Textured CeO2 thin films on nickel tape by sol-gel process

Cerium oxide (CeO₂) is one of the preferred buffer layer for fabrication of coated conductors, especially when e-beam evaporation technique is used for YBCO processing. Therefore, processing of CeO₂ buffer layers has been extensively studied by several vacuum deposition techniques. However, a nonvacuum process is desired for fabrication of coated conductors to make coated conductors widely available in the market. In order to develop a nonvacuum process for fabrication of coated conductors, we fabricated textured cerium oxide (CeO₂) buffer layers on biaxially textured-Ni [100] substrates by sol-gel process. The solution was prepared from metal-organic precursor, Cerium 2,4-pentanedionate, and was deposited on the Ni substrates using a reel-to-reel sol-gel dip coating system. The textured films were annealed at 1150 °C for 10 min under 4% H₂-Ar gas flow. Extensive texture analysis has been done to characterize the texture of CeO₂ buffer layers. X-ray diffraction (XRD) of the buffer layer showed strong out-of-plane orientation on Ni tape. The CeO₂ [111] pole figure indicated a single cube-on-cube textured structure. The omega and phi scans revealed good out-of-plane and in-plane alignments. The full-width-at-half-maximum (FWHM) values of omega and phi scans of CeO₂ films were 6.47° and 7.26°, respectively. ESEM micrographs of the CeO₂ films revealed pinhole free, crack-free and dense microstructures.