Magnetostriction of the Fe$_{75}$Ga$_{25-x}Z_{x}$ ($Z$ = Al, Ge, Si) alloys: calculation by the magnetic torque method

This work presents an ab initio study of the effect of a small addition of the third element of III and IV groups on the elastic and magnetoelastic properties of Fe$_{75}$Ga$_{25}$ alloy. The dependencies of the tetragonal elastic modulus $C'$, magnetoelastic constant $-b_1$, and the tetragonal magnetostrictive constant $\lambda_{001}$ on the concentration of the $Z$-element in the cubic crystal structures A2 and D0$_3$ were obtained with the help of the density functional theory and the magnetic torque method in Fe$_{75}$Ga$_{25-x}Z_{x}$ ($Z$ = Al, Ge, Si) alloys (0 $\le x\le$ 6 at.%). It is shown that the addition of Al and Si atoms leads to an increase in the tetragonal elastic modulus compared to the Fe$_{75}$Ga$_{25}$ binary alloy. A correlation was established in the dependence equilibrium lattice constants $a_0(x)$ and $\lambda_{001}(x)$ in the studied ternary alloys for the A2 structure.