Abstract
Na2Ti3O7 powder is synthesized through solid-state reaction route. Powder containing rods of micrometric dimensions is obtained. Samples of the material are investigated by scanning electron microscopy, differential thermal analysis and X-ray diffraction. The studied material exhibits polyphasic behavior with two monoclinic type phases existing; i.e. the major phase of Na2Ti3O7 and the secondary phase Na2Ti6O13. Electrical properties of pellets pressed from powder are measured by impedance spectroscopy in a wide temperature range, ranging from 650°C to −40°C. Basing on the impedance spectra, an electrical equivalent circuit model of sample impedance is proposed. It is found, that electrical properties of Na2Ti3O7 at low temperatures, around the room temperature, show strong dependence on history of the sample and on the atmosphere in which the measurement is conducted. Upon exposure to air at low temperature, changes of ionic conductivity by three-four orders of magnitude are recorded. However, the crystal structure of both phases which exists in the studied material does not reflect these significant changes of electrical properties and remains stable in the whole studied temperature range. It is proposed that the observed effect can be explained by adsorption of moisture on the surface of the grains, which creates additional conduction paths for electric charge.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
