Anomalous magnetic behaviour in non-resonant microwave absorption study of Bi-2212 superconductors

The non-resonant microwave absorption (NRMA) studies in silver doped polycrystalline Bi/sub 2/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub 8/ samples have been carried out. The NRMA signal has been observed not only below Tc but also above Tc which is much above the fluctuation regime when the DC magnetic field was swept from -50 G to +50 G through 0G. Anomalous magnetic hysteresis behaviour has been observed where the forward curve lies above the return curve even at lower temperatures. The observed curve has been simulated by taking into consideration the sum of reversible losses as well as irreversible losses using Dulcic and Portis models. This leads to anomalous magnetic hysteresis behaviour as has been observed experimentally.