Dielectric properties and relaxation behavior of Sm substituted SrTiO3 ceramics sintered in nitrogen atmosphere

Abstract

SrTiO3, Sm0.02Sr0.97TiO3, and Sr0.99TiO3 ceramics were prepared by a solid-state reaction method. The structural analysis show that all ceramics are cubic perovskite structure, and the A-site substitution of Sr2+ and Sr vacancies have some impact on the lattice parameters of Sm0.02Sr0.97TiO3, and Sr0.99TiO3 ceramics. Compared with the Sr0.99TiO3 ceramics sintered in N2, of which the dielectric constant was 305 (at 1 kHz and room temperature) and dielectric loss less than 0.007, the dielectric properties of Sm0.02Sr0.97TiO3 ceramics sintered in nitrogen (N2) perform a giant permittivity (>104) as well as a very low tanδ (mostly <0.04) over a broad temperature range from 25 to 200 °C. It could be proved that the Sr vacancies have no contribution to the giant permittivity of the Sm0.02Sr0.97TiO3 ceramics sintered in N2. Based on the relaxation behaviors, X-ray photoelectron spectroscopy (XPS) Spectrum and complex-impedance analysis of ceramics sintered in N2, the giant permittivity and low dielectric loss of the ceramics sintered in N2 were due to the donor doping and the oxygen vacancies.