Increase of electric performances in Bi2Sr2-xRbxCo2O8+δ laser grown ceramics induced by annealing
| Autor: | C. Özçelik, Andres Sotelo, Bekir Özçelik, M. A. Torres, Gizem Çetin, Mehmet Gürsul, M. A. Madre |
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| Přispěvatelé: | Çukurova Üniversity, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Gobierno de Aragón, Universidad de Zaragoza, European Commission |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Incongruent melting Annealing (metallurgy) Doping Analytical chemistry 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Electrical resistivity and conductivity Seebeck coefficient visual_art Thermoelectric effect visual_art.visual_art_medium General Materials Science Charge carrier Ceramic 0210 nano-technology |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | Bi2Sr2-xRbxCo2O8+δ materials with 0 ≤ x ≤ 0.125 were fabricated via the classical solid-state route, and textured using the laser floating zone method. As-grown materials were composed of different secondary phases due to the incongruent melting of this compound. These secondary phases were drastically reduced through an annealing procedure, consisting in heating at 800 °C for 12 h. XRD has not detected any secondary phase on the annealed samples, due to the overlapping of thermoelectric and main secondary phase diffraction peaks. SEM observations have confirmed this microstructural evolution, and shown that Rb-substitution further decreases the secondary phases content and enhances grain orientation. These microstructural features, together with the possible increment of charge carrier concentration due to Rb-doping, decreased electrical resistivity, while Seebeck coefficient has only been slightly reduced. Consequently, the Rb doped samples reached higher power factor (PF) values than the pure ones. The biggest PF values at room temperature (0.11 mW/K2m) are higher than the reported for single crystals (0.07 mW/K2m), while at 650 °C (0.20 mW/K2m), they are also higher than the obtained in textured samples and measured along the conducting plane (0.14 mW/K2m). This study was carried out within the scope of Cukurova University Scientific Research Projects Unit FBA-2019-12034. The authors wish to thank the Spanish MINECO-FEDER (Project MAT2017-82183-C3-1-R), and the Gobierno de Aragón-FEDER (Research Group T 54-17R) for financial support. Authors acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. |
| Databáze: | OpenAIRE |
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