abstract
In order to identify the effects of Pr additions on thermoelectric properties of strontium titanate, crystal structure, electrical and thermal conductivity, and Seebeck coefficient of Sr1-xPrxTiO3 (x = 0.02-0.30) materials were studied at 400 < T < 1180 K under highly reducing atmosphere. The mechanism of electronic transport was found to be similar up to 10% of praseodymium content, where generation of the charge carriers upon substitution resulted in significant increase of the electrical conductivity, moderate decrease in Seebeck coefficient, and general improvement of the power factor. Formation of point defects in the course of substitution led to suppression of the lattice thermal conductivity, whilst the contribution from electronic component was increasing with carrier concentration. Possible formation of layered structures and growing distortion of the perovskite lattice resulted in relatively low thermoelectric performance for Sr0.80Pr0.20TiO3 and Sr0.70Pr0.30TiO3. The maximum dimensionless figure of merit was observed for Sr0.90Pr0.10TiO3 and amounted to similar to 0.23 at 670K and similar to 0.34 at 1170 K, close to the values, obtained in similar conditions for the best bulk thermoelectrics, based on rare-earth substituted SrTiO3. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790307]
keywords
HIGH-TEMPERATURE; DOPED SRTIO3; SINGLE-CRYSTALS; CERAMICS; OXIDES; SR; CONDUCTIVITY; POWER
subject category
Physics
authors
Kovalevsky, AV; Yaremchenko, AA; Populoh, S; Weidenkaff, A; Frade, JR
our authors
Aleksey Yaremchenko
Principal Researcher
Andrei Kavaleuski
Principal Researcher
Jorge Ribeiro Frade
Retired Professoracknowledgements
This work was supported by the FCT, Portugal (Ciencia-2008, Project No. PEst-C/CTM/LA0011/2011 and FCT Researcher 2012 program, Grant No. IF/00302/2012). Financial support from the SNF-NCCR Manep and the DfG-SPP thermoelectrics is greatly acknowledged. The authors are thankful to K. Galazka (EMPA) and S. Mikhalev, M. J. Pinho Bastos (UA) for their experimental assistance.