abstract
Nb-doped Ca0.97Y0.01La0.01Yb0.01Mn1-xNbxO3 materials were prepared to assess their thermoelectric properties. Samples were obtained by sintering at 1583 K for 12 h involving planetary milled precursors. XRD analysis indicated primarily thermoelectric phase with minor CaMn2O4. Microstructural observations revealed decreasing grain size with increasing Nb content. However, electrical resistivity decreases for the samples with Nb-content up to 0.03, which can be associated with the increase of the charge carrier concentration. The lowest value at 1073 K (9.2m Omega cm) is among the best reported in the literature. Seebeck coefficient decreased with Nb-doping, and the best PF value at 1073 K has been determined for 0.01Nb samples (similar to 0.48mW/K(2)m). Assuming the thermal conductivity at 1073 K similar to that at 473 K, the calculated ZT values are among the typically reported in this family. These results highlight the promise of CaMnO3-based materials for integration in thermoelectric modules working under steady-state mode, where the high PF values are of great importance.
keywords
ELECTRICAL-PROPERTIES; COMBUSTION SYNTHESIS; SUBSTITUTED CAMNO3; PERFORMANCE; MICROSTRUCTURE; TRANSPORT; MANGANITES; PHASES
subject category
Materials Science
authors
Amirkhizi, P; Torres, MA; Depriester, M; Hedayati, M; Sotelo, A; Madre, MA; Kovalevsky, AV; Rasekh, S
our authors
Andrei Kavaleuski
Principal Researcher
Mehdi Hedayati
PhD Student
Parisa Amirkhizi
Junior Researcher
Shahed Rasekh
Junior ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
The authors wish to thank the Gobierno de Aragon (Grupo de Investigacion T54_23R) for financial support. Sh. Rasekh acknowledges the support of the Research Employment Contract FCT-CEECIND/02608/2017. This work was also developed within the scope of the PhD project of P. Amirkhizi (grant 2020.08051.BD funded by FCT) and the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020), UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020), financed by national funds through the FCT/MCTES (PIDDAC). M. A. Madre, M. A. Torres, and A. Sotelo acknowledge the grant CEX2023-001286-S funded by MICIU/AEI/10.13039/501100011033. Authors would like to acknowledge the use of Servicio General de Apoyo a la Investigacion-SAI, Universidad de Zaragoza. Authors are also thanksful to P. Masselin (LPCA laboratory, Dunkerque) for the shaping of samples for thermal measurements.