Low temperature sintering and microwave dielectric properties of 0.5LaAlO 3–0.5SrTiO 3 ceramics using copper oxide additions

Abstract

The microwave dielectric properties and the microstructures of 0.5LaAlO 3–0.5SrTiO 3 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 0.5LaAlO 3–0.5SrTiO 3 ceramics. It is found that 0.5LaAlO 3–0.5SrTiO 3 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, 0.5LaAlO 3–0.5SrTiO 3 ceramics with 0.25 wt.% CuO addition possess a dielectric constant ( ε r) of 35.2, a Q× f value of 24 000 (at 8 GHz) and a temperature coefficient of resonant frequency ( τ f ) of −13.5 ppm/°C.