Investigation of multi-deposition for high I/sub c/ YBCO coated conductors prepared by PLD on self-epitaxial CeO/sub 2/ buffers

For fabrication of YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) coated conductors with high J/sub c/, we have investigated pulsed laser deposition (PLD) of YBCO on the "self-epitaxial" PLD-CeO/sub 2/ layer on an ion beam assisted deposition (IBAD)-Gd/sub 2/Zr/sub 2/O/sub 7/ (GZO) buffered Hastelloy tape. A multiple coating of YBCO layer (multi-deposition) improved the uniformity in transport properties. In order to increase I/sub c/, we investigated the proper depositing conditions for a thick YBCO layers. It was found that raising the referential deposition temperature, in accordance with the YBCO layer growths, is effective to suppress a-axis oriented grains and increase I/sub c/. A high I/sub c/ as high as 293 A was obtained in a 10 cm long conductor. Furthermore, we succeeded in the deposition of a 0.8 m long YBCO coated conductor with the end-to-end I/sub c/ of 225 A and J/sub c/ of 1.13 MA/cm/sup 2/. The latter coated conductor also exhibited good uniformity, whose standard deviation of I/sub c/ distribution is 2.2%. These results demonstrated that the multi-deposition applying heater temperature increase corresponding to the YBCO thickness is effective in a preparation of high I/sub c/ and uniform YBCO coated conductors.