Study of Compositional and Artificial Pinning Effects on Superconductivity of Pulsed-Laser Deposited Gd-123 Films for Coated Conductor Applications

摘要

Critical temperature $(T_{c})$ , critical current density $(J_{rm c})$ and flux pinning characteristics of superconducting films are crucially influenced by their chemical composition. We studied the effect of small composition variations on superconductivity of ${rm GdBa}_{2}{rm Cu}_{3}{rm O}_{7-{rm x}}$ (Gd-123) films grown by pulsed laser deposition (PLD) technique. Several pathways to control the composition of Gd-123 films were studied: variation of clearance between edge of laser plume and substrate surface, utilization of off-stoichiometric target compositions and addition of ${rm BaZrO}_{3}$. Positive effect of Ba-deficiency on superconductivity of Gd-123 films was shown. Comparative study of Gd-123 and Y-123 films on ${rm CeO}_{2}$ capped ${rm Gd}_{2}{rm Zr}_{2}{rm O}_{7}({rm GZO})$ buffered Hastelloy tapes confirmed the advantage of Gd-based compositions for application in magnetic fields and their high potential for fabrication of long-length coated conductors.