Ferromagnetic Anisotropy Energies of Ni and Fe Metals —Band Model—

Abstract

The ferromagnetic anisotropy energies of Ni and Fe metals are calculated based on the differences between the crystal energies with the different directions of the spontaneous magnetization. These crystal energies are calculated by taking into account the variations of the spin-orbit interaction and the magnitude of the spontaneous magnetization, on the basis of the energy bands of ferromagnetic Ni and Fe metals, where the redistribution of the conduction electrons for each direction of the spontaneous magnetization is also taken into account. The obtained results are in agreement with the experimental results. The doubly degenerate energy levels in the energy bands, intersecting the Fermi level, produce the dominant contributions to the anisotropy energy. In Ni metal the temperature dependence of the anisotropy constants can be explained by the temperature variation of the Fermi level, and for Fe metal it can be explained in consideration of the decrease of the exchange splitting.