First-principles study of magnetic properties of Fe-Ni based alloys

Investigations of the magnetic properties of Fe-Ni based alloys are important from the fundamental as well as technological points of view. Furthermore, the magnetization at saturation and Curie temperature ($T_{\rm C}$) of FeNi can be tuned for specific applications by alloying with other metallic species. We have performed electronic structure calculations on Fe-Ni-$M$ alloys, where $M$ are 3d transition metals, to determine how the magnetization depends on the species $M$ and alloy composition. Electronic band structure and total energies are calculated by the Korringa-Kohn-Rostoker method within the coherent-potential-approximation (KKR-CPA). For the KKR-CPA calculations, we use the generalized gradient approximation of the exchange and correlation functional. In the case of Fe$_{0.50}$Ni$_{0.45}M_{0.05}$ ($M$=Sc, Ti, V, Cr, Mn, and Co), the early 3$d$ atoms have antiparallel magnetic moments to the Fe or Ni, whereas the late ones, Mn and Co, have a parallel magnetic moment.