Phase stability and site preference of the disordered TbCu7-type compound PrCo7−xTx (T = Ti, Zr, Hf, Cu)

The phase stability, lattice constants and site preference of the disordered TbCu7-type rare-earth intermetallic compound PrCo7−xTx (T = Ti, Zr, Hf, Cu) are studied via interatomic pair potentials based on Chen's lattice inversion method. The results show that the ternary element T (T = Ti, Zr, Hf) can decrease the internal energy and stabilize the PrCo7 structure. The calculations also show that the T atoms preferentially occupy the 2e sites. The calculated lattice parameters and site preference are in agreement with the experimental data. The results indicate that the interatomic pair potentials are valid for studying some structural properties of the disordered intermetallics.