Enhanced high-field performance in PLD films fabricated by ablation of YSZ-added YBa₂Cu₃O_7−<i>x</i>target

Abstract

YBa2Cu3O7−x+Y2O3-stabilized ZrO2 (YBCO+YSZ) mixed films were prepared on SrTiO3/MgO substrates by pulsed-laser deposition from a YBCO target with a thin YSZ sector on top. The Jc at 77 K for the mixed YBCO+YSZ thin film was enhanced. The Jc at 77 K for the pure film and the mixed YBCO+YSZ thin film were 1.46 and 1.95 MA cm−2 (self field) (and 0.09 and 0.28 MA cm−2 (, B = 5 T)), respectively, even when both films were prepared using the same deposition conditions. The maximum pinning force of a doped film (77 K, ) was 15.9 GN m−3, which is comparable to the value reached by NbTi at 4.2 K. In the YSZ-added sample, the angular dependence of Jc showed a broad peak at due to the flux pinning by the c-axis correlated defects. Elongated nanorods grown parallel to the c axis were consistently observed in the cross-sectional TEM images.