Enhanced dielectric properties and improved thermal stability in TiO2-based ceramics by Cu and Nb co-doping

Abstract

TiO2-based ceramics have application potential in multilayer ceramic capacitors because of its large dielectric constant and low dielectric loss. In this work, Cu2+, Nb5+ co-doped TiO2 ceramics (CNTO) with colossal permittivity and low loss were designed and prepared via an oxide mixed method, and the effect of Cu2+, Nb5+ co-doped amount on dielectric properties were systematically investigated. Remarkably, the compositions of (Cu1/3Nb2/3)0.005Ti0.995O2 and (Cu1/3Nb2/3)0.01Ti0.99O2 exhibit large dielectric permittivity (εr) of ∼27,060 and ∼41,200 accompanied with low dielectric loss (tan δ) of ∼0.011 and ∼0.032 at 1 kHz, respectively. Based on dielectric properties, relaxation behavior assessments and X-ray photoelectron spectroscopy analysis, we confirmed that the high dielectric permittivity of CNTO ceramics mainly originates from the electron-pinned defect-dipole (EPDD) effect. Moreover, the temperature stability value of εr keeps stable of ±7.5% at 1 kHz from −200 to 200 °C for (Cu1/3Nb2/3)0.005Ti0.995O2 and from 10 to 200 °C for (Cu1/3Nb2/3)0.01Ti0.99O2 ceramics, which separately meet the X9F and Z9F capacitor requirements, respectively. The findings presented in this work might have important strategic significance for promoting the miniaturization of electronic components.