Temperature-dependence of electrical properties for the ceramic composites based on potassium polytitanates of different chemical composition
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The samples of ceramic materials based on potassium polytitanate (PPT) characterized with various TiO2/K2O molar ratio, are produced by calcination at 900 °C and investigated. AC conductivity (σac) of the obtained ceramics is measured at different temperatures between 200 and 800 °C in frequency range of 0.1 Hz–1 MHz. The method of combined impedance and modulus spectroscopy is used to analyze the obtained results. The activation energies of DC conductivity, bulk and grain-boundary conductivity as well as relaxation frequency for studied composites are estimated. Using the correlated barrier hopping (CBH) model, the energies of potential barrier between neighboring defect sites for all kinds of investigated materials are presented. The bulk and grain boundary parameters of the produced ceramic materials based on potassium polytitanates are calculated. The mechanism of different vacancies formation in the investigated ceramic system is discussed. The influence of precursor chemical composition on electrical properties for the ceramic composites based on potassium polytitanates is studied.
KeywordsMultiphase ceramics Impedance spectroscopy Electric conductivity Relaxation processes Oxygen vacancies Grain boundary
This research was financially supported by Ministry of Education and Science of the Russian Federation (project 4.6197.2017/8.9).
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