Effect of the annealing process on the microstructure of La2Zr2O7 thin layers epitaxially grown on LaAlO3 by metalorganic decomposition

• Published in: Journal of crystal growth 2009-05, Vol.311 (11), p.3204-3210
• Main Authors: JIMENEZ, C, CAROFF, T, RAPENNE, L, MORLENS, S, SANTOS, E, ODIER, P, WEISS, F
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Diffusion in solids; Exact sciences and technology; Material chemistry; Materials science; Methods of crystal growth; physics of crystal growth; Other materials; Physics; Specific materials; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Transport properties of condensed matter (nonelectronic)
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2009.03.021

La2Zr2O7 (LZO) films have been grown by Metalorganic Decomposition (MOD) to be used as buffer layers for coated conductors. A characteristic feature of LZO thin films deposited by MOD is the formation of nanovoids in an almost single crystal structure of LZO pyrochlore phase. Annealing parameters (heating ramp, temperature, pressure...) were varied to establish their influence on the microstructure of the LZO layers. XRD and TEM were used for sample characterisation. The epitaxial pyrochlore phase was obtained for annealing temperatures higher that 850°C whatever the other annealing conditions. However, the film microstructure, in particular, nanovoids shape and size, is strongly dependent on heating ramp and pressure during annealing. When using low heating ramp, percolation of voids creates diffusion channels for oxygen which are detrimental for the substrate protection during coated conductor fabrication. From this point of view high heating rates are more adapted to the growth of LZO layers.