New reentrant superconducting-normal transition in Sr1-xKxBiO3 superconductor: magnetotransport and magnetization study

We report a new reentrant superconducting-normal resistive transition obser ved in the Sr1-xKxBiO3 superconductor. Unlike the previous reports about th e reentrant resistive transition where the superconducting region becomes r educed and finally resumes the normal state by increasing the external magn etic field (H) or the current (I), we observed the recovery of superconduct ivity induced by applying H or increasing I. Subsequent de magnetization me asurement shows a gradual decrease of the diamagnetic susceptibility - appe arance of the paramagnetic Meissner effect - at low fields (H < 50 Oe) in t he same temperature range where the reentrant normal resistivity was measur ed. The sample dependence of the reentrant resistive transition suggests th e important role of grain boundaries in our samples. Possible physical orig ins of the field induced superconductivity observed in Sr1-xKxBiO3 are disc ussed.