resumo
Manganites present fascinating physical properties which can be tuned according with the method and pro-cessing conditions. In this work, Ca1-xPrxMnO3 (x = 0.03, 0.06, 0.1) materials were prepared by the Laser Floating Zone (LFZ) technique, under different pulling rates (25-100 mm/h) in air and argon atmospheres, obtaining fibres with 2.5 mm diameter. Such processing conditions promote the formation of secondary phases in (Ca,Pr)MnO3 fibres. The formation of the perovskite phase at slow pulling rates was observed. The effects of the LFZ conditions on the phase composition, microstructural features, electric and magnetic properties of as-grown and thermally post-processed fibres are analysed and discussed. The results indicate that the LFZ processing conditions have a great impact on the electrical and magnetic properties of the prepared manganites. Secondary phases increase with pulling rate and the effects imposed by their formation can be minimized by additional heat treatment at high temperatures, improving the electric conductivity and magnetization of the thermally-treated fibres.
palavras-chave
THERMOELECTRIC PROPERTIES; OXYGEN REDUCTION; PEROVSKITE; PRASEODYMIUM; CALCIUM; CAMNO3; CONDUCTIVITY
categoria
Materials Science; Physics
autores
Ferreira, NM; Carreira, F; Kovalevsky, AV; Costa, FM; Valente, MA
nossos autores
Andrei Kavaleuski
Investigador principal
Nuno Miguel Freitas Ferreira
Bolseiro de pós-DoutoramentoProjectos
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)
agradecimentos
This work was supported by FCT, Portugal within i3N (LA/P/0037/2020 & UIDB/50025/2020 & UIDP/50025/2020), financed by COMPETE 2020 Program and National Funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. FC and AK acknowledge the support of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC).This work is also funded by national funds (OE), through FCT in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of article 23, of the Decree-Law57/2016, of August 29, changed by Law 57/2017, of July 19.