STUDY OF PREPARATION AND PROPERTY OF YBa_2Cu_3O_(7-δ)-Ag_x COMPOSITE SUPERCONDUCTORS PREPARED BY SOL-GEL PROCESS

摘要

YBa2Cu3O7-δ-Agx composite superconductorswere prepared by hybrid sintering process using YBa2Cu3O7-δ-Agx ultrafine powder and AgO2 finepower,which were pre-pared by sol-gel process and precipitation process respective-ly.The effect of the Ag content on superconducting cricticaltransition temperature of YBa2Cu3O7-δ-Agx was not evident aslong as YBa2Cu3O7-δ-Agx can form continuous network.ButAg can increase superconduction crictical current and densityof the composite superconductors.The normal state（i.e.non-superconducting state at room temperature）resistivity shows apercolation threshold at 20%～30% Ag,whereas the super-conduction network shows a percolationthreshold at 70%～80% Ag.