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

Materials Science and Engineering B 110 (2004) 94–102 Nb-doped SrTiO3 buffer layers on LaAlO3 substrates by metalorganic deposition for YBCO superconducting films Erdal Celik a,b,∗, Yutaka Yamadab , Izumi Hirabayashib , Yuh Shioharab,c a Department of Metallurgical and Materials Engineering, Faculty of Engineering, Dokuz Eylul University, Bornova, Izmir 35100, Turkey b Superconductivity Research Laboratory, ISTEC, 2-4-1, Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan c Superconductivity Research Laboratory, 10-13 Shinonome 1-chome, Koto-ku, Tokyo 135-0062, Japan Received 15 October 2003; accepted 4 March 2004 Abstract 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 5 min in air and subsequently annealed at 1150 ◦C for 10 min 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. © 2004 Elsevier B.V. All rights reserved. Keywords: Nb-STO; Sol–gel; Buffer layer; LAO; PLD; YBCO 1. Introduction