Magnetic anisotropy of FeGa alloys

Cubic magnetocrystalline anisotropy constants, K1 and K2, for Fe1−xGax alloys were measured using magnetization curves with x=0.05, 0.125, 0.14, 0.18, and 0.20. Thin circular (110) disks all with 〈100〉, 〈110〉, and 〈111〉 in the plane of the disk were used to measure K1 and K2. K1 was also measured with (100) circular disks. K1 for 5 at. % Ga content was found to be larger than that of pure Fe. (All compositions mentioned hereafter are atomic percents.) K1 and K2 both drop gradually up to 18 at. % Ga substitution. Then there is a sharp drop in the magnitude of both constants. K2 was found to be equal to −9K1/4 and the 〈110〉 and 〈111〉 directions were equally hard magnetically for all compositions considered in this study. Calculation of the anisotropy energy density verifies this result. K1 measured from both (110) and (100) disks was reasonably consistent.