Atomic force microscopy study of bicrystal SrTiO3 substrates and YBCO thin films

• Published in: Surface and interface analysis Vol. 29; no. 3; pp. 221 - 226
• Main Authors: Vallet, C. E., Prouteau, C. S., Feenstra, R., Hamet, J. F., Verebelyi, D. T., Christen, D. K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.03.2000; Wiley
• Subjects: AFM; bicrystal; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cuprates superconductors (high tc and insulating parent compounds); Exact sciences and technology; High-Tc compounds; High-tc films; Physics; SrTiO3; Structure and morphology; thickness; substrate; Superconducting films and low-dimensional structures; Superconductivity; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Y-based cuprates; YBCO; Grain boundaries; Atomic force microscopy; Annealing; Inorganic compounds; Bicrystals; Ternary compounds; Transition element compounds; Experimental study; Substrates; Thin films; Critical current; Barium oxides; Morphology; High-Tc superconductors; Strontium titanates; Quaternary compounds; Copper oxides; Yttrium oxides
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/(SICI)1096-9918(200003)29:3<221::AID-SIA724>3.0.CO;2-2

Single‐crystal substrates allow the epitaxial deposition of high‐Tc superconductor (HTS) films that exhibit high critical current densities (Jc). The decrease in Jc observed for films deposited on polycrystalline crystals is attributed to misorientation between adjacent grains. To understand better this phenomenon, deposition of HTS films on bicrystal substrates is used to model the effects of a single grain boundary. The surfaces of strontium titanate (001) bicrystals with tilt boundary orientations of 7°, 15° and 24° were analyzed by atomic force microscopy (AFM). Annealing conditions were found to be a key factor for obtaining atomically smooth surfaces. The grain boundary morphologies were analyzed from sections of the AFM images. Images of YBa2Cu3O7−x (YBCO) films produced on these substrates by pulsed‐laser deposition are shown for regions that include the grain boundaries. Different morphologies of YBCO thin films are presented. Copyright © 2000 John Wiley & Sons, Ltd.