Spectroscopic investigations of adsorption during fabrication of Ag/(Bi,Pb)(2)Sr2Ca2Cu3Ox superconducting tape

Intrusion and inheritance of adsorbed gases during fabrication of silver-sheathed (Bi, Pb)(2)Sr2Ca2Cu3Ox (2223) superconducting tape (Ag/Bi-2223) are confirmed and studied by Fourier transform infrared spectroscopy, x-ray photoemission spectroscopy and Auger electron spectroscopy. Handling in air of precursor powder (BPSCCO powder), composed of (Bi, Pb)(2)Sr2CaCu2Ox (2212), (Ca, Sr)(2)PbO4, (Ca, Sr)(2)CuO3, CuO and (Bi, Pb)(2)Sr2CuOx (2201), causes the physisorption of CH2 or CH3, O-2, CO2, H2O and carbide and chemisorption of CO2 and H2O to form CO3 groups and hydroxyl on the powder. These adsorbates are inherited by the superconducting layer of the Ag/Bi-2223 tape and exist at grain boundaries of the 2223 phase to form weak links, which dramatically degrade the intergrain critical current density (J(c)). Mechanisms of intrusion and inheritance of adsorbates are systematically discussed. Our results highlight the importance of atmosphere control during the handling of BPSCCO powder for obtaining high-J(c) tape.