Nb-doped SrTiO₃ buffer layers on LaAlO₃ substrates by metalorganic deposition for YBCO superconducting films

The metalorganic deposition (MOD) method has been developed as a low-cost process for YBCO-coated conductor. In this study, Nb-doped SrTiO₃ (Nb-STO) buffer layers have been fabricated on LaAlO₃ (LAO) single crystal substrates by MOD using triethanol amine for YBCO films. The gel-coated substrates were dried on hot plate at 300°C for 5min in air and subsequently annealed at 1150°C for 10min under 4% H₂-Ar gas flow. These films were extensively characterized by X-ray diffraction (XRD), pole figure XRD, atomic force microscope (AFM) and scanning electron microscope (SEM). It was found that highly textured, crack-free, smooth, homogenous and dense Nb-STO films with a strong (1 0 0) orientation on LAO substrate especially when using triethanol amine to improve the wettability of the coating solution. YBCO films have been deposited on the Nb-STO-buffered LAO substrates by pulsed laser deposition (PLD). It was also determined that YBCO films on Nb-STO-buffered LAO substrate had the transition temperature of 91 K.