Growth and Property of High-Tc Phase in Bi(Pb)-Sr-Ca-Cu-O Sputtered Films
The purpose of this work is to investigate annealing process or conditions for Bi(Pb)-Sr-Ca- Cu-O sputtered films in order to promote the growth of the high-Tc phase. The composition of the specimen film was adjusted to the stoichiometry of the high-Tc phase (the atomic ratio of Bi :Pb:Sr:Ca:Cu = 1:0.2:1:1:1.5) by changing the composition of the target and sputtering conditions.
A new method, in which a MgO plate was put on the film surface, was developed to keep the concentration of Pb in the film during the anneal. The optimum annealing temperature was 830 ~ 850°C. A volume fraction of the high-Tc phase was attained above 70% in superconducting phases with good reproducibility. A preferential growth of c-axis perpendicular to the film was observed.
As a result,Tc of zero resistance of 105K and a critical current density in excess of 3x104 A/cm2 were achieved.
KeywordsPreferential Growth Annealed Film Optimum Annealing Temperature Specimen Film Sintered Bulk
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