Dielectric properties, microstructure and charge compensation of MnO2-doped BaTiO3-based ceramics in a reducing atmosphere

Based on the relationship of dipole formation and charge compensation, we prepared BaTiO3-based (x%MnO2-0.05%Nb2O5–BaTiO3, x%Mn–Nb-BT) ceramics using a solid-phase reaction in air and a reducing atmosphere. The influences of MnO2 doping and sintering atmospheres on crystal structure, charge compensation and dielectric properties were comprehensively studied. The ion substitution mechanism, solid solubility, and crystallinity of x%Mn–Nb-BT ceramics in different atmospheres were resolved by X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) spectroscopy. X-ray photoelectron spectroscopy (XPS) showed that the percentages of oxygen vacancy and Ti3+ in this system were both affected by MnO2 doping and the atmosphere due to the reducibility of Mn4+ and the reducing atmosphere. Thus, the influence of doped MnO2 and the atmosphere on dipole formation and charge compensation was deeply discussed. These results provide further insight into the important role of MnO2 in improving the anti-reduction performance of BT-based ceramics.