Low temperature sintering and microwave dielectric properties of 0.5LaAlO3–0.5SrTiO3 ceramics using copper oxide additions

The microwave dielectric properties and the microstructures of 0.5LaAlO3–0.5SrTiO3 ceramics with CuO addition prepared with conventional solid-state route have been investigated. Doping with CuO (up to 1 wt.%) can effectively promote the densification and remain comparable dielectric properties of 0.5LaAlO3–0.5SrTiO3 ceramics. It is found that 0.5LaAlO3–0.5SrTiO3 ceramics can be sintered at 1400 °C due to the sintering aid effect resulted from CuO as addition observed by scanning electron microscopy. The dielectric constant as well as the Q×f value decreases with increasing CuO content. At 1460 °C, 0.5LaAlO3–0.5SrTiO3 ceramics with 0.25 wt.% CuO addition possess a dielectric constant (εr) of 35.2, a Q×f value of 24 000 (at 8 GHz) and a temperature coefficient of resonant frequency (τf) of −13.5 ppm/°C.