Ab initio study of 59Co NMR spectra in Co2FeAl1−xSix Heusler alloys

Ab initio electronic structure calculation of a series of Co2FeAl1−xSix Heusler alloys has been performed, using the Korringa–Kohn–Rostoker-coherent potential approximation method to explain experimental 59Co NMR spectra. Two prominent features are explained semi-quantitatively—a global shift of the 59Co resonance line due to alloying with Al and Si atoms in Co2FeAl1−xSix, and the effect of local disorder in creating distinct satellite lines of 59Co NMR in Co2FeAl. The importance is stressed of the positive contribution to the 59Co hyperfine field from valence electron polarization, which emerges from the half-metallic band structure inherent in Co-based Heusler alloys.