TEMPERATURE AND MAGNETIC-FIELD DEPENDENCE OF MICROWAVE-ABSORPTION IN RB3C60 SUPERCONDUCTOR

The temperature dependence of the surface resistance of Rb3C60 at 9.2 GHz has been measured from 370 to 5 K. As well as the expected drop at the superconducting transition temperature, anomalous changes are obs erved at 370 and 190 K and attributed to phase transitions in the mate rial. The dc and ac magnetic field dependence of the surface resistanc e in the superconducting state is measured. Both low dc and ac magneti c field weak link induced absorption are observed as well as high dc m agnetic field vortex induced dissipation.