Preface. Contents of volumes 1-6. 1. Magnetism in ultrathin transition metal films (U. Gradmann). 2. Energy band theory of metallic magnetism in the elements (V.L. Moruzzi, P.M. Marcus). 3. Density functional theory of the ground state magnetic properties of rare earths and actinides (M.S.S. Brooks, B. Johansson). 4. Diluted magnetic semiconductors (J. Kossut, W. Dobrowolski). 5. Magnetic properties of binary rare-earth 3d-transition-metal intermetallic compounds (J.J.M. Franse, R.J. Radwanski). 6. Neutron scattering on heavy fermion and valence fluctuation 4f-systems (M. Loewenhaupt, K.H. Fischer). Author index. Subject index. Materials index.

Handbook of Magnetic Materials

Spintronic devices exploit the spin, as well as the charge, of electrons and could bring new capabilities to the microelectronics industry However, in order for spintronic devices to meet the ever-increasing demands of the industry, innovation in terms of materials, processes and circuits are required Here, we review recent developments in spintronics that could soon have an impact on the microelectronics and information technology industry We highlight and explore four key areas: magnetic memories, magnetic sensors, radio-frequency and microwave devices, and logic and non-Boolean devices We also discuss the challenges—at both the device and the system level—that need be addressed in order to integrate spintronic materials and functionalities into mainstream microelectronic platforms This Review Article examines the potential of spintronics in four key areas of application —memories, sensors, microwave devices, and logic devices — and discusses the challenges that need be addressed in order to integrate spintronic materials and functionalities into mainstream microelectronic platforms

Opportunities and challenges for spintronics in the microelectronics industry

hysteresis in magnetism (electromagnetism)

Power saving has been a central driving force for the development of new materials. In this framework, soft magnetic composites appear as a feasible concept to be applied in strategic topics for modern society including sensing, energy generation, and conversion. With a unique freedom regarding material selection based on powder metallurgy techniques, this engineering magnetic material class allows novel designs able to drive operation conditions to new limits, unlocking the potential of novel applications. This document reviews soft magnetic composites by using a multidisciplinary approach addressing underlying physics responsible for their magnetic performance, limitations, and future trends.

Past, present, and future of soft magnetic composites

Review of static and dynamic wireless electric vehicle charging system

To expend the engineering application of novel high frequency magnetic materials, magnetic properties of these materials in different magnetic fields need to be further studied. This paper proposes a novel high frequency two-dimensional (2-D) magnetic properties tester for high frequency magnetic materials, such as nanocrystalline alloy. The magnetic field distribution on the specimen is simulated to verify the theoretical feasibility and rationality of this tester by the finite element software. Considering the dimension and physical properties of specimen, the improved B-H sensing structure is designed that can extract the stable inducted voltage through many experiments and comparisons. Moreover, the frequency-domain feedback control system is used to obtain the desired waveform. Based on the experimental data, measuring error of the tester is systematically analyzed. The losses of square nanocrystalline specimen under alternating magnetization condition are compared with the official data at 20 kHz. The results show that the measurement of the tester has well precision. Finally, the 2-D rotational magnetic properties of nanocrystalline alloy are preliminary measured.

Design and Analysis of a Novel Two-Dimensional High Frequency Magnetic Tester for Nanocrystalline Alloy Material

The vibration of electric power device is a serious problem, and is difficult to estimate in its design optimization stage. In this paper, a dynamic magnetostriction model accounting for the dynamic hysteresis behavior is presented by combining the Becker-Doring crystal magnetostriction model and J-A dynamic hysteresis model. The proposed model can correctly describe the physical mechanism of magnetostriction. To compute the vibration of a transformer core, the presented model is incorporated into the finite-element analysis (FEA), and both the Maxwell stress and the magnetostriction are obtained simultaneously. Meanwhile, the vibration of a three-phase transformer prototype is measured to verify the simulation results. It demonstrated that the proposed method was found to adequately predict the vibration of transformer cores.

