J/sub c/ increase of BPSCCO-2223 bulk by composing with Ag wires

Abstract

To improve the superconducting properties of the high-T/sub c/ superconductors, we prepared the (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub y/ (BPSCCO-2223) bulk composite with embedded Ag wires. The composites were hand-made by stacking alternately Ag wires into the oxide powder in the thickness direction, and then the prepared samples sintered at 840/spl deg/C for 50 hours. SEM and EPMA observation showed that good c-axis oriented and densely structured BPSCCO-2223 plate-like grains could be formed around the interfacial region between BPSCCO-2223 oxide and metal Ag wire. We measured critical current density (J/sub c/) performance at 77.3 K and self-field and/or 4.2 K under several magnetic fields. As the J/sub c/ values of the BPSCCO-2223/Ag wires composite bulks were higher than that of BPSCCO-2223 bulk without Ag wires, J/sub c/ values were improved with increasing the number of Ag wires at several measurement conditions. The maximum J/sub c/ was obtained about 230 A/cm/sup 2/ at 77.3 K and self-field, 800 A/cm/sup 2/ at 4.2 K and self-field when forty-two Ag wires were composed. These J/sub c/ values corresponded to about twice that of BPSCCO-2223 oxide bulk without Ag wire. The improvement of J/sub c/ value was brought about by forming good c-axis oriented and densely structured BPSCCO-2223 plate-like grains.