluid...

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

Sol-gel hybrid materials for aerospace applications: Chemical characterization and comparative investigation of the magnetic properties

Science.gov (United States)

Catauro, Michelina; Mozzati, Maria Cristina; Bollino, Flavia

2015-12-01

In the material science field, weightless conditions can be successfully used to understand the relationship between manufacturing process, structure and properties of the obtained materials. Aerogels with controlled microstructure could be obtained by sol-gel methods in microgravity environment, simulated using magnetic levitation if they are diamagnetic. In the present work, a sol-gel route was used to synthesize class I, organic-inorganic nanocomposite materials. Two different formulations were prepared: the former consisted in a SiO2 matrix in which different percentages of polyethylene glycol (PEG) were incorporated, the latter was a ZrO2 matrix entrapping different amounts of poly (ε-caprolactone) (PCL). Fourier Transform Infrared Spectroscopy (FT-IR) detected that the organic and the inorganic components in both the formulation interact by means of hydrogen bonds. X-ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials and Scanning Electron Microscope (SEM) showed that they have homogeneous morphology and are nanocomposites. Superconducting Quantum Interference Device (SQUID) magnetometry confirmed the expected diamagnetic character of those hybrid systems. The obtained results were compared to those achieved in previous studies regarding the influence of the polymer amount on the magnetic properties of SiO2/PCL and ZiO2/PEG hybrids, in order to understand how the diamagnetic susceptibility is influenced by variation of both the inorganic matrix and organic component.

The Investigation of New Magnetic Materials and Their Phenomena Using Ultrafast Fresnel Transmission Electron Microscopy

Science.gov (United States)

Schliep, Karl B.

State-of-the-art technology drives scientific progress, pushing the boundaries of our current understanding of fundamental processes and mechanisms. Our continual scientific advancement is hindered only by what we can observe and experimentally verify; thus, it is reasonable to assert that instrument development and improvement is the cornerstone for technological and intellectual growth. For example, the invention of transmission electron microscopy (TEM) allowed us to observe nanoscale phenomena for the first time in the 1930s and even now it is invaluable in the development of smaller, faster electronics. As we uncover more about the fundamentals of nanoscale phenomena, we have realized that images alone reveal only a snapshot of the story; to continue progressing we need a way to observe the entire scene unfold (e.g. how defects affect the flow of current across a transistor or how thermal energy propagates in nanoscale systems like graphene). Recently, by combining the spatial resolution of a TEM with the temporal resolution of ultrafast lasers, ultrafast electron microscopy ? or microscope ? (UEM) has allowed us to simultaneously observe transient nanoscale phenomena at ultrafast timescales. Ultrafast characterization techniques allow for the investigation of a new realm of previously unseen phenomenon inherent to the transient electronic, magnetic, and structural properties of materials. However, despite the progress made in ultrafast techniques, capturing the nanoscale spatial sub-ns temporal mechanisms and phenomenon at play in magnetic materials (especially during the operation of magnetic devices) has only recently become possible using UEM. With only a handful of instruments available, magnetic characterization using UEM is far from commonplace and any advances made are sparsely reported, and further, specific to the individual instrument. In this dissertation, I outline the development of novel magnetic materials and the establishment of a UEM lab at

The complex initial reluctivity, permeability and susceptibility spectra of magnetic materials

Science.gov (United States)

Hamilton, N. C.

2015-03-01

The HF complex permeability spectrum of a magnetic material is deduced from the measured impedance spectrum, which is then normalized to a series permeability spectrum. However, this series permeability spectrum has previously been shown to correspond to a parallel magnetic circuit, which is not appropriate. Some of the implications of this truth are examined. This electric/magnetic duality has frustrated efforts to interpret the shape of the complex magnetic permeability spectra of materials, and has hindered the application of impedance spectroscopy to magnetic materials. In the presence of magnetic loss, the relationship between the relative magnetic permeability and the magnetic susceptibility is called into question. The use of reluctivity spectra for expressing magnetic material properties is advocated. The relative loss factor, tanδm/μi is shown to be an approximation for the imaginary part of the reluctivity. A single relaxation model for the initial reluctivity spectra of magnetic materials is presented, and its principles are applied to measurements of a high permeability ferrite. The results are presented as contour plots of the spectra as a function of temperature.

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

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.

Topology optimization for design of segmented permanent magnet arrays with ferromagnetic materials

Science.gov (United States)

Lee, Jaewook; Yoon, Minho; Nomura, Tsuyoshi; Dede, Ercan M.

2018-03-01

This paper presents multi-material topology optimization for the co-design of permanent magnet segments and iron material. Specifically, a co-design methodology is proposed to find an optimal border of permanent magnet segments, a pattern of magnetization directions, and an iron shape. A material interpolation scheme is proposed for material property representation among air, permanent magnet, and iron materials. In this scheme, the permanent magnet strength and permeability are controlled by density design variables, and permanent magnet magnetization directions are controlled by angle design variables. In addition, a scheme to penalize intermediate magnetization direction is proposed to achieve segmented permanent magnet arrays with discrete magnetization directions. In this scheme, permanent magnet strength is controlled depending on magnetization direction, and consequently the final permanent magnet design converges into permanent magnet segments having target discrete directions. To validate the effectiveness of the proposed approach, three design examples are provided. The examples include the design of a dipole Halbach cylinder, magnetic system with arbitrarily-shaped cavity, and multi-objective problem resembling a magnetic refrigeration device.

Moessbauer and magnetic studies of parent material from argentine pampas soils

International Nuclear Information System (INIS)

Bidegain, J. C.; Bartel, A. A.; Sives, F. R.; Mercader, R. C.

2007-01-01

In order to establish a correlation between the different types of soils using hyperfine and magnetic parameters as climatic and environmental proxies, we have studied the differentiation of soil developed around 38.5 o south latitude, in the central Pampas of Argentina, by means of Moessbauer spectroscopy and environmental magnetism. The soils transect (climosequence) investigated stretches from the drier west (around 64 o W) to the more humid east (at around 59 o W) in the Buenos Aires Province, covering a distance of 600 km. The soils studied developed during recent Holocene geologic times in a landscape characterized by small relict plateaus, slopes and depressions, dunes and prairies. The parent material consists of eolian sandy silts overlying calcrete layers. The low mean annual precipitation in the western parts of the region gives rise to soils without B-horizons, which limits the agricultural use of land. The preliminary results show an increase of the paramagnetic Fe 3+ relative concentration from west to east in the soils investigated. Magnetite is probably mainly responsible for the observed enhancement in the susceptibility values. The magnetic response of the parent material is similar to that of the loess part of the previously investigated loess-paleosol sequences of the Argentine loess plateau.

Characterization of magnetic colloids by means of magnetooptics

OpenAIRE

Baraban, Larysa; Erbe, Artur; Leiderer, Paul

2007-01-01

A new, efficient method for the characterization of magnetic colloids based on the Faraday effect is proposed. According to the main principles of this technique, it is possible to detect the stray magnetic field of the colloidal particles induced inside the magnetooptical layer. The magnetic properties of individual particles can be determined providing measurements in a wide range of magnetic fields. The magnetization curves of capped colloids and paramagnetic colloids were measured by mean...

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)

Purpose of the Materials Characterization Center

International Nuclear Information System (INIS)

Mendel, J.E.

1984-09-01

The Materials Characterization Center (MCC) at the Pacific Northwest Laboratory is the experimental arm of the Materials Characterization Organization (MCO), which was established by the US Department of Energy (DOE) in FY 1980 to ensure high quality characterization and qualification of waste package materials essential to the reliable performance of DOE nuclear waste management programs. MCC is responsible for publishing key test methods and data in the Nuclear Waste Materials Handbook (DOE/TIC-11400). It sponsors a continuing series of workshops that address materials characterization test method issues. It supplies well-characterized reference and testing materials for use by the DOE nuclear waste management programs. It develops generic test methods and supports the repository waste package projects in developing selected site-specific test methods and performing confirmatory testing of these methods. When these test methods are approved by the MRB they constitute the formal tests to be used by laboratories to test and qualify materials, evaluate waste package components, and assure compliance with standards and/or specifications for the final product

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.

Material Characterization of Fatigue Specimens made from Meta-stable Austenitic Stainless Steel

Energy Technology Data Exchange (ETDEWEB)

Niffenegger, M.; Grosse, M.; Kalkhof, D.; Leber, H. [Paul Scherrer Institut Villigen (Switzerland); Vincent, A.; Pasco, L.; Morin, M. [Insa de Lyon (France)

2003-07-01

The main objective of the EU-project CRETE (Contract No.: FIS5-1999-00280) was to assess the capability and the reliability of innovative NDT-inspection techniques for the detection of material degradation, induced by thermal fatigue and neutron irradiation, of metastable austenitic and ferritic low-alloy steel. Several project partners tested aged or irradiated samples, using various techniques (acoustic, magnetic and thermoelectric). However, these indirect methods require a careful interpretation of the measured signal in terms of micro-structural evolutions due to ageing of the material. Therefore the material had to be characterized in its undamaged, as well as in its damaged state. The present report summarises only the material characterization of the fatigue specimens. It is issued simultaneously as an PSI Bericht and the CRETE work package 3 (WP3) report. Each partner according to their own specifications purchased three materials under investigation, namely AISI 347, AISI 321 and AISI 304L. After sending the material to PSI, all fatigue specimens were manufactured by the same Swiss company. Each partner was responsible for his fatigue tests which are documented in the report WP1, written by FANP. In order to characterize the material in its unfatigued as well as in its fatigued state and to consider microstructural changes related to fatigue damage the methods listed below were employed either by PSI or by INSA de Lyon: (1) Inductive Coupled Plasma Emission Photometry (ICP-OES) was applied to determine the chemical composition, (2) Scanning electron microscopy (SEM) for observing cracks, slip bands between grain and twin boundaries, - Ferromaster for measuring the magnetic permeability, (3) Physical Properties Measuring System (PPMS) for measuring magnetization characteristics, (4) Neutron- and advanced X-ray diffraction methods for the quantitative determination of martensite, - Transmission electron microscopy (TEM) for the observation of crystalline

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)

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).

Materials Characterization Facility

Data.gov (United States)

Federal Laboratory Consortium — The Materials Characterization Facility enables detailed measurements of the properties of ceramics, polymers, glasses, and composites. It features instrumentation...

A novel automated alternating current biosusceptometry method to characterization of controlled-release magnetic floating tablets of metronidazole.

Science.gov (United States)

Ferrari, Priscileila Colerato; dos Santos Grossklauss, Dany Bruno Borella; Alvarez, Matheus; Paixão, Fabiano Carlos; Andreis, Uilian; Crispim, Alexandre Giordano; de Castro, Ana Dóris; Evangelista, Raul Cesar; de Arruda Miranda, José Ricardo

2014-08-01

Alternating Current Biosusceptometry is a magnetically method used to characterize drug delivery systems. This work presents a system composed by an automated ACB sensor to acquire magnetic images of floating tablets. The purpose of this study was to use an automated Alternating Current Biosusceptometry (ACB) to characterize magnetic floating tablets for controlled drug delivery. Floating tablets were prepared with hydroxypropyl methylcellulose (HPMC) as hydrophilic gel material, sodium bicarbonate as gas-generating agent and ferrite as magnetic marker. ACB was used to characterize the floating lag time and the tablet hydration rate, by quantification of the magnetic images to magnetic area. Besides the buoyancy, the floating tablets were evaluated for weight uniformity, hardness, swelling and in vitro drug release. The optimized tablets were prepared with equal amounts of HPMC and ferrite, and began to float within 4 min, maintaining the flotation during more than 24 h. The data of all physical parameters lied within the pharmacopeial limits. Drug release at 24 h was about 40%. The ACB results showed that this study provided a new approach for in vitro investigation of controlled-release dosage forms. Moreover, using automated ACB will also be possible to test these parameters in humans allowing to establish an in vitro.in vivo correlation (IVIVC).

Engineered materials for all-optical helicity-dependent magnetic switching

Science.gov (United States)

Fullerton, Eric

2014-03-01

The possibilities of manipulating magnetization without applied magnetic fields have attracted growing attention over the last fifteen years. The low-power manipulation of magnetization, preferably at ultra-short time scales, has become a fundamental challenge with implications for future magnetic information memory and storage technologies. Here we explore the optical manipulation of the magnetization of engineered materials and devices using 100 fs optical pulses. We demonstrate that all optical - helicity dependent switching (AO-HDS) can be observed not only in selected rare-earth transition-metal (RE-TM) alloy films but also in a much broader variety of materials, including alloys, multilayers, heterostructures and RE-free Co-Ir-based synthetic ferrimagnets. The discovery of AO-HDS in RE-free TM-based synthetic ferrimagnets can enable breakthroughs for numerous applications since it exploits materials that are currently used in magnetic data storage, memories and logic technologies. In addition, this materials study of AO-HDS offers valuable insight into the underlying mechanisms involved. Indeed the common denominator of the diverse structures showing AO-HDS in this study is that two ferromagnetic sub-lattices exhibit magnetization compensation (and therefore angular momentum compensation) at temperatures near or above room temperature. We are highlighting that compensation plays a major role and that this compensation can be established at the atomic level as in alloys but also over a larger nanometers scale as in the multilayers or in heterostructures. We will also discuss the potential to extend AO-HDS to new classes of magnetic materials. This work was done in collaboration with S. Mangin, M. Gottwald, C-H. Lambert, D. Steil, V. Uhlíř, L. Pang, M. Hehn, S. Alebrand, M. Cinchetti, G. Malinowski, Y. Fainman, and M. Aeschlimann. Supported by the ANR-10-BLANC-1005 ``Friends,'' a grant from the Advanced Storage Technology Consortium, Partner University Fund

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

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

Materials Characterization Center program plan

International Nuclear Information System (INIS)

Nelson, R.D.; Ross, W.A.; Hill, O.F.; Mendel, J.E.; Merz, M.D.; Turcotte, R.P.

1980-03-01

The Materials Characterization Center (MCC) has been established at Pacific Northwest Laboratory as part of the Materials Characterization Organization for providing an authoritative, referenceable basis for establishing nuclear waste material properties and test methods. The MCC will provide a data base that will include information on the components of the waste emplacement package - the spent fuel or processed waste form and the engineered barriers - and their interaction with each other and as affected by the environment. The MCC will plan materials testing, develop and document procedures, collect and analyze existing materials data, and conduct tests as necessary

Characterization of ureasil-polyethylene oxide/chitosan hybrid materials

Energy Technology Data Exchange (ETDEWEB)

Paredes Zaldivar, M.; Pulcinelli, S.H.; Peniche Covas, C.; Santilli, C.V. [Universidad de la Habana, Havana (Cuba); Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica

2016-07-01

Full text: Siloxane-polyether hybrids are an interesting and versatile family of multifunctional organic-inorganic hybrid materials, also named ureasils. Ureasils have been the object of intensive studies in the last years due to their versatility and wide range of applications. Polyethylene oxide (PEO) and chitosan are biocompatible and low toxicity polymers that were used as organic phase while the inorganic phase was siloxane. Therefore, the aim of this work was the characterization of these hybrids that were prepared by the sol–gel route. Hydrochloric and acetic acids were used as catalysts. Due to the insolubility of chitosan in ethanol and organic solvents, water was used in the hydrolysis solution as the main component or alone. The obtained materials were transparent, rubbery, flexible and water-insoluble. They were characterized by different physicochemical techniques such as FTIR (Fourier Transform Infrared Spectroscopy), DSC (Differential Scanning Calorimetry), TG (Thermogravimetric Analysis), XRD (X-Ray Diffraction), SAXS (Small Angle X-ray Scattering) and NMR (Nuclear Magnetic Resonance Spectroscopy). Results showed that chitosan addition did not provoke appreciable changes in the thermal properties but modifies the polycondensation degree and the nanoscopic structure of the materials. Significant changes were not found neither by the hydrolysis solution nor by the type of acid, except in the thermal stability. It depended on the type of acid catalyst, being higher in hybrids prepared with HCl. We can conclude that these materials can be synthesized just with water as the hydrolysis solution and that any of the two acids can be used as catalyst without significantly affect its final properties. (author)

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

Quantitative interpretation of magnetic properties as a way to characterize biogeophysical signatures of biodegraded contaminated sites

Science.gov (United States)

Ustra, A.; Kessouri, P.; Leite, A.; Mendonça, C. A.; Bandeira, N.

