JOURNAL OF RARE EARTHS, Vol 31, No 9, Sep 2013, P 885 Effects of praseodymium doping on thermoelectric transport properties of CaMnO3 compound system ZHANG Feipeng (ᓴ亲吣)1,2,*, NIU Baocheng (⠯ֱ៤)1, ZHANG Kunshu (ᓴസк)1, ZHANG Xin (ᓴ ᗏ)2, LU Qingmei (䏃⏙ṙ)2, ZHANG Jiuxing (ᓴЙ݈)2 (1 Institute of Physics, Henan University of Urban Construction, Pingdingshan 467036, China; Key Laboratory of Advanced Functional Materials, Chinese Ministry of Education, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China) Received 17 May 2013; revised 25 June 2013 Abstract: The rare earth Pr doped Ca1–xPrxMnO3 (x=0, 0.06, 0.08, 0.1, 0.12, and 0.14) compound bulk samples were prepared to study the effect of Pr doping on thermoelectric transport properties of CaMnO3 compound system The doped samples exhibited single phase composition within the experimental doping range, with condensed bulk microstructure and small porosities The electrical resistivity was remarkably reduced for doped samples, on account of the enhanced carrier concentration; the absolute value of Seebeck coefficient was deteriorated mainly due to enhanced electron carrier concentration The electrical performances of the doped samples reflected by resistivity and Seebeck coefficient fluctuations were optimistically tuned, with an optimized power factor value of 0.342 mW/(m·K2) at 873 K for x=0.08 sample, which was very much higher comparing with that of the un-doped sample The lattice thermal conduction was really confined, leading to distinctly repressed total thermal conductivity The thermoelectric performance was noticeably improved by Pr doping and the dimensionless figure of merit ZT for the Ca0.92Pr0.08MnO3 compound was favorably optimized with the maximum value 0.16 at 873 K Keywords: CaMnO3 compound; Pr doping; thermoelectric properties; rare earths More and more efforts have been paid to the field of thermoelectric (TE) materials in the past decades owing to their clean energy conversion between heat and electricity through Seebeck effect and Peltier effect The efficiency of energy transformation is positively correlated to the materials’ dimensionless figure of merit ZT formulated by: ZT=Į2T/ȡț (1) where Į, ȡ, T and ț are the Seebeck coefficient, the electrical resistivity, the absolute temperature and the total thermal conductivity, respectively[1–3] For crystal phase materials, the total thermal conductivity ț is usually regarded as composing of the carrier thermal conductivity component țc and the lattice thermal conductivity component țL: ț=țc+țL (2) Good TE materials should have high Seebeck coefficient Į, low electrical resistivity ȡ and total thermal conductivity ț simultaneously Nevertheless, these parameters are not independent of each other; they are closely correlated to transport mechanism, for instance, the sort of charge carriers, the carrier density, mobility, carrier effective mass, phonon mean free path, vibration and phonon modes A good combination of transport parameters is needed in order to achieve a considerable ZT value for applicable TE materials[4] They are also sensitive to materials’ microstructures and textures, thereafter the materials preparation techniques The hotspot systems are tellurides, silicides, sulphide, half-Heusler alloys, clathrates, skutterudites and oxides[4–10] The oxides-based TE materials have many advantages over alloys-based materials such as atmospheric stability, easy fabrication, cheapness, high temperature stability, etc.[4] The n-type CaMnO3 compound shows semiconductorlike conductivity (dȡ/dT