Finite-temperature magnetism of FexPd1-x and CoxPt1-x alloys

The finite-temperature magnetic properties of FexPd1-x and CoxPt1-x alloys have been investigated. It is shown that the temperature-dependent magnetic behavior of these alloys cannot be described properly unless the coupling between the magnetic moments at the Fe and Co mediated through the interactions with the induced magnetic moments of the nonmagnetic Pd and Pt atoms is included. A scheme for the calculation of the Curie temperature (T-C) for this type of systems is presented that is based on the extended Heisenberg Hamiltonian with the appropriate exchange parameters J(ij) obtained from ab initio electronic-structure calculations. Within the present study the Korringa-Kohn-Rostoker Green's-function method has been used to calculate the Jij parameters. The Curie temperatures obtained for Fe(x)Pd(1-)x and CoxPt1-x alloys are compared with the corresponding experimental data. The experimental results for FexPd1-x alloys have been obtained within anomalous Hall-effect measurements. The agreement between theoretical results and all available experimental data is rather good.