Low-temperature dielectric response of NaTaO3 ceramics and films

Abstract

In this work, NaTiO3 ceramics are prepared by conventional mixed oxide method and NaTiO3 films are deposited by rf magnetron sputtering on Si/SiO2/TiO2/Pt substrates. The dielectric response of the obtained NaTiO3 ceramics and films is analyzed as a function of frequency and temperature. Between 1kHz and 1MHz, the dielectric permittivity of NaTiO3 ceramics is frequency independent and increases on cooling up to ~324, which is to the best of our knowledge, the highest value ever reported for NaTaO3 ceramics. In contrast, NaTiO3 films exhibit a dielectric relaxation between ~20 and 30K, following the Arrhenius law with activation energy ~51meV and pre-exponential term ~10-15s. Dissimilarities in the dielectric response of NaTiO3 ceramics and films are explained by the influence of oxygen vacancies.