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

Magnetostriction (MS) caused by the global magnetization of limbs and yokes and magnetic forces are the undisputed causes of the vibration and noise in power transformer cores. This paper presents a novel way to reduce the vibration and noise, in which nanocrystalline soft magnetic composite (NSMC) material with high permeability is used to fill the step-lap joint gaps of the power transformer magnetic cores. In order to numerically predict the effectiveness of the proposed method, a 3-D magneto-mechanical strong coupled model including MS and magnetic anisotropy of steel sheet was founded. Then, the numerical model was applied to analyze the step-lap joint region of the corner of magnetic cores. The analysis results illustrated that the deformation and noise of core with NSMC are lower than with the traditional epoxy damping material. Moreover, the validity of the proposed new way was verified by the simplified step-lap joint cores, which were achieved based on Epstein Frames.

/pdf/numerical-computation-for-a-new-way-to-reduce-vibration-and-38l6hbwcix.pdf

Numerical computation for a new way to reduce vibration and noise due to magnetostriction and magnetic forces of transformer cores

This paper proposes an analytical model for the prediction of air gap magnetic field distribution for axial flux permanent magnet (AFPM) machine with various types of misalignments. The AFPM machine geometry is first transformed to a polar representation. Consequently, the subdomain model based on current sheet technique is developed. Then the stator coordinate system is chosen as reference coordinate to consider both static/dynamic angular and axis misalignments. The back electromagnetic forces and cogging torque are obtained accordingly based on Maxwell's equations. The results show that the proposed approach agrees with the finite-element method. The model is further validated by experiments under healthy, dynamic angular and axis misalignment conditions, which can validate the proposed approach. It turns out that the proposed approach can predict the performance of AFPM machines with types of misalignment quickly and effectively, which is greatly significant for further fault detection.

Analytical Modeling of Misalignment in Axial Flux Permanent Magnet Machine

This paper investigates the vibration characteristic of a permanent magnet synchronous motor (PMSM) including magnetostriction (MS) and harmonics, which are the potential cause of additional vibration and noise from PMSM. First, a strong coupled model between the magnetic field and the mechanical deformation in the stator is built based on the piezomagnetic laws. Then, the vibration analysis of a 1.5 kW PMSM is carried out in finite element by using the model and measured MS curves. And finally, the vibration of a 1.5 kW PMSM is tested and both analysis and measured results indicate that MS and harmonics are significant and must be accounted for motor core electromagnetic design.

Magnetoelastic Numerical Analysis of Permanent Magnet Synchronous Motor Including Magnetostriction Effects and Harmonics

Plug-in hybrid electric vehicle (PHEV) depends mostly on the electric drive system where the internal combustion engine just acts as the auxiliary unit, which has strict constraints for the drive machine. According to the Toyota Prius configuration, one novel PHEV drive system in this paper has been brought forward which primarily includes one drive machine operating as both motor and generator, energy storage unit combining supercapacitor and battery. In the novel PHEV, the ideal tendency is to use the drive machine over the entire torque/speed range, including starting/acceleration, high speed cruising, regenerative braking, etc. The flux-switching permanent magnet machine (FSPMM) for the drive system has been studied in details. Firstly, the structure and operation principle are analyzed theoretically. In order to achieve higher torque/power density and lower torque ripple, FSPMM with 6/7 (stator/rotor) poles and 12/14 poles according to plenty of investigations are optimized based on our setting objective function decided by actual projects. Moreover, it analyzes several typical performance curves, such as cogging/rating torque, flux linkage, back-EMF, and self-/mutual-inductances. Finally the flux-weakening ability and efficiency are estimated by experience. The results indicate that FSPMM is one ideal candidate for our PHEV drive system for its strong thermal dissipation ability, good mechanical robustness, strong flux-weakening ability, etc.

/pdf/flux-switching-permanent-magnet-machine-drive-system-for-15zt891fp0.pdf

Flux-switching permanent magnet machine drive system for plug-in hybrid electrical vehicle

When a transformer is de-energized, the magnetic core material will contain a certain amount of residual magnetic flux. This flux may intensify saturation and lead to high transient in-rush current upon remagnetizing. This paper describes a novel method for analyzing and detecting the residual flux, based on the nonlinear magnetizing characteristics (also called Φ- I characteristics) of the core. A model of toroidal transformer core was built to simulate transients, which takes the process of initial energization of the nonloaded transformer core into consideration. The relationship between residual flux density and the magnetizing current was then approximated. Measurements of residual flux density for a simple laboratory setup verified that the simulation gave reasonable values.

Yongjian Li

Papers

Numerical computation for a new way to reduce vibration and noise due to magnetostriction and magnetic forces of transformer cores

Analytical Modeling of Misalignment in Axial Flux Permanent Magnet Machine

Magnetoelastic Numerical Analysis of Permanent Magnet Synchronous Motor Including Magnetostriction Effects and Harmonics

Flux-switching permanent magnet machine drive system for plug-in hybrid electrical vehicle

Residual Flux in the Closed Magnetic Core of a Power Transformer