立方结构Fe基磁性材料弹性系数第一性原理计算

Calculating elastic constants of Fe-based cubic magnetic material using first principles

通过赝势平面波法(CASTEP)及全电势线性缀加平面波法(FLAPW),以bcc_Fe为对象,研究第一性原理计算立方结构Fe基磁性材料弹性系数的方法,分析影响计算立方结构Fe基磁性材料弹性系数准确度的各项因素.结果表明,在第一性原理弹性系数计算中,晶格常数是决定弹性系数计算准确度的关键因素;势函数的选择也会影响计算准确度.使用全电势基矢的FLAPW法可以得到更为精准的弹性系数计算结果.计算得到bcc_Fe的弹性系数C11,C12,C44分别为246GPa,121GPa,113GPa,与实验值基本一致.利用本方法,计算了新型Fe_Ga磁致伸缩材料的弹性系数C11,C12,C44分别为207GPa,166GPa及108GPa.

Using the first principles full potential linearized augmented plane wave （FLAPW） method and the pseudopotential plane wave （CASTEP） method, the elastic constants of Fe-based magnetic cubic phases are investigated. The key point is confirmed to be the lattice constants when calculating elastic constants, and the basis sets also affect the precision of calculation. More precise results were got by FLAPW. The elastic constants C11, C12, C44 of bcc-Fe are 283 GPa, 158 GPa and 112 GPa, respectively, which approximately consist with the intrinsic ones. The elastic constants C11, C12, C44 of Fe-Ga magnetostrictive material are calculated to be 207 GPa, 166 GPa and 108 GPa, respectively.