Title :
Critical current in Tl-base high-Tc oxides synthesized through a diffusion process
Author :
Tachikawa, K. ; Kikuchi, A. ; Kinoshita, T. ; Komiya, S.
Author_Institution :
Fac. of Eng., Tokai Univ., Kanagawa, Japan
fDate :
6/1/1995 12:00:00 AM
Abstract :
In the TBCCO diffusion composites, the 2223 phase is easily formed within a short reaction time. The critical current at 77 K is significantly improved by the F addition to the coating layer. The F addition decreases the degradation of critical current under magnetic field at 77 K, and shifts the irreversibility line to higher temperature. The XRD study reveals that the F addition clearly promotes the phase transformation from 2223 to 1223. Meanwhile, the annealing in flowing O/sub 2/ at 550/spl deg/C-600/spl deg/C also increases the critical current at 71 K. A J/sub c/ of about 10,000 A/cm/sup 2/ is obtained at 77 K in the TBCCO diffusion layer by the F addition and the O/sub 2/ annealing.<>
Keywords :
X-ray diffraction; annealing; barium compounds; calcium compounds; chemical interdiffusion; composite superconductors; critical current density (superconductivity); critical currents; high-temperature superconductors; solid-state phase transformations; superconducting thin films; thallium compounds; 2223 phase; 550 to 600 C; 77 K; F addition; O/sub 2/; Tl-base superconducting oxides; TlBaCaCuO; X-ray diffraction; annealing; coating layer; critical current; critical current density; diffusion composites; diffusion layer; diffusion process synthesis; flowing O/sub 2/; high temperature superconductors; irreversibility line; magnetic field; phase transformation; Annealing; Bars; Coatings; Critical current; Diffusion processes; Magnetic shielding; Powders; Probes; Temperature; X-ray scattering;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
