Electronic structure, magnetism, and stability of Co-doped NiAl

Total-energy and electronic-structure calculations for Co-doped NiAl are reported. The energy of a substitutional Co in NiAl is found to be approximately 11 mRy. For the doping levels considered (0--25 % substitution on the transition-metal site) no evidence of structural instabilities or anomalies in elastic behavior is found. However, magnetic behavior is predicted for large Co concentrations. Strong nonrigid-band behavior is found for the doped system, and a high electronic density of states is associated with the Co atoms.