of magnetic materials with MDGRAPE-2 B. G. Elmegreen R. H. Koch M. E. Schabes T. Crawford T. Ebisuzaki H. Furusawa T. Narumi R. Susukita K. Yasuoka The use of accelerator hardware for micromagnetics simulations is described, along with some initial results. The accelerator calculates the dipole interactions at 400 gigaflops, allowing large simulations to be performed with arbitrary geometries. ...

The factors that make certain magnetic materials behave similarly to corresponding Ising models are reviewed. Examples of extensively studied materials include Dy(C2H5SO4)3.9H2) (DyES), Dy3Al5O12 (DyAlG), DyPO4, Dy2Ti2O7, LiTbF4, K2CoF4, and Rb2CoF4. Various comparisons between theory and experiment for these materials are examined. The agreement is found to be generally very good, even when th...

Abstract Using a 11.4 GHz, 50-MW, <1 μs, pulsed power source and a TE013-like mode copper cavity, we have been measuring critical magnetic fields of superconductors for accelerator cavity applications. This device can eliminate both thermal and field emission effects due to a short pulse and no electric field at the sample surface. A model of the system is presented in this paper along with a d...

MnBi has attracted much attention in recent years due to its potential as a rare-earth-free permanent magnet material. It is unique because its coercivity increases with increasing temperature, which makes it a good hard phase material for exchange coupling nanocomposite magnets. MnBi phase is difficult to obtain, partly because the reaction between Mn and Bi is peritectic, and partly because M...

The magnetization of a magnetic material can be reversed by using electric currents that transport spin angular momentum. In the reciprocal process a changing magnetization orientation produces currents that transport spin angular momentum. Understanding how these processes occur reveals the intricate connection between magnetization and spin transport, and can transform technologies that gener...

A virtual instrumentation based scheme is developed for the characterization of magnetic materials. The principle used for measurement is derived from the comparison method of testing instrument transformers. A prototype has been developed by suitably modifying an instrument transformer test set. Characterization of magnetic materials at single frequency and multiple frequencies have been carri...

Both physical and phenomenological models are necessary to obtain good descriptions of coercivity in soft magnetic materials. The former models give insight into the processes involved, while the latter models compute quickly. The differences between modeling soft and hard materials are the parameters sizes and the importance of eddy currents.

The demagnetization processes and the magnetic viscosity have been studied on a bulk-amorphous Nd 60 Fe 30 Al 10 rod at room temperature. Many unique magnetic properties have been found in this novel hard magnetic material. A clear hysteresis was present on the minor loops, though the total and irreversible susceptibilities exhibited single-phase magnet behavior. A signi"cant magnetic viscosity...

Nanostructured magnetic materials are intensively investigated due to their unusual properties and promise for possible applications. The key issue for these materials is to understand the limits between their physical properties (transport, magnetism, mechanical, etc.) and their chemical–physical structure. In principle, a detailed knowledge of the chemical and physical structures allows calcu...

A trend of increased Electric Power in Aircraft stresses the need of robust, low weight systems with low losses. New hard and soft magnetic materials have made it feasible to work with high speed and high frequency. Applications of new soft magnetic materials and hard magnetic materials like NeFeB magnets have enabled high density power generation systems. A new concept comprising a high speed ...