Finite-Temperature Magnetism of Concentrated Ferromagnetic Alloys

A spin fluctuation theory developed previously by the present author using the functional integral method is generalized to discuss the finite-temperature properties of concentrated ferromagnetic binary alloys, A x B 1- x . We study the concentration- and temperature-dependences of various quantities such as the average magnetic moment, the local magnetic moment relevant to each constituent atom, the total spin susceptibility and partial susceptibilities of A and B atoms. It is shown that the theory in the limit of T =0 K reduces to that proposed by Hasegawa and Kanamori, and that the defect inherent in the one-electron theory of magnetic alloys is removed by including the effect of spin fluctuations. Numerical calculations are carried out for FeCr alloys.