| 摘要 |
PURPOSE:To obtain an oxide superconductor having high critical temp. by specifying a crystal structure and a peak intensity of powder X-ray diffraction, of an oxide contg. Sr, Ca, Bi and Cu. CONSTITUTION:An Sr compd., a Ca compd., a Bi compd. and a Cu compd. are mixed to obtain a mixture wherein an atomic ratio of Sr/Ca is >=0.1 and <=1.5, an atomic ratio of Sr/Bi is >=0.8 and <=2.0, and an atomic% of Cu basing on the total amt. of metallic elements is >=25% and <=65%. After drying and compression-molding the mixture, Bi2O3 is removed by calcining the molded product at 750-820 deg.C. It is calcined further at 830-875 deg.C. Thus, an oxide superconductor contg. a material having a crystal structure having lattice constants (a=5.40+ or -0.20Angstrom , b=27.0+ or -1.0Angstrom , c=36.8+ or -1.0Angstrom ; alpha=90+ or -1 deg., beta=90+ or -1 deg., gamma=90+ or -1 deg.), is obtd., wherein a ratio H (an intensity of diffraction peak at 24.04+ or -0.20 deg., which is specific for a material having above-described lattice constants) to L (intensity of diffraction peak at 23.19+ or -0.20 deg., which is specific for a material having a similar structure of an Aurivillus phase contg. the above-described 4 elements), is >=0.4. |
