RTU Research Information System
Latviešu English

Publikācija: Charge-Carrier Hopping in Highly Conductive CaMn1-xMxO3-δ Thermoelectrics

Publication Type Scientific article indexed in SCOPUS or WOS database
Funding for basic activity Unknown
Defending: ,
Publication language English (en)
Title in original language Charge-Carrier Hopping in Highly Conductive CaMn1-xMxO3-δ Thermoelectrics
Field of research 2. Engineering and technology
Sub-field of research 2.5 Materials engineering
Authors Philipp Theil
Sascha Populoh
Songhak Yoon
Gesine Saucke
Kristaps Rubenis
Anke Weidenkaff
Keywords Perovskite, Oxide, Transport Properties, Jahn-Teller Effect, Energy Materials
Abstract Highly dense CaMn1-xMxO3-δ (with M = Nb, Mo, Ta, W and 0 ≤ x ≤ 0.08) n-type thermoelectric materials with low electrical resistivities are prepared from nano-crystalline powders. Their room temperature power factors outperform the best reported results by 30% or more. In combination with the thermal conductivities promising figure-of-merits of ZTM=Ta,x=0.04 = 0.21 and ZTM=W,x=0.04 = 0.20 were achieved at 1160 K. The relative changes and temperature dependencies of the Seebeck coefficient, the electrical resistivity, and the power factor are described with a small-polaronhopping-based mechanism. In the limits of high-temperatures and low substitution levels the Seebeck coefficients are in good agreement with Heikes formula. At high substitutions the efficiency of the doping presumably decreases due to trapping states caused by the formation of bands from Jahn-Teller lowered eg orbitals of Mn3+. Jahn-Teller distortion of Mn3+ also leaves its footprints in the orthorhombic distortion of the crystal structure along the b-axis.
DOI: 10.1021/acs.jpcc.5b05882
Hyperlink: http://pubs.acs.org/doi/10.1021/acs.jpcc.5b05882 
Reference Theil, P., Populoh, S., Yoon, S., Saucke, G., Rubenis, K., Weidenkaff, A. Charge-Carrier Hopping in Highly Conductive CaMn1-xMxO3-δ Thermoelectrics. The Journal of Physical Chemistry C, 2015, Volume 119, Issue 38, pp.21860-21867. ISSN 1932-7447. Available from: doi:10.1021/acs.jpcc.5b05882
Additional information Citation count:
ID 21319