Anomalous Magneto-optical Hysteresis Loops of Sputtered Gd-Co Films

Hysteresis loop anomaly in Gd-Co films has been studied by measuring magneto-optical Kerr loops at a temperature range from 20 to 60°C. Anomalous loops were observed at one surface of the films and in a certain temperature range. The other surface always gave normal loops. All the features of the observed anomalous loops can be explained by a magnetization gradient model along the film thickness.