Magnetic susceptibility anomalies and inverse magnetic transitions in iron-enriched garnet films

Abstract Anomalous properties both of the dynamic magnetic susceptibility and the spontaneous magnetization of Y 3 - x Fe 5 + x O 12 garnet films have been experimentally observed. The most significant anomalies are the following: (a) an orientational magnetic transition at room temperature in the range of the applied magnetic field of 300–700 Oe; (b) a spontaneous magnetization vector reversal in the temperature range of 110–275 °C and the corresponding jump of the dynamic susceptibility at zero magnetic field; (c) oscillations of the magnetization in the paramagnetic state of the sample and the corresponding jumps of the dynamic susceptibility at the planar magnetic field H = 200 Oe. It has been established that all reported anomalies exhibit an inverse behavior, namely, with decrease of the applied magnetic field (or temperature) a reverse hysteresis of the field (or temperature) dependences both of the dynamic magnetic susceptibility and the spontaneous magnetization is observed. Possible reasons for such a behavior of the measured dependences are also discussed.