Spectroscopic investigations of adsorption during fabrication of superconducting tape

Abstract

Intrusion and inheritance of adsorbed gases during fabrication of silver-sheathed (Bi, Pb) 2 Sr 2 Ca 2 Cu 3 O x (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 Sr 2 CaCu 2 O x (2212), (Ca, Sr) 2 PbO 4 , (Ca, Sr) 2 CuO 3 , CuO and (Bi, Pb) 2 Sr 2 CuO x (2201), causes the physisorption of CH 2 or CH 3 , O 2 , CO 2 , H 2 O and carbide and chemisorption of CO 2 and H 2 O to form CO 3 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.

Phase development and critical current density of Bi-2223 tapes fabricated by groove rolling

“…Since the reaction kinetics are very slow, long periods of sintering at temperatures close to its decomposition temperature are required [11][12][13][14].…”

X-ray photoelectron spectroscopy of ceramic composites Bi,Pb-2223/Ag annealed in an atmosphere with a reduced content of oxygen (7.5% O2 + 92.5% N2)

“…The possible belong ing of each component is designated according to the data of Refs. [12,[23][24][25][26][27]. It is obvious that the appear ance of some components in the О 1s and C 1s spectra is related to the deposition of H 2 O vapors, oxygen, and carbon on the surface of the ceramics after the removal of the Ag shell in air.…”