Colossal permittivity and ultralow dielectric loss in (Nd0.5Ta0.5)xTi1-xO2 ceramics

Abstract Giant permittivity ceramic is one of the most significant classes of material to realize the miniaturization and integration of a high-performance capacitor. In this paper, to realize good giant dielectric properties, the (Nd0.5Ta0.5)xTi1-xO2 ceramics (NTTO x = 0.005, 0.01, 0.03, 0.05) were synthesized by a standard conventional solid-state reaction. Comparing with the previous co-doped TiO2 ceramics giant permittivity material system, NTTO ceramics perform extremely colossal permittivity and ultralow dielectric loss (1%NTTO: e = 82052, tanδ = 0.008 at 1 kHz; 5%NTTO: e = 170131, tanδ = 0.090 at 1 kHz). The broad distinction of the dielectric behavior between the (Nd0.5Ta0.5)xTi1-xO2 ceramics can be explained by the impedance analysis and the calculated polarization activation energies. The main electron-pinned defect-dipole (denoted as EPDD) polarization corresponds to the ultralow loss, embodying in the maximum value of Egb (the activation energy of the grain boundary), Ea2 (the EPDD polarization activation energies) and the minimum value of Ea1 (the total polarization activation energies). Though the interfacial polarization can cause the permittivity increase, it can also give rise to poor frequency stability and higher loss.