PINNING AND THE INTRINSIC MAGNETIC-FIELD DEPENDENCE OF THE MIXED-STATE HALL CONDUCTIVITY IN AMORPHOUS MO3SI AND YBA2CU3O7-DELTA

We have investigated the pinning and magnetic-field dependence of the mixed-state Hall conductivity sigma(xy) in thin films of two supercond uctors, amorphous Mo3Si and YBa2Cu3O7-delta. The effects of pinning we re varied by measuring at different current densities j. In both super conductors, sigma(xy) is independent of j (and, therefore, pinning) in support of theory. The magnetic-field dependence of sigma(xy), at lar ge and small magnetic fields strongly supports calculations based on t ime-dependent Ginzburg-Landau theory. In addition, we find sample inho mogeneities can cause a fictitious current dependence of sigma xy. We argue this explains the conflicting reports of the pinning and magneti c-field dependence of sigma(xy) found in the literature.