@Article{D0TA04781C,
author ="Chatterjee, Arindom and Chavez-Angel, Emigdio and Ballesteros, Belen and Caicedo, Jose Manuel and Padilla-Pantoja, Jessica and Leboran Alvarez, Victor and Sotomayor Torres, Clivia Maria and Rivadulla, Francisco and Santiso, Jose",
title  ="Large thermoelectric power variations in epitaxial thin films of layered perovskite GdBaCo2O5.5±? with different preferred orientation and strain",
journal  ="J. Mater. Chem. A",
year  ="2020",
pages  ="-",
publisher  ="The Royal Society of Chemistry",
doi  ="10.1039/D0TA04781C",
url  ="http://dx.doi.org/10.1039/D0TA04781C",
abstract  ="The growth of thin epitaxial films of the layered perovskite material GdBaCo2O5.5±? (GBCO) on different single crystal substrates SrTiO3 (STO){,} (LaAlO3)0.3(Sr2TaAlO6)0.7 (LSAT) and LaAlO3 (LAO) is described as a way to study changes in the thermoelectric properties by means of the induced epitaxial strain. In addition to the changes in strain the films grow with considerably different preferred orientations and domain microstructure: GBCO films on STO are purely c-axis oriented (c-perpendicular) with an average 0.18% in-plane tensile strain; GBCO on LSAT are composed of domains with mixed orientation (c-parallel and c-perpendicular) with an average 0.71% in-plane compressive strain; while on LAO it is b-axis oriented (c-parallel) with an average 0.89% in-plane compressive strain. These differences result in important changes in the sign and temperature dependence of the thermopower while the electrical conductivity remains almost isotropic. In general{,} compressively strained films show negative thermopower (n-type) while tensile strained film show positive thermopower (p-type) at low temperatures{,} probing the adaptive nature of GdBaCo2O5.5±? compound. These results point to the spontaneous generation of oxygen vacancies to accommodate epitaxial stress as responsible for this effect."
}