Spin Relaxation on Yttrium Iron Garnet near Curie Temperature Studied by High Frequency Magnetic Susceptibility

Abstract

The high frequency magnetic susceptibilities in yttrium iron garnet are observed in the temperature range from 546 K and 553 K in the high frequency range from 100 kHz to 100 MHz and the low frequency range lower than 100 Hz. The anomalous sharp peak appears in the temperature dependence curves of the imaginary part of the magnetic susceptibility in MHz range and is broadened with increasing frequency. From frequency dependence of the magnetic susceptibilities it is made clear that the relaxation of spin system occurs in the above two frequency ranges and relaxation process near the Curie temperature is not monodispersive but polydispersive. The temperature dependence of the relaxation time in spin system is obtained near the Curie temperature and is corresponding with the critical slowing down phenomena.