High-temperature dielectric properties of (Al, Nb) co-doped SrTiO3 ceramics

SrTi1-x(Al, Nb)xO3 (x=0, 0.005, 0.05, and 0.1) ceramic samples were prepared using the conventional solid-state reaction method. The dielectric properties of these samples were investigated in temperature range of 50-600 °C and frequency range of 102-106 Hz. The samples show two dielectric relaxations related to grain and grain boundary. The effects of (Al, Nb) co-doping were found to have influence on the grain-boundary relaxation by reducing its activation energy and enhancing the conductivity. Our results show that it is unsuitable to enhance the dielectric properties of SrTiO3 via (Al, Nb) co-doping.