Giant dielectric response and relaxation behavior of Bi3+/W6+ co-doped TiO2 ceramics

Abstract

With the rapid development of electronic information technology, dielectric ceramics are widely used in the field of passive devices such as multi-layer ceramic capacitors. In this paper, (Bi_2/3W_1/3)_xTi_1−xO₂ (BWTO_x) ceramics with superior dielectric properties have been prepared by using a traditional solid-state method. Remarkably, at a (Bi_2/3W_1/3)⁴⁺ doping level of 0.01, a (Bi_2/3W_1/3)_0.01Ti_0.99O₂ ceramic achieved a giant dielectric permittivity of ∼1.5 × 10⁴ and a low loss tangent of ∼0.07 at 1 kHz, as well as a good temperature independence, which could satisfy the operating temperature standards for X9R capacitors. The abnormal dielectric relaxation in the low temperature region can be explained by the interface polarization. Data based on the complex impedance spectroscopy and X-ray photoemission spectroscopy results indicate that the colossal permittivity of BWTO_x ceramics is mainly ascribed to the internal barrier layer capacitance effect. The findings of this work could provide valuable insights for achieving large dielectric constants and good temperature stability simultaneously in BWTO_x and other related electronic ceramic materials.