Effect of Co substitution on Ni${}_2$MnGe Heusler alloy: ab initio study

Abstract

Ab initio calculations shown that the Co substitution instead of Ni in Ni${}_2$MnGe with the L2${}_1$ crystallographic structure leads to a decrease of the lattice constant and an increase of the total magnetic moment of the Ni${}_{2-x}$Co${}_x$MnGe compounds. The Mn(B) has the largest local moment above $3{\mu }_B$ coupled parallel to moments on the Ni(A,C) and Co(A,C), which are found in the ranges of $0.19÷0.26{\mu }_B$ for Ni(A,C) and $1.03÷0.97{\mu }_B$ for Co(A,C) for studied range of $x$. Using the results stemming from the total energy calculations, the values of bulk modulus and its pressure derivatives are estimated according to the Murnaghan EOS.

3 pages, 3 figures; The European Conference Physics of Magnetism 2017; submitted to Acta Physica Polonica A