Fe-Ga磁致伸缩合金自旋轨道耦合效应研究

磁致伸缩和磁晶各向异性来源于自旋轨道耦合及晶体场效应，两种效应作用效果将对Fe-Ga大磁致伸缩合金研究方向将起指导作用.通过基于均匀梯度近似的线形缀加平面波法研究了Fe-Ga磁致伸缩合金中D03、B2-like、L12结构在施加自旋轨道耦合效应前后Fe原子3d轨道劈裂情况，轨道电子数及磁晶各向异性.结果表明，自旋轨道耦合效应可以进一步劈裂D03及L12立方结构晶体场，D03和L12结构中Fe原子3d轨道电子数，尤其是dxy和d(x2-y2)轨道下自旋电子数由于自旋轨道耦合作用发生改变；但自旋轨道耦合对B2-like结构作用微弱.Fe-Ga磁致伸缩合金中磁晶各向异性主要由晶体场效应决定.

Spin-Orbit Coupling Effect in Fe-Ga Magnetostrictive Material Alloys

It is generally known that the spin-orbit coupling and crystal field effects are the origin of magnetostriction and magnetocrystalline anisotropy, and can direct the experimental research of the magnetostrictive alloys. In this paper, the 3d orbit splitting, electron occupancy and magnetocrystalline anisotropy of Fe-Ga magnetostrictive alloys for D03, B2-like and L12 structures with and without spin-orbit coupling are investigated by the first principles. It shows that the spin-orbit coupling further split the crystal fields of cubic structures for D03 and L12 structures, and the spin-orbit coupling almost has no effect on the B2-like structure. So the magnetocrystalline anisotropy of Fe-Ga alloy is mainly determined by the crystal field effect.