Atomistic simulation of rare earth compounds Sm2Fe17-xTx (T = Ti, V, Cr, Mo, Ni)

By using the interatomic pair potential obtained with the lattice inversion method, the structural stability of Sm2Fe17-xTx (T = Ti, V, Cr, Mo, Ni) of the rhombohedral Th2Zn17-type structure is studied. Calculated results show that adding Ti, V, Cr or Mo atoms makes the crystal cohesive energy of Sm2Fe17-xTx decrease markedly, proving that these atoms can stabilize Sm2Fe17-xTx structure. The calculated lattice constants coincide quite well with experimental values. The ternary element T preferentially substitutes for Co in the 6c site only. The calculated results also show that Ni does not stabilize the system with the structure of Th2Zn17-type. Moreover, the phonon densities of states are first evaluated for the Sm2Fe17-xTx (T = Ti, V, Cr, Mo) compounds with the rhombohedral Th2Zn17-type structure. This may be an attempt to predict the thermodynamic properties for the rare earth materials with complex structures