Significance and Interpretation of Magnetic Anisotropy Measurements in Amorphous Gadolinium--Cobalt Films

The constant Ku of magnetic uniaxial anisotropy is measured sputtered amorphous Gd--Co films by different methods. Considerable discrepancies are found between the results of static and of ferromagnetic resonance measurements, especially in the region of magnetic compensation. The reasons for the different results are probably inhomogenous composition and microstructure of the films and slightly field-dependent magnetic parameters of amorphous Gd--Co. To get more insight in the origin of Ku in amorphous Gd--Co, measurements in a broad temp. range are performed before and after annealing. The results show clearly two main contributions to Ku. Atomic short range order leads to positive Ku and disappears during annealing. Stresses in the films produce negative Ku at temp. below that during preparation and are not significantly influenced by annealing. 18 ref.--AA