摘要 |
PURPOSE:To produce an oxide superconductor having high critical temp., uniform quality, and sharp transition characteristics of superconductivity by calcining a compsn. contg. Tl and Cu at <= a specified temp. CONSTITUTION:Starting materials such as Tl2O, CaCO3, BaCO3, CuO, etc. are mixed in a specified proportion, and calcined preliminarily after pulverizing, then pulverized again and formed. The oxide superconductor is obtd. by calcining the formed product at <=850 deg.C. Since, by this method, the formed product is calcined at <=875 deg.C where transition of Tl2O in the compsn. to a lower oxide causes, a Tl-Ba-Ca-Cu-O oxide superconductor having high critical temp. at ca. 115-125K is prepd. If the compsn. is calcined in an atmosphere contg. vapor of Tl2O instead of calcining the compsn. at <=850 deg.C, the transition of Tl2O to a lower oxide can be prevented. |