Perpendicular magnetic anisotropy in Dy-Fe multilayered films

The periodicity dependence of the crystallographic structure and saturation magnetization are examined for Dy-Fe and Tb-Fe multilayered films prepared by an evaporation technique. The magnetization of Dy-Fe films changes nonlinearly with the periodic length Lambda , while that of Tb-Fe decreases linearly with shortening of Lambda . The perpendicular anisotropy K/sub u/ increases reciprocally with Lambda owing to the surface anisotropy K/sub s/. The value of K/sub s/ for Tb-Fe is about 1.7 times higher than for Dy-Fe at room temperature. The value of Dy-Fe increases with decreasing temperature; also, K/sub s/ at 80 K is about 1.5 times its value at room temperature.<>