Calculation of Ferromagnetic Anisotropy Energies for Ni and Fe Metals

The calculation of the anisotropy energies for Ni and Fe metals is performed with use of the perturbation theory, on the basis of the energy bands given by Yamashita et al. The spin-orbit interaction is taken into account in the tight binding approximation up to the fourth and sixth order perturbations. The first and second anisotropy constants K 1 and K 2 at 0°K are estimated to be -4.6×10 5 ergs/c.c. and -0.5×10 5 ergs/c.c. for Ni metal and 6.0×10 5 ergs/c.c. and 1.2×10 5 ergs/c.c. for Fe metal, respectively, where the values of the spin-orbit interaction constants are adopted as 350 cm -1 for Ni metal and 230 cm -1 for Fe metal. The calculated temperature dependences of these anisotropy constants are qualitatively in agreement with the experimental results, and explain the experimental results of the anisotropy constants K 1 and K 2 at room temperatures.