Dependence of critical temperature and critical current of oriented Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8+ delta </sub> thick films on the oxygen content
T Moriomoto; J Shimoyama; J Kase; E Yanagisawa; T Moriomoto; Res. Center, Asahi Glass Co. Ltd., Yokohama, Japan; J Shimoyama; Res. Center, Asahi Glass Co. Ltd., Yokohama, Japan; J Kase; Res. Center, Asahi Glass Co. Ltd., Yokohama, Japan; E Yanagisawa; Res. Center, Asahi Glass Co. Ltd., Yokohama, Japan
Журнал:
Superconductor Science and Technology
Дата:
1992-01-01
Аннотация:
Thermogravimetric measurement of Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8+ delta </sub> was carried out as functions of temperature and partial pressure of oxygen (PO<sub>2</sub>). Dependencies of thermodynamic quantities, lattice constant and critical temperature (T<sub>c</sub>) on oxygen nonstoichiometry, delta , show anomalous behaviors at the same delta of 0.235. Furthermore, Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8+ delta </sub> phase is found to decompose to Bi-Sr-Ca-O, Bi<sub>2</sub>Sr<sub>2</sub>CuO<sub>y</sub> and other phases at low temperature under high PO<sub>2</sub>. Effects of oxygen nonstoichiometry and the phase decomposition on critical current density (J<sub>c</sub>) of Bi-2212/Ag melt-solidified thick films were also studied.
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