Influence of Bi2O3 and MnO2 doping on microwave properties of [(Pb,Ca) La](Fe,Nb)O3 dielectric ceramics

The effect of Bi2O3 and MnO2 addition in [(Pb0.5Ca0.5)0.92La0.08](Fe0.5Nb0.5)O3 system on the sintering and dielectric properties have been investigated using X-ray diffractions and post-resonator measurement. Perovskite and pyrochlore phase exist in samples with MnO2 content ≤2 wt.% while specimens with Bi2O3 doping possessed the third unknown phase. The dielectric properties could be obviously adjusted as well as reducing the sintering temperature in both Bi2O3 and MnO2 addition system. It was found that Bi2O3 and MnO2 co-doping could reduce the sintering temperature more effectively by 100-140 °C while improve the microwave dielectric properties. Microwave dielectric properties of ɛr = 91.1, Qf = 4870 GHz and τf = 18.5 ppm/°C could be obtained in [(Pb0.5Ca0.5)0.92La0.08](Fe0.5Nb0.5)O3 system when k = 1, w = 1 wt.% and sintered at 1050 °C for 4 h.