Investigation of high <i>J</i>_cY Ba₂Cu₃O_7 <i>x</i> coated conductors prepared by pulsed laser deposition on <i>self-epitaxial</i>   CeO₂ buffers

Abstract

For Y Ba2Cu3O7−x (YBCO) coated conductors with high Jc, we have been investigating pulsed laser deposition (PLD) processing using the 'self-epitaxial' PLD-CeO2 layer on an ion beam assisted deposition (IBAD)-Gd2Zr2O7 (GZO) buffered Hastelloy tape. In this study using short samples of 10 mm in length by 10 mm in width, a high critical current density, Jc, value of 4.4 MA cm−2 was obtained for a substrate with the delta phi value of 2.4°. We also confirmed the relationship that the Jc value of YBCO increased exponentially with decreasing in-plane grain alignment of YBCO. Furthermore, we also succeeded in deposition of a high Jc and thick YBCO film; the thickness was 1.2 µm and the Jc value was 2.3 MA cm−2. This value corresponds to 276 A/cm-width. Based on these results, a metre long YBCO coated conductor was fabricated using a reel-to-reel system. Consequently, Jc of 1 MA cm−2 was obtained for a long coated conductor. Now, work is in progress to fabricate a longer and thicker YBCO coated conductor with high critical current, Ic.