| 摘要 |
PURPOSE:To obtain an oxide superconductor having high critical temp. by allowing laminated structure units having a specified thickness to be present in same crystallites of a laminated structure units consisting of Sr, Ca, Cu, and O existing between atomic layers consisting of Bi and O. CONSTITUTION:An Sr compd. such as SrCO3, etc., a Ca compd., a Bi compd., and a Cu compd. are mixed in proportions of each metal element expressed in terms of atomic ratio expressed by 0.1<=Sr/Ca<=1.5; and 0.8<=Sr/Bi<=2.0, wherein the proportion of Cu atom basing on the amt. of whole metal elements is regulated by 25 wt.%<=Cu<=65wt.%. The mixture is calcined primarily at 750-820 deg.C. Obtd. product is then calcined secondarily at 850-870 deg.C. Thus, an oxide superconductor having laminated structure units of Sr atom layer, Ca atom layer, Cu atom layer, and O atom layer are interposed between atom layers of Bi and O, wherein layer units having 15.4+ or -1 DBE 1, 18.4+ or -1 DBE 1, 22.5+ or -2 DBE 1 thickness are contained in same crystallites. In this case, the probability of presence of the layer unit of 18.4+ or -1 DBE 1 thickness in the whole layer units is >=50% and the obtained oxide superconductor exhibits a powder X ray diffraction pattern for CuKalpha line (1.5418 DBE 1) having peaks of diffraction at angles of diffraction (theta) defined by 2theta=4.86+ or -0.20 deg., 2theta=24.04+ or -0.20 deg., etc. |
