Peak effect in the superconducting mixed state of bulk Mo-Re alloys: a dc magnetization study

Abstract

We have observed, in our dc magnetization studies, the peak e ect (PE) in the superconducting mixed state of two compositions, Mo 0:825 Re 0:175 and Mo 0:8 Re 0:2 , of the binary alloy system Mo 1¡x Re x . The PE occurs close to the H c2 …T † line at temperatures below T c , similar to the well studied compound CeRu 2 . A detailed investigation of the various characteristics of this peak e ect and a comparison with other superconductors of current interest show that the observed behaviour can be explained within the realm of critical state models of hard type-II superconductors. Our results show that the anomalies reported in CeRu 2 and NbSe 2 are not universal to materials showing a PE close to the H c2 …T † line and may, therefore, have an important bearing on the phenomenology of type-II superconductors.