Colossal Permittivity and Multiple Effects in