Microwave absorption studies of Y-Ba-Cu-O

We have measured the magnetic field dependence of the microwave absorption of bulk ceramic Y1Ba2Cu3Ox as a function of temperature. Below the superconducting transition temperature, the microwave absorption increases with increasing magnetic-flux penetration into the sample, and the absorption exhibits considerable hysteresis resulting from hysteresis in sample magnetization. Also, when the applied magnetic field is removed there is a remanant absorption due to the remanant sample magnetization. © 1988 The American Physical Society.