Study of dielectric properties of nanocrystalline material BaTiO3-SiO2

Within the temperature range of -50-200 & DEG;C the dielectric properties of nanocrystalline samples of BaTiO3 and BaTiO3-SiO2 (1 wt % SiO2) were studied at frequencies of 25 Hz-1 MHz. The addition of 1 wt % SiO2 to the BaTiO3 leads to a noticeable decrease in the dielectric permittivity of the material and a slight decrease in the temperatures of the ferroelectric phase transition and the transition from the orthorhombic toward tetragonal phase. It is shown that the BaTiO3-SiO2 sample exhibits some features of a relaxor ferroelectric. It is revealed that a significant contribution to the ac conductivity in the ferroelectric phase of BaTiO3 - SiO2 comes from the domain and interphase boundaries dynamics. Above TC, the hopping mechanism of conduction dominates.