Grain orientations and grain boundary networks of YBa2Cu3O7−δ films deposited by metalorganic and pulsed laser deposition on biaxially textured Ni–W substrates

• Published in: Journal of materials research Vol. 21; no. 4; pp. 923 - 934
• Main Authors: Feldmann, D.M., Holesinger, T.G., Cantoni, C., Feenstra, R., Nelson, N.A., Larbalestier, D.C., Verebelyi, D.T., Li, X., Rupich, M.
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.04.2006
• Subjects: ALIGNMENT; CRITICAL CURRENT; DEPOSITION; DIFFRACTION; ELECTRONS; EPITAXY; Grain boundaries; GRAIN ORIENTATION; LASERS; MATERIALS SCIENCE; SUBSTRATES; Superconducting; THICKNESS; TRANSPORT; Grain boundaries; Superconducting; Epitaxy
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/jmr.2006.0110

We report a detailed study of the grain orientations and grain boundary (GB) networks in YBa2Cu3O7-δ (YBCO) films ∼0.8 μm thick grown by both the in situ pulsed laser deposition (PLD) process and the ex situ metalorganic deposition (MOD) process on rolling-assisted biaxially textured substrates (RABiTS). The PLD and MOD growth processes result in columnar and laminar YBCO grain structures, respectively. In the MOD-processed sample [full-width critical current density Jc(0 T, 77 K) = 3.4 MA/cm2], electron back-scatter diffraction (EBSD) revealed an improvement in both the in-plane and out-of-plane alignment of the YBCO relative to the template that resulted in a significant reduction of the total grain boundary misorientation angles. A YBCO grain structure observed above individual template grains was strongly correlated to larger out-of-plane tilts of the template grains. YBCO GBs meandered extensively about their corresponding template GBs and through the thickness of the film. In contrast, the PLD-processed film [full width Jc(0 T, 77 K) = 0.9 MA/cm2] exhibited nearly perfect epitaxy, replicating the template grain orientations. No GB meandering was observed in the PLD-processed film with EBSD. Direct transport measurement of the intra-grain Jc(0 T, 77 K) values of PLD and MOD-processed films on RABiTS revealed values up to 4.5 and 5.1 MA/cm2, respectively. As the intra-grain Jc values were similar, the significantly higher full-width Jc for the MOD-processed sample is believed to be due to the improved grain alignment and extensive GB meandering.