Electron momentum density in Ni₇₅Cu₂₅and Ni₇₅Co₂₅disordered alloys: a high-resolution Compton-scattering study

Abstract

We report high-resolution Compton profiles (CPs) of Ni75Cu25 and Ni75Co25 disordered, ferromagnetic alloys measured along [100], [110] and [111] crystallographic directions. The directional CP anisotropies, profile derivatives and reciprocal form factors B(z) are analysed in detail and compared with first-principles KKR-CPA (Korringa–Kohn–Rostoker coherent potential approximation) calculations. Good overall agreement is found between the experimental and theoretical anisotropies. It follows from experiment that the majority-spin Fermi surface of the Ni75Cu25 and Ni75Co25 alloys occurs at higher momentum than the theory predicts. Also, a splitting in the secondary maxima in experimental B(z) functions of the alloys is observed, which is not predicted by the KKR-CPA calculations.