Contact Resistance and V-I Characteristics in a Ag-Doped Bi-Sr-Ca-Cu-O Superconductor

Abstract

Contact resistance and V-I characteristics were investigated in Ag-doped and undoped Bi-Sr-Ca-Cu-O bulk samples prepared by the floating-zone method. In undoped samples, with increasing current pulse width, rapidity of voltage rise in V-I characteristics increases and J _c decreases. The contact resistance is nonohmic and temperature dependence is semiconductorlike. In a Ag-doped sample, rapidity of voltage rise and J _c are not influenced by pulse width, and deviation of J _c among samples is small. The ohmic contact resistance has metallike temperature dependence, and its value is less than 1/500 of that in an undoped sample.