Deposition of high-textured buffer layers for YBCO coated conductors by all-IPAT-process

An approach (IPAT, in situ postannealing textured) for fabrication of oxide buffer layers directly on rolling-assisted biaxially textured metal substrates is presented. CeO2 seed films with different growth orientations were prepared by direct-current magnetron sputtering. The effects of deposition temperature and sputtering power on epitaxial orientation of CeO2 thin films were examined. Subsequently YSZ and CeO2 films were deposited to complete the buffer layer structure via the same IPAT process. The best samples exhibited a highly biaxial texture, as indicated by FWHM values in the range of 4-5°, and 2-4° for the in-plane and out-of-plane orientations, respectively. Secondary ion mass spectrometer analysis confirmed the effective prevention of buffer layer against Ni and W metal interdiffusion. Atomic force microscope observations revealed a smooth, dense and crack-free surface morphology. This IPAT process represents a significant advance over existing techniques and avoids substrate oxidation and film cracking issues. Furthermore, metal film can be sputter deposited at much higher rates relative to oxides, making the approach industrially scalable and economical.