Effect of a multi-buffer layer (Sm2O3/CeO2) on the superconducting properties of an EuBa2Cu3O7−δ thin film

In order to suppress the influence of facets, annealing of a thick CeO2 film and insertion of a Sm2O3 buffer layer were carried out. Annealing of R-Al2O3 with a 200-nm-thick CeO2 buffer layer at 1000 °C for 3 h resulted in improvement in the surface morphology and crystallinity of the buffer layer. However, microcracks were observed on the surface of the CeO2 film, and EuBa2Cu3O7−δ (EBCO) thin films directly deposited on annealed substrates exhibited Tce's of about 84 K or lower. By depositing 100-nm-thick Sm2O3 second buffer layers on annealed CeO2, EBCO thin films exhibited Tce's of 90.1 K and Jc's of 5.5 MA/cm2 at 77.3 K.