Effect of Fe2O3 Doping on Phase Formation, Microstructure, Dielectric and Magnetic Properties of BNT-BKT-KNN Ceramics Prepared by the Solid-State Combustion Technique

Lead-free 0.81(Bi0.5Na0.5TiO3)-0.18(Bi0.5K0.5TiO3)-0.01(K0.5Na0.5NbO3) (BNT-BKT-KNN) ceramics doped with Fe2O3 (0–0.8 wt%), were prepared via the solid-state combustion method using glycine as fuel. The effect of Fe2O3 doping on the phase formation, microstructure, dielectric and magnetic properties of the ceramics was investigated. The XRD and Raman spectra of all ceramics indicated a pure perovskite structure with coexisting rhombohedral and tetragonal phases. The microstructure showed a polygon grain shape for all compositions. The average grain size and density of the ceramics tended to increase from 0.38 to 0.77 μm and 5.56 to 5.80 g/cm3 with increasing x content. The ceramics with 0.4 wt% Fe2O3 doping showed the highest maximum dielectric constant (εm=5424) which corresponded to the microstructure and density results. Without Fe2O3 doping, the BNT-BKT-KNN ceramic showed diamagnetic behavior, whereas all of the Fe2O3 doped ceramics exhibited paramagnetic behavior, measured at a temperature of 25°C.