Lanthanum titanate ceramics: Electrical characterizations in large temperature and frequency ranges

Ceramics of the La2O3–TiO2 system have very good dielectric properties, which make La2Ti2O7 a good candidate for microwave applications. Using radio-frequency magnetron sputtering, we have deposited LaTiOxNy oxynitride thin films on (0 0 1) strontium titanate and glass substrates, starting from a homemade oxide target. The microwave dielectric properties of La2Ti2O7 ceramic have been investigated in the 100 Hz to 10 GHz range in order to have a reference for further studies. The evolution of ɛ′ and ɛ″ shows a space charge domain with a critical frequency Fc = 1 GHz. Measurements in the temperature range from 20 to 880 °C have been carried out to study phase transitions and conduction mechanisms.