Two step dependence of critical temperature on oxygen content for the Bi-Pb-Sr-Ca-Cu-O superconductor

✍ Scribed by Norimitsu Murayama; Yasuharu Kodama; Shuji Sakaguchi; Fumihiro Wakai

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 235 KB
• Volume: 181
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(91)90119-j

✦ Synopsis

Single phase Bil.sPbo.33Srl.99Ca I.s6CuaOy superconducting powder was prepared by a solid-state reaction. The weight loss (Aw) due to the oxygen desorption was investigated in Ar gas by thermogravimetric analysis, and the critical temperature (To) was measured for the powder which was quenched from 500 ° C-830°C to room temperature in Ar gas. For the powder quenched from 500°C, the T~ was 107 K. The value of T c decreased to 98 K when Aw reached 0.41 wt.%. In this Aw range, IdTc/dAw[ decreased with increasing Aw. In the Aw range of 0.41 wt.%-0.53 wt.%, the Tc remarkably decreased from 98 K to 88 K with increasing Aw. In the Aw range of 0.53 wt.%-0.73 wt.%, the Tc was almost constant. That is, the double step behavior was observed in the Tc versus oxygen content curve for the 110 K phase. The oxygen sites for variable stoichiometry were discussed on the basis of the results of thermal analyses and the change in lattice parameters in addition to this.