二维伊辛模型的畴壁动力学

摘要

Surface will change the structure and transition temperature of nanometer magnetic thin film,so many activities have been devoted to the domain-wall dynamics.With Monte Carlo simulations, the non-equilibrium critical dynamics of the two-dimensional Ising model with a magnetic domain interface is numerically studied in this paper.The semi-ordered initial state consists of two fully-ordered domains with opposite spin directions.The domain interface grows as time evolves.The same form of inside domain wall and outside is obtained by analyzing dynamic scaling behavior.The critical exponent of magnetization has very differences between the inside the domain interface and the outside.The difference is β0 =1, it is induced by a semi-ordered initial state.%表面可以改变纳米磁性薄膜的结构和相变温度,畴壁动力学由此成为研究的重点.本文采用动力学蒙特卡罗模拟方法,对二维Ising模型磁畴界面的非平衡动力学展开数值研究.系统初态设为半正半负,即由完全有序但自旋取向完全相反的两部分组成,其间的磁畴壁随时间生长.通过对磁化标度形式的分析,发现畴壁内外的动力学标度形式虽然相同,但临界指数在数值上却存在很大差异,相差一个β0=1,这是由初始条件导致的.