Numerical Calculation for Power Transformer Vibration Based on Dynamic Magnetostriction Model

In this work, we have conducted systematic studies on the interfacial conditions for gallium nitride (GaN)-based trench metal/insulator/semiconductor (MIS)-type barrier Schottky rectifier (TMBS) with the help of the T-CAD tools. Our results show that the donor-type traps tend to reduce the Schottky barrier height (<inline-formula> <tex-math notation="LaTeX">${q}\varphi _{s}$ </tex-math></inline-formula>), which weakens the charge coupling effect, increases the leakage current, and finally reduces the breakdown voltage (BV). On the contrary, the acceptor-type traps at the contact interface and mesa sidewall will increase <inline-formula> <tex-math notation="LaTeX">${q}\varphi _{s}$ </tex-math></inline-formula> and the turn-on voltage (<inline-formula> <tex-math notation="LaTeX">${V}_{\mathrm{ON}}$ </tex-math></inline-formula>) because they can capture electrons in the mesa region and show the negative polarity. This then enhances the electron depletion at the contact interface and the mesa sidewall, resulting in an increase in <inline-formula> <tex-math notation="LaTeX">${q}\varphi _{s}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">${V}_{\mathrm{ON}}$ </tex-math></inline-formula>. Therefore, this process can increase the reverse blocking characteristics. However, for solving the complicated interfacial conditions in the Schottky contact region, we propose using an MIS structure with a 1-nm Al2O3 insulation layer for the GaN-based TMBS rectifiers. Based on the results, the tunneling process and thermionic-emission (TE) process take into account for the current transport mechanism for the MIS-TMBS rectifiers. Meanwhile, the 1-nm thick Al2O3 interlayer increases the effective Schottky barrier height (<inline-formula> <tex-math notation="LaTeX">${q}\varphi _{s} + {q}\varphi _{T}$ </tex-math></inline-formula>), which significantly reduces the reverse leakage. In addition, this design offers more freedom in selecting the Schottky contact electrode for the MIS-TMBS rectifier.

MIS-Based GaN Schottky Barrier Diodes: Interfacial Conditions on the Reverse and Forward Properties

In the manufacturing process of electrical machines, laser cutting is widely used to produce the laminations of cores. The internal stresses introduced by the high-energy laser beam will lead to deterioration in the magnetic properties of the non-oriented silicon steels. To accurately predict the core losses of the electrical machines, it is important to analyze the deterioration degree and the deterioration mechanism of the non-oriented steel sheets caused by laser cutting. In this paper, first, the local magnetic properties of the non-oriented steel 35WW250 at different positions are measured under the alternating sinusoidal excitation, in which the degradation degree is evaluated based on the core loss from the macroscopic perspective. Second, from the microscopic perspective, the observed magnetic domain patterns at the edge and those evolutions under the excitation of the magnetic field are investigated. The experimental results demonstrate that laser cutting can lead to the magnetic degradation of the non-oriented steels with a transverse depth of 18 mm from the edge. Moreover, the laser cutting process leads to significant variations in the patterns of the magnetic domains at different positions. The magneto-optical observation and local magnetic measurement verified the effectiveness of the analytical method, which is of great significance for the evaluation and improvement of the processing technique of the silicon steels.

Magnetic properties deterioration of non-oriented steel due to laser cutting

Multiobjective particle swarm optimization (MOPSO) is applied to optimize six structural parameters of a 27-slot/30-pole permanent magnet synchronous machine (PMSM) with external rotor, including slot opening, magnet height, stator outer radius, thickness of rotor yoke, width of tooth, and stack length. Three conflicting objectives, namely torque, torque ripple, and volume, are improved simultaneously after applying MOPSO. MOPSO is combined with Kriging surrogate model (KSM) of torque and torque ripple, which reduces number of times to use time-consuming finite element analysis (FEA) in the process of machine optimization. KSMs are established based on samples obtained by FEA, which reflects relations between various structural parameters of machine and torque and torque ripple.

Yongjian Li

Papers

Design and Analysis of a Novel Two-Dimensional High Frequency Magnetic Tester for Nanocrystalline Alloy Material

Numerical Calculation for Power Transformer Vibration Based on Dynamic Magnetostriction Model

MIS-Based GaN Schottky Barrier Diodes: Interfacial Conditions on the Reverse and Forward Properties

Magnetic properties deterioration of non-oriented steel due to laser cutting

Multiobjective Particle Swarm Optimization Design of Permanent Magnet Machine for Torque Density Improvement and Torque Ripple Suppression