Ba-Ca-Cu-O compositions superconducting at up to 126K and methods for making same

Year	Description
1999	Invention patented by Ching-Wu Chu, Yu-Yi Xue, and Zhong L. Du on July 5th, 1999. Abstract: A material having a superconducting transition temperature (T.sub.c) of 126 K under ambient pressure has been identified. The superconducting material belongs to a Ba--Ca--Cu--O compound family where the cation ratio of Ba:Ca:Cu is 2:2.5+0.5:3.5.+-.0.5. The superconducting material is produced from precursor oxides having nominal formula Ba.sub.2 Ca.sub.n-1+x Cu.sub.u/y O.sub.x wherein n=3 or 4 and x is 0.4 to 1.0 and y is 0 to 0.8 using high-pressure synthesis. Final synthesis temperature was maintained at less than 950.degree. C. Formation of the superconducting material is sensitive to the state of the precursor oxides, the carbon content of the precursor, and the synthesis temperature, pressure and time.
Source: selected by the editor from original sources.

Invention: Ba-Ca-Cu-O compositions superconducting at up to 126K and methods for making same