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

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)(x)Ti1-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: epsilon = 82052, tan delta = 0.008 at 1 kHz; 5%NTTO: epsilon = 170131, tan delta = 0.090 at 1 kHz). The broad distinction of the dielectric behavior between the (Nd0.5Ta0.5)(x)Ti1-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 E-gb (the activation energy of the grain boundary), E-a2 (the EPDD polarization activation energies) and the minimum value of E-a1 (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.