Self-consistent embedded-cluster model for magnetic impurities: β′NiAl

Substitutional transition metal impurities occupying either A or B sites in AB intermetallic compounds with CsCl structure have been treated by a self-consistent molecular-orbital method. The electronic energy levels and charge and spin densities of MX₈ clusters representing a central atom and its nearest neighbors have been calculated in the Hartree-Fock-Slater spin-polarized model, using a numerical discrete variational method. The crystal lattice is included through a self-consistent empirical pseudopotential scheme. Results for Fe, Ni, and Co impurities in β′-NiAl are discussed in connection with experimental resistivity, Mössbauer isomer shift, and NMR data.