abstract
Donor-doped CaMnO(3)is ann-type semiconductor with perovskite structure, being considered as a potentialn-type leg in thermoelectric modules. This oxide presents stability at high temperatures and allows tuning the relevant electrical and thermal transport properties through doping. In this work, Ca(0.9)Gd(0.1)MnO(3)precursors have been prepared to produce fibres through the laser floating zone technique using different pulling rates. However, as-grown fibres did not present thermoelectric properties due to the presence of high amounts of secondary phases, leading to very high electrical resistivity values. The results have highlighted the importance of annealing procedures to reduce electrical resistivity, due to the decrease of secondary phases amount, and producing promising thermoelectric performances. The annealed samples present higher ZT values when the growth rate is decreased, reaching around 0.22 for the lowest growth rate, which is very close to the best values reported in the literature for these materials. Moreover, this procedure possesses an additional advantage considering that these samples can be directly used asn-type legs in thermoelectric modules for high-temperature applications. However, further studies should be made to determine the optimal amount of dopant.
keywords
SUBSTITUTED CAMNO3; PERFORMANCE; BI
subject category
Engineering; Materials Science; Physics
authors
Ferreira, NM; Sarabando, AR; Ferro, MC; Madre, MA; Dura, OJ; Sotelo, A
our authors
Nuno Miguel Freitas Ferreira
Post-Doc FellowshipGroups
acknowledgements
The authors gratefully acknowledge the support of i3N (UID/CTM/50025/2019) and CICECO-Aveiro Institute of Materials (UID/CTM/50011/2019), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. This work is funded by national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. M. A. Madre and A. Sotelo recognize the MINECO-FEDER (MAT2017-82183-C3-1-R) and Gobierno de Aragon-FEDER (Research Group T 54-17 R) for funding.