Resumo

VILLA, Jorge I  e  RODRIGUEZ, Julio E. ELECTRICAL RESISTIVITY AND SEEBECK COEFFICIENT IN Ca(La)MnO COMPOUNDS PREPARED BY SOLID STATE REACTION METHOD. Momento [online]. 2017, n.54, pp.1-13. ISSN 0121-4470.

Abstract By using the solid state reaction method samples of Ca_1-xLa_x MnO₃ (0 < x < 0.15) were prepared. Their transport properties were studied by electrical resistivity ρ(T) and Seebeck coefficient S(T) measurements as a function of temperature and lanthanum content, in the temperature range between 100 and 290K. The structural and morphological properties were studied by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM), respectively. The Seebeck coefficient is negative throughout the studied temperature range indicating a conduction given by negative charge carriers, its magnitude decreases with the lanthanum content from | - 261| µ V/K to | - 120| µ V/K. The electrical resistivity shows a semiconducting behavior, it was interpreted in terms of small polaron hopping model. Thermoelectric properties of the obtained compounds were studied by the thermoelectric power factor PF, which reaches maximum values around 2 µW/K²cm, these values become this kind of ceramics promising thermoelectric compound, to be used in technological applications.

Palavras-chave : Termoelectric materials; Ca(La)MnO compounds; transport properties.

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