PREPARATION OF HIGH-T(C) SUPERCONDUCTING (BI,PB)2SR2CA2CU3OY PHASE VIA AN OXALATE ROUTE

(Bi,Pb)2Sr2Ca2Cu3Oy (2-2-2-3) (above 90%) has been prepared at a sintering temperature of 852-degrees-C within 10 h by sol-gel processing. Plate-like fine crystalline (Bi,Pb)2Sr2CaCu2Oz (2-2-1-2) (a-b plane diameter 1 mum, c direction thickness 0.1 mum) powder was used to prepare this 2-2-2-3 phase material. The 2-2-1-2 powder was prepared by a metal oxalate reaction using metal nitrate as metal sources, ethanol as solvent, and organic compounds as chelating agents to prepare the sol, and followed by a series of drying and calcination processes. The fine crystalline 2-2-1-2 powder was obtained at a temperature of 800-degrees-C for 10 h. T(c) (onset) of this 2-2-2-3 phase material was 105 K and T(c)(zero) was 92 K, which was obtained by pelleting the powder and measuring the resistivity by the four-probe method.