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

Single-sided linear induction motors (SLIMs) have lately been applied in transportation system traction drives, particularly in the intermediate speed range. This is because they have merits, such as the ability to exert thrust on the secondary without mechanical contact, high acceleration or deceleration, less wheel wear, small turning circle radius, and flexible road line. The theory of operation for these machines can be directly derived from rotary induction motors (RIMs). However, while the cut-open primary magnetic circuit has many inherent characteristics of the RIM equivalent circuits, several issues involving the transversal edge and longitudinal end effects and the half-filled slots at the primary ends need to be investigated. In this paper, a T-model equivalent circuit is proposed which is based on the 1-D magnetic equations of the air gap, where half-filled slots are considered by an equivalent pole number. Among the main five parameters, namely, the primary resistance, primary leakage inductance, mutual inductance, secondary resistance, and secondary inductance, the mutual inductance and the secondary resistance are influenced by the edge and end effects greatly, which can be revised by four relative coefficients, i.e., Kr, Kx, Cr, and Cx. Moreover, two-axis equivalent circuits (dq or αβ) according to the T-model equivalent circuit are obtained using the power conversion rule, which are analogous with those of the RIM in a two-axis coordinate system. The linear induction motor dynamic performance, particularly the mutual inductance and the secondary resistance, can be analyzed by the four coefficients. Experimental verification indicates that both the T-model and the new two-axis circuits are reasonable for describing the steady and dynamic performance of the SLIM. These two models can provide good guidance for the electromagnetic design and control scheme implementation for SLIM applications.

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Equivalent Circuits for Single-Sided Linear Induction Motors

Wireless charging electric vehicles (EV) is the development trend of EV. However, the battery taken by EVs has the disadvantages of big volume, long time to recharge, and limited driving distance. In this paper, an innovative dynamic wireless charging system based on magnetic coupled resonant power transmission is presented. The transmitting coil of this charging system can selectively turn ON/OFF for charging vehicles while driving. The structures of the transmitting coil and receiving coil are researched and improved. In addition, the dispersed coupling structure named grouped periodic series spiral coupler is proposed, and its characteristics are described. A simulation of coupling coefficients at different $D$ values is carried out. A prototype is built to experiment on the dynamic wireless charging process of EV. Meanwhile, the coil coupling and variation of transmission efficiency are analyzed. The comparison of the experiment indicated that the EV can obtain a stable charging process under 25 mm transmission distance using the improved receiving coil with $R$ : $H$ : $D=4:5:13$ . Moreover, the dynamic charging process is relatively stable without an obvious fluctuation while passing the interval between two transmitting coils, and the transmission efficiency is promoted by 50%.

Coil Design and Efficiency Analysis for Dynamic Wireless Charging System for Electric Vehicles

Compared with the conventional fixed speed drive, a major factor that handicaps the wide acceptance of variable speed drive with high efficiency permanent magnet (PM) motors is its high cost. This paper presents an effort to reduce the material and manufacturing costs of PM motors by using the soft magnetic composite (SMC), and the highly matured powder metallurgic technology. Because the SMC's magnetic properties are quite different from that of the traditional silicon steel sheets, special efforts have been made on measurement and modelling of vectorial magnetic properties, electrical machine topologies, and drive schemes in order to make the best use of the material. Various PM SMC motors of transverse flux topologies have been designed, fabricated, and tested. The detailed results are presented and discussed.

Development of PM Transverse Flux Motors With Soft Magnetic Composite Cores

Soft magnetic composite (SMC) materials are especially suitable for developing electrical machines with complex structure and three-dimensional (3-D) magnetic flux path. In these SMC machines, the magnetic field is in general 3-D and rotational, so the mechanism and calculation of core loss may be quite different from that in traditional electrical machines with laminated steels in which the magnetic field is restrained. This paper investigates the calculation of core loss in a permanent magnet claw pole motor with SMC stator core. First, core loss models are developed based on the experimental data on SMC samples by using a 3-D magnetic property tester. Then, 3-D magnetic time-stepping field finite element analysis (FEA) is conducted to find the flux density locus in each element when the rotor rotates. The core loss is computed based on the magnetic field FEA results by using the developed core loss models. The calculations agree well with the experimental measurements on the SMC motor prototype.

Core Loss Calculation for Soft Magnetic Composite Electrical Machines

Magnetic components in power electronic equipment usually suffer from nonsinusoidal excitations. In this paper, a brief description about the existing core loss calculation methods for nonsinusoidal excitations is given. Then calculation formulas of aforementioned methods for two typical excitation waveforms, that is, square and rectangular with variable duty cycle ${D}$ , are derived. Core loss of nanocrystalline FT-3KS, under above two nonsinusoidal excitations, is measured on an established test setup. The accuracy and applicability of each method are discussed theoretically and verified experimentally, especially in terms of different duty cycles and frequencies. It is found that the waveform coefficient Steinmetz equation (WcSE) is more applicable for the case of relatively small harmonics content of magnetic field intensity ${H}$ (normal duty cycle region), while the improved generalized Steinmetz equation (IGSE) has better precision where the harmonics count (extreme duty cycle region). In addition, the IGSE can better follow the changing trend of core loss with ${D}$ and have better frequency applicability than WcSE, which is proven to be not valid in low frequency (where the static hysteresis loss dominates). The results can provide reference for core loss prediction under nonsinusoidal excitations.

Yongjian Li

Papers

Equivalent Circuits for Single-Sided Linear Induction Motors

Coil Design and Efficiency Analysis for Dynamic Wireless Charging System for Electric Vehicles

Development of PM Transverse Flux Motors With Soft Magnetic Composite Cores

Core Loss Calculation for Soft Magnetic Composite Electrical Machines

Comparative Analysis of Core Loss Calculation Methods for Magnetic Materials Under Nonsinusoidal Excitations