Site Selectivity and Structural Stabilization in Cu-Doped or Fe-Doped MnCoGe

Abstract

We performed first-principles calculations to investigate the effect of Cu or Fe partial substitution in MnCoGe on the stabilization of the hexagonal structure. In the case of Cu partial substitution at x = 0.125, a substitution for one site is more effective than that for both sites. In the case of Fe partial substitution at x = 0.125, there is no difference between two types of substitution for both sites and the Mn site. The result of Fe partial substitution at x = 0.25 indicates that Fe partial substitution for both sites is more effective than that for the Mn or the Co site.

Fig. 3 ΔE = E_hex − E_orth as a function of (a) Cu or (b) Fe content, where E_hex (E_orth) is total energy of the hexagonal (orthorhombic) structure. The symbols, open triangle, square and circle show partial substitution for Co, Mn and both sites, respectively.