abstract
Bi1.6Pb0.4Sr2Co2O8 samples have been textured by the Laser Floating Zone (LFZ) process using Nd:YAG, and CO2 laser radiation. Using different wavelengths resulted in significant structural and microstructural modifications. Powder XRD patterns showed that the thermoelectric phase is the major one in both cases. Microstructural studies revealed that all samples presented the same phases but with much lower content of secondary ones in those processed with the CO2 laser. Electrical resistivity showed different behavior for the two types of samples, being in general, lower for the CO2 grown rods. Seebeck coefficient is lower for the CO2 grown samples up to 300 degrees C, and higher in the high-temperature range, reaching 240 mu V/K at 650 degrees C, which is one of the highest values obtained so far in these compounds. Moreover, thermal conductivity at 600 degrees C for these samples (0.93 W/ K m) is among the lowest reported in the literature. As a consequence, ZT values at 600 degrees C reached 0.42 in CO2 textured materials, about two times higher than the obtained in Nd:YAG ones. This value is among the highest reported so far in the literature, and is comparable to the performance attained for the same composition containing nanoparticles addition. All these properties, combined with the fact that the processed materials can be directly integrated into thermoelectric modules, render them highly attractive for industrial production.
keywords
GROWTH; PERFORMANCE; POWER; MAGNETORESISTANCE; FABRICATION; GENERATORS; COBALTITES; PHASE
subject category
Materials Science
authors
Amirkhizi, P; Madre, MA; Dura, OJ; Torres, MA; Sotelo, A; Kovalevsky, A; Rasekh, S
our authors
Andrei Kavaleuski
Principal Researcher
Parisa Amir Khizi
PhD Student
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) and Universidad de Zaragoza (UZ2022-IAR-09) 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, UIDP/50011/2020 & LA/P/0006/2020, financed by National funds through the FCT/MCTES (PID-DAC) . Authors would like to acknowledge the use of Servicio General de Apoyo a la Investigacion-SAI, Universidad de Zaragoza.