Tungsten-bronze-type BaNd2Ti4O12 ceramics with high permittivity and ultra-low dielectric loss under low frequency

Abstract

High dielectric constant and ultra-low dielectric loss are important for electronic device applications of dielectrics. In this work, the novel ceramic BaNd2Ti4O12, synthesized via solid-state reaction, exhibits remarkable dielectric stability, with excellent dielectric properties (ε′ = 117 and tanδ = 6.27 × 10−4, at 1 kHz) and high dielectric strength (Eb = 260 kV/cm). By exploring its polarization behavior and loss mechanisms at low frequencies for the first time, we found that the sustained high dielectric constant is attributed to the synergy of defect dipole polarization and interface polarization, while the observed exponential increase of dielectric loss is primarily caused by the conduction loss, with a minor contribution from the anelastic relaxation loss. In the low-temperature range of 50∼350 °C, the relaxation behavior is governed by the aggregation and subsequent thermal ionization of the oxygen vacancies, whereas at temperatures above 350 °C, it is predominated by the long-range motion of the doubly ionized oxygen vacancies. These findings provide valuable insights for the potential electronic device applications of BaNd2Ti4O12.