Effects of Y2O3 doping on the dielectric properties and microstructures of SrTiO3–LaAlO3 microwave dielectric ceramics

Herein, SrTiO3–LaAlO3 (ST-LA) microwave dielectric ceramics were prepared by a conventional solid-state reaction. The addition of Y2O3 had no significant influences on the phases of ST-LA ceramics, and all the ST-LA samples exhibited single perovskite phase with no secondary phase. The dense and uniform microstructures were obtained after Y2O3-doping. Energy-dispersive X-ray spectroscopy showed that Y3+ was homogeneously distributed in the grains. Raman spectra revealed the vibration modes of the crystal structures and the distortion degrees of BO6. The change in the doping amount of Y2O3 substantially affected the dielectric properties of ST-LA ceramics at microwave frequencies. Moreover, excellent microwave dielectric properties with εr=44.01, Q×f=59065GHz(at5.966GHz) and τf=6.09 ppm/°C were achieved for 0.3 wt%Y2O3-doped 0.55SrTiO3-0.45LaAlO3 ceramics, showing the potential application in fifth-generation communication.