PURPOSE: To improve superconducting characteristics by firing a compsn. represented by a specified chemical formula in an inert to oxidizing or reducing atmosphere.
CONSTITUTION: Oxides or other compds. of the constituent elements of a compsn. represented by the formula (where A is one or more among alkaline earth metals, alkali metals, lanthanides, Y and Sc, B is one or more among Ta, Pb, Bi, In, Sb, Sn, Nb, V, Ti, Mn and Cr, B' is one or more among Ta, Pb, Bi, In, Sb, Sn, Nb, V, Ti, Mn and Cr, O is one or more among oxygen, fluorine and chlorine, X is 0.01-2, y is 0-2.5, z is 0-2.5 and w is 2-16) are mixed in a prescribed weight ratio and pulverized. The resulting compsn. is fired at ≥700°C in an atmosphere under so regulated partial pressure of oxygen that at least one of the elements B and B' has plural valences. An oxide superconducting material having ≥30K critical temp. and perovskite structure or its analogous crystal structure is obtd.
TAKEUCHI SEIJI
DOI TOSHIYA
KAMO YUICHI
MATSUDA SHINPEI