2017-12-01

Magnetic minerals in soils and rocks are one way to study biogechemical and paleoenvironmental processes. The ultrafine fraction of these minerals (superparmagnetic (SP) and stable single domain (SSD)) are usually investigated in environmental magnetism studies, since changes in mineralogy, concentration, size and morphology of the magnetic grains can be related to biogeochemical processes. In this study, we use low-field frequency dependent susceptibility (FDS) and isothermal remanent magnetization (IRM) to characterize the magnetic properties of materials in environmental magnetism. Magnetic susceptibility (MS) measurements are frequently used as a proxy of magnetic minerals present in soils and rocks. MS is a complex function of magnetic mineralogy and grain size, as well as magnitude and frequency of the applied field. This work presents a method for inverting low-field FDS data. The inverted parameters can be interpreted in terms of grain size variations of magnetic particles on the SP-SSD transition. This work also presents a method for inverting IRM demagnetization curves, to obtain the saturation magnetization, the individual magnetic moment for an assemblage of ultrafine SP minerals and estimate the concentration of magnetic carriers. IRM magnetization curves can be interpreted as resulting from distinct contributions of different mineral phases, which can be described by Cummulative Log-Gaussian (CLG) distributions. Each acquisition curve provides fundamental parameters that are characteristic of the respective mineral phase. The CLG decomposition is widely used in an interpretation procedure named mineral unmixing. In this work we present an inversion method for mineral unmixing, implementing the genetic algorithm to find the parameters of distinct components. These methodologies have been tested by synthetic models and applied to data from environmental magnetism studies. In this work we apply the proposed methodologies to characterize the magnetic

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

Characterizing kernels of operators related to thin-plate magnetizations via generalizations of Hodge decompositions

International Nuclear Information System (INIS)

Baratchart, L; Hardin, D P; Saff, E B; Lima, E A; Weiss, B P

2013-01-01

Recently developed scanning magnetic microscopes measure the magnetic field in a plane above a thin-plate magnetization distribution. These instruments have broad applications in geoscience and materials science, but are limited by the requirement that the sample magnetization must be retrieved from measured field data, which is a generically nonunique inverse problem. This problem leads to an analysis of the kernel of the related magnetization operators, which also has relevance to the ‘equivalent source problem’ in the case of measurements taken from just one side of the magnetization. We characterize the kernel of the operator relating planar magnetization distributions to planar magnetic field maps in various function and distribution spaces (e.g., sums of derivatives of L p (Lebesgue spaces) or bounded mean oscillation (BMO) functions). For this purpose, we present a generalization of the Hodge decomposition in terms of Riesz transforms and utilize it to characterize sources that do not produce a magnetic field either above or below the sample, or that are magnetically silent (i.e. no magnetic field anywhere outside the sample). For example, we show that a thin-plate magnetization is silent (i.e. in the kernel) when its normal component is zero and its tangential component is divergence free. In addition, we show that compactly supported magnetizations (i.e. magnetizations that are zero outside of a bounded set in the source plane) that do not produce magnetic fields either above or below the sample are necessarily silent. In particular, neither a nontrivial planar magnetization with fixed direction (unidimensional) compact support nor a bidimensional planar magnetization (i.e. a sum of two unidimensional magnetizations) that is nontangential can be silent. We prove that any planar magnetization distribution is equivalent to a unidimensional one. We also discuss the advantages of mapping the field on both sides of a magnetization, whenever experimentally

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

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

Manganese ferrite prepared using reverse micelle process: Structural and magnetic properties characterization

Energy Technology Data Exchange (ETDEWEB)

Hashim, Mohd, E-mail: md.hashim09@gmail.com [Department of Physics, Aligarh Muslim University, Aligarh 202002 (India); Shirsath, Sagar E. [Spin Device Technology Centre, Department of Engineering, Shinshu University, Nagano 380-8553 (Japan); Meena, S.S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mane, M.L. [Department of Physics, S.G.R.G. Shinde Mahavidyalaya, Paranda 413502, MS (India); Kumar, Shalendra [School of Materials Science and Engineering, Changwon National University, Changwon, Gyeongnam 641-773 (Korea, Republic of); Bhatt, Pramod [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ravi [Centre for Material Science Engineering, National Institute of Technology, Hamirpur, HP (India); Prasad, N.K.; Alla, S.K. [Deptartment of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Shah, Jyoti; Kotnala, R.K. [National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110012 (India); Mohammed, K.A. [Department of Mathematics & Physics Sciences, College of Arts and Sciences, University of Nizwa, Nizwa (Oman); Şentürk, Erdoğan [Department of Physics, Sakarya University, Esentepe, 54187 Sakarya (Turkey); Alimuddin [Department of Physics, Aligarh Muslim University, Aligarh 202002 (India)

2015-09-05

Highlights: • Preparation of Mn{sup 3+} substituted MnFe{sub 2}O{sub 4} ferrite by Reverse microemulsion process. • Characterization by XRD, SEM, VSM, Mössbauer spectroscopy and dielectric measurements techniques. • Magnetic properties of MnFe{sub 2}O{sub 4} enhanced after Mn{sup 3+} substitution. • The dielectric constant and ac conductivity increased with Mn{sup 3+} substitution. - Abstract: Reverse microemulsion process was employed to prepare of nanocrystalline Mn{sup 3+} substituted MnFe{sub 2−x}Mn{sub x}O{sub 4} ferrites. The structural, magnetic and dielectric properties were studied for different concentrations of Mn{sup 3+}. The structural and microstructural properties were analyzed using X-ray diffraction technique (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy techniques. The phase identification of the materials was studied by Rietveld refined XRD patterns which reveals single phase with cubic symmetry for the samples. The lattice parameters were ranged in between 8.369 and 8.379 Å and do not show any significant change with the substitution of Mn{sup 3+}. The average particles size was found to be around 11 ± 3 nm. Magnetization results obtained from the vibrating sample magnetometer (VSM) confirm that the substitution of Mn{sup 3+} in MnFe{sub 2}O{sub 4} ferrite caused an increase in the saturation magnetization and coercivity. The dependence of Mössbauer parameters on Mn{sup 3+} substitution has been analyzed. Magnetic behavior of the samples were also studied at field cooled (FC) and zero field cooled (ZFC) mode. The dependence of Mössbauer parameters on Mn{sup 3+} substitution was also analyzed. All the magnetic characterization shows that Mn{sup 3+} substitution enhance the magnetic behavior of MnFe{sub 2}O{sub 4} ferrite nanoparticles.

Electromagnetic Processing of Materials Materials Processing by Using Electric and Magnetic Functions

CERN Document Server

Asai, Shigeo

2012-01-01

This book is both a course book and a monograph. In fact, it has developed from notes given to graduate course students on materials processing in the years 1989 to 2006. Electromagnetic Processing of Materials (EPM), originates from a branch of materials science and engineering developed in the 1980s as a field aiming to create new materials and/or design processes by making use of various functions which appear when applying the electric and magnetic fields to materials. It is based on transport phenomena, materials processing and magnetohydrodynamics. The first chapter briefly introduces the history, background and technology of EPM. In the second chapter, the concept of transport phenomena is concisely introduced and in the third chapter the essential part of magnetohydrodynamics is transcribed and readers are shown that the concept of transport phenomena does not only apply to heat, mass and momentum, but also magnetic field. The fourth chapter describes electromagnetic processing of electrica...

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,

Nondestructive materials characterization with applications to aerospace materials

CERN Document Server

Nagy, Peter; Rokhlin, Stanislav

2004-01-01

With an emphasis on aircraft materials, this book describes techniques for the material characterization to detect and quantify degradation processes such as corrosion and fatigue. It introduces readers to these techniques based on x-ray, ultrasonic, optical and thermal principles and demonstrates the potential of the techniques for a wide variety of applications concerning aircraft materials, especially aluminum and titanium alloys. The advantages and disadvantages of various techniques are evaluated. An introductory chapter describes the typical degradation mechanisms that must be considered and the microstructure features that have to be detected by NDE methods. Finally, some approaches for making lifetime predictions are discussed. It is suitable as a textbook in special training courses in advanced NDE and aircraft materials characterization.

Carbon based magnetism an overview of the magnetism of metal free carbon-based compounds and materials

CERN Document Server

Makarova, Tatiana

2006-01-01

Magnetism is one of the most intriguing phenomena observed in nature. Magnetism is relevant to physics and geology, biology and chemistry. Traditional magnets, an ubiquitous part of many everyday gadgets, are made of heavy iron- or nickel based materials. Recently there have been reports on the observation of magnetism in carbon, a very light and biocompatible element. Metal-free carbon structures exhibiting magnetic ordering represent a new class of materials and open a novel field of research that could lead to many new technologies. · The most complete, detailed, and accurate Guide in the magnetism of carbon · Dynamically written by the leading experts · Deals with recent scientific highlights · Gathers together chemists and physicists, theoreticians and experimentalists · Unified treatment rather than a series of individually authored papers · Description of genuine organic molecular ferromagnets · Unique description of new carbon materials with Curie temperatures well above ambient.

Impact-limiting materials characterization

International Nuclear Information System (INIS)

Glass, R.E.; Duffey, T.A.; McConnell, P.

1993-01-01

Three types of impact-limiting materials have been characterized which have applications in packages for the transport of radioactive materials. These materials are aluminum honeycombs, polyurethane foams, and aluminum foams. The results of the materials characterization have indicated strengths and weaknesses for each type of material. The polyurethane foams provide good impact limiting ability and excellent thermal insulation. However, they burn when subjected to the regulatory thermal event in the presence of air. The aluminum honeycombs provide excellent impact resistance in specific impact orientations. However, they provide relatively poor resistance to thermal assault. Finally, the aluminum foams exhibit relatively poor impact energy absorption capacities, significant variability in energy absorption, and limited thermal insulation. The development of the figures of merit examined the response of the materials to the impact event with the intent of maximizing the energy absorption of the materials with respect to either the volume or mass of the materials. Three figures of merit will be presented for the structural response. The figure of merit for the thermal event is based on minimizing the heat flux to the containment boundary. The paper presents a discussion of the test methods, a summary of the data and the figures of merit for each material. (J.P.N.)

Core-shell magnetic nanowires fabrication and characterization

Energy Technology Data Exchange (ETDEWEB)

Kalska-Szostko, B., E-mail: kalska@uwb.edu.pl [Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok (Poland); Faculty of Physics, University of Bialystok, Ciolkowskiego 1L, 15-245 Bialystok, Poland (Poland); Klekotka, U.; Satuła, D. [Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok (Poland); Faculty of Physics, University of Bialystok, Ciolkowskiego 1L, 15-245 Bialystok, Poland (Poland)

2017-02-28

Highlights: • New approach for nanowires modification are presented. • Physical and chemical characterization of the nanowires are shown. • Properties modulations as an effect of the surface layer composition are discussed. - Abstract: In this paper, a new way of the preparation of core-shell magnetic nanowires has been proposed. For the modification Fe nanowires were prepared by electrodeposition in anodic aluminium oxide matrixes, in first step. In second, by wetting chemical deposition, shell layers of Ag, Au or Cu were obtained. Resultant core-shell nanowires structure was characterized by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, and energy dispersive x-ray. Whereas magnetic properties by Mössbauer spectroscopy.

Materials Characterization of Feraheme/Ferumoxytol and Preliminary Evaluation of Its Potential for Magnetic Fluid Hyperthermia

Directory of Open Access Journals (Sweden)

Jon Dobson

2013-08-01

Full Text Available Feraheme, is a recently FDA-cleared superparamagnetic iron oxide nanoparticle (SPION-based MRI contrast agent that is also employed in the treatment of iron deficiency anemia. Feraheme nanoparticles have a hydrodynamic diameter of 30 nm and consist of iron oxide crystallites complexed with a low molecular weight, semi-synthetic carbohydrate. These features are attractive for other potential biomedical applications such as magnetic fluid hyperthermia (MFH, since the carboxylated polymer coating affords functionalization of the particle surface and the size allows for accumulation in highly vascularized tumors via the enhanced permeability and retention effect. This work presents morphological and magnetic characterization of Feraheme by transmission electron microscopy (TEM, Energy dispersive X-ray spectroscopy (EDX, and superconducting quantum interference device (SQUID magnetometry. Additionally, the results of an initial evaluation of the suitability of Feraheme for MFH applications are described, and the data indicate the particles possess promising properties for this application.

Multi-pole magnetization of NdFeB magnets for magnetic micro-actuators and its characterization with a magnetic field mapping device

International Nuclear Information System (INIS)

Toepfer, J.; Pawlowski, B.; Beer, H.; Ploetner, K.; Hofmann, P.; Herrfurth, J.

2004-01-01

Multi-pole magnetization of NdFeB plate magnets of thickness between 0.25 and 2 mm with a stripe pattern and a pole pitch of 2 or 1 mm was performed by pulse magnetization. The experimental conditions of the magnetization process were optimized to give a maximum surface flux density at the poles. The magnetic field distribution above the magnets was measured with a field mapping device that automatically scans the surface of the magnet with a Hall probe. It is demonstrated for different magnet geometries that the field mapping system is a useful device to study the magnetic surface pole structure. The characterization of the pole flux density of multi-pole NdFeB flat magnets is an important prerequisite for the application of these magnets in miniature actuators

Knitted radar absorbing materials (RAM) based on nickel–cobalt magnetic materials

International Nuclear Information System (INIS)

Teber, Ahmet; Unver, Ibrahim; Kavas, Huseyin; Aktas, Bekir; Bansal, Rajeev

2016-01-01

There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, K_u, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under −20 dB return loss over a moderate bandwidth). - Graphical abstract: Here, we added the graphical abstract that provides summary the contents of the article in a concise pictorial form. - Highlights: • Flexible lightweight, thin, reconfigurable radar absorbing materials are proposed. • Polyacrylonitrile (PAN) fabrics are coated with nickel, cobalt magnetic materials. • The coating times affects microwave constitutive parameters and absorption. • Microwave absorption measurements were done via transmission line technique. • Microwave absorption is due to dielectric losses rather than magnetic losses.

Knitted radar absorbing materials (RAM) based on nickel–cobalt magnetic materials

Energy Technology Data Exchange (ETDEWEB)

Teber, Ahmet, E-mail: aht10003@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States); Unver, Ibrahim, E-mail: iunver@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Kavas, Huseyin, E-mail: huseyin.kavas@medeniyet.edu.tr [Department of Physics, Istanbul Medeniyet University, Istanbul 34000 (Turkey); Aktas, Bekir, E-mail: aktas@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Bansal, Rajeev, E-mail: rajeev@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States)

2016-05-15

There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, K{sub u}, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under −20 dB return loss over a moderate bandwidth). - Graphical abstract: Here, we added the graphical abstract that provides summary the contents of the article in a concise pictorial form. - Highlights: • Flexible lightweight, thin, reconfigurable radar absorbing materials are proposed. • Polyacrylonitrile (PAN) fabrics are coated with nickel, cobalt magnetic materials. • The coating times affects microwave constitutive parameters and absorption. • Microwave absorption measurements were done via transmission line technique. • Microwave absorption is due to dielectric losses rather than magnetic losses.

Sm and Y radiolabeled magnetic fluids: magnetic and magneto-optical characterization

Energy Technology Data Exchange (ETDEWEB)

Aquino, R. [Complex Fluids Group, Instituto de Quimica, Universidade de Brasilia, Caixa Postal 04478, 70919-970 Brasilia (DF) (Brazil) and Laboratoire des Milieux Deet Heterogenes, Universite Pierre et Marie Curie (Paris 6), Site de Boucicaut, case 86, 140, Rue de Lourmel, 75015 Paris (France)]. E-mail: reaquino@unb.br; Gomes, J.A. [Complex Fluids Group, Instituto de Fisica, Universidade de Brasilia, 70919-970 Brasilia (DF) (Brazil); Tourinho, F.A. [Complex Fluids Group, Instituto de Quimica, Universidade de Brasilia, Caixa Postal 04478, 70919-970 Brasilia (DF) (Brazil); Dubois, E. [Laboratoire des Liquides Ioniques et Interfaces Chargees, Universite Pierre et Marie Curie (Paris 6), Batiment F, Case 63, 4 place Jussieu, 75252 Paris Cedex 05 (France); Perzynski, R. [Laboratoire des Milieux Deet Heterogenes, Universite Pierre et Marie Curie (Paris 6), Site de Boucicaut, case 86, 140, Rue de Lourmel, 75015 Paris (France); Silva, G.J. da [Complex Fluids Group, Instituto de Fisica, Universidade de Brasilia, 70919-970 Brasilia (DF) (Brazil); Depeyrot, J. [Complex Fluids Group, Instituto de Fisica, Universidade de Brasilia, 70919-970 Brasilia (DF) (Brazil)

2005-03-15

We report on magnetic fluids based on samarium and ytrium-doped nanoparticles. The nanostructures chemical composition is checked and X-ray diffraction provides both their mean size and a structural characterization. Magnetization and magneto-optical birefringence results are presented and well agree with the pure maghemite behavior. Since these particles can become radioactive after neutron activation, they could therefore represent a new perspective for biomedical applications in the radiation therapy of cancer.

Sm and Y radiolabeled magnetic fluids: magnetic and magneto-optical characterization

Science.gov (United States)

Aquino, R.; Gomes, J. A.; Tourinho, F. A.; Dubois, E.; Perzynski, R.; da Silva, G. J.; Depeyrot, J.

2005-03-01

We report on magnetic fluids based on samarium and ytrium-doped nanoparticles. The nanostructures chemical composition is checked and X-ray diffraction provides both their mean size and a structural characterization. Magnetization and magneto-optical birefringence results are presented and well agree with the pure maghemite behavior. Since these particles can become radioactive after neutron activation, they could therefore represent a new perspective for biomedical applications in the radiation therapy of cancer.

Sm and Y radiolabeled magnetic fluids: magnetic and magneto-optical characterization

International Nuclear Information System (INIS)

Aquino, R.; Gomes, J.A.; Tourinho, F.A.; Dubois, E.; Perzynski, R.; Silva, G.J. da; Depeyrot, J.

