Journal article

Publication year: 2016

Pages: 1284-1295

Journal: physica status solidi (a) – applications and materials science

Volume number: 213

Issue number: 5

ISSN: 1862-6300

eISSN: 1862-6319

DOI Link: https://doi.org/10.1002/pssa.201532725

Publisher: Wiley

Abstract: 
Sodium cobaltate (NaxCoO2, NCO) is a model type thermoelectric material for high temperature applications, which is representative for the class of non-stoichiometric and mixed ion-electron conducting thermoelectrics (e.g., Cu2-xSe). The present study deals with the kinetic instability of the originally homogeneous chemical composition when a temperature gradient is applied - a common situation in thermoelectric materials with a mobile component (element), but rarely considered in thermoelectric materials research so far. In order to investigate a well reproducible system, highly epitaxial thin films of NaxCoO2 with an atmosphere protective capping layer of alumina are prepared via pulsed laser deposition on sapphire (001) and lanthanum aluminate (111). A self-designed non-isothermal set-up allows the precise determination of the heat of transport for mobile sodium as 8.3 kJ mol(-1) and, therefore, the quantification of thermodiffusion (i.e., the Ludwig-Soret effect in the stationary state). The experiments also allow to estimate the chemical diffusion coefficient of sodium at 422K as about (D) over bar (Na) = 5 x 10(-4) cm(2) s(-1). (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Harvard Citation style: Schneider, C., Schichtel, P., Mogwitz, B., Straubinger, R., Beyer, A., Rohnke, M., et al. (2016) Thermomigration and Soret effect in NaxCoO2 as thermoelectric material: Preparation and characterization of sodium cobaltate thin films, physica status solidi (a) – applications and materials science, 213(5), pp. 1284-1295. https://doi.org/10.1002/pssa.201532725

APA Citation style: Schneider, C., Schichtel, P., Mogwitz, B., Straubinger, R., Beyer, A., Rohnke, M., Volz, K., & Janek, J. (2016). Thermomigration and Soret effect in NaxCoO2 as thermoelectric material: Preparation and characterization of sodium cobaltate thin films. physica status solidi (a) – applications and materials science. 213(5), 1284-1295. https://doi.org/10.1002/pssa.201532725