Correlation effect in bcc iron at finite temperatures

Abstract

Self-consistent second-order perturbation theory is applied to a multi-band Hubbard model to study the static and the dynamical properties of iron at finite temperatures. Reasonable values of the Curie temperature and the Curie constant are obtained for a realistic band structure and realistic values of the local Coulomb interaction. The dynamical transverse susceptibility in the ferromagnetic phase is calculated, and a spin wave mode vanishing in the long-wavelength limit is correctly obtained. The spin stiffness constant is found to be enhanced compared with that obtained using the random phase approximation.