Title :
Influence of the oxygenation process in the critical currents of bulk melt textured YBa/sub 2/Cu/sub 3/O/sub 7/
Author :
Martinez, B. ; Pinol, S. ; Gomis, V. ; Sandiumenge, F. ; Vilalta, N. ; Fontcuberta, J. ; Obradors, X.
Author_Institution :
Inst. de Ciencia de Mater., CSIC, Barcelona, Spain
fDate :
6/1/1995 12:00:00 AM
Abstract :
Bulk superconducting YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/ composites have been prepared through a directional solidification process allowing to obtain quasi-single crystals up to 10-12 cm in length with critical currents well above 10/sup 5/ A/cm/sup 2/ at 77 K and zero field. Low temperature oxygenation processes have been required to reach the optimal superconducting performances of the samples. For short oxygenation times, oxygen deficient bands parallel to the a-b planes have been observed while, on the other hand, an aging process has also been detected at long oxygenation times. We show that the critical currents and irreversibility lines are strongly influenced by these effects, as well as the microstructure of the samples, made evident through a careful transmission electron microscopy (TEM) investigation.<>
Keywords :
ageing; barium compounds; composite superconductors; critical currents; crystal microstructure; high-temperature superconductors; oxidation; transmission electron microscopy; yttrium compounds; 10 to 12 cm; 77 K; O deficient bands; YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/; YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/ composites; aging; critical current; directional solidification; irreversibility lines; microstructure; oxygenation; transmission electron microscopy; Annealing; Bars; Critical current; High temperature superconductors; Magnetic field measurement; Magnetic materials; Microstructure; Optical microscopy; Superconducting epitaxial layers; Transmission electron microscopy;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
