Title :
Spatial distribution of structural and superconducting properties in high processing rate melt textured YBCO
Author :
Vecchione, A. ; Gombos, M. ; Pace, S. ; Polichetti, M.
Author_Institution :
Dipt. di Fisica, Salerno Univ., Italy
fDate :
6/1/1999 12:00:00 AM
Abstract :
In this work, we report on directionally solidified YBCO bars fabricated by the horizontal Bridgman technique based on sample transport in a thermal gradient. We employ a pulling rate in the furnace three orders of magnitude higher than the value of 0.5 mm/h generally used to maximize the critical current densities. We cut the produced sample in several slices perpendicularly to the pulling direction with the purpose of analysing the spatial distribution of superconducting, morphological and structural properties as a function of their position along the pulling direction. X-ray diffraction and SEM analyses show that partial texturing occurs even at very high pulling rates. Each slice has an onset of the critical temperature at /spl sim/90 K Moreover, the critical current densities at 77 K and at 1 Tesla are estimated from dc magnetisation curves in hundreds of A/cm/sup 2/.
Keywords :
X-ray diffraction; barium compounds; critical current density (superconductivity); crystal growth from melt; high-temperature superconductors; magnetisation; scanning electron microscopy; superconducting transition temperature; texture; yttrium compounds; 1 T; 77 K; DC magnetisation curves; SEM; X-ray diffraction; YBaCuO; critical current density; critical temperature; directionally solidified YBCO bars; horizontal Bridgman technique; partial texturing; pulling rate; Bars; Cooling; Critical current density; Fabrication; Furnaces; Neodymium; Powders; Solids; Temperature; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on