Large thermoelectric power variations in epitaxial thin films of layered perovskite GdBaCo2O5.5±δwith a different preferred orientation and strain
Chatterjee, Arindom (Institut Català de Nanociència i Nanotecnologia)
Chávez Ángel, Emigdio (Institut Català de Nanociència i Nanotecnologia)
Ballesteros, Belén (Institut Català de Nanociència i Nanotecnologia)
Caicedo Roque, Jose Manuel (Institut Català de Nanociència i Nanotecnologia)
Padilla-Pantoja, Jessica (Institut Català de Nanociència i Nanotecnologia)
Leborán, Víctor (Universidade de Santiago de Compostela. Departamento de Química Física)
Sotomayor Torres, Clivia M. (Institut Català de Nanociència i Nanotecnologia)
Rivadulla, Francisco (Universidade de Santiago de Compostela. Departamento de Química Física)
Santiso, José (Institut Català de Nanociència i Nanotecnologia)

Date:	2020
Abstract:	This work describes the growth of thin epitaxial films of the layered perovskite material GdBaCoO(GBCO) on different single crystal substrates SrTiO(STO), (LaAlO)(SrTaAlO)(LSAT) and LaAlO(LAO) as an approach to study changes in the thermoelectric properties by means of the induced epitaxial strain. In addition to strain changes, the films grow with considerably different preferred orientations and domain microstructures: GBCO films on STO are purelyc-axis oriented (c) with an average 0. 18% in-plane tensile strain; GBCO on LSAT is composed of domains with a mixed orientation (candc) with an average 0. 71% in-plane compressive strain; while on LAO it isb-axis oriented (c) with an average 0. 89% in-plane compressive strain. These differences result in important cell volume changes, as well as in the orthorhombicity of thea-bplane of the GBCO structure, which in turn induce a change in the sign and temperature dependence of the thermopower, while the electrical conductivity remains almost unchanged. In general, compressively strained films show negativeSthermopower (n-type) while tensile strained films show a positiveS(p-type) at low temperatures, probing the adaptive nature of the GdBaCoOcompound. These results point to the spontaneous generation of oxygen vacancies to partially accommodate the epitaxial stress as the main cause for this effect.
Grants:	European Commission 734187 European Commission 645658 Ministerio de Economía y Competitividad MAT2016-77100-C2-1-P Ministerio de Economía y Competitividad SEV-2017-0706 Ministerio de Ciencia e Innovación MAT2016-80762-R Ministerio de Ciencia e Innovación PGC2018-101743-B-I00 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-327
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Electrical conductivity ; Epitaxial thin films ; In-plane compressive strain ; Preferred orientations ; Single crystal substrates ; Spontaneous generation ; Temperature dependence ; Thermoelectric properties
Published in:	Journal of materials chemistry, Vol. 8, issue 38 (Oct. 2020) , p. 19975-19983, ISSN 2050-7496

DOI: 10.1039/d0ta04781c

Postprint 19 p, 1.6 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles