颗粒膜量子磁盘热稳定性的损伤扩散研究

Thermal Stability Study of the Granular Film Quantum Magnetic Disk by the Damage Spreading Method

利用损伤扩散方法研究了颗粒膜量子磁盘的热稳定性。考虑颗粒尺寸和位置的涨落并用Voronoi模型近似描述颗粒点阵。颗粒形状近似为扁圆柱形量子线,其磁矩垂直于薄膜平面。推导了颗粒间静磁相互作用的表达式。蒙特卡洛模拟表明,颗粒间的长程相互作用使损伤很难扩散,系统稳定性增强,而颗粒半径的涨落也利于系统的热稳定。

In this paper, we study the thermal stability of the granular film quantum magnetic disk by using the damage spreading method. The fluctuation of the granular sizes and locations is taken into account and Voronoi model is used to describe the granular array. The granular shape is approximated as flat cylindrical nanowire, and its magnetic moment is perpendicular to the film plane. The granules locate in the centers of the units of the two-dimensional random lattice-Voronoi structure, and the radius meet to the Gaussian distribution. The analytical expression for the magnetostatic interaction between granules was derived. Monte Carlo simulation showed that the damage is difficult to spread out due to the long-range interactions between granules, in other words, the long-range interactions between granules enhance the system stability. The fluctuation of the granule radius is also conducive to the thermal stability of the system.