Investigation of structural stability and site preference of Dy(Fe,T)12 and Dy(Fe,T)12Nx (T=Ti, V, Cr, Nb, Mo)

The Fe-ternary Dy(Fe,T)12 (T=Ti, V, Cr, Nb, Mo) systems, in which Fe is replaced by T, have been studied to ascertain the effect of substitution on their phase stability and site preference. Calculation is based on a series of interatomic pair potentials related to the rare earth and transition metals, which are obtained by a strict lattice inversion method. Calculated results show that either Ti, V, Cr, Nb, or Mo atoms can stabilize Dy(Fe,T)12 with ThMn12-type structure. These stabilizing elements T prefer to substitute for Fe in 8i sites. Moreover, the N atoms preferentially occupy 2b interstitial sites and the increase of Curie temperature of Dy(Fe,T)12Nx with N is explained qualitatively by the exchange interaction model. The method utilized in the present investigation offers a rather easy and direct way to study the structural properties of Dy(Fe,T)12 and Dy(Fe,T)12Nx.