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Artigo Científico | Materiais Semicondutores e Ferroelétricos | Inglês | 02/03/2003
Autores: Marcos A. de Lima Nobre, S. Lanfredi
Palavras-chave: impedance spectroscopy, semiconductor, spinel, varistor
Resumo: Impedance spectroscopy technique was used to investigate the electric properties of Zn7Sb2O12, an electroceramic with inverse spinel type structure. The electric characterization of the Zn7Sb2O12 semiconducting ceramic was performed at temperature from 250 to 550 °C, in the frequency range from 5 Hz to 13 MHz. Zinc antimoniate phase was synthesized by the polymeric precursors method. The bulk resistance curve as a function of temperature exhibits a thermistor behavior with negative temperature coefficient. The bulk conductivity follows the Arrhenius law with two linear branches of different slopes positioned at around a region of transition, 450 °C > T > 350 °C. The activation energy values at low temperature (< 350 °C) and high temperature (> 450 °C) are equals to 0.78 and 0.61 eV, respectively. The existence of a phase transition limiting these regions is discussed.
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