Magnetocrystalline Anisotropy in Fe(5~6 wt%)-Si(3~4 wt%)-Al Alloy Single Crystals

Temperature dependence of the magnetocrystalline anisotropy constant, K1, and the magnetostriction constants, ¿100 and ¿111, were determined for alloy single crystals containing 4.8 wt% Si, 5.0 wt% Al, bal Fe and 4.7 wt% Si, 3.8 wt% Al, bal Fe. The temperature dependence and magnitude of K1 for the two alloys were found to be completely different: K1 = 9.1 × 10³ erg/cm³ for the former, and 1.1 × 10⁵ erg/cm³ for the latter alloy, both at room temperature. The values of ¿100 and ¿111 (× 10^¿6) at room temperature were found to be 4.8 and 9.8 for the former, and 7.8 and 5.7 for the latter alloy. A unique diffraction line, due to the existence of a DO3 type ordered structure, was clearly observed for both alloys. From the results obtained, the following were concluded: 1) a discrete change in the values of K1 occurs at the phase boundary between the ¿ and the ¿ + DO3 phases; 2) the magnitude of K1 for the alloy samples consisting of the DO3 ordered phase is smaller than that for the ¿ + DO3 phase.