Observation of a local conductivity in vortex liquid regime of YBa2Cu3O7-delta single crystal

We attached two current contacts and two voltage contacts on both sides of MTG-YBCO single crystals, and performed transport measurement applying the current parallel and perpendicular to the CuO2 layers in the case of the ap plied magnetic field up to 7.5 T parallel to the c axis. The results show t hat in the dissipative regime, the voltage signal on the side of the applie d current contacts is larger than that on the opposite side, and the ratio of voltage signals increases at first and then decreases with decreasing te mperature. The temperature dependence of resistivity along the c axis is co nsistent with that in the ab plane. The critical temperature T-c(c) along t he c axis is higher than that in the ab plane, indicating that the coupling between the layers is stronger as the temperature decreases, and a 3D char acter is seen at lower temperature. (C) 2000 Elsevier Science B.V. All righ ts reserved.