| 摘要 |
PURPOSE: To prevent the formation of nonsuperconducting materials and to increase critical current density by reducing and increasing the amts. of Sr and Ca in a Bi2 Sr2 CaCu2 Oz superconducting material by the same molar number, respectively, and carrying out heating to a temp. above the m.p. of the material under a specified partial pressure of oxygen and slow cooling. CONSTITUTION: Powdery starting materials prepd. so as to regulate the molar ratio of Bi:Sr:Ca:Cu to 2:(2-x):(1+x):2 (0.20<=x<=0.70) are heated to a temp. above the m.p. of a Bi2 Sr2 CaCu2 Oz superconducting material in an atmosphere under 0.002-0.06atm partial pressure of oxygen and they are cooled to a temp. below the m.p. by at least 20 deg.C at <=6 deg.C/hr cooling rate. A (Sr, Ca)Cu2 O2 phase and a Bi2 Sr2 CaO6 phase as nonsuperconducting materials are not formed and the objective Bi2 Sr2-x Ca1+x Cu2 Oz superconducting material having high critical current density is obtd. |
