Energy band structure of BBC iron at finite temperatures

Abstract

Using the KKR method generalized for the case of non-collinear spin structures, we have calculated the electron spectrum, the density of states, and the total energy of a number of helical magnetic configurations for bbc iron. Regions of the electron spectrum have been singled out which exhibit a substantially different response to a perturbation of the magnetic structure. The changes are most pronounced over the energy range where a superposition of two ferromagnetic density-of-states peaks occurs and are of a hydridization character. An interpretation is provided of the difference in the temperature behavior of Γ'25 levels with opposite spin projections as obtained in a photoemission experiment. Curves of the local magnetic moment and total energy versus the angle between the spins of adjacent atoms have been calculated. An explanation is given of why the value of the magnetic moment is stable over a wide range of angles. It is shown that in the region of stability of the value of the magnetic moment the total-energy curve is close to the corresponding Heisenberg curve. At large angles the calculated curve lies considerably higher than the Heisenberg curve. A simple statistical model is formulated which reduces to a consideration of a helical cluster in a mean field due to an environment. The temperature dependences of the magnetization, of the electron density of states, and of the mean angle between the spins of adjacent atoms are considered.