2005-01-01

We report on magnetic fluids based on samarium and ytrium-doped nanoparticles. The nanostructures chemical composition is checked and X-ray diffraction provides both their mean size and a structural characterization. Magnetization and magneto-optical birefringence results are presented and well agree with the pure maghemite behavior. Since these particles can become radioactive after neutron activation, they could therefore represent a new perspective for biomedical applications in the radiation therapy of cancer

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

Synthesis and characterization of ultrafine well-dispersed magnetic nanoparticles

International Nuclear Information System (INIS)

Liu, Z.L.; Wang, H.B.; Lu, Q.H.; Du, G.H.; Peng, L.; Du, Y.Q.; Zhang, S.M.; Yao, K.L.

2004-01-01

Ultrafine well-dispersed magnetic nanoparticles were directly prepared in aqueous solution using controlled coprecipitation method. The structure, size, size distributions and magnetic properties of the magnetic nanoparticles, characterized by TEM, XRD and VSM, indicated the formation of single domain nanoparticles with average size smaller than 5 nm. The magnetic nanoparticles show superparamagnetism and a lower saturation magnetization is found as a consequence of smaller particle size. The relevant conditions for obtaining these magnetic colloids are discussed and the so-prepared magnetic nanoparticles are stable in a wide pH range

Structure and magnetic properties of SiO{sub 2}/PCL novel sol–gel organic–inorganic hybrid materials

Energy Technology Data Exchange (ETDEWEB)

Catauro, Michelina, E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Bollino, Flavia [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Cristina Mozzati, Maria [Department of Physics, CNISM and INSTM, University of Pavia, Via Bassi 6, 27100 Pavia (Italy); Ferrara, Chiara; Mustarelli, Piercarlo [Department of Chemistry, Section of Physical Chemistry, University of Pavia and INSTM, Via Taramelli 16, 27100 Pavia (Italy)

2013-07-15

Organic–inorganic nanocomposite materials have been synthesized via sol–gel. They consist of an inorganic SiO{sub 2} matrix, in which different percentages of poly(ε-caprolactone) (PCL) have been incorporated. The formation of H-bonds among the carbonyl groups of the polymer chains and Si–OH group of the inorganic matrix has been proved by means of Fourier transform infrared spectroscopy (FT-IR) analysis and has been confirmed by solid-state nuclear magnetic resonance (NMR). X-Ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials. Scanning electron microscope (SEM) micrograph and atomic force microscope (AFM) topography showed their homogeneous morphology and nanostructure nature. Considering the opportunity to synthesize these hybrid materials under microgravity conditions by means of magnetic levitation, superconducting quantum interference device (SQUID) magnetometry has been used to quantify their magnetic susceptibility. This measure has shown that the SiO{sub 2}/PCL hybrid materials are diamagnetic and that their diamagnetic susceptibility is independent of temperature and increases with the PCL amount. - Graphical abstract: Characterization and magnetic properties of SiO{sub 2}/PCL organic–inorganic hybrid materials synthesized via sol–gel. FT-IR, Fourier transform infrared spectroscopy; solid-state NMR: solid-state nuclear magnetic resonance; SQUID: superconducting quantum interference device. - Highlights: • Sol–gel synthesis of SiO{sub 2}/PCL amorphous class I organic–inorganic hybrid materials. • FT-IR and NMR analyses show the hydrogen bonds formation between SiO{sub 2} and PCL. • AFM and SEM analyses confirm that the SiO{sub 2}/PCL are homogenous hybrid materials. • The SQUID measures show that the simples are diamagnetic. • Diamagnetic susceptibility of SiO{sub 2}/PCL materials increases with the PCL amount.

Properties and characterization of modern materials

CERN Document Server

Altenbach, Holm

2017-01-01

This book focuses on robust characterization and prediction methods for materials in technical applications as well as the materials’ safety features during operation. In particular, it presents methods for reliably predicting material properties, an aspect that is becoming increasingly important as engineering materials are pushed closer and closer to their limits to boost the performance of machines and structures. To increase their engineering value, components are now designed under the consideration of their multiphysical properties and functions, which requires much more intensive investigation and characterization of these materials. The materials covered in this monograph range from metal-based groups such as lightweight alloys, to advanced high-strength steels and modern titanium alloys. Furthermore, a wide range of polymers and composite materials (e.g. with micro- and nanoparticles or fibres) is covered. The book explores methods for property prediction from classical mechanical characterization-...

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°.

Review and comparison of magnet designs for magnetic refrigeration

DEFF Research Database (Denmark)

Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders

2010-01-01

One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a large effort should therefore be invested in improving...... the magnet design. A detailed analysis of the efficiency of different published permanent magnet designs used in magnetic refrigeration applications is presented in this paper. Each design is analyzed based on the generated magnetic flux density, the volume of the region where this flux is generated...... and the amount of magnet material used. This is done by characterizing each design by a figure of merit magnet design efficiency parameter, Λcool. The designs are then compared and the best design found. Finally recommendations for designing the ideal magnet design are presented based on the analysis...

Magnetic zeolites a and p synthesized from kaolin: synthesis and characterization

Energy Technology Data Exchange (ETDEWEB)

Bessa, R.A.; Oliveira, C.P.; Nascimento, R.F.; Bohn, F.; Loiola, A.R. [Universidade Federal do Ceara (UFCE), CE (Brazil)

2016-07-01

Full text: Zeolites are hydrated aluminosilicates of open chain, formed by silica and alumina tetrahedral structures linked by common oxygen atoms, generating interconnected pores and cages with molecular dimensions and well defined sizes that limit matter transference between internal surface and application medium. They can be found naturally or synthesized using different aluminum and silicon sources that may modify the produced zeolite. Their industrial application has grown enormously over the last century. However, a big issue that still remains is the difficulty in retrieving zeolite powders when used in aqueous media. This work reports the use of kaolin as an alternative raw material for zeolite syntheses by means of hydrothermal route and subsequent preparation of magnetic composites through magnetite impregnation. The syntheses of two different zeolites were carried out by mixing appropriate amounts of metakaolin (kaolin previously calcined at 600 deg C for 2 h), sodium metasilicate and sodium hydroxide solution, aged for 18 h and heated at 100 °C for 4-48 h. After these processes, the final materials were washed several times with distilled water, filtered and dried at 80 deg C for 12 h. Magnetic composites were prepared by impregnating the zeolites with of Fe3O4 nanoparticles (NP) synthesized by the partial oxidation and precipitation of Fe2+ ions. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, FTIR spectroscopy and magnetization measurements. The results of XRD and FTIR provide evidence of the success in the synthesis of both zeolites A and P as well as Fe3O4. Subsequently, composites were formed by mixtures of zeolite A + NP and zeolite P + NP. The existence of secondary crystalline phases was also confirmed. However, it did not interfered significantly in the results as these phases appear as minor amounts and are most likely residues from the clay used as the main silica and alumina sources. Scanning

Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

Energy Technology Data Exchange (ETDEWEB)

Li, Shaoping, E-mail: shaoping.li@wdc.com; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek [Western Digital Corp., 44100 Osgood Road, Fremont, California 94539 (United States)

2014-05-07

In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail.

Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

International Nuclear Information System (INIS)

Li, Shaoping; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek

2014-01-01

In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail

Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

Science.gov (United States)

Li, Shaoping; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek

2014-01-01

In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail. PMID:24753633

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

Classification of analysis methods for characterization of magnetic nanoparticle properties

DEFF Research Database (Denmark)

Posth, O.; Hansen, Mikkel Fougt; Steinhoff, U.

2015-01-01

The aim of this paper is to provide a roadmap for the standardization of magnetic nanoparticle (MNP) characterization. We have assessed common MNP analysis techniques under various criteria in order to define the methods that can be used as either standard techniques for magnetic particle...... characterization or those that can be used to obtain a comprehensive picture of a MNP system. This classification is the first step on the way to develop standards for nanoparticle characterization....

Magnetic characterization techniques for nanomaterials

CERN Document Server

2017-01-01

Sixth volume of a 40 volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about Magnetic Characterization Techniques for Nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.

Apparatus and method for materials processing utilizing a rotating magnetic field

Science.gov (United States)

Muralidharan, Govindarajan; Angelini, Joseph A.; Murphy, Bart L.; Wilgen, John B.

2017-04-11

An apparatus for materials processing utilizing a rotating magnetic field comprises a platform for supporting a specimen, and a plurality of magnets underlying the platform. The plurality of magnets are configured for rotation about an axis of rotation intersecting the platform. A heat source is disposed above the platform for heating the specimen during the rotation of the plurality of magnets. A method for materials processing utilizing a rotating magnetic field comprises providing a specimen on a platform overlying a plurality of magnets; rotating the plurality of magnets about an axis of rotation intersecting the platform, thereby applying a rotating magnetic field to the specimen; and, while rotating the plurality of magnets, heating the specimen to a desired temperature.

Investigations on the magnetization behavior of magnetic composite particles

Energy Technology Data Exchange (ETDEWEB)

Eichholz, Christian [Process Research and Chemical Engineering, BASF SE, Ludwigshafen (Germany); Knoll, Johannes, E-mail: johannes.knoll@kit.edu [Institute of Mechanical Engineering and Mechanics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Lerche, Dietmar [L.U.M. GmbH, Berlin (Germany); Nirschl, Hermann [Institute of Mechanical Engineering and Mechanics, Karlsruhe Institute of Technology, Karlsruhe (Germany)

2014-11-15

In life sciences the application of surface functionalized magnetic composite particles is establishing in diagnostics and in downstream processing of modern biotechnology. These magnetic composite particles consist of non-magnetic material, e.g. polystyrene, which serves as a matrix for the second magnetic component, usually colloidal magnetite. Because of the multitude of magnetic cores these magnetic beads show a complex magnetization behavior which cannot be described with the available approaches for homogeneous magnetic material. Therefore, in this work a new model for the magnetization behavior of magnetic composite particles is developed. By introducing an effective magnetization and considering an overall demagnetization factor the deviation of the demagnetization of homogeneously magnetized particles is taken into account. Calculated and experimental results show a good agreement which allows for the verification of the adapted model of particle magnetization. Besides, a newly developed magnetic analyzing centrifuge is used for the characterization of magnetic composite particle systems. The experimental results, also used for the model verification, give both, information about the magnetic properties and the interaction behavior of particle systems. By adding further components to the particle solution, such as salts or proteins, industrial relevant systems can be reconstructed. The analyzing tool can be used to adapt industrial processes without time-consuming preliminary tests with large samples in the process equipments. - Highlights: • New model for magnetizability calculation of magnetic composite particles. • New method for particle bulk characterization relating to their magnetizability. • Model verification due to experimental data.

Investigations on the magnetization behavior of magnetic composite particles

International Nuclear Information System (INIS)

Eichholz, Christian; Knoll, Johannes; Lerche, Dietmar; Nirschl, Hermann

2014-01-01

In life sciences the application of surface functionalized magnetic composite particles is establishing in diagnostics and in downstream processing of modern biotechnology. These magnetic composite particles consist of non-magnetic material, e.g. polystyrene, which serves as a matrix for the second magnetic component, usually colloidal magnetite. Because of the multitude of magnetic cores these magnetic beads show a complex magnetization behavior which cannot be described with the available approaches for homogeneous magnetic material. Therefore, in this work a new model for the magnetization behavior of magnetic composite particles is developed. By introducing an effective magnetization and considering an overall demagnetization factor the deviation of the demagnetization of homogeneously magnetized particles is taken into account. Calculated and experimental results show a good agreement which allows for the verification of the adapted model of particle magnetization. Besides, a newly developed magnetic analyzing centrifuge is used for the characterization of magnetic composite particle systems. The experimental results, also used for the model verification, give both, information about the magnetic properties and the interaction behavior of particle systems. By adding further components to the particle solution, such as salts or proteins, industrial relevant systems can be reconstructed. The analyzing tool can be used to adapt industrial processes without time-consuming preliminary tests with large samples in the process equipments. - Highlights: • New model for magnetizability calculation of magnetic composite particles. • New method for particle bulk characterization relating to their magnetizability. • Model verification due to experimental data

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

Characterization of Li4Ti5O12 and LiMn2O4 spinel materials treated with aqueous acidic solutions

NARCIS (Netherlands)

Simon, D.R.

2007-01-01

In this thesis an investigation of two spinel materials, Li4Ti5O12 and LiMn2O4 used for Li-ion battery applications is performed interms of formation and reactivity towards acidic solutions. Subsequent characterizations such as structural, magnetic, chemical, and electrochemical characterizations

Optimal needle placement for the accurate magnetic material quantification based on uncertainty analysis in the inverse approach

International Nuclear Information System (INIS)

Abdallh, A; Crevecoeur, G; Dupré, L

2010-01-01

The measured voltage signals picked up by the needle probe method can be interpreted by a numerical method so as to identify the magnetic material properties of the magnetic circuit of an electromagnetic device. However, when solving this electromagnetic inverse problem, the uncertainties in the numerical method give rise to recovery errors since the calculated needle signals in the forward problem are sensitive to these uncertainties. This paper proposes a stochastic Cramér–Rao bound method for determining the optimal sensor placement in the experimental setup. The numerical method is computationally time efficient where the geometrical parameters need to be provided. We apply the method for the non-destructive magnetic material characterization of an EI inductor where we ascertain the optimal experiment design. This design corresponds to the highest possible resolution that can be obtained when solving the inverse problem. Moreover, the presented results are validated by comparison with the exact material characteristics. The results show that the proposed methodology is independent of the values of the material parameter so that it can be applied before solving the inverse problem, i.e. as a priori estimation stage

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

Controlling Magnetic and Ferroelectric Order Through Geometry: Synthesis, Ab Initio Theory, Characterization of New Multi-Ferric Fluoride Materials

Energy Technology Data Exchange (ETDEWEB)

Halasyamani, Shiv [Univ. of Houston, TX (United States); Fennie, Craig [Cornell Univ., Ithaca, NY (United States)

2016-11-03

We have focused on the synthesis, characterization, and ab initio theory on multi-functional mixed-metal fluorides. With funding from the DOE, we have successfully synthesized and characterized a variety of mixed metal fluoride materials.

Surface, interface and thin film characterization of nano-materials using synchrotron radiation

International Nuclear Information System (INIS)

Kimura, Shigeru; Kobayashi, Keisuke

2005-01-01

From the results of studies in the nanotechnology support project of the Ministry of Education, Culture, Sports, Science and Technology of Japan, several investigations on the surface, interface and thin film characterization of nano-materials are described; (1) the MgB 2 thin film by X-ray diffraction, (2) the magnetism of the Pt thin film on a Co film by X-ray magnetic circular dichroism measurement, (3) the structure and physical properties of oxygen molecules absorbed in a micro hole of the cheleted polymer crystal by the direct observation in X-ray powder diffraction, and (4) the thin film gate insulator with a large dielectric constant, thermally treated HfO 2 /SiO 2 /Si, by X-ray photoelectron spectroscopy. (M.H.)

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.

Magnetic refrigeration cycle analysis using selected thermodynamic property characterizations for gadolinium gallium garnet

International Nuclear Information System (INIS)

Murphy, R.W.

1992-01-01

Magneto-thermodynamic property characterizations were selected, adapted, and compared to material property data for gadolinium gallium garnet in the temperature range 4--40 K and magnetic field range 0--6 T. The most appropriate formulations were incorporated into a model in which methods similar to those previously developed for other materials and temperature ranges were used to make limitation and relative performance assessments of Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. Analysis showed that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as those for materials previously examined, substantial improvements in cooling capacity/temperature lift combinations can be achieved using regenerative cycles within specified fields limits if significant loss mechanisms are mitigated

Material Response Characterization

Science.gov (United States)

1977-08-01

models fit to vertical UX and TX data and a mean stress tension cutoff criterion. Because tests on the Kayenta sands one materials had revealed a definite...parameters. 9 This data characterizing the anisotropic response of the upper 30 feet of Kayenta material should not just be filed away; it should be used...9. Johnson, J. N., et al, "Anisotropic Mechanical Properties of Kayenta Sandstone (MIXED COMPANY Site) for Ground Motion Calculations," Terra Tek TR

Analytical nondestructive evaluation for materials characterization

International Nuclear Information System (INIS)

Raj, Baldev

1993-01-01

Science and technology of nondestructive testing and evaluation has contributed immensely to the safety and productivity of industrial plants. In recent years, nondestructive evaluation (NDE) has emerged as a frontline research area of equal if not greater technological relevance, for materials characterization as well. A comprehensive range of techniques from qualitative nondestructive testing for quality control of engineering products and materials to quantitative NDE for materials characterization is being used by the engineering industry and materials researchers, for better understanding of the manufacturing practices and materials behaviour. Quantitative NDE is considered essential for ensuring fitness for purpose at the start of the life in case the component has been designed using fracture mechanics parameters. Quantitative NDE is also vital for assessing degradation of material during service. Moreover, quantitative NDE enables characterization of dynamics of certain phenomenon (not achievable by destructive test methodologies) leading to better understanding of the performance of materials in relation to unavoidable defects in the materials. As the next logical step, the need for an analytical approach to NDE is felt. The need and motivation for such an approach is addressed and the means to achieve this objective are identified. It is argued that analytical NDE is essential to meet the challenges of characterization, intelligent processing of materials and life prediction of components and plants. These requirements are of significant importance in the context of recent developments in materials engineering, and for enhancing the competitive advantage of Indian engineering industry in the international market. (author). 9 refs., 3 figs

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.

