Enhanced dielectric performance of (Ag1/4Nb3/4)0.01Ti0.99O2 ceramic prepared by a wet-chemistry method

Abstract

The (Ag1/4Nb3/4)0.01Ti0.99O2 ceramic, with ultra-high permittivity and relatively low dielectric loss, was synthetized by a sol-seed method. Significant influences of Ti concentration on the phase structure, microstructure, and dielectric performances were observed. By optimizing the Ti concentration, high active powders and effectively controlled grain uniformity were obtained, which is great benefit for depressing the calcining temperature. The sample shows an ultra-high permittivity (εr ~43271 at 1 kHz) and relatively low dielectric loss (tanδ ~ 0.048 at 1 kHz) at room temperature, meanwhile, the temperature coefficient of εr keeps in ±15% within the temperature range from −78 to 130°C, fortunately for X7R capacitor. Based on the XPS results, the defect cluster structure was revealed and giant permittivity is closely associated with the electron pinned defect dipole.