${\rm SmBa}_{2}{\rm Cu}_{3}{\rm O}_{7-\delta }$ Coated Conductors on the IBAD-MgO Substrate Fabricated by the Ex-situ Conversion

We investigated the ex-situ conversion process of amorphous precursor films for SmBa₂Cu₃O_7-delta (SmBCO) coated conductors (CC). Amorphous precursor films were first deposited on the LaMnO₃/homoepi-MgO/ IBAD-MgO/Y₂O₃/Al₂O₃/Hastelloy substrate by e-beam co-evaporation and subsequently crystallized to the superconducting phase at various post-annealing temperatures in two different reduced oxygen pressures. In 100 ppm of O₂ in Ar, c-axis oriented SmBCO grains with minor a-axis oriented grains were grown at 825degC whereas polycrystalline SmBCO film with some a -axis oriented grains was formed at 800degC. In the temperature region of 825 ~ 850degC, protruded spots were observed on the sample surface. In 6 ppm of O₂ in Ar, SmBCO film composed of a-axis oriented SmBCO grains with partial c-axis oriented grains were obtained at 700degC but other phases were formed above 725degC. The SmBCO sample grown at 700degC exhibited Tc _,zero value of 90.2 K. However, its Jc value at 77 K was negligibly small due to the formation of a-axis oriented grains.