[S-IT21] Innovation through the Integration of Solid Earth Science and Materials Science

[SIT21-P01] Theoretical approach to the pattern formation in spin systems via the time-dependent Ginzburg-Landau equation

*Ryoji Anzaki¹, Shin-ichi Ito^1,2, Hiromichi Nagao^1,2, Masaichiro Mizumaki³, Masato Okada⁴, Ichiro Akai⁵ (1.ERI/UTokyo, 2.IST/UTokyo, 3.JASRI, 4.GSFS/UTokyo, 5.IINa, Kumamoto Univ.)

Keywords:magnetic materials, pattern formation, symmetry

In this research, we study the two-dimensional classical spin model with the time-dependent Ginzburg-Landau equation as a model for magnetic thin materials. We classify the spatial patterns at the equilibrium (i.e., phases) using the spin Z₂ and spatial symmetries. We approximate the equilibrium equation of the system using the RPSA [R. Anzaki et al., Ann. Phys. 353 107 (2015)] and developed a method to predict the type of phases that are realized for each set of model parameters. The figure shows the phase diagram of the system for the system thickness (p₄) and dipole-dipole interaction intensity (p₁). In this figure, 'Symmetric', 'T', and '*Z' indecate the phases with no magnetization, no total magnetization but spatial patterns, and others, respectively. The quantities are normalized via coordinate-scale transformations. The finding of this research is accepted as a Regular Article in Physical Review B.