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...

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.

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

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.)

Nano-magnetic particles used in biomedicine: core and coating materials.

Science.gov (United States)

Karimi, Z; Karimi, L; Shokrollahi, H

2013-07-01

Magnetic nanoparticles for medical applications have been developed by many researchers. Separation, immunoassay, drug delivery, magnetic resonance imaging and hyperthermia are enhanced by the use of suitable magnetic nanoparticles and coating materials in the form of ferrofluids. Due to their low biocompatibility and low dispersion in water solutions, nanoparticles that are used for biomedical applications require surface treatment. Various kinds of coating materials including organic materials (polymers), inorganic metals (gold, platinum) or metal oxides (aluminum oxide, cobalt oxide) have been attracted during the last few years. Based on the recent advances and the importance of nanomedicine in human life, this paper attempts to give a brief summary on the different ferrite nano-magnetic particles and coatings used in nanomedicine. Copyright © 2013 Elsevier B.V. All rights reserved.

Lanthanide phosphonates: Synthesis, thermal stability and magnetic characterization

Energy Technology Data Exchange (ETDEWEB)

Amghouz, Z., E-mail: amghouz.uo@uniovi.es [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Garcia, J.R.; Garcia-Granda, S. [Departamentos de Quimica Fisica y Analitica y Quimica Organica e Inorganica, Universidad de Oviedo - CINN, 33006 Oviedo (Spain); Clearfield, A. [Department of Chemistry, Texas A and M University, College Station, TX 77842-3012 (United States); Rodriguez Fernandez, J.; Pedro, I. de [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, 33007 Oviedo (Spain)

2012-09-25

Highlights: Black-Right-Pointing-Pointer Report of the complete series of lanthanide 1,4-phenylbis(phosphonate). Black-Right-Pointing-Pointer Synthesis under conventional hydrothermal synthesis or microwave-assisted hydrothermal synthesis. Black-Right-Pointing-Pointer Cation size is the key factor for the structural and particles size variations. Black-Right-Pointing-Pointer Thermal behaviour is characterized by unusual very high thermal stability. - Abstract: Series of novel organic-inorganic hybrids materials based on trivalent lanthanides (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and 1,4-phenylbis(phosphonate) obtained under hydrothermal conditions either by oven heat or microwave irradiation. The anhydrous compounds containing La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho, are isostructural. However, the compounds based on Y, Er, Tm, Yb, and Lu are hydrated and their structures have not yet been solved. The series of compounds are characterized by PXRD, TEM, SEM-EDX and thermal analyses (TG-MS and DSC). TEM study show a variable particles size with a minimum mean-particle size of ca. 30 nm. These compounds exhibit unusual very high thermal stability. The size of particles and the thermal stability are depending on lanthanide(III) cation features. All the investigated materials show paramagnetic behaviour. The magnetic susceptibility data follow a Curie-Weiss laws with paramagnetic effective moments in good agreement with those expected for Ln{sup 3+} free ions.

Composite materials processing, applications, characterizations

CERN Document Server

2017-01-01

Composite materials are used as substitutions of metals/traditional materials in aerospace, automotive, civil, mechanical and other industries. The present book collects the current knowledge and recent developments in the characterization and application of composite materials. To this purpose the volume describes the outstanding properties of this class of advanced material which recommend it for various industrial applications.

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.

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.

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.

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.

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.

Influence of processing on structure property correlations in τ-MnAl rare-earth free permanent magnet material

Energy Technology Data Exchange (ETDEWEB)

Singh, Nidhi; Mudgil, Varun; Anand, Kanika; Srivastava, A.K.; Kotnala, R.K.; Dhar, Ajay, E-mail: adhar@nplindia.org

2015-06-05

Highlights: • The reported magnetic properties of τ-MnAl show a significant scatter in their data. • We report the synthesis of τ-MnAl employing different processing routes. • The observed magnetic properties were correlated with the synthesis route. • The resulting microstructure has been correlated with the magnetic properties. - Abstract: In order to understand the genesis of the magnetic τ-phase of MnAl alloy, which due to its multiphase nature is generally difficult to synthesize as a single-phase, we have synthesized it employing three different materials processing routes, namely, arc melting, mechanical alloying, and a combination of these two. Structural and microstructural characterizations employing X-ray diffraction and high resolution transmission electron microscopy demonstrate that irrespective of the material processing route employed, the formation of τ-MnAl phase was always accompanied by other non-magnetic phases, e.g., β-MnAl and γ-MnAl. However, the relative fraction of these phases was found to be dependent on the materials processing route and hence on the grain size of the parent phase. The arc melted alloy had the largest grain size and the highest fraction of the τ-MnAl phase, while the alloy prepared by mechanical alloying showed the smallest grain size and the lowest fraction of the magnetic phase. The largest value of Curie temperature, magnetic moment, coercivity and remanence were observed in the sample prepared by a combination of arc melting and mechanical alloying. Our results suggest that in addition to the τ-MnAl phase fraction the magnetic properties could be related to the density of structural defects.

Influence of processing on structure property correlations in τ-MnAl rare-earth free permanent magnet material

International Nuclear Information System (INIS)

Singh, Nidhi; Mudgil, Varun; Anand, Kanika; Srivastava, A.K.; Kotnala, R.K.; Dhar, Ajay

2015-01-01

Highlights: • The reported magnetic properties of τ-MnAl show a significant scatter in their data. • We report the synthesis of τ-MnAl employing different processing routes. • The observed magnetic properties were correlated with the synthesis route. • The resulting microstructure has been correlated with the magnetic properties. - Abstract: In order to understand the genesis of the magnetic τ-phase of MnAl alloy, which due to its multiphase nature is generally difficult to synthesize as a single-phase, we have synthesized it employing three different materials processing routes, namely, arc melting, mechanical alloying, and a combination of these two. Structural and microstructural characterizations employing X-ray diffraction and high resolution transmission electron microscopy demonstrate that irrespective of the material processing route employed, the formation of τ-MnAl phase was always accompanied by other non-magnetic phases, e.g., β-MnAl and γ-MnAl. However, the relative fraction of these phases was found to be dependent on the materials processing route and hence on the grain size of the parent phase. The arc melted alloy had the largest grain size and the highest fraction of the τ-MnAl phase, while the alloy prepared by mechanical alloying showed the smallest grain size and the lowest fraction of the magnetic phase. The largest value of Curie temperature, magnetic moment, coercivity and remanence were observed in the sample prepared by a combination of arc melting and mechanical alloying. Our results suggest that in addition to the τ-MnAl phase fraction the magnetic properties could be related to the density of structural defects

Microstructural characterization of rare earth-cobalt magnets

International Nuclear Information System (INIS)

Mishra, R.K.; Thomas, G.

1979-10-01

Structural faults and phase transformations in R 2 -Co 17 magnets are studied using transmission electron microscopy. The magnetization mechanism in a step aged Sm (Co, Fe, Cu, Zr) alloy is determined to be by domain wall pinning in the 1:5 phase of the cellular microstructure. Limitations of the electron metallography technique to study these materials are pointed out

Synthesis and characterization of cationic lipid coated magnetic nanoparticles using multiple emulsions as microreactors

Energy Technology Data Exchange (ETDEWEB)

Akbaba, Hasan; Karagöz, Uğur [Ege University, Faculty of Pharmacy, Department of Pharmaceutical Biotechnology, 35100 Izmir (Turkey); Selamet, Yusuf [Izmir Institute of Technology, Faculty of Science, Department of Physics, 35433 Izmir (Turkey); Kantarcı, A. Gülten, E-mail: gulten.kantarci@ege.edu.tr [Ege University, Faculty of Pharmacy, Department of Pharmaceutical Biotechnology, 35100 Izmir (Turkey)

2017-03-15

The aim of this study was to develop a novel iron oxide nanoparticle synthesis method with in-situ surface coating. For this purpose multiple emulsions were used as microreactors for the first time and magnetic iron oxide particles synthesized in the core of cationic solid lipid nanoparticles. DLS, SEM, TEM, VSM, Raman Spectrometer, XRD, and XPS techniques were performed for characterization of the magnetic nanoparticles. Obtained magnetic nanoparticles are superparamagnetic and no additional process was needed for surface adjustments. They are positively charged as a result of cationic lipid coating and has appropriate particle size (<30 nm) for drug or nucleic acid delivery. Structure analysis showed that magnetic core material is in the form of magnetite. Saturation magnetization value was measured as 15–17 emu g{sup −1} for lipid coated magnetic nanoparticles obtained by multiple emulsion method which is reasonably sufficient for magnetic targeting. - Highlights: • A novel iron oxide nanoparticle synthesis method with in-situ surface coating. • Combining advantages of microemulsions and multiple emulsion methods. • Multiple emulsions were used as microreactors for magnetic nanoparticle synthesis. • Superparamagnetic iron oxide particles synthesized in the core of cationic lipids. • Possible delivery systems for nucleic acids, oil soluble compounds or drugs.

Permanent magnets including undulators and wigglers

CERN Document Server

Bahrdt, J

2010-01-01

After a few historic remarks on magnetic materials we introduce the basic definitions related to permanent magnets. The magnetic properties of the most common materials are reviewed and the production processes are described. Measurement techniques for the characterization of macroscopic and microscopic properties of permanent magnets are presented. Field simulation techniques for permanent magnet devices are discussed. Today, permanent magnets are used in many fields. This article concentrates on the applications of permanent magnets in accelerators starting from dipoles and quadrupoles on to wigglers and undulators.

Characterization of human breast disease using phosphorus magnetic resonance spectroscopy and proton magnetic resonance imaging

International Nuclear Information System (INIS)

Merchant, T.E.

1992-01-01

This thesis provides the fundamental characterization and differentiation of breast tissues using in vivo and ex vivo MR techniques in the hope that these techniques and experimental findings will be used on a larger scale and in a predictive manner in order to improve the specificity of diagnosis and treatment of breast cancer. In this dissertation, clinical studies were performed using proton magnetic resonance imaging and phosphorus magnetic resonance spectro-scopy ( 31 P MRS) to characterize and differentiate malignant breast tumors, benign breast tumors and normal breast tissues in vivo. These studies were carried out following the methodical characterization of chemical extracts of malignant breast tumor, benign breast tumor and normal breast parenchymal surgical tissue specimens using high resolution 31 P MRS. Alterations in breast tissue metabolism, as a result of pathological processes, were postulated to be responsible for measurable differences between malignant breast tumors, benign breast tumors and normal breast tissues using magnetic resonance techniques. (author). 365 refs.; 37 figs.; 25 tabs

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.…

Characterization of magnetic biochar amended with silicon dioxide prepared at high temperature calcination

Directory of Open Access Journals (Sweden)

Baig Shams Ali

2016-09-01

Full Text Available Calcination is considered to increase the hardness of composite material and prevent its breakage for the effective applications in environmental remediation. In this study, magnetic biochar amended with silicon dioxide was calcined at high temperature under nitrogen environment and characterized using various techniques. X-ray diffraction (XRD analysis revealed elimination of Fe3O4 peaks under nitrogen calcination and formation of Fe3Si and iron as major constituents of magnetic biochar-SiO2 composite, which demonstrated its superparamagnetic behavior (>80 A2·kg−1 comparable to magnetic biochar. Thermogravimetric analysis (TGA revealed that both calcined samples generated higher residual mass (>96 % and demonstrated better thermal stability. The presence of various bands in Fourier transform infrared spectroscopy (FT-IR was more obvious and the elimination of H–O–H bonding was observed at high temperature calcination. In addition, scanning electron microscopy (SEM images revealed certain morphological variation among the samples and the presence of more prominent internal and external pores, which then judged the surface area and pore volume of samples. Findings from this study suggests that the selective calcination process could cause useful changes in the material composites and can be effectively employed in environmental remediation measures.

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...

Analysis of magnetic nanoparticles using quadrupole magnetic field-flow fractionation

International Nuclear Information System (INIS)

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

2005-01-01

The new technique of quadrupole magnetic field-flow fractionation is described. It is a separation and characterization technique for particulate magnetic materials. Components of a sample are eluted from the separation channel at times dependent on the strength of their interaction with the magnetic field. A quadrupole electromagnet allows a programmed reduction of field strength during analysis of polydisperse samples

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

Characterization of proton exchange membrane materials for fuel cells by solid state nuclear magnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Kong, Zueqian [Iowa State Univ., Ames, IA (United States)

2010-01-01

Solid-state nuclear magnetic resonance (NMR) has been used to explore the nanometer-scale structure of Nafion, the widely used fuel cell membrane, and its composites. We have shown that solid-state NMR can characterize chemical structure and composition, domain size and morphology, internuclear distances, molecular dynamics, etc. The newly-developed water channel model of Nafion has been confirmed, and important characteristic length-scales established. Nafion-based organic and inorganic composites with special properties have also been characterized and their structures elucidated. The morphology of Nafion varies with hydration level, and is reflected in the changes in surface-to-volume (S/V) ratio of the polymer obtained by small-angle X-ray scattering (SAXS). The S/V ratios of different Nafion models have been evaluated numerically. It has been found that only the water channel model gives the measured S/V ratios in the normal hydration range of a working fuel cell, while dispersed water molecules and polymer ribbons account for the structures at low and high hydration levels, respectively.

Preparation and Characterization of Nonylphenol Magnetic Molecularly Imprinted Polymer

International Nuclear Information System (INIS)

Chen, F. Y.; Ba, S. P.; Tang, Y. B.; Wang, X. G.

2015-01-01

Nonylphenol (NP) is a toxic xenobiotic compound classified as an endocrine disrupter, which can interface with the hormonal system of numerous organisms, and then cause a series of pathological changes. It is of great significance to remove nonyl phenol from the environment. In this paper, an effective method for the preparation of molecularly imprinted nanoparticles was reported. Firstly, Fe/sub 3/O/sub 4/ at the rate SiO/sub 2/ magnetic carrier material modified by trimethoxysilane was achieved through three-step reaction. After that, the selective magnetic molecularly imprinted polymer sorbent for NP (Fe/sub 3/O/sub 4/ at the rate SiO/sub 2/-MIP) was synthesized by surface molecular imprinting technique, using NP as template, 4-vinyl pyridine(4-Vpy) as functional monomers, ethylene glycol dimethacrylate (EGDMA) as cross linker and azobisisobutyronitrile (AIBN) as initiator. The morphous, composition, structure and performance of polymer adsorbent was characterized by SEM, TEM, FT-IR, XRD, EDS, VSM and nitrogen adsorption-desorption techniques. The results indicated that the polymer adsorbent was successfully prepared. The size of the polymer particle was about 50 nm, the aperture on the surface was 3.71 nm, the BET specific surface area was 61.80 m/sup 2/g and the Langmuir specific surface area was 101.24 m/sup 2/g. The selective adsorption rate for NP of 0.5 mmol/L attained value of 86.5%, and for NP with low concentration (less than 2.0 mg/L), the selective adsorption rate reached more than 90%. The synthesized magnetic molecularly imprinted polymer had higher selective recognition ability towards the template molecule nonylphenol. It has good magnetism and can be rapidly separated after being employed by using adscititious magnetic field. It has potential application value in treatment and enrichment of nonylphenol. (author)

Characterization of dielectric materials

Energy Technology Data Exchange (ETDEWEB)

King, Danny J.; Babinec, Susan; Hagans, Patrick L.; Maxey, Lonnie C.; Payzant, Edward A.; Daniel, Claus; Sabau, Adrian S.; Dinwiddie, Ralph B.; Armstrong, Beth L.; Howe, Jane Y.; Wood, III, David L.; Nembhard, Nicole S.

2017-06-27

A system and a method for characterizing a dielectric material are provided. The system and method generally include applying an excitation signal to electrodes on opposing sides of the dielectric material to evaluate a property of the dielectric material. The method can further include measuring the capacitive impedance across the dielectric material, and determining a variation in the capacitive impedance with respect to either or both of a time domain and a frequency domain. The measured property can include pore size and surface imperfections. The method can still further include modifying a processing parameter as the dielectric material is formed in response to the detected variations in the capacitive impedance, which can correspond to a non-uniformity in the dielectric material.

Rapid determination of iron oxide content in magnetically modified particulate materials

Czech Academy of Sciences Publication Activity Database

Šafařík, Ivo; Nýdlová, L.; Pospíšková, K.; Baldíková, E.; Maděrová, Z.; Šafaříková, Miroslava

2016-01-01

Roč. 26, June (2016), s. 114-117 ISSN 1674-2001 Institutional support: RVO:60077344 Keywords : magnetic iron oxide s * magnetic permeability meter * magnetically modified materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.621, year: 2016

Metallic Magnetic Nanoparticles

Directory of Open Access Journals (Sweden)

A. Hernando

2005-01-01

Full Text Available In this paper, we reviewed some relevant aspects of the magnetic properties of metallic nanoparticles with small size (below 4 nm, covering the size effects in nanoparticles of magnetic materials, as well as the appearance of magnetism at the nanoscale in materials that are nonferromagnetic in bulk. These results are distributed along the text that has been organized around three important items: fundamental magnetic properties, different fabrication procedures, and characterization techniques. A general introduction and some experimental results recently obtained in Pd and Au nanoparticles have also been included. Finally, the more promising applications of magnetic nanoparticles in biomedicine are indicated. Special care was taken to complete the literature available on the subject.

