Thermal instability in a ferrimagnetic resonator strongly coupled to a loop-gap microwave cavity

We study the nonlinear response of a ferrimagnetic sphere resonator (FSR) strongly coupled to microwave loop-gap (LGR). The measured in regime weak nonlinearity allows extraction FSR Kerr coefficient and its cubic damping rate. find that there is certain range driving parameters which system exhibits instability. In range, self-sustained modulation reflected power off generated. instability attributed absorption-induced heating above Curie temperature.