铁磁准同型相界附近畴结构和磁致伸缩响应的压力依赖效应:相场模拟

The Pressure Dependence of Domain Structure and Magnetoelastic Response Near Ferromagnetic Morphotropic Phase Boundary:Phase-Field Simulation

最近,在超磁致伸缩材料(Giant Magnetostrictive Materials,GMMs)体系发现的类似于铁电材料"准同型相界(Morphotropic Phase Boundary,MPB)"的铁磁MPB效应引起了研究者的广泛关注.但是前期关于铁磁MPB的研究大都集中在实验领域,铁磁MPB处超敏磁弹响应机制尚不清晰.不同于传统唯象模型,我们结合微弹理论开发了能够充分考虑不同相之间的应力、应变相容的相场微磁微弹模型.通过该模型研究了铁磁MPB处不同外场(压力、磁场)条件下磁化翻转和畴结构演化情况,阐明了相界附近微结构演化和宏观磁弹响应的依赖关系.相场微磁微弹理论对超磁致伸缩材料MPB的成功描述为调节铁磁准同型相界提供了有效的科学途径,有望为新型超磁致伸缩材料的高效、低成本开发提理论指导.

Recently,a parallel ferromagnetic morphotropic phase boundary(MPB),which is very similar with that of ferroelectric MPB,has been found in giant magnetostrictive materials(GMMs)system.This discovery of ferromagnetic MPB has caused wide concern.However,the existing work on ferromagnetic MPB has mainly focused on experimental field,while the ultra-sensitive magnetoelastic mechanism has not been revealed.Different from the traditional phenomenological models,we have developed a phase-field model combining micromagnetic and microelastic theory,in which stress and strain compatibility was included.The magnetization switching and domain evolution in the vicinity of ferromagnetic MPB under various external fields(stress or magnetic field)were simulated using this phase-field model.The dependence relationship between microstructure evolution and macroscopic magnetoelastic response was also revealed.Our work could not only point out an effective way for adjusting the ferromagnetic MPB,but also provide powerful guidance for developing new magneostrictive materials with high efficiency and low cost.