Resumo

SALDARRIAGA-AGUDELO, Wilmer de Jesus; BUENDIA, Melisa  e  ZAPATA-SANCHEZ, Victor Hugo. Electrical characterization of Co ₃ O ₄ + PVAL system using the complex impedance spectroscopy (IS) technique at high temperatures. Rev. Cient. [online]. 2018, n.32, pp.129-134. ISSN 0124-2253.  https://doi.org/10.14483/23448350.12420.

Results in impedance spectroscopy show high values in electrical conductivity (10-3-10-4 S/cm) in Co3O4 + PVAL samples, with sweeps temperature between 80 and 200 °C, this indicate a strong structural bond between the ions of Co3+Co2+ and its surroundings with the system, finding activation energy ∼ 1.13 eV for the cobalt ion, adjusting by means of the Arrhenius model. The frequency sweeps show a dynamic behavior reflected in the graphs of the imaginary part of the electrical module and the impedance between 42 Hz and 5 MHz, allowing the adjustment and data analysis of a RC circuit with order of capacitance values of 1 nF. The results of the conductance frequently show a behavior that obeys the universal law of relaxation of Jonscher (σ = σdc + α ωn) with values obtained for the exponent n (0,7< n < 1), also the graphs of the Peak relaxation frequency ωp vs. Temperature shows a process thermally activated with the same energy of ion activation.

Palavras-chave : composites; complex impedance; cobalt oxide; polyvinyl alcohol; polymers.

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