Pinning and the intrinsic magnetic-field dependence of the mixed-state Hall conductivity in amorphous Mo3Si and YBa2Cu3O7-δ

We have investigated the pinning and magnetic-field dependence of the mixed-state Hall conductivity σxy in thin films of two superconductors, amorphous Mo3Si and YBa2Cu3O7-δ. The effects of pinning were varied by measuring at different current densities j. In both superconductors, σxy is independent of j (and, therefore, pinning) in support of theory. The magnetic-field dependence of σxy at large and small magnetic fields strongly supports calculations based on time-dependent Ginzburg-Landau theory. In addition, we find sample inhomogeneities can cause a fictitious current dependence of σxy. We argue this explains the conflicting reports of the pinning and magnetic-field dependence of σxy found in the literature. copyright 1997 The American Physical Society