Suppression of dissipative flux-motion in a high-Tc (Bi,Pb)-2212 superconductor by Dy-doping

Abstract The temperature and magnetic field dependences of the activation energy and flux-pinning properties of Dy-doped (Bi,Pb)-2212 superconductor are systematically measured for a broad doping range. The behaviour of vortex dynamics close to a vortex-liquid to glass transition [ U o ( B , T g ) = k B T g ] is analysed by the modified thermally activated flux-creep theory. The results show that the temperature and field dependence of U o ( B , T ) is related to the strong thermal fluctuation at elevated temperatures and fields which can be suppressed by the introduction of the point defects due to Dy-doping. These point defects act as additional flux-pinning centers and the superconductor remains in the glassy-vortex-state.