Reprint of Multiscale model approaches to the design of advanced permanent magnets

Coarse-graining in micromagnetic simulations of dynamic hysteresis loops

“…The renormalization group (RG) approach of Grinstein and Koch [7], based on mapping a Fourier space analysis of the non-linear sigma model to ferromagnets in order to scale A, K, eld H and magnetization M, has garnered signi cant attention. However, to the best of our knowledge, no scaling theory has been applied to the calculation of magnetization-eld (MH) hysteresis loops [8], which are the foundation of experimental characterization of magnetic systems.…”

Non-collinearity Effects on Magnetocrystalline Anisotropy for R2Fe14B Magnets

“…Furthermore, the fields of engineering strongly require theoretical guidelines to develop magnets, the performance of which exceeds that of Nd-Fe-B magnets. Most recently, the above-mentioned numerical methods have been applied to a realistic model for rare-earth intermetallics, and quantitative results comparable to the experimental results were obtained by first-principles calculations [10][11][12][13][14][15] and by Monte Carlo methods [16][17][18][19][20]. On the other hand, to date, simpler analyses have also been conducted on the basis of phenomenological theory [21][22][23][24] or mean field theory (MFT) [3,14,[25][26][27] to understand the mechanism of the coercive forces of rare-earth permanent magnets and to identify the factors dominating these mechanisms.…”