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

Perspectives for high-performance permanent magnets: applications, coercivity, and new materials

Science.gov (United States)

Hirosawa, Satoshi; Nishino, Masamichi; Miyashita, Seiji

2017-03-01

High-performance permanent magnets are indispensable in the production of high-efficiency motors and generators and ultimately for sustaining the green earth. The central issue of modern permanent magnetism is to realize high coercivity near and above room temperature on marginally hard magnetic materials without relying upon the critical elements such as heavy rare earths by means of nanostructure engineering. Recent investigations based on advanced nanostructure analysis and large-scale first principles calculations have led to significant paradigm shifts in the understandings of coercivity mechanism in Nd-Fe-B permanent magnets, which includes the discovery of the ferromagnetism of the thin (2 nm) intergranular phase surrounding the Nd2Fe14B grains, the occurrence of negative (in-plane) magnetocrystalline anisotropy of Nd ions and some Fe atoms at the interface which degrades coercivity, and visualization of the stochastic behaviors of magnetization in the magnetization reversal process at high temperatures. A major change may occur also in the motor topologies, which is currently overwhelmed by the magnetic flux weakening interior permanent magnet motor type, to other types with variable flux permanent magnet type in some applications to open up a niche for new permanent magnet materials. Keynote talk at 8th International Workshop on Advanced Materials Science and Nanotechnology (IWAMSN2016), 8-12 November 2016, Ha Long City, Vietnam.

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,…

Non-destructive characterization of the materials for future nuclear reactors

International Nuclear Information System (INIS)

Snopek, J.; Slugen, V.

2016-01-01

For our experiments, we have used Barkhausen noise technique, which is powerful non-destructive method for monitoring stresses in lattices of magnetic materials. We have also used PAS, which is powerful non-destructive method for diagnosing vacancy defects in variable materials. We researched some ODS steels, which are primarily going to be used as fuel cladding or reactor pressure vessel internal components. This thesis describes the behavior of the microstructure of the oxide dispersion strengthened steels at intermediate temperature. Two, in principle, different techniques were used for the characterization of the microstructure of the oxide dispersion strengthened steels thermally aged at 475 grad C and 650 grad C. Both techniques, namely Positron annihilation lifetime spectroscopy (PAS) and Barkhausen noise (BN) measurements are very sensitive to metallurgical modifications and presence of nano-sized imperfections in the crystal lattice. Precipitation of the nano-sized α' phases shift the Barkhausen noise signal. (authors)

Theoretical and experimental investigation of magnetic materials for DC beam curent transformers

CERN Document Server

Kottman, P

1997-01-01

Toroidal cores made of high-permeability magnetic materials are fundamental building blocks of DC beam current transformers (DCBT). The impact of the properties of the magnetic cores on the overall performance of DCBT was studied. The principle of the DCBT operation is based on the superposition of AC and DC electromagnetic fields in the cores. This effect was studied in detail in two magnetic materials currently used in a construction of DCBT at CERN. The simulation of the DCBT operation was made using the results of these studies and the theoretical model for description of a B-H hysteresis curve of magnetic materials. This simulation allows to evaluate the influence of various factors (a shape of the B-H curve, deviations of core parameters, presence of noise) on the performance of DCBT. A survey of available high-permeability magnetic materials suitable for DCBT is presented.

The synthesis, characterization, and application of multifunctional magnetic nanoparticles

Science.gov (United States)

Tackett, Ronald J.

In recent years, the field of nanotechnology has been one of extreme activity. Among other things, this activity is driven by the push for consumer technologies that are lighter, stronger, and most importantly smaller. With this push from the everyday consumer, the need for a basic understanding of the underlying physics of nanoscale materials has never been more evident. In this dissertation, the author investigates the many physical differences, in particular the differences in the magnetic properties, between nanoscale materials and their bulk counterparts. Starting out with a brief overview of magnetism, the author sets out to explore the fantastic changes in the magnetic properties of materials that occur when the physical dimensions of the materials become smaller than typical magnetic length scales. Among the first differences noticed arises when nanoscale ferromagnets are investigated. While the magnetic properties of bulk ferromagnets are governed by magnetic domain dynamics, when a material becomes small enough that only one domain is possible, a new type of magnetic behavior known as superparamagnetism arises. While this superparamagnetic behavior is well understood in terms of thermally activated spin reversal through an energy barrier, many factors, such as interactions between separate nanoparticles, cause deviations from this simple picture. The effects of these factors are investigated. In addition to the effects of interactions, the relation of nanoscale magnetics and its coupling to the dielectric properties of nanoparticles is investigated. This investigation, motivated by recent research focusing on the search for materials whose magnetic and electronic properties are influenced by each other, shows that nanomaterials can show a coupling between these properties that isn't necessarily the intrinsic coupling of the two properties, but an effect from the surface layers of nanoparticles, which are generally ignored in bulk systems due to the fact

Characterization of plutonium-containing materials and storage canisters

International Nuclear Information System (INIS)

Mason, R.E.

1997-01-01

Throughout the weapons complex, plutonium materials are stored in various containers. Some plutonium has been stored for 20 yr or more. The physical and chemical properties of the plutonium material and the containers that hold it are often not well characterized. The U.S. Department of Energy (DOE) 3013 standard sets criteria to which stored material must conform. The 3013 standard regulates materials that hold 50% or greater plutonium, and the other 50% is not specified and is usually unknown. The Materials Identification and Surveillance project is tasked to characterize representative materials and begin to characterize the other 50% and to show that materials can be brought into 3013 criteria conformance through thermal treatments

Growth and characterization of epitaxial thin films and multiferroic heterostructures of ferromagnetic and ferroelectric materials

Science.gov (United States)

Mukherjee, Devajyoti

Multiferroic materials exhibit unique properties such as simultaneous existence of two or more of coupled ferroic order parameters (ferromagnetism, ferroelectricity, ferroelasticity or their anti-ferroic counterparts) in a single material. Recent years have seen a huge research interest in multiferroic materials for their potential application as high density non-volatile memory devices. However, the scarcity of these materials in single phase and the weak coupling of their ferroic components have directed the research towards multiferroic heterostructures. These systems operate by coupling the magnetic and electric properties of two materials, generally a ferromagnetic material and a ferroelectric material via strain. In this work, horizontal heterostructures of composite multiferroic materials were grown and characterized using pulsed laser ablation technique. Alternate magnetic and ferroelectric layers of cobalt ferrite and lead zirconium titanate, respectively, were fabricated and the coupling effect was studied by X-ray stress analysis. It was observed that the interfacial stress played an important role in the coupling effect between the phases. Doped zinc oxide (ZnO) heterostructures were also studied where the ferromagnetic phase was a layer of manganese doped ZnO and the ferroelectric phase was a layer of vanadium doped ZnO. For the first time, a clear evidence of possible room temperature magneto-elastic coupling was observed in these heterostructures. This work provides new insight into the stress mediated coupling mechanisms in composite multiferroics.

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)

Structural characterization of ferrite nanoparticles and composite materials using synchrotron radiation

International Nuclear Information System (INIS)

Albuquerque, A.S.; Macedo, W.A.A.; Plivelic, T.; Torriani, I.L.; Jimenez, J.A.L.; Saitovich, E.B.

2001-01-01

During the last decade nanocrystalline magnetic materials have been widely studied due to the multiple technological applications. Amongst the magnetic materials of major technological interest are the soft magnetic ferrites and the granular solids formed by ferrites dispersed in non-magnetic matrices. It is a well known fact that the magnetic properties of these materials, such as coercivity, magnetic saturation and magnetization, depend on the shape, size and size distribution of the nanoparticles. For this reason, the general purpose of this work was to obtain structural information on ferrite nanoparticles (NiFe 2 O 4 and NiZnFe 2 O 4 ) and granular solids obtained by dispersion of these particles in non magnetic matrices, like SiO 2 and SnO 2 . The ferrite samples were prepared by co-precipitation and heat treated between 300 and 600 deg. C at the Applied Physics Laboratory of tile CDTN. The granular solids, with 30% in volume concentration of ferrite, were obtained by mechanical alloying with milling times (t m ) varying between 1.25 and 10 h, at the CBPF

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.

Synthesis and characterization of magnetic nanoparticles of oxides for dual MnFe2O4 bioseparation, stabilized in fatty acid and the system chitosan - Eu(TTA)3(TPPO)2. Studies on the influence of doping with Gd3+, Tb3+, Ho3+ e Eu3+ in structural and magnetic properties

International Nuclear Information System (INIS)

Kovacs, Thelma Antunes Rodrigues

2014-01-01

This work was synthesized and characterized ferrite magnetic nanoparticles manganese, using the chemical coprecipitation method. By varying the heating time under 98°C (0, 10,20,40,60 3 80 minutes), the molar percentage of doping (1, 3, 5, 7, and 10%), gadolinium, europium, terbium and holmium. Magnetic ferrite nanoparticles and manganese ferrite doped with manganese were synthesized by coprecipitation method starting with chloride solutions of metals (iron (III), manganese (II), europium (III), gadolinium (III), terbium (III) and holmium (III)) and NaOH 5mol.L -1 as precipitating agent. The magnetic nanoparticles were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, magnetization curves, and thermal analysis. Most of manganese ferrite particles showed superparamagnetic behavior. After the characterization it was found that the samples synthesized manganese ferrite with more than 40 minutes heating time, crystal structure showed the characteristic pattern of the inverted manganese ferrite spinel type. The stabilization of the samples in oleic acid nanoparticles produced with a hydrophobic outer layer and facilitated by coating chitosan biopolymer, since this has a positive charge. Among the doped samples there was no significant change in the magnetic behavior. Several techniques for characterizing these materials have been used such as X-ray diffraction spectrum in the infrared region, magnetization curves and thermal analysis. The resins were tested as magnetic material for the separation of biological materials. In this paper, are used as biological targets separation of bovine serum albumin. (author)

Contribution to the study of superconducting magnets using high transition temperature superconducting materials

International Nuclear Information System (INIS)

Lecrevisse, Thibault

2012-01-01

The new industrial superconductors using high critical temperature compounds offer new possibilities for superconducting magnetism. Indeed they allow higher magnetic field with the same classical cryogenics at 4.2 K on one hand, and on the other hand they also pave the way for superconducting magnets working between 10 K and 30 K. The high temperature superconductors are then needed in order to produce magnetic fields higher than 16 T (case of HTS dipole insert for Large Hadron Collider at CERN) or to increase the specific density stored in one SMES (Superconducting Magnetic Energy Storage, in the case of the SuperSMES ANR Project).Nevertheless the indisputable assets (critical temperature, critical magnetic field, mechanical stresses) brought by the use of High critical temperature superconductors like YBCO, used in superconducting magnets, require to solve some challenges. Their behavior is still badly understood, especially during the resistive transitions. To succeed in protecting these conductors we need a new reflection on protection schemes designed to avoid the thermal and mechanical damages. The answer to the question: 'Can we use those materials in the long run inside superconducting magnets?' is now inescapable.Some answers are given here. The use of the conductors is approached through various experimental studies to understand the material (electrical characterization and modeling of the critical surface) and to define the key stages of high critical temperature superconducting magnets manufacturing (work on the junctions between conductors and pancakes). This study led to the creation of two coils in order to identify the issues related to the use of YBCO tapes. A numerical thermo-electrical model of the high critical temperature superconductor has been developed and a numerical code based on the CEA software CASTEM (Finish Elements Model) allowed to study the resistive transition (or quench) behavior of those conductor and coil. The code has been

Characterization of magnetic tunnel junction test pads

DEFF Research Database (Denmark)

Østerberg, Frederik Westergaard; Kjær, Daniel; Nielsen, Peter Folmer

2015-01-01

We show experimentally as well as theoretically that patterned magnetic tunnel junctions can be characterized using the current-in-plane tunneling (CIPT) method, and the key parameters, the resistance-area product (RA) and the tunnel magnetoresistance (TMR), can be determined. The CIPT method...

Mechanical-property changes of structural composite materials after low-temperature proton irradiation: Implications for use in SSC magnet systems

International Nuclear Information System (INIS)

Morena, J.; Snead, C.L. Jr.; Czajkowski, C.; Skaritka, J.

1993-01-01

Longterm physical, mechanical, electrical, and other properties of advanced composites, plastics, and other polymer materials are greatly affected by high-energy proton, neutron, electron, and gamma radiation. The effects of high-energy particles on materials is a critical design parameter to consider when choosing polymeric structural, nonstructural, and elastomeric matrix resin systems. Polymer materials used for filled resins, laminates, seals, gaskets, coatings, insulation and other nonmetallic components must be chosen carefully, and reference data viewed with caution. Most reference data collected in the high-energy physics community to date reflects material property degradation using other than proton irradiations. In most instances, the data were collected for room-temperature irradiations, not 4.2 K or other cryogenic temperatures, and at doses less than 10 8 --10 9 Rad. Energetic proton (and the accompanying spallation-product particles) provide good simulation fidelity to the expected radiation fields predicted for the cold-mass regions of the SSC magnets, especially the corrector magnets. The authors present here results for some structural composite materials which were part of a larger irradiation-characterization of polymeric materials for SSC applications

Synthesis and characterization of magnetic cobalt ferrite nanoparticles covered with 3-aminopropyltriethoxysilane for use as hybrid material in nano technology; Sintese e caracterizacao de nanoparticulas magneticas de ferrita de cobalto recobertas por 3-aminopropiltrietoxissilano para uso como material hibrido em nanotecnologia

Energy Technology Data Exchange (ETDEWEB)

Camilo, Ruth Luqueze

2006-07-01

Nowadays with the appear of nano science and nano technology, magnetic nanoparticles have been finding a variety of applications in the fields of biomedicine, diagnosis, molecular biology, biochemistry, catalysis, etc. The magnetic functionalized nanoparticles are constituted of a magnetic nucleus, involved by a polymeric layer with active sites, which ones could anchor metals or selective organic compounds. These nanoparticles are considered organic inorganic hybrid materials and have great interest as materials for commercial applications due to the specific properties. Among the important applications it can be mentioned: magneto hyperthermia treatment, drugs delivery in specific local of the body, molecular recognition, biosensors, enhancement of nuclear magnetic resonance images quality, etc. This work was developed in two parts: 1) the synthesis of the nucleus composed by superparamagnetic nanoparticles of cobalt ferrite and, 2) the recovering of nucleus by a polymeric bifunctional 3-aminopropyltriethoxysilane. The parameters studied in the first part of the research were: pH, hydroxide molar concentration, hydroxide type, reagent order of addition, reagent way of addition, speed of shake, metals initial concentrations, molar fraction of cobalt and thermal treatment. In the second part it was studied: pH, temperature, catalyst type, catalyst concentration, time of reaction, relation ratios of H{sub 2}O/silane, type of medium and the efficiency of the recovering regarding to pH. The products obtained were characterized using the following techniques X-ray powder diffraction (DRX), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), spectroscopy of scatterbrained energy spectroscopy (DES), atomic emission spectroscopy (ICP-AES), thermogravimetric analysis (TGA/DTGA), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and magnetization curves (VSM). (author)

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-xDy_xFe_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< 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.

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

Magnetic- and material-limiter discharges in Tokapole II

International Nuclear Information System (INIS)

Moyer, R.A.

1988-01-01

Disruptive instabilities were 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 plate 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 were identified. The magnetic-limiter configuration enables routine passing of the stability barriers at q(a) = 2 and q(a) = 1, where q(a) is 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

Estimation of non-linear effective permeability of magnetic materials with fine structure

International Nuclear Information System (INIS)

Waki, H.; Igarashi, H.; Honma, T.

2006-01-01

This paper describes a homogenization method for magnetic materials with fine structure. In this method, the structures of the magnetic materials are assumed to be periodic, and the unit cell is defined. The effective permeability is determined on the basis of magnetic energy balance in the unit cell. This method can be applied not only for linear problems but also for non-linear ones. In this paper, estimation of the effective permeability of non-linear magnetic materials by using the homogenization method is described in detail, and then the validity for the non-liner problems is tested for two-dimensional problems. It is shown that this homogenization method gives accurate non-linear effective permeability

NMR characterization of thin films

Science.gov (United States)

Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

2010-06-15

A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

NMR characterization of thin films

Science.gov (United States)

Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

2008-11-25

A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

Digestion of Alumina from Non-Magnetic Material Obtained from Magnetic Separation of Reduced Iron-Rich Diasporic Bauxite with Sodium Salts

Directory of Open Access Journals (Sweden)

Guanghui Li

2016-11-01

Full Text Available Recovery of iron from iron-rich diasporic bauxite ore via reductive roasting followed by magnetic separation has been explored recently. However, the efficiency of alumina extraction in the non-magnetic materials is absent. In this paper, a further study on the digestion of alumina by the Bayer process from non-magnetic material obtained after magnetic separation of reduced iron-rich diasporic bauxite with sodium salts was investigated. The results indicate that the addition of sodium salts can destroy the original occurrences of iron-, aluminum- and silicon-containing minerals of bauxite ore during reductive roasting. Meanwhile, the reactions of sodium salts with complex aluminum- and silicon-bearing phases generate diaoyudaoite and sodium aluminosilicate. The separation of iron via reductive roasting of bauxite ore with sodium salts followed by magnetic separation improves alumina digestion in the Bayer process. When the alumina-bearing material in bauxite ore is converted into non-magnetic material, the digestion temperature decreases significantly from 280 °C to 240 °C with a nearly 99% relative digestion ratio of alumina.

