Thick SmBCO/IBAD-MgO Coated Conductor for High Current Carrying Power Applications

Long-length (Sm_1+xB_2-xC₃O_7-y) coated conductor was fabricated using ion beam assisted deposition (IBAD)-MgO template (LaMnO₃/IBAD - MgO/Y₂O₃/Al₂O₃/Hastelloy) by the reactive co-evaporation method for electric power applications. SmBCO superconducting layers with thicknesses from 1 to 3 ??m were deposited to investigate the effect of SmBCO thickness on the in-plane texture, surface morphology and superconducting properties. In this study, the optimal deposition conditions were examined to make thick SmBCO coated conductor without degradation of critical current density. The oxygen partial pressure and temperature were controlled in the range of 1~20 mTorr and 600 ~ 800??C, respectively. SmBCO/IBAD-MgO coated conductors showed high critical current densities over 2.0 MA/cm² with small amount of degradation by increasing the thickness of superconducting layer up to 3 ??m. The critical current of 637.5 A/cm-w (J_C = 2.12 MA/cm²) at 77 K in self- field was obtained in 3 ??m-thick and 1 m long coated conductor. This is the highest critical current reported so far of the coated conductor with SmBCO superconducting layer deposited by co-evaporation.