Texture analysis of RF-sputtered CeO2 buffer layers and superconducting MOD-YBCO films

Abstract

CeO2 buffer layers were deposited on YSZ single-crystal substrates using an RF-sputtering method. The development of crystalline textures of sputtered CeO2 films at different sputtering pressure and their effects on YBCO films, deposited by Metal Organic Deposition (MOD), were investigated. Both CeO2 and subsequent YBCO films grew well epitaxially. The relative XRD peak intensities of CeO2 (200) to substrate YSZ (200) increased with deposition pressure in the range of 3–5mTorr and were inversely proportional to the θ–2θ scan FWHM values of CeO2 (200). Also, the reaction layers of BaCeO3 were thicker in the samples with lower CeO2 (200) intensities and poor out-of-plane alignment when CeO2 were deposited at the lower pressure of 3.3mTorr. It is noted, however, that the superconducting layer grew well epitaxially on these BaCeO3 layers, possibly due to the epitaxial relation between CeO2 and YBCO. The superconducting critical currents of MOD-YBCO films showed an increasing tendency as both the Δ2θ (CeO2) and BaCeO3 peak intensities decreased.