Full-spin-wave-scaled stochastic micromagnetism for mesh-independent simulations of ferromagnetic resonance and reversal  

作　　者：Harald Oezelt Luman Qu Alexander Kovacs Johann Fischbacher Markus Gusenbauer Roman Beigelbeck Dirk Praetorius Masao Yano Tetsuya Shoji Akira Kato Roy Chantrell Michael Winklhofer Gergely T.Zimanyi Thomas Schrefl 

机构地区：[1]Department for Integrated Sensor Systems,Danube University Krems,2700,Wiener Neustadt,Austria [2]Department of Physics,University of California,Davis,CA,95616,USA [3]Christian Doppler Laboratory for Magnet design through physics informed machine learning,2700,Wiener Neustadt,Austria [4]Institute for Analysis and Scientific Computing,Vienna University of Technology,1040,Wien,Austria [5]Toyota Motor Corp.,Toyota City,471-8572,Japan [6]Department of Physics,University of York,York,YO105DD,UK [7]Institute for Biology and Environmental Sciences IBU,Carl von Ossietzky University of Oldenburg,26129,Oldenburg,Germany

出　　处：《npj Computational Materials》2022年第1期315-323,共9页计算材料学（英文）

基　　金：The authors acknowledge the financial support by the Vienna Science and Technology Fund(WWTF)under grant MA141-044.

摘　　要：In this paper,we address the problem that standard stochastic Landau-Lifshitz-Gilbert(sLLG)simulations typically produce results that show unphysical mesh-size dependence.The root cause of this problem is that the effects of spin-wave fluctuations are ignored in sLLG.We propose to represent the effect of these fluctuations by a full-spin-wave-scaled stochastic LLG,or FUSSS LLG method.In FUSSS LLG,the intrinsic parameters of the sLLG simulations are first scaled by scaling factors that integrate out the spin-wave fluctuations up to the mesh size,and the sLLG simulation is then performed with these scaled parameters.We developed FUSSS LLG by studying the Ferromagnetic Resonance(FMR)in Nd_(2)Fe_(14)B cubes.The nominal scaling greatly reduced the mesh size dependence relative to sLLG.We then performed three tests and validations of our FUSSS LLG with this modified scaling.(1)We studied the same FMR but with magnetostatic fields included.(2)We simulated the total magnetization of the Nd_(2)Fe_(14)B cube.(3)We studied the effective,temperature-and sweeping rate-dependent coercive field of the cubes.In all three cases,we found that FUSSS LLG delivered essentially mesh-size-independent results,which tracked the theoretical expectations better than unscaled sLLG.Motivated by these successful validations,we propose that FUSSS LLG provides marked,qualitative progress towards accurate,high precision modeling of micromagnetics in hard,permanent magnets.

关 键 词：STOCHASTIC wave scaling 

分 类 号：O17[理学—数学]