Abstract:

The paramagnetic Meissner effect (PME) is related to the appearance of a positive magnetization when a superconducting specimen is field cooled through its critical temperature. In this work we report on the PME and ac magnetization in roll-bonded Cu-Nb (RB/Cu-Nb) layered composites. We present typical DC magnetization loops obtained in the normal magnetic field configuration that show the PME. In addition, we present ac magnetization measurements that reveal a crossover behavior at a characteristic field value. We show evidence that such a crossover behavior, attributed to activation processes of vortices, is probably related to the disappearance of the PME in the RB/Cu-Nb layered composites.