Preparation of epitaxial YBa_2Cu_3O_(7-y) films and CeO_2 buffer layer on Ni-5at.W substrates by MOD method

摘要

Biaxially textured CeO_2 films were deposited on Ni-5at.%W (Ni-5W) tapes by a metal-organic deposition (MOD) method. Subsequent YBa_2Cu_3O_(7-y) (YBCO) films were prepared using the (MOD) method leading to a simplified coated conductor architecture of YBCO/CeO_2/Ni-5W. X-ray diffraction measurements revealed an epitaxial growth of the CeO_2 buffer layer the 7.06°, 5.16°, for the out-of-plane and in-plane alignment, respectively. The superconducting coated film with a texture spread down to the out-of-plane texture is ω = 6.2° and the in-plane texture is Φ = 7.6°. The results indicate that single CeO_2-buffered Ni-5W tapes are suitable for the epitaxial growth of YBCO higher cube texture and the epitaxial YBCO film was obtained. To microstructural investigations, the film's SEM results showed a dense, smooth and crack-free surface morphology. The superconducting properties were measured by four probe method. The superconducting transition temperature (T_c) was about 90 K with a narrow transition of 0.8 K and the critical current density (J_c) was about 1.5×10~4 A/cm~2 at 77 K, 4T.