Title :
Microstructural development and superconducting properties of BaO 2-added Bi2Sr2CaCu2O8+x
Author :
Trociewitz, Ulf P. ; Sahm, Peter R. ; Koritala, Rachel E. ; Brandao, Luiz ; Bacaltchuk, Cristiane ; Schwartz, Justin
Author_Institution :
Nat. High Magnetic Field Lab., Florida State Univ., Tallahassee, FL, USA
fDate :
3/1/2001 12:00:00 AM
Abstract :
Investigations on the effects of Ba additions in Bi-2212 superconductors are focussed on compositional, microstructural, and magnetization studies. In previous studies, we showed that BaO2 reacts with Bi-2212 to form second phases. Zero-field and in-field transport properties in Ag-clad BaO2 added Bi-2212 tapes had been improved at 4.2 K. SEM micrographs, pole figures, and transport critical currents versus magnetic field orientation suggest that BaO2 has a strong influence on the microstructural properties. Magnetization studies revealed that BaO2 does not affect the pinning properties of optimally added Bi-2212. To estimate the potential of BaO2 additions in creating possible pinning sites, TEM investigations were carried out focussing on sub-micrometer inclusions and growth defects in the superconducting phase
Keywords :
barium compounds; bismuth compounds; calcium compounds; critical currents; crystal microstructure; flux pinning; high-temperature superconductors; inclusions; magnetisation; scanning electron microscopy; stoichiometry; strontium compounds; transmission electron microscopy; 4.2 K; Ag-clad BaO2 added Bi-2212 tapes; Ba additions; BaO2-added Bi2Sr2CaCu2O8+x; Bi-2212 superconductors; Bi2Sr2CaCu2O8-BaO 2; SEM micrographs; TEM investigations; compositional studies; growth defects; in-field transport; magnetization studies; microstructural development; microstructural studies; pinning properties; pole figures; second phases; sub-micrometer inclusions; superconducting properties; transport critical currents; zero-field transport; Bismuth; Contracts; Critical current; High temperature superconductors; Magnetic fields; Magnetic properties; Magnetization; Powders; Strontium; Superconductivity;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
