Anomalous hysteresis studies in Bi-2223/Bi-2212 superconductors by non-resonant microwave absorption (NRMA) with special reference to energy stabilized Josephson (ESJ) fluxons

Abstract

Magnetic hysteresis of granular high temperature superconducting Bi-2223/Bi-2212 pellets has been studied by non-resonant microwave absorption (NRMA) method. It has been found that the nature of hysteresis is anomalous at all temperatures below T c. This nature has been analyzed by considering the role of energy stabilized Josephson (ESJ) fluxons, which was not attempted in its totality previously. A comparative study has also been done which is based on data acquired from literature of both NRMA and DC magnetization measurements on granular superconductors. This comparison distinctly shows the difference, i.e. normal hysteresis in DC magnetization studies, whereas, anomalous hysteresis in NRMA studies under similar conditions of low temperatures and low magnetic fields. The discussion brings out the suggestion that, the anomalous hysteresis observed by NRMA method is a manifestation of inevitable generation and detection of ESJ fluxons.