Transport properties of silver-doped Y-Ba-Cu-O thin films

Transport properties of dilute silver-doped Y-Ba-Cu-O thin films prepared by a laser ablation technique have been investigated. The Hall coefficient and critical current density were measured as a function of temperature and in magnetic field up to 1.0 T. Silver doping is shown to result in significant changes in the temperature- and magnetic-field dependence of the transport properties of these films. The Hall coefficient in silver-doped films shows a clear decrease from that in silver-free films, consistent with an increase in the hole concentration caused by the silver impurities. This result lends a direct support to the observation that dilute silver dopants behave as acceptors but without appreciable influence on the transition temperature. The magnetic-field dependence of the normalized critical current density J _c(H)/J_c(0) is enhanced by silver doping, mainly due to a decrease in the effective weak-link area at the grain boundaries.