Site preference and thermodynamic properties of R3Ni13-xCoxB2（R=Y,Nd and Sm）

This paper investigates the structural stability of intermetallics R3Ni13-xCoxB2(R=Y,Nd and Sm) with Nd 3 Ni 13 B 2-type structure and the site preferences of the transition element Co by using a series of interatomic pair potentials.The space group remains unchanged upon substitution of Co for Ni in R3Ni13-xCoxB2 and the calculated lattice constants are found to agree with reports in literatures.The calculated cohesive energy curves show that Co atoms substitute for Ni with a strong preference for the 3g sites and the order of site preference is 3g,4h and 6i.Moreover,the total and partial phonon densities of states are first evaluated for the R 3 Ni 13 B 2 compounds with the hexagonal Nd 3 Ni 13 B 2-type structure.