| 摘要 |
PURPOSE:To improve critical temp. and critical magnetic field characteristic and to make transition temp. range of superconductivity narrower, by forming a single phase of Y, La, etc. -B, Sr, etc.-Cu-oxide phase. CONSTITUTION:The oxide superconductive material of this invention is a perovskite type oxide of tetragonal system having oxygen defect comprising a single phase having the structure expressed by the formula. If the formula, 0<y>2.5: A is at least one kin among Y, La, Yb, Lu, Sc, Al, and B; B is at least one kind among Ba, Sr, and Ca. For example, if A is Y and B is Ba, 1mol. Y2O3 is mixed with 4mol. BaCO3 and 6mol. CuO, and the mixture is heated in O2 at ca.950 deg.C for ca.24hr, then pulverized again by crushing. About 5-7wt.% 10% aq. PVA soln. is added to obtd. powder to form to a green billet, which is then heat-treated again in O2 at ca.100 deg.C for ca.5h4. The oxide of Y-Ba-Cu prepd. by this method has a single phase of a structure as illustrated by the drawing. |
