The constant Ku of magnetic uniaxial anisotropy is measured in 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 inhomogeneous 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 temperature 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 temperatures below the temperature during preparation and are not significantly influenced by annealing.

No abstract

In‐plane compensation surfaces may occur in thin ferrimagnetic films if the material has a magnetic compensation point and if a concentration gradient exists in the direction of the film normal. These planes with zero magnetization move through the film thickness at changing temperature and divide the film into sublayers. According to the magnetization directions in these sublayers, different configurations are possible. The temperature dependent transition fields between such configurations are calculated using a simple model. From these calculations, hysteresis loops for Faraday and Kerr effect observation can be constructed. The results are compared with measurements on films of gadolinium–iron garnet and amorphous gadolinium cobalt.