Dielectric properties of Tm3+- modified K0.5Na0.5Nb0.7Ta0.3O3 ceramics

The effects of rare-earth oxide on dielectric properties of K0.5Na0.5NbO3 (KNN)-based ceramics have been rarely investigated in detail. In this work, Tm2O3 was introduced into the KNN structure for the first time to synthesize (1–x)K0.5Na0.5Nb0.7Ta0.3O3·xTm2O3 (x=0.1–1.0%) powders via a solvothermal method. The corresponding ceramics were prepared through atmospheric sintering, and their crystal phases, microstructures, and dielectric properties were systematically examined. The introduction of Tm3+ promoted the refinement of KNN grain, room-temperature dielectric permittivity increased obviously from 998 to 1990 at 100 kHz, relaxation dispersion γ increased from 1.345 to 1.569. The results of this study suggest that the dielectric properties of K0.5Na0.5Nb0.7Ta0.3O3 system can be effectively tuned via Tm3+ modification.