Atomistic simulation of rare earth compounds Sm 2Fe 17−xT x (T = Ti, V, Cr, Mo, Ni)

Abstract

By using the interatomic pair potential obtained with the lattice inversion method, the structural stability of Sm 2Fe 17− x T x (T = Ti, V, Cr, Mo, Ni) of the rhombohedral Th 2Zn 17-type structure is studied. Calculated results show that adding Ti, V, Cr or Mo atoms makes the crystal cohesive energy of Sm 2Fe 17− x T x decrease markedly, proving that these atoms can stabilize Sm 2Fe 17− x T x structure. The calculated lattice constants coincide quite well with experimental values. The ternary element T preferentially substitutes for Co in the 6 c site only . The calculated results also show that Ni does not stabilize the system with the structure of Th 2Zn 17-type. Moreover, the phonon densities of states are first evaluated for the Sm 2Fe 17− x T x (T = Ti, V, Cr, Mo) compounds with the rhombohedral Th 2Zn 17-type structure. This may be an attempt to predict the thermodynamic properties for the rare earth materials with complex structures.