Investigations of thick YBCO coated conductor with high critical current using IBAD-PLD method

Thick YBCO film were deposited by the PLD method on the self-epitaxial CeO2 buffered substrate: a CeO2 cap layer was deposited by the PLD method on Gd2Zr2O7 buffered Hastelloy tape by the IBAD method and highly texturing up to 4° was obtained. We have investigated the Δϕ, Ra value, amount of existing a-axis oriented crystals, and Ic of YBCO coated conductor with increasing YBCO thickness. To obtain YBCO coated conductors with high Ic, good in-plane texturing of the CeO2 layer is required. However, the value of Ic saturated at a certain YBCO thickness, critical thickness, dc. As the YBCO thickness increased, the surface morphology became much rougher. Consequently, the surface temperature of YBCO becomes lower and the amount of a-axis oriented crystals in YBCO increased. Then, thick YBCO film exhibited dc. To solve this problem, we fabricated YBCO by multi-layer deposition using the Reel-to-Reel system, which was carried out at various temperatures. This process increases Jc from 0.54 to 0.89 A/cm2.