Variability of superconducting transition temperatures of Ag-clad Bi(2223) tapes

The zero-field intersample variability of the superconducting transition temperature was measured for two commercially supplied Ag-clad Bi2Sr2Ca2Cu3Ox (Bi(2223)) 37 filament tapes, one 103 m and the second 193 m long. The resistivity of six 30 cm long pieces of each tape was measured with increasing and decreasing temperature. Hys teresis and time-dependent effects were observed. For the 103 m tape; upon cooling, the resistivity deviates from the conventional behavior at (11.4.3.3.2) K and complete superconductivity is achieved at (105.1.3.9) K. With increasing temperature, deviation from superconductivity starts at (112.5.4.6) K and superconductivity is completely gone at (121.8.3.1) K. The corresponding temperatures for the 193 m tape are (113.4.4.9), (108.6.3.6), (108.9.7.4) and (118.1.7.4) K. For one sample of the 193 m tape, the corresponding temperatures are (107.9.3.1), (102.5.5.9), (100.8.4.3) and (112.0.3.3) K. The anomalously broad foot structure in the zero field resistive transition previously seen by Zhao et al. (Ref. 1) in single crystals of Bi2Sr2CaCu2Ox (Bi(2212)) was observed here, too.