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 effect (PE) in the superconducting mixed state of two compositions, Mo_0.825Re_0.175 and Mo_0.8Re_0.2, of the binary alloy system Mo_1-xRe_x. The PE occurs close to the H_c2(T) line at temperatures below T_C, similar to the well studied compound CeRu₂. A detailed investigation of the various characteristics of this peak effect 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 CeRu₂ and NbSe₂ 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.