Hall effect and sign reversal in normal and mixed state of Gd(Ba2-xNdx)Cu3O7 system

Hall effect measurements have been performed for Gd(Ba2-xNdx)Cu3O7, (0<x<0.2) system in normal and mixed states. In the normal state 1/T behavior have been seen for RH in this system as in other HTSC systems. In the superconducting state the sign reversal have been studied and it became clear that the system with 0.1 doping agrees with Kopnin-Dorsey theory, which according to it Hall conductivity, σxy, in vortex state is sum of two parts; σnxy normal hall conductivity, which comes from normal state in the center of vortex and is proportional to H, and vortex state conductivity σVxy, which comes from state of vortexes and is proportional to H1.