Effect of Processing on Microstructure and J_c of Ag-sheatbed(BiPb)_2Sr_2Ca_2Cu_3O_x Tapes

Ag-sheathed(Bi,Pb)_2Sr_2Ca_2Cu_3O_x tapes were fabricated by a powder-in-tube method.A high criticalcurrent density of 2.8×10~4 A/cm~2 at 77K,0T and 4×10~4 A/cm~2 at 4.2K,5T(H⊥ab),6.3×10~4 A/cm~2 at 4.2K,7T(H∥ab)is obtained.The microstructure of the tapes with high J_c values was in-vestigated by transmission electron microscope(TEM)and X-ray energy dispersive spectrum system(EDS).For comparison,a tape fabricated by a different procedure with a low J_c of about 1×10~4 A/cm~2 at77K,0T was also studied.The relationship between J_c and microstructure of the tapes and the effect of theprocessing on the microstructure and J_c were elucidated.     

A Study on S.R.Topography of the Structural Defects in High-J_c Superconducting YBaCuO Crystal Prepared by the MTG Technique

It is well known that for technological application,a great effort has been done to enchance J_c value ofsuperconducting YBaCuO sintered bulk.Except oxygen content,the main problem for increasing critical cur-rent density J_c is to eliminate the weak link and to control crystallographic anisotropy.It is necessary tomake YBaCuO superconducting bulk have a strong texture with C-axis orientation.Since Jin et al.has suc-