Effect of Eu magnetism on the electronic properties of the candidate Dirac material EuMnBi2

Science.gov (United States)

May, Andrew F.; McGuire, Michael A.; Sales, Brian C.

2014-08-01

The crystal structure and physical properties of the layered material EuMnBi2 have been characterized by measurements on single crystals. EuMnBi2 is isostructural with the Dirac material SrMnBi2 based on single-crystal x-ray diffraction, crystallizing in the I4/mmm space group (No. 139). Magnetic susceptibility measurements suggest antiferromagnetic (AFM) ordering of moments on divalent Eu ions near TN=22 K. For low fields, the ordered Eu moments are aligned along the c axis, and a spin flop is observed near 5.4 T at 5 K. The moment is not saturated in an applied field of 13 T at 5 K, which is uncommon for compounds containing Eu2+. The magnetic behavior suggests an anisotropy enhancement via interaction between Eu and the Mn moments that appear to be ordered antiferromagnetically below ≈310 K. A large increase in the magnetoresistance is observed across the spin flop, with absolute magnetoresistance reaching ≈650% at 5 K and 12 T. Hall effect measurements reveal a decrease in the carrier density below TN, which implies a manipulation of the Fermi surface by magnetism on the sites surrounding the Bi square nets that lead to Dirac cones in this family of materials.

Synthesis, characterization and magnetic properties of room-temperature nanofluid ferromagnetic graphite

OpenAIRE

Souza, N. S.; Sergeenkov, S.; Speglich, C.; Rivera, V. A. G.; Cardoso, C. A.; Pardo, H.; Mombru, A. W.; Rodrigues, A. D.; de Lima, O. F.; Araujo-Moreira, F. M.

2009-01-01

We report the chemical synthesis route, structural characterization, and physical properties of nanofluid magnetic graphite (NFMG) obtained from the previously synthesized bulk organic magnetic graphite (MG) by stabilizing the aqueous ferrofluid suspension with an addition of active cationic surfactant. The measured magnetization-field hysteresis curves along with the temperature dependence of magnetization confirmed room-temperature ferromagnetism in both MG and NFMG samples. (C) 2009 Americ...

Synthesis, characterization and magnetic properties of Fe/MCM-48

International Nuclear Information System (INIS)

Oliva, M.I; Elias, V.R; Eimer, G.A; Silvetti, S.P; Urreta, S.E

2008-01-01

Mesoporous silicates called MCM-48 have a structure of interconnected pores with a cubic three dimensional arrangement, with diameters ranging from 1-10nm. This kind of pore configuration has elevated surface areas (more than 1000 m 2 /g) so these molecular MCM-48 sieves are useful for supporting and encapsulating nanophases of different transition metals, metal oxides and organometallic compounds. Nanocomposites are formed with potential applications in the areas of electronics, optics, magnetism, energy storage, drug transport and catalysis. For this work MCM-48 materials were synthesized and then modified with Fe by the wet impregnation method. Two sources of Fe were used: Fe(NO 3 ) 3 .9H 2 O and FeSO 4 .7H 2 O. The silica, previously roasted at 773 K, was suspended in a large amount of aqueous solution that initially contained the amount of iron to be deposited (5%p/p) and that was agitated for a short time. The mixture was then placed in a bath at 353K without agitation for 8 hours. Finally the water was eliminated in a rotating evaporator at 333K. The powder obtained was dried in a stove at 333K for 8 hours and calcined at 773K for 4 hours. The microstructure of the resulting composites was characterized by X-ray diffraction (XRD) and ultraviolet-visible diffuse reflectance (UVvis-DR). The magnetic properties were studied as a function of the temperature following zero field cooling (ZFC) and field cooling (FC) protocols between 300K and 5K and by measuring the hysterisis curves at different temperatures in the same range. The DRX studies confirmed a MCM-48 type structure for all the matrices, consistent with the high surface areas - around 1300 m 2 /g- measured. The structure and the surface areas of the composites were affected by the addition of the metal. While the UVvis-DR and DRX analyses of the composites obtained showed that the iron subjects in the final material are similar for both sources of iron used, they have different magnetic behaviors

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.

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...

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°).

Special-purpose materials for magnetically confined fusion reactors. Third annual progress report

International Nuclear Information System (INIS)

1981-11-01

The scope of Special Purpose Materials covers fusion reactor materials problems other than the first-wall and blanket structural materials, which are under the purview of the ADIP, DAFS, and PMI task groups. Components that are considered as special purpose materials include breeding materials, coolants, neutron multipliers, barriers for tritium control, materials for compression and OH coils and waveguides, graphite and SiC, heat-sink materials, ceramics, and materials for high-field (>10-T) superconducting magnets. It is recognized that there will be numerous materials problems that will arise during the design and construction of large magnetic-fusion energy devices such as the Engineering Test Facility (ETF) and Demonstration Reactor (DEMO). Most of these problems will be specific to a particular design or project and are the responsibility of the project, not the Materials and Radiation Effects Branch. Consequently, the Task Group on Special Purpose Materials has limited its concern to crucial and generic materials problems that must be resolved if magnetic-fusion devices are to succeed. Important areas specifically excluded include low-field (8-T) superconductors, fuels for hybrids, and materials for inertial-confinement devices. These areas may be added in the future when funding permits

Measurement and characterization techniques for thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Tritt, T M

1997-07-01

Characterization of thermoelectric materials can pose many problems. A temperature difference can be established across these materials as an electrical current is passed due to the Peltier effect. The thermopower of these materials is quite large and thus large thermal voltages can contribute to many of the measurements necessary to investigate these materials. This paper will discuss the chracterization techniques necessary to investigate these materials and provide an overview of some of the potential systematic errors which can arise. It will also discuss some of the corrections one needs to consider. This should provide an introduction to the characterization and measurement of thermoelectric materials and provide references for a more in depth discussion of the concepts. It should also serve as an indication of the care that must be taken while working with thermoelectric materials.

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.)

Neutron scattering studies of magnetism in the high-Tc materials

International Nuclear Information System (INIS)

Sinha, S.K.

1990-01-01

In this paper, I shall attempt to review what has been learned about magnetism in the high-T c family of compounds using neutron scattering techniques. Whether or not it is true that magnetic effects are involved in an essential way in the mechanism for superconductivity in these materials (a point which has not yet been firmly established), they offer fascinating examples for the study of magnetism for its own sake, being realizations of spin 1/2 2D quantum antiferromagnets. Further, the rare earth spins in these materials also order at low temperatures reminiscent of the coexistence of antiferromagnetism and superconductivity in the earlier well-studied families of magnetic superconductors such as ErRh 4 B 4 and the Chevrel-phase compounds, with the difference that the ordering here is primarily 2D in character

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...

Characterization of the magnetic micro- and nanostructure in unalloyed steels by magnetic force microscopy

Science.gov (United States)

Batista, L.; Rabe, U.; Hirsekorn, S.

2013-01-01

The formation of a cementite phase influences significantly the macroscopic mechanical and magnetic properties of steels. Based on a correlation between mechanical and magnetic properties, mechanical properties as well as the morphology and content of the cementite phase can be inspected by electromagnetic non-destructive testing methods. The influence of the carbon content on bulk magnetic properties of unalloyed steels is studied on a macroscopic scale by hysteresis loop and Barkhausen noise measurements. The micro- and nanostructure is investigated by atomic force microscopy and magnetic force microscopy. Surface topography images and magnetic images of globular cementite precipitates embedded in a ferrite matrix are presented. The size, shape, and orientation of the precipitates influence the domain configuration. Applied external magnetic fields cause magnetization processes mainly in the ferrite matrix: Bloch walls move and are pinned by the cementite precipitates. The correlation between the microscopic observations and macroscopic magnetic properties of the material is discussed.

Material stabilization characterization management plan

International Nuclear Information System (INIS)

GIBSON, M.W.

1999-01-01

This document presents overall direction for characterization needs during stabilization of SNM at the Plutonium Finishing Plant (PFP). Technical issues for needed data and equipment are identified. Information on material categories and links to vulnerabilities are given. Comparison data on the material categories is discussed to assist in assessing the relative risks and desired processing priority

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.

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

Penerapan Three Tier-Test untuk Identifikasi Kuantitas Siswa Yang Miskonsepsi Pada Materi Magnet

Directory of Open Access Journals (Sweden)

Reny Silviani

2017-10-01

Full Text Available Proses pembelajaran yang bersifat informative dan hanya ditekankan pada konsep teoritik saja dapat menyebabkan siswa kurang menguasai konsep ilmiah.Faktor yang menyebabkan rendahnya penguasaan konsep siswa adalah miskonsepsi. Miskonsepsi merupakan kekeliruan dalam memahami suatu konsep materi pembelajaran yang tidak akurat, yang dapat menyebabkan ketidaksesuaian antara konsep yang dimiliki pribadi dengan konsep ilmiah. Dengan adanya miskonsepsi yang terjadi, hal ini dapat menghambat siswa untuk menerima informasi yang baru, sehingga siswa menolak untuk mengubah miskonsepsinya menjadi konsep ilmiah. Penelitian ini bertujuan untuk mengidentifikasi mengenai kuantitas siswa yang miskonsepsi pada materi magnet. Penelitian ini merupakan penelitian deskriptif kuantitatif dengan teknik pengambilan sampel adalah purposive sampling.Instrumen penelitian yang digunakan adalah three tier-test. Penggunaan three tier-test yaitu untuk mengidentifikasi kuantita ssiswa yang miskonsepsi. Jawaban yang telah dianalisis, selanjutnya akan dihitung dalam bentuk persentase. Hasil dari penelitian menunjukkan bahwa terdapat 3 konsep distribusi atau sebaran miskonsepsi pada materi magnet, yaitu; 1. Semua benda berwarna perak ditarik magnet; 2. Tarikan magnet yang lebih besar pasti lebih kuat dari tarikan magnet yang kecil; 3. Semua logam dapat ditarik magnet.Miskonsepsi tertinggi terdapat pada konsep tarikan magnet yang lebih besar pasti lebih kuat dari tarikan magnet yang kecil. Diharapkan hasil dari penelitian ini dapat dijadikan referensi untuk mencari solusi dalam menurunkan kuantitas siswa yang miskonsepsik hususnya pada materi magnet.

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...

Macroscopic simulation of isotropic permanent magnets

International Nuclear Information System (INIS)

Bruckner, Florian; Abert, Claas; Vogler, Christoph; Heinrichs, Frank; Satz, Armin; Ausserlechner, Udo; Binder, Gernot; Koeck, Helmut; Suess, Dieter

2016-01-01

Accurate simulations of isotropic permanent magnets require to take the magnetization process into account and consider the anisotropic, nonlinear, and hysteretic material behaviour near the saturation configuration. An efficient method for the solution of the magnetostatic Maxwell equations including the description of isotropic permanent magnets is presented. The algorithm can easily be implemented on top of existing finite element methods and does not require a full characterization of the hysteresis of the magnetic material. Strayfield measurements of an isotropic permanent magnet and simulation results are in good agreement and highlight the importance of a proper description of the isotropic material. - Highlights: • Simulations of isotropic permanent magnets. • Accurate calculation of remanence magnetization and strayfield. • Comparison with strayfield measurements and anisotropic magnet simulations. • Efficient 3D FEM–BEM coupling for solution of Maxwell equations.

THz characterization of hydrated and anhydrous materials

Science.gov (United States)

Sokolnikov, Andre

2011-06-01

The characterization of anhydrous and hydrated forms of materials is of great importance to science and industry. Water content poses difficulties for successful identification of the material structure by THz radiation. However, biological tissues and hydrated forms of nonorganic substances still may be investigated by THz radiation. This paper outlines the range of possibilities of the above characterization, as well as provides analysis of the physical mechanism that allows or prevents penetration of THz waves through the substance. THz-TDS is used to measure the parameters of the characterization of anhydrous and hydrated forms of organic and nonorganic samples. Mathematical methods (such as prediction models of time-series analysis) are used to help identifying the absorption coefficient and other parameters of interest. The discovered dependencies allow designing techniques for material identification/characterization (e.g. of drugs, explosives, etc. that may have water content). The results are provided.

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

Characterization of the magnetic anisotropy in thin films of La1-xSrxMnO3 using the planar Hall effect

International Nuclear Information System (INIS)

Bason, Y.; Klein, L.; Yau, J.B.; Hong, X.; Ahn, C.H.

2004-01-01

Thin films of the colossal magnetoresistance material La 1-x Sr x MnO 3 (LSMO) grown on SrTiO 3 substrates exhibit bi-axial magnetocrystalline anisotropy with easy axes along the [110] and [1 anti 1 0] directions. We have recently discovered that the intrinsic biaxial magnetic anisotropy combined with a giant planar Hall effect lead to striking switching behavior in the transverse resistivity of LSMO films (Appl. Phys. Lett. 84, 2593 (2004)). Here we use this phenomenon as a sensitive tool for measuring in-plane magnetization in order to characterize the magnetic anisotropy. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

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

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.

The 2017 Magnetism Roadmap

International Nuclear Information System (INIS)

Sander, D; Valenzuela, S O; Makarov, D

2017-01-01

Building upon the success and relevance of the 2014 Magnetism Roadmap, this 2017 Magnetism Roadmap edition follows a similar general layout, even if its focus is naturally shifted, and a different group of experts and, thus, viewpoints are being collected and presented. More importantly, key developments have changed the research landscape in very relevant ways, so that a novel view onto some of the most crucial developments is warranted, and thus, this 2017 Magnetism Roadmap article is a timely endeavour. The change in landscape is hereby not exclusively scientific, but also reflects the magnetism related industrial application portfolio. Specifically, Hard Disk Drive technology, which still dominates digital storage and will continue to do so for many years, if not decades, has now limited its footprint in the scientific and research community, whereas significantly growing interest in magnetism and magnetic materials in relation to energy applications is noticeable, and other technological fields are emerging as well. Also, more and more work is occurring in which complex topologies of magnetically ordered states are being explored, hereby aiming at a technological utilization of the very theoretical concepts that were recognised by the 2016 Nobel Prize in Physics. Given this somewhat shifted scenario, it seemed appropriate to select topics for this Roadmap article that represent the three core pillars of magnetism, namely magnetic materials, magnetic phenomena and associated characterization techniques, as well as applications of magnetism. While many of the contributions in this Roadmap have clearly overlapping relevance in all three fields, their relative focus is mostly associated to one of the three pillars. In this way, the interconnecting roles of having suitable magnetic materials, understanding (and being able to characterize) the underlying physics of their behaviour and utilizing them for applications and devices is well illustrated, thus giving an

The 2017 Magnetism Roadmap

Science.gov (United States)

Sander, D.; Valenzuela, S. O.; Makarov, D.; Marrows, C. H.; Fullerton, E. E.; Fischer, P.; McCord, J.; Vavassori, P.; Mangin, S.; Pirro, P.; Hillebrands, B.; Kent, A. D.; Jungwirth, T.; Gutfleisch, O.; Kim, C. G.; Berger, A.

2017-09-01

Building upon the success and relevance of the 2014 Magnetism Roadmap, this 2017 Magnetism Roadmap edition follows a similar general layout, even if its focus is naturally shifted, and a different group of experts and, thus, viewpoints are being collected and presented. More importantly, key developments have changed the research landscape in very relevant ways, so that a novel view onto some of the most crucial developments is warranted, and thus, this 2017 Magnetism Roadmap article is a timely endeavour. The change in landscape is hereby not exclusively scientific, but also reflects the magnetism related industrial application portfolio. Specifically, Hard Disk Drive technology, which still dominates digital storage and will continue to do so for many years, if not decades, has now limited its footprint in the scientific and research community, whereas significantly growing interest in magnetism and magnetic materials in relation to energy applications is noticeable, and other technological fields are emerging as well. Also, more and more work is occurring in which complex topologies of magnetically ordered states are being explored, hereby aiming at a technological utilization of the very theoretical concepts that were recognised by the 2016 Nobel Prize in Physics. Given this somewhat shifted scenario, it seemed appropriate to select topics for this Roadmap article that represent the three core pillars of magnetism, namely magnetic materials, magnetic phenomena and associated characterization techniques, as well as applications of magnetism. While many of the contributions in this Roadmap have clearly overlapping relevance in all three fields, their relative focus is mostly associated to one of the three pillars. In this way, the interconnecting roles of having suitable magnetic materials, understanding (and being able to characterize) the underlying physics of their behaviour and utilizing them for applications and devices is well illustrated, thus giving an

Quantitative Characterization of Nanostructured Materials

Energy Technology Data Exchange (ETDEWEB)

Dr. Frank (Bud) Bridges, University of California-Santa Cruz

2010-08-05

The two-and-a-half day symposium on the "Quantitative Characterization of Nanostructured Materials" will be the first comprehensive meeting on this topic held under the auspices of a major U.S. professional society. Spring MRS Meetings provide a natural venue for this symposium as they attract a broad audience of researchers that represents a cross-section of the state-of-the-art regarding synthesis, structure-property relations, and applications of nanostructured materials. Close interactions among the experts in local structure measurements and materials researchers will help both to identify measurement needs pertinent to real-world materials problems and to familiarize the materials research community with the state-of-the-art local structure measurement techniques. We have chosen invited speakers that reflect the multidisciplinary and international nature of this topic and the need to continually nurture productive interfaces among university, government and industrial laboratories. The intent of the symposium is to provide an interdisciplinary forum for discussion and exchange of ideas on the recent progress in quantitative characterization of structural order in nanomaterials using different experimental techniques and theory. The symposium is expected to facilitate discussions on optimal approaches for determining atomic structure at the nanoscale using combined inputs from multiple measurement techniques.

