铁磁纳米结构磁化状态及其磁-力耦合效应的相场模拟

基于随时间变化的Ginzburg-Landau(TDGL)方程,建立了模拟铁磁材料磁-力耦合效应的相场模型。从弱解形式出发,推导出了相关控制方程的有限元格式,然后编制程序进行数值求解。由于有限元对复杂边界有良好的适用性,该模型可用于不同形状铁磁材料的畴结构模拟。通过相场模拟,发现铁磁纳米结构中的磁化会形成涡旋结构,与实验观察到的磁化涡旋结构符合较好。由非均匀磁化引起的结构的变形、应力等力学参量都可以通过模拟一并得到。本文结果表明,改变结构形状可以有效控制磁畴结构的形态,适当的外应力可以改变磁畴结构及其对外磁性的大小。

Phase-field simulation for the magnetization state and magneto-mechanical coupling effect in ferro-magnetic nano-structures

Based on the time-dependent Ginzburg-Landau (TDGL) equation,a phase-field model was proposed to simulate the magneto-mechanical behavior of the ferro-magnetic materials.The finite element formulation was derived from the weak form of governing equation and then solved through a program code.Due to the applicability of the finite element method for complex boundary,the model could be used for domain simulation in samples with different shapes.The vortex magnetization configuration is obtained in ferro-magnetic nano-structures through the simulations,which is consistent with the experimental observations.The non-uniform stress and deformation of the structures caused by the non-uniform magnetization can be obtained simultaneously.The simulation results show that the magnetization configuration can be controlled effectively by changing the sample's shape,and the magnetic domain structure,as well as its magnetic value,can be changed by an external stress.