SmBa 2 Cu 3 O 7 - delta Coated Conductors on the IBAD-MgO Substrate Fabricated by the Ex-situ Conversion Process

We investigated the ex-situ conversion process of amorphous precursor films for SmBa sub(2)Cu sub(3)O sub(7- delta ) (SmBCO) coated conductors (CC). Amorphous precursor films were first deposited on the LaMnO sub(3)/homoepi-MgO/ IBAD-MgO/Y sub(2)O sub(3)/Al sub(2)O sub(3)/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 O sub(2) in Ar, c-axis oriented SmBCO grains with minor a-axis oriented grains were grown at 825 degree C whereas polycrystalline SmBCO film with some a -axis oriented grains was formed at 800 degree C. In the temperature region of 825 ~ 850 degree C, protruded spots were observed on the sample surface. In 6 ppm of O sub(2) in Ar, SmBCO film composed of a-axis oriented SmBCO grains with partial c-axis oriented grains were obtained at 700 degree C but other phases were formed above 725 degree C. The SmBCO sample grown at 700 degree C exhibited Tc sub(,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.