abstract
This study explores the effect of single doping with different rare earth elements (Y, La, and Yb) on the structural, morphological and electrical properties of CaMnO3 bulk ceramics, aiming to improve their thermoelectric performance. Ca(1-x)RxMnO3 (R = Y, La, Yb; x = 0, 0.05, 0.10) samples were synthesized via a solid-state reaction. XRD analysis confirmed the thermoelectric CaMnO3 phase as the major one, with orthorhombic perovskite structure. Small amounts of secondary phases (CaMn2O4 and Mn2O3) were also detected in some doped samples. The addition of dopants influenced the unit cell parameters, producing a shift to lower 2 theta angles, confirming their incorporation into the ceramic structure. SEM micrographs revealed a significant reduction in grain size upon doping. Electrical resistivity measurements showed a metallic behavior for all doped samples. The Y-doped samples exhibited the highest resistivity values while the Yb-doped samples showed the lowest values (6.8 m Omega cm for the 0.10 doped one), which are among the lowest found in literature for this compound. The Seebeck coefficient values show minor changes for 0.05 doped samples when they decreased with increasing concentration of dopant. Consequently, the highest values were observed for 0.05-doped sample (-215 mu V/K), independently of the dopant. This value is much higher than the ones typically reported in the literature. The highest value of the power factor was calculated for the 0.05 Yb doped sample, reaching approximately 0.56 mW/K2
keywords
THERMOELECTRIC PERFORMANCE; POWER
subject category
Materials Science
authors
Amirkhizi, P; Madre, MA; Constantinescu, G; Torres, MA; Sotelo, A; Kovalevsky, AV; Rasekh, S
our authors
Andrei Kavaleuski
Principal Researcher
Gabriel Constantinescu
Researcher
Parisa Amirkhizi
Junior Researcher
Shahed Rasekh
Junior ResearcherProjects
Thermoelectric oxide composites: design through controlled interactions (TEOsINTE)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
H2020 Marie Sklodowska-Curie Actions, Grant/Award Number: 101003375; Gobierno de Aragon, Grant/Award Number: UZ2022-IAR; Fundacao para a Ciencia e a Tecnologia, Grant/Award Numbers: 2020.08051.BD, CEEIND/02608/2017, LA/P/0006/2020, UIDB/00481/2020, UIDP/00481/2020, UIDP/50011/2020, UIDB/50011/2020; Ministerio de Ciencia, Innovacion y Universidades, Grant/Award Number: CEX2023-001286-S; Agencia Estatal de Investigacion, Grant/Award Number: CEX2023-001286-S.