First principles study of half Heusler alloys PdFeBi and PdCoBi

First principles calculations based on density functional theory have been performed on half-Heusler alloys PdFeBi and PdCoBi of three different atomic configurations. This structural difference comes from the placement of the transition-metal element Pd, Fe, Co and the main group element Bi and the vacancy within the full-Heusler structure. The optimized lattice constant and electronic properties are determined by calculation. The comparison of total energy, lattice constant and magnetic moment are made for PdFeBi and PdCoBi. The differences reflect the atomic arrangements of the three phases and varied transition metal elements Fe, Co. A simple and rational physical reason is given too. The localized magnetic moments come from the d-d interaction between the transition metal elements. Due to the large magnetic moment, the possible applications for these half-Heusler alloys are given.