抄録
It is important to prepare bulk samples with high critical current density Jc to obtain the superconducting magnets of oxide superconductors. Many investigators have tried to improve the Jc values of Bi 2212 wire and tapes. We investigated the effect of intermediate cold press on Jc of Bi 2223 bulk specimens. The application of a uniaxial pressure on an already sintered sample (without intermediate crushing) leads to an improvement of Jc. Jc of the sample with intermediate coldpress is 2.5 times larger in zero field and 60 times larger in 0.1T than that of the sample without intermediate cold-press. After the application of the uniaxial pressure, density and texture of grains were increased. This means that the observed enhancement of Jc with intermediate cold-press is due to the densification (lowering the weak links) and texturing effects.
