Laser processing of CaMnO3-based materials for thermoelectric applications

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N M Ferreira, F Amaral, M A Madre, A Sotelo, A V Kovalevsky and F M Costa

i3N, Portugal
Universidade de Aveiro, Portugal
CSIC-Universidad de Zaragoza, Spain

: J Nucl Ene Sci Power Generat Technol

Abstract

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Today, a particular interest is given to the oxide-based thermoelectric materials, due to enhanced thermal and redox stability, attractive properties at high temperature, the absence of toxicity, and natural abundance of the constituent compounds. The objective of this work is to assess the possibilities for processing oxide thermoelectrics through laser floating zone (LFZ) method, including identification of the appropriate treatment conditions and main structural and microstructural factors affecting the thermoelectric performance. Known Nb- and La-substituted calcium manganite-based materials, possessing promising thermoelectric properties, were selected as a model system. Detailed structural (XRD) and microstructural (SEM/ EDS) studies were performed for the samples, grown at various pulling rates. The results on electrical conductivity, Seebeck coefficient and thermal conductivity indicate that high thermoelectric performance can be triggered by laser processing. Effects of pulling rate, dopants and thermal treatment to the fibres on these properties are discussed, suggesting that careful optimization of the laser treatment conditions is necessary, when seeking high thermoelectric performance in oxides by LFZ processing.

Recent Publications

1. N M Ferreira, F M Costa, A V Kovalevsky, M A Madre, M A Torres, et al. (2018) New environmentally friendly Ba-Fe-O thermoelectric material by flexible laser floating zone processing. Scripta Materialia 145(2018):54–57.

2. N M Ferreira, S Rasekh, A V Kovalevsky, F M Costa, M A Madre, et al. (2017) Thermoelectric oxides processed by laser floating zone technique. J. Mat Sci. 5(2017):5.

3. Kovalevsky A V, Aguirre M H, Populoh S, Patrício S G, Ferreira N M, et al. (2017) Designing strontium titanate-based thermoelectrics: insight into defect chemistry mechanisms. Journal of Materials Chemistry A 5(8):3909–3922.

4. A Sotelo, F M Costa, N M Ferreira, A Kovalevsky, M C Ferro, et al. (2016) Tailoring Ca3Co4O9 microstructure and performances using a transient liquid phase sintering additive. J. Eur. Ceram. Soc. 36(2016):1025.

5. M A Madre, F M Costa, N M Ferreira, S I R Costa, Sh Rasekh, et al. (2016) High thermoelectric performance in Bi2-xPbxBa2Co2Ox promoted by directional growth and annealing. Journal of the European Ceramic Society 36(2016):67–74.

Biography

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N M Ferreira completed his degree in Physics Engineering from the University of Aveiro and completed his PhD in Physics Engineering in 2014. From the year 2015 he is a researcher at I3N - pole UA, was an associate member+ assistant teacher in UA-DF. He has a good knowledge in laser systems, structural characterization techniques, and AC and DC electric measurements homemade systems.

E-mail: nmferreira@ua.pt