FABRICATION OF BULK SUPERCONDUCTORS YBA2CU3-XTEXO7-DELTA WITH HIGHLY ORIENTED LAYER STRUCTURE USING THE MELT-TEXTURE GROWTH-PROCESS

We report on the successful fabrication of bulk samples satisfying the nominal composition YBa2Cu3-xTexO7-delta and containing highly single-crystal-like texture. While this type of crystal growing process is not new, our process requires only the existence of spatial temperature gradient in some parts of the common tube furnace. The samples with tellurium were found to be much more stable and better superconductors than the Y-123 specimen. Large layer textures with cross-section approximately 50 x 500 mum2 were observed to grow inside the usual bulk sample. The critical currents were measured by the d.c. magnetization method and found to be easily greater than 6000 A cm-2 for the samples with Te.