Effect of La doping on microwave dielectric properties of translucent polycrystalline alumina ceramic

In this paper, the microstructure and microwave dielectric properties of translucent polycrystalline alumina (PCA) with different amounts of La2O3 (co-doped with 500 ppm MgO) were investigated. Compared with those doped only with 500 ppm MgO, the translucent PCA co-doped with 500 ppm La2O3 exhibited a higher Q×f value, which might be caused by the significantly larger ionic radius of La3+. As the La2O3 content was further increased, the presence of an increasing amount of impurities (LaAl11O18) would deteriorate the Q×f value significantly.