Signal loss in magnetic resonance imaging caused by intraoral anchored dental magnetic materials

International Nuclear Information System (INIS)

Blankenstein, F.H.; Naumann, M.; Truong, B.; Thomas, A.; Schroeder, R.J.

2006-01-01

Purpose: to measure the maximum extent of the signal loss areas in the center of the susceptibility artifacts generated by ferromagnetic dental magnet attachments using three different sequences in the 1.5 and 3.0 Tesla MRI. Materials and methods: five different pieces of standard dental magnet attachments with volumes of 6.5 to 31.4 mm 3 were used: a NdFeB magnet with an open magnetic field, a NdFeB magnet with a closed magnetic field, a SmCo magnet with an open magnetic field, a stainless steel keeper (AUM-20) and a PdCo piece. The attachments were placed between two cylindrical phantoms and examined in 1.5 and 3.0 Tesla MRI using gradient echo and T1- and T2-weighted spin echoes. We measured the maximum extent of the generated signal loss areas parallel and perpendicular to the direction of B O . Results: in gradient echoes the artifacts were substantially larger and symmetrically adjusted around the object. The areas with total signal loss were mushroom-like with a maximum extent of 7.4 to 9.7 cm parallel to the direction of B O and 6.7 to 7.4 cm perpendicular to B O . In spin echoes the signal loss areas were obviously smaller, but not centered. The maximum values ranged between 4.9 and 7.2 cm (parallel B O ) and 3.6 and 7.0 cm (perpendicular B O ). The different ferromagnetic attachments had no clinically relevant influence on the signal loss neither in 1.5 T nor 3.0 T MRI. Conclusions: ferromagnetic materials used in dentistry are not intraorally standardized. To ensure, that the area of interest is not affected by the described artifacts, the maximum extent of the signal loss area should be assumed: a radius of up to 7 cm in 1.5 and 3.0 T MRI by T1 and T2 sequences, and a radius of up to 10 cm in T2* sequences. To decide whether magnet attachments have to be removed before MR imaging, physicians should consider both the intact retention of the keepers and the safety distance between the ferromagnetic objects and the area of interest. (orig.)

Design of an ellipsoidal mirror for freewave characterization of materials at microwave frequencies

International Nuclear Information System (INIS)

Rojo, M; Muñoz, J; Molina-Cuberos, G J; Margineda, J; García-Collado, Á J

2016-01-01

Free-wave characterization of the electromagnetic properties of materials at microwave frequencies requires that scattering at the edges of the samples and/or holder be minimized. Here, an ellipsoidal mirror is designed and characterized in order to decrease the size of the beam, thereby avoiding the scattering problems, even when relatively small samples are used. In the experimental configuration, both the emitting antenna and sample are located at the mirror focuses. Since both the emitted and reflected (focused) beams are Gaussian in nature, we make use of Gaussian beam theory to carry out the design. The mirror parameters are optimized by numerical simulations (COMSOL Multiphysics ® ) and then experimentally tested. An experimental setup is presented for dielectric, magnetic and chiral measurement in the 4.5–18 GHz band. (paper)

Non-destructive characterization of materials by single-sided NMR

International Nuclear Information System (INIS)

Goga, Nicolae-Octavian

2007-01-01

The experiments conducted in this work demonstrate the efficiency and sensitivity of single-sided NMR for investigating macromolecular materials on large time and length scales. Elastomers can readily be characterized by unilateral NMR of protons in terms of a variety of parameters, which correlate with the overall molecular mobility. In this way information about the cross-link density, state of cure and strain, the effects of aging and product heterogeneity can obtained. For these purposes, the NMR-MOUSE was used to optimize product development and to monitor product and production quality on-line. The sensor is also suitable for nondestructive probing of the mechanical deformation in cross-linked elastomers. A special magnet design that fits a stress-strain device has been used for complementary investigation of a series of different rubber stripes during mechanical testing. The profile NMR-MOUSE was found to be a unique tool for the characterization of changes induced by the UV irradiation in natural rubber. The aging profiles were interpreted for the first time based on a novel model in which the radiation absorption coefficient depends on the depth in the sample. (orig.)

Non-destructive characterization of materials by single-sided NMR

Energy Technology Data Exchange (ETDEWEB)

Goga, Nicolae-Octavian

2007-08-20

The experiments conducted in this work demonstrate the efficiency and sensitivity of single-sided NMR for investigating macromolecular materials on large time and length scales. Elastomers can readily be characterized by unilateral NMR of protons in terms of a variety of parameters, which correlate with the overall molecular mobility. In this way information about the cross-link density, state of cure and strain, the effects of aging and product heterogeneity can obtained. For these purposes, the NMR-MOUSE was used to optimize product development and to monitor product and production quality on-line. The sensor is also suitable for nondestructive probing of the mechanical deformation in cross-linked elastomers. A special magnet design that fits a stress-strain device has been used for complementary investigation of a series of different rubber stripes during mechanical testing. The profile NMR-MOUSE was found to be a unique tool for the characterization of changes induced by the UV irradiation in natural rubber. The aging profiles were interpreted for the first time based on a novel model in which the radiation absorption coefficient depends on the depth in the sample. (orig.)

Characterization of magnetization processes in nanostructured rare earth-transition metal films

International Nuclear Information System (INIS)

Zheng Guangping; Zhan Yangwen; Liu Peng; Li Mo

2003-01-01

We synthesize rare earth-transition metal (RE-TM) amorphous films using the electrodeposition method (RE=Nd, Gd and TM=Co). Nanocrystructured RE-TM films are prepared by thermal treatment of as-synthesized films below the glass-crystal transition temperature. Based on the magnetoelastic effect, the magnetization processes in nanostructured samples are characterized by acoustic internal friction measurements using the vibrating-reed technique. Since internal friction and the Young's modulus are sensitive to grain boundary and magnetic domains movement, this technique seems to characterize the effects of nanostructures on the magnetization processes in RE-TM films well. We find that the magnetoelastic effect in nanostructured RE-TM film increases with an increase in grain size

Magnetic entropy and cooling

DEFF Research Database (Denmark)

Hansen, Britt Rosendahl; Kuhn, Luise Theil; Bahl, Christian Robert Haffenden

2010-01-01

Some manifestations of magnetism are well-known and utilized on an everyday basis, e.g. using a refrigerator magnet for hanging that important note on the refrigerator door. Others are, so far, more exotic, such as cooling by making use of the magnetocaloric eect. This eect can cause a change...... in the temperature of a magnetic material when a magnetic eld is applied or removed. For many years, experimentalists have made use of dilute paramagnetic materials to achieve milliKelvin temperatures by use of the magnetocaloric eect. Also, research is done on materials, which might be used for hydrogen, helium...... or nitrogen liquefaction or for room-temperature cooling. The magnetocaloric eect can further be used to determine phase transition boundaries, if a change in the magnetic state occurs at the boundary.In this talk, I will introduce the magnetocaloric eect (MCE) and the two equations, which characterize...

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.

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.

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.

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

Microstructural pavement material characterization: some examples

CSIR Research Space (South Africa)

Mgangira, Martin B

2008-07-01

Full Text Available in the way materials respond to loading at the macro-level. The objective of the paper is to demonstrate how Scanning Electron Microscopy (SEM) as an example of advanced measurement techniques was used for material characterization. A range of samples...

Low temperature magnetic characterization of EuO1-x

Science.gov (United States)

Rimal, Gaurab; Tang, Jinke

EuO is a widely studied magnetic semiconductor. It is an ideal case of a Heisenberg ferromagnet as well as a model magnetic polaron system. The interesting aspect of this material is the existance of magnetic polarons in the low temperature region. We study the properties of oxygen deficient EuO prepared by pulsed laser deposition. Besides normal ferromagnetic transitions near 70K and 140K, we observe a different transition at 16K. We also observe a shift in the coercivity for field cooling versus zero field cooling. Possible mechanisms driving these behaviors will be discussed. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (DEFG02-10ER46728) and by the School of Energy Resources of the University of Wyoming.

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

Magnetic nanocomposites based on phosphorus-containing polymers—structural characterization and thermal analysis

Science.gov (United States)

Alosmanov, R. M.; Szuwarzyński, M.; Schnelle-Kreis, J.; Matuschek, G.; Magerramov, A. M.; Azizov, A. A.; Zimmermann, R.; Zapotoczny, S.

2018-04-01

Fabrication of magnetic nanocomposites containing iron oxide nanoparticles formed in situ within a phosphorus-containing polymer matrix as well as its structural characterization and its thermal degradation is reported here. Comparative structural studies of the parent polymer and nanocomposites were performed using FTIR spectroscopy, x-ray diffraction, and atomic force microscopy. The results confirmed the presence of dispersed iron oxide magnetic nanoparticles in the polymer matrix. The formed composite combines the properties of porous polymer carriers and magnetic particles enabling easy separation and reapplication of such polymeric carriers used in, for example, catalysis or environmental remediation. Studies on thermal degradation of the composites revealed that the process proceeds in three stages while a significant influence of the embedded magnetic particles on that process was observed in the first two stages. Magnetic force microscopy studies revealed that nanocomposites and its calcinated form have strong magnetic properties. The obtained results provide a comprehensive characterization of magnetic nanocomposites and the products of their calcination that are important for their possible applications as sorbents (regeneration conditions, processing temperature, disposal, etc).

Imaging systems and materials characterization

International Nuclear Information System (INIS)

Murr, L.E.

2009-01-01

This paper provides a broad background for the historical development and modern applications of light optical metallography, scanning and transmission electron microscopy, field-ion microscopy and several forms of scanning probe microscopes. Numerous case examples illustrating especially synergistic applications of these imaging systems are provided to demonstrate materials characterization especially in the context of structure-property-performance issues which define materials science and engineering

Use of magnetic carbon composites from renewable resource materials for oil spill clean up and recovery

Science.gov (United States)

Viswanathan, Tito

2014-02-11

A method for separating a liquid hydrocarbon material from a body of water. In one embodiment, the method includes the steps of mixing a plurality of magnetic carbon-metal nanocomposites with a liquid hydrocarbon material dispersed in a body of water to allow the plurality of magnetic carbon-metal nanocomposites each to be adhered by an amount of the liquid hydrocarbon material to form a mixture, applying a magnetic force to the mixture to attract the plurality of magnetic carbon-metal nanocomposites each adhered by an amount of the liquid hydrocarbon material, and removing said plurality of magnetic carbon-metal nanocomposites each adhered by an amount of the liquid hydrocarbon material from said body of water while maintaining the applied magnetic force, wherein the plurality of magnetic carbon-metal nanocomposites is formed by subjecting one or more metal lignosulfonates or metal salts to microwave radiation, in presence of lignin/derivatives either in presence of alkali or a microwave absorbing material.

Preparation of new nano magnetic material Fe3O4@g-C3N4 and good adsorption performance on uranium ion

Science.gov (United States)

Long, Wei; Liu, Huijun; Yan, Xueming; Fu, Li

2018-03-01

A new nano magnetic material Fe3O4@g-C3N4 was prepared by deposition reduction method, which performed good adsorption performance to uranium ion. Characterization results showed that the g-C3N4 particles were wrapped around the nano magnetic Fe3O4 particles, and the textural properties of this material was improved, so the adsorption performance to uranium ion was good. Adsorption experiments of this material demonstrated that the optimum pH value was 10, the optimum mass of adsorbent was 6.5 mg and the optimum adsorption time was 150 min in the initial concentration of 140 mg/L uranium ion solution system, and the maximum adsorption capacity was up to 352.1 mg/g and the maximum adsorption rate was more than 90%.

Applications of Evolutionary Algorithms to Electromagnetic Materials Characterization and Design Problems

Science.gov (United States)

Frasch, Jonathan Lemoine

Determining the electrical permittivity and magnetic permeability of materials is an important task in electromagnetics research. The method using reflection and transmission scattering parameters to determine these constants has been widely employed for many years, ever since the work of Nicolson, Ross, and Weir in the 1970's. For general materials that are homogeneous, linear, and isotropic, the method they developed (the NRW method) works very well and provides an analytical solution. For materials which possess a metal backing or are applied as a coating to a metal surface, it can be difficult or even impossible to obtain a transmission measurement, especially when the coating is thin. In such a circumstance, it is common to resort to a method which uses two reflection type measurements. There are several such methods for free-space measurements, using multiple angles or polarizations for example. For waveguide measurements, obtaining two independent sources of information from which to extract two complex parameters can be a challenge. This dissertation covers three different topics. Two of these involve different techniques to characterize conductor-backed materials, and the third proposes a method for designing synthetic validation standards for use with standard NRW measurements. All three of these topics utilize modal expansions of electric and magnetic fields to analyze propagation in stepped rectangular waveguides. Two of the projects utilize evolutionary algorithms (EA) to design waveguide structures. These algorithms were developed specifically for these projects and utilize fairly recent innovations within the optimization community. The first characterization technique uses two different versions of a single vertical step in the waveguide. Samples to be tested lie inside the steps with the conductor reflection plane behind them. If the two reflection measurements are truly independent it should be possible to recover the values of two complex

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.

Magnetic edge states and magnetotransport in graphene antidot barriers

DEFF Research Database (Denmark)

Thomsen, M. R.; Power, Stephen; Jauho, Antti-Pekka

2016-01-01

Magnetic fields are often used for characterizing transport in nanoscale materials. Recent magnetotransport experiments have demonstrated that ballistic transport is possible in graphene antidot lattices (GALs). These experiments have inspired the present theoretical study of GALs in a perpendicu......Magnetic fields are often used for characterizing transport in nanoscale materials. Recent magnetotransport experiments have demonstrated that ballistic transport is possible in graphene antidot lattices (GALs). These experiments have inspired the present theoretical study of GALs...

Modular Approaches to Flouride-Bridged Molecular Magnetic Materials

DEFF Research Database (Denmark)

Pedersen, Kasper Steen

Abstract While oxygen and nitrogen are ubiquitous as bridging ligators in molecule-based magnetic systems, fluoride is much less explored and studied in this respect. In this project, new polynuclear complexes and one-dimensional polymeric systems, based on fluoride linkages between transition...... metal ions and between transition metal and lanthanide ions, have been synthetized and thoroughly characterized. Assembly of kinetically robust 3d fluoride complexes with various lanthanide precursors has proven to be a convenient route to small heterometallic complexes. However, the use of more labile...... interactions in a lower total spin polynuclear complex had a larger magnetic entropy change during a adiabatic demagnetization than an, all ferromagnetically coupled, complex with a larger spin ground state. Diffuse orbitals and strong magnetic anisotropy resulting from large values of the spinorbit coupling...

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.

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.)

Rare-earth-free high energy product manganese-based magnetic materials.

Science.gov (United States)

Patel, Ketan; Zhang, Jingming; Ren, Shenqiang

2018-06-14

The constant drive to replace rare-earth metal magnets has initiated great interest in an alternative. Manganese (Mn) has emerged to be a potential candidate as a key element in rare-earth-free magnets. Its five unpaired valence electrons give it a large magnetocrystalline energy and the ability to form several intermetallic compounds. These factors have led Mn-based magnets to be a potential replacement for rare-earth permanent magnets for several applications, such as efficient power electronics, energy generators, magnetic recording and tunneling applications, and spintronics. For past few decades, Mn-based magnets have been explored in many different forms, such as bulk magnets, thin films, and nanoparticles. Here, we review the recent progress in the synthesis and structure-magnetic property relationships of Mn-based rare-earth-free magnets (MnBi, MnAl and MnGa). Furthermore, we discuss their potential to replace rare-earth magnetic materials through the control of their structure and composition to achieve the theoretically predicted magnetic properties.

Superconductor Requirements and Characterization for High Field Accelerator Magnets

Energy Technology Data Exchange (ETDEWEB)

Barzi, E.; Zlobin, A. V.

2015-05-01

The 2014 Particle Physics Project Prioritization Panel (P5) strategic plan for U.S. High Energy Physics (HEP) endorses a continued world leadership role in superconducting magnet technology for future Energy Frontier Programs. This includes 10 to 15 T Nb₃Sn accelerator magnets for LHC upgrades and a future 100 TeV scale pp collider, and as ultimate goal that of developing magnet technologies above 20 T based on both High Temperature Superconductors (HTS) and Low Temperature Superconductors (LTS) for accelerator magnets. To achieve these objectives, a sound conductor development and characterization program is needed and is herein described. This program is intended to be conducted in close collaboration with U.S. and International labs, Universities and Industry.

X-rays and magnetism

International Nuclear Information System (INIS)

Fischer, Peter; Ohldag, Hendrik

2015-01-01

Magnetism is among the most active and attractive areas in modern solid state physics because of intriguing phenomena interesting to fundamental research and a manifold of technological applications. State-of-the-art synthesis of advanced magnetic materials, e.g. in hybrid structures paves the way to new functionalities. To characterize modern magnetic materials and the associated magnetic phenomena, polarized x-rays have emerged as unique probes due to their specific interaction with magnetic materials. A large variety of spectroscopic and microscopic techniques have been developed to quantify in an element, valence and site-sensitive way properties of ferro-, ferri-, and antiferromagnetic systems, such as spin and orbital moments, and to image nanoscale spin textures and their dynamics with sub-ns time and almost 10 nm spatial resolution. The enormous intensity of x-rays and their degree of coherence at next generation x-ray facilities will open the fsec time window to magnetic studies addressing fundamental time scales in magnetism with nanometer spatial resolution. This review will give an introduction into contemporary topics of nanoscale magnetic materials and provide an overview of analytical spectroscopy and microscopy tools based on x-ray dichroism effects. Selected examples of current research will demonstrate the potential and future directions of these techniques. (report on progress)

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)

Effect of high entropy magnetic regenerator materials on power of the GM refrigerator

International Nuclear Information System (INIS)

Hashimoto, Takasu; Yabuki, Masanori; Eda, Tatsuji; Kuriyama, Toru; Nakagome, Hideki

1994-01-01

In previous work the authors have proved that heavy rare earth compounds with low magnetic transition temperature T c are very useful as regenerator materials in low temperature range. Applying the magnetic material Er 3 Ni particles to the 2nd regenerator of the GM refrigerator, they were able to reach the 2 K range but could not obtain high refrigeration power at 4.2 K. This is thought to be due to the temperature dependence of the magnetic specific heat. They present here a method by which high refrigeration power is obtained at low temperature. The simplest means of obtaining high power is with a hybrid structure regenerator which is composed of two kinds of magnetic materials, high T c and low T c materials. Computer simulation and experiments were carried out to verify the superiority of the hybrid regenerator. The authors succeeded experimentally in obtaining the high power of ∼ 1.1 watt at 4.2 K. They will report other detailed results and discuss developing way of the magnetic regenerator in future

Makeup and uses of a basic magnet laboratory for characterizing high-temperature permanent magnets

Science.gov (United States)

Niedra, Janis M.; Schwarze, Gene E.

1991-01-01

A set of instrumentation for making basic magnetic measurements was assembled in order to characterize high intrinsic coercivity, rare earth permanent magnets with respect to short term demagnetization resistance and long term aging at temperatures up to 300 C. The major specialized components of this set consist of a 13 T peak field, capacitor discharge pulse magnetizer; a 10 in. pole size, variable gap electromagnet; a temperature controlled oven equipped with iron cobalt pole piece extensions and a removable paddle that carries the magnetization and field sensing coils; associated electronic integrators; and sensor standards for field intensity H and magnetic moment M calibration. A 1 cm cubic magnet sample, carried by the paddle, fits snugly between the pole piece extensions within the electrically heated aluminum oven, where fields up to 3.2 T can be applied by the electromagnet at temperatures up to 300 C. A sample set of demagnetization data for the high energy Sm2Co17 type of magnet is given for temperatures up to 300 C. These data are reduced to the temperature dependence of the M-H knee field and of the field for a given magnetic induction swing, and they are interpreted to show the limits of safe operation.

Magnetic Multi-Scale Mapping to Characterize Anthropogenic Targets

Science.gov (United States)

Le Maire, P.; Munschy, M.

2017-12-01

The discovery of buried anthropic objects on construction sites can cause delays and/or dangers for workers and for the public. Indeed, every year 500 tons of Unexploded-ordnance are discovered in France. Magnetic measurements are useful to localize magnetized objects. Moreover, it is the cheapest geophysical method which does not impact environment and which is relatively fast to perform. Fluxgate magnetometers (three components) are used to measure magnetic properties bellow the ground. These magnetic sensors are not absolute, so they need to be calibrated before the onset of the measurements. The advantage is that they allow magnetic compensation of the equipment attached to the sensor. So the choice of this kind sensor gives the opportunity to install the equipment aboard different magnetized supports: boat, quad bike, unmanned aerial vehicle, aircraft,... Indeed, this methodology permits to perform magnetic mapping with different scale and different elevation above ground level. An old French aerial military plant was chosen to perform this multi-scale approach. The advantage of the site is that it contains a lot of different targets with variable sizes and depth, e.g. buildings, unexploded-ordnances of the two world wars, trenches, pipes,… By comparison between the different magnetic anomaly maps at different elevations some of the geometric parameters of the magnetic sources can be characterized. The comparison between measured maps at different elevations and the prolonged map highlights the maximum distance for the target's detection (figure).

Exfoliated BN shell-based high-frequency magnetic core-shell materials.

Science.gov (United States)

Zhang, Wei; Patel, Ketan; Ren, Shenqiang

2017-09-14

The miniaturization of electric machines demands high frequency magnetic materials with large magnetic-flux density and low energy loss to achieve a decreased dimension of high rotational speed motors. Herein, we report a solution-processed high frequency magnetic composite (containing a nanometal FeCo core and a boron nitride (BN) shell) that simultaneously exhibits high electrical resistivity and magnetic permeability. The frequency dependent complex initial permeability and the mechanical robustness of nanocomposites are intensely dependent on the content of BN insulating phase. The results shown here suggest that insulating magnetic nanocomposites have potential for application in next-generation high-frequency electric machines with large electrical resistivity and permeability.

Using Virtual Testing for Characterization of Composite Materials

Science.gov (United States)

Harrington, Joseph

Composite materials are finally providing uses hitherto reserved for metals in structural systems applications -- airframes and engine containment systems, wraps for repair and rehabilitation, and ballistic/blast mitigation systems. They have high strength-to-weight ratios, are durable and resistant to environmental effects, have high impact strength, and can be manufactured in a variety of shapes. Generalized constitutive models are being developed to accurately model composite systems so they can be used in implicit and explicit finite element analysis. These models require extensive characterization of the composite material as input. The particular constitutive model of interest for this research is a three-dimensional orthotropic elasto-plastic composite material model that requires a total of 12 experimental stress-strain curves, yield stresses, and Young's Modulus and Poisson's ratio in the material directions as input. Sometimes it is not possible to carry out reliable experimental tests needed to characterize the composite material. One solution is using virtual testing to fill the gaps in available experimental data. A Virtual Testing Software System (VTSS) has been developed to address the need for a less restrictive method to characterize a three-dimensional orthotropic composite material. The system takes in the material properties of the constituents and completes all 12 of the necessary characterization tests using finite element (FE) models. Verification and validation test cases demonstrate the capabilities of the VTSS.

Mechanical alignment of particles for use in fabricating superconducting and permanent magnetic materials

International Nuclear Information System (INIS)

Nellis, W.J.; Maple, M.B.

1992-01-01

This patent describes a method of fabricating oriented compacts of superconducting and/or permanent magnetic material. It comprises: providing a base layer of support material, mechanically orienting aligned superconducting or permanently magnetic particles into the desired orientation on the base layer, without mixing the particles with a liquid, optionally covering the particles with a support material, fabricating the base layer and oriented particles assemblage into a desired construct and recovering the resulting fabricated material

Multifaceted Material Substitution: The Case of NdFeB Magnets, 2010-2015

Science.gov (United States)

Smith, Braeton J.; Eggert, Roderick G.

2016-07-01

Substitution is an important response for material users when faced with disruption to the availability or price of an essential material. In economic terms, substitution refers to the ability of firms to alter their patterns of material use in response to exogenous market shocks. Substitution comes in different forms which vary from situation to situation. This paper uses expert opinion to identify the specific forms of substitution that occurred in permanent magnets, specifically neodymium-iron-boron magnets, following the significant increase in rare earth prices in 2010-2011. The paper provides a framework for understanding the multifaceted nature of substitution and assesses the relative importance of five different types of substitution. Technology-for-element, grade-for-grade, and system-for-system substitution appear to have been more important than element-for-element and magnet-for-magnet substitution. Cost pass-through and absorption were also important responses.

Impact of fluorine based reactive chemistry on structure and properties of high moment magnetic material

Energy Technology Data Exchange (ETDEWEB)

Yang, Xiaoyu, E-mail: xiaoyu.yang@wdc.com; Chen, Lifan; Han, Hongmei; Fu, Lianfeng; Sun, Ming; Liu, Feng; Zhang, Jinqiu [Western Digital Corporation, 44100 Osgood Road, Fremont, California 94539 (United States)

2014-05-07

The impact of the fluorine-based reactive ion etch (RIE) process on the structural, electrical, and magnetic properties of NiFe and CoNiFe-plated materials was investigated. Several techniques, including X-ray fluorescence, 4-point-probe, BH looper, transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS), were utilized to characterize both bulk film properties such as thickness, average composition, Rs, ρ, Bs, Ms, and surface magnetic “dead” layers' properties such as thickness and element concentration. Experimental data showed that the majority of Rs and Bs changes of these bulk films were due to thickness reduction during exposure to the RIE process. ρ and Ms change after taking thickness reduction into account were negligible. The composition of the bulk films, which were not sensitive to surface magnetic dead layers with nano-meter scale, showed minimum change as well. It was found by TEM and EELS analysis that although both before and after RIE there were magnetic dead layers on the top surface of these materials, the thickness and element concentration of the layers were quite different. Prior to RIE, dead layer was actually native oxidation layers (about 2 nm thick), while after RIE dead layer consisted of two sub-layers that were about 6 nm thick in total. Sub-layer on the top was native oxidation layer, while the bottom layer was RIE “damaged” layer with very high fluorine concentration. Two in-situ RIE approaches were also proposed and tested to remove such damaged sub-layers.

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

Thermal effects on transducer material for heat assisted magnetic recording application

Energy Technology Data Exchange (ETDEWEB)

Ji, Rong, E-mail: Ji-Rong@dsi.a-star.edu.sg; Xu, Baoxi; Cen, Zhanhong; Ying, Ji Feng; Toh, Yeow Teck [Data Storage Institute, Agency for Science, Technology and Research (A-STAR), 5 Engineering Drive 1, Singapore 117608 (Singapore)

2015-05-07

Heat Assisted Magnetic Recording (HAMR) is a promising technology for next generation hard disk drives with significantly increased data recording capacities. In HAMR, an optical near-field transducer (NFT) is used to concentrate laser energy on a magnetic recording medium to fulfill the heat assist function. The key components of a NFT are transducer material, cladding material, and adhesion material between the cladding and the transducer materials. Since transducer materials and cladding materials have been widely reported, this paper focuses on the adhesion materials between the Au transducer and the Al{sub 2}O{sub 3} cladding material. A comparative study for two kinds of adhesion material, Ta and Cr, has been conducted. We found that Ta provides better thermal stability to the whole transducer than Cr. This is because after thermal annealing, chromium forms oxide material at interfaces and chromium atoms diffuse remarkably into the Au layer and react with Au to form Au alloy. This study also provides insights on the selection of adhesion material for HAMR transducer.

The actual problems of the standardization of magnetically hard materials and permanent magnets

International Nuclear Information System (INIS)

Kurbatov, P.A.; Podolskiy, I.D.

1998-01-01

The standardization of industrial products raises their accordance with functional purpose, contributes to technological developments and the elimination of technical barriers in trade. The progress of the world trade necessitates the certification of permanent magnets and their manufacturing methods. According to ISO/IEC recommendations, the certification standards should contain the clear requirements to operation parameters of products, that can be impartially controlled. The testing procedures should be clearly formulated and assure that the results may be reproduced. This calls for creation of a system of interconnected certification standards: the standard for technical characteristics of prospective commercial magnetically hard materials, the standard specifications for permanent magnets, the standards for typical testing procedures and the standards for metrological assurance of measurements. (orig.)

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.

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.

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.

Magnetic Phase Diagram of α-RuCl3

Science.gov (United States)

Sears, Jennifer; Kim, Young-June; Zhao, Yang; Lynn, Jeffrey

The layered honeycomb material α-RuCl3 is thought to possess unusual magnetic interactions including a strong bond-dependent Kitaev term, offering a potential opportunity to study a material near a well understood spin liquid phase. Although this material orders magnetically at low temperatures and is thus not a realization of a Kitaev spin liquid, it does show a broad continuum of magnetic excitations reminiscent of that expected for the spin liquid phase. It has also been proposed that a magnetic field could destabilize the magnetic order in this material and induce a transition into a spin liquid phase. Low temperature magnetization and specific heat measurements in this material have suggested a complex magnetic phase diagram with multiple unidentified magnetic phases present at low temperature. This has provided motivation for our work characterizing the magnetic transitions and phase diagram in α-RuCl3. I will present detailed bulk measurements combined with magnetic neutron diffraction measurements to map out the phase diagram and identify the various phases present.

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

Methods of characterization of multiphase Nd-Fe-B melt-spun alloys

Directory of Open Access Journals (Sweden)

Grujić A.

2007-01-01

Full Text Available Nanocomposite permanent magnetic materials based on Nd-Fe-B alloys with a low Nd content are a new type of permanent magnetic material. The microstructure of these nanocomposite permanent magnets is composed of a mixture of magnetically soft and hard phases providing the so called exchange coupling effect. Beside the optimization process parameters, methods of characterization have a very important role in the design of an optimal magnetic matrix of multiphase melt-spun Nd-Fe-B alloys. Different methods and techniques of characterization were used for observation and study of the microstructure evolution during crystallization. A summary results of measurements using different methods of characterization are presented to enable a better insight into relations between the microstructure and magnetic properties of the investigated melt-spun Nd-Fe-B alloys. .

PREFACE: 3rd International Workshop on Materials Analysis and Processing in Magnetic Fields (MAP3)

Science.gov (United States)

Sakka, Yoshio; Hirota, Noriyuki; Horii, Shigeru; Ando, Tsutomu

2009-07-01

The 3rd International Workshop on Materials Analysis and Processing in Materials Fields (MAP3) was held on 14-16 May 2008 at the University of Tokyo, Japan. The first was held in March 2004 at the National High Magnetic Field Laboratory in Tallahassee, USA. Two years later the second took place in Grenoble, France. MAP3 was held at The University of Tokyo International Symposium, and jointly with MANA Workshop on Materials Processing by External Stimulation, and JSPS CORE Program of Construction of the World Center on Electromagnetic Processing of Materials. At the end of MAP3 it was decided that the next MAP4 will be held in Atlanta, USA in 2010. Processing in magnetic fields is a rapidly expanding research area with a wide range of promising applications in materials science. MAP3 focused on the magnetic field interactions involved in the study and processing of materials in all disciplines ranging from physics to chemistry and biology: Magnetic field effects on chemical, physical, and biological phenomena Magnetic field effects on electrochemical phenomena Magnetic field effects on thermodynamic phenomena Magnetic field effects on hydrodynamic phenomena Magnetic field effects on crystal growth Magnetic processing of materials Diamagnetic levitation Magneto-Archimedes effect Spin chemistry Application of magnetic fields to analytical chemistry Magnetic orientation Control of structure by magnetic fields Magnetic separation and purification Magnetic field-induced phase transitions Materials properties in high magnetic fields Development of NMR and MRI Medical application of magnetic fields Novel magnetic phenomena Physical property measurement by Magnetic fields High magnetic field generation> MAP3 consisted of 84 presentations including 16 invited talks. This volume of Journal of Physics: Conference Series contains the proceeding of MAP3 with 34 papers that provide a scientific record of the topics covered by the conference with the special topics (13 papers) in

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.

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.

Contemporary dielectric materials

CERN Document Server

Saravanan, R

2016-01-01

This book deals with experimental results of the physical characterization of several important, dielectric materials of great current interest. The experimental tools used for the analysis of these materials include X-ray diffraction, dielectric measurements, magnetic measurements using a vibrating sample magnetometer, optical measurements using a UV-Visible spectrometer etc.

Composite Materials with Magnetically Aligned Carbon Nanoparticles and Methods of Preparation

Science.gov (United States)

Hong, Haiping (Inventor); Peterson, G.P. (Bud) (Inventor); Salem, David R. (Inventor)

2018-01-01

The present invention relates to magnetically aligned carbon nanoparticle composites and methods of preparing the same. The composites comprise carbon nanoparticles, host material, magnetically sensitive nanoparticles and surfactant. The composites may have enhanced mechanical, thermal, and/or electrical properties.

High temperature material characterization and advanced materials development

International Nuclear Information System (INIS)

Ryu, Woo Seog; Kim, D. H.; Kim, S. H. and others

2005-03-01

The study is to characterize the structural materials under the high temperature, one of the most significant environmental factors in nuclear systems. And advanced materials are developed for high temperature and/or low activation in neutron irradiation. Tensile, fatigue and creep properties have been carried out at high temperature to evaluate the mechanical degradation. Irradiation tests were performed using the HANARO. The optimum chemical composition and heat treatment condition were determined for nuclear grade 316NG stainless steel. Nitrogen, aluminum, and tungsten were added for increasing the creep rupture strength of FMS steel. The new heat treatment method was developed to form more stable precipitates. By applying the novel whiskering process, high density SiC/SiC composites with relative density above 90% could be obtained even in a shorter processing time than the conventional CVI process. Material integrated databases are established using data sheets. The databases of 6 kinds of material properties are accessible through the home page of KAERI material division