Giant Dielectric Response and Relaxation Behavior of Bi3+/W6+ Co-Doped Tio2 Ceramics

Abstract

Due to the rapid development of electronic information industry, dielectric ceramics are widely used in passive components such as multilayer ceramic capacitors. In this paper, (Bi2/3W1/3)xTi1-xO2 (BWTOx) ceramics with superior dielectric properties have been prepared by a traditional solid-state method. Remarkably, at a (Bi2/3W1/3)4+ doping level of 0.01, a (Bi2/3W1/3)0.01Ti0.99O2 ceramic achieved a high dielectric constant of ~1.5×104 and a low loss of ~0.07 at 1kHz, as well as a good temperature stability, which could meet the application temperature requirements of X9R capacitors. The abnormal dielectric relaxation in the low temperature region is explained by the interface effect. Data based on the complex impedance spectroscopy and XPS results indicates that the high dielectric constant of BWTOx ceramics is mainly attributed to the internal barrier layer capacitance (IBLC) effect. The finding in this work could provide valuable insights into how to realize a high permittivity and a good temperature stability in TiO2 based ceramics.

Keywords: Giant permittivity, Co-doped TiO2 ceramics, IBLC, Dielectric relaxation