Thermoelectric properties of (1-x)LaCoO3•xLa0.7Sr0.3MnO3 composite

JOURNAL OF ALLOYS AND COMPOUNDS

卷:749

Article

Kumar, Ashutosh¹  Kumari, Karuna¹  Jayachandran, B.²  Sivaprahasam, D.²  Thakur, Ajay D.¹ 

[1] Indian Inst Technol Patna, Dept Phys, Bihta 801106, India

[2] Indian Inst Technol Madras, ARC Int, Res Pk, Madras 600133, Tamil Nadu, India

关键词: Thermal conductivity;    Electrical conductivity;    Perovskites;    Manganites;    Cobaltate;    Composite;   

DOI  :  10.1016/j.jallcom.2018.03.347

来源: Elsevier

【 摘 要 】

We report the thermoelectric (TE) properties of (1-x) LaCoO3.xLa(0.7)Sr(0.3)MnO(3) (0 < x < 0.50) composite in a temperature range 320-800 K. Addition of La0.7Sr0.3MnO3 to LaCoO3 in small amount (5 weight %) improves the overall Seebeck coefficient (a) at higher temperatures. The electrical conductivity however decreases due to a decrease in carrier concentration of the composite. The decrease in electrical conductivity of the composite at high temperature may be attributed to the insulating nature of the LSMO above room temperature. Thermal conductivity (k) of all the samples increases with an increase in the temperature, but decreases with increasing LSMO content. We also report the local variation of Seebeck coefficient across the composite samples measured using a precision Seebeck measurement system. A maximum value of 0.09 for the figure of merit (ZT) is obtained for 0.95LaCoO(3).0.05La(0.7)Sr(0.)3MnO(3) at 620 K which is significantly higher than the ZT of either of LaCoO3 or La0.7Sr0.3MnO3 at 620 K. This suggests the potential for enhancement of operating temperatures of hitherto well known low temperature thermoelectric materials through suitable compositing approach. (C) 2018 Elsevier B.V. All rights reserved.

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