Fabrication of Superconducting Y-Ba-Cu Oxide Through an Improved Diffusion Process

The formation of the YBa 2 Cu 3 O 7- y layer has been investigated by a modified diffusion process as a basic research for high- T c superconductor fabrication. The starting materials were Y 2 BaCuO 5 and barium cuprate (Ba:Cu=3:5), unlike the ordinary sintering technique. A dense layer of YBa 2 Cu 3 O 7- y was formed on Y 2 BaCuO 5 substrate, and the starting barium cuprate layer was fully converted to the superconducting phase. X-ray diffractometry revealed that the layer consisted of an orthorhombic crystal structure. A zero resistance of 91.5 K and a critical current density of 1900 A/cm 2 (77 K, 0 T) were achieved in the layer.