High rate deposition by PLD of YBCO films for coated conductors

In order to scale-up high-performance YBa₂Cu₃O_7-δ (YBCO) coated conductors, we have been investigating pulsed laser deposition (PLD) of YBCO on the "self-epitaxial" PLD-CeO₂ layer on an ion-beam-assisted deposition (IBAD)-Gd₂Zr₂O₇ (GZO) buffered Hastelloy tape. Our continuous PLD system was designed so that the laser beam scans YBCO targets during deposition and raises plural and discrete plumes (multi-plume), and the substrate was turned three times (multi-turn) around the substrate heater to enlarge its deposition area. The multi-plume and multi-turn (MPT) PLD indicated a capability to unite high rate deposition and high J_c by enlarging the deposition area under the proper condition. A 21 m long YBCO coated conductor with high end-to-end I_c of 85.0 A and J_c of 1.13 MA/cm² was prepared by MPT-PLD. The uniformities of the grain alignment and transport property were also achieved. Furthermore, we succeeded in deposition of a 45.8 m long YBCO layer. The I_c was as high as 182 A, that the multiplication of I_c and length reached the highest value of 8.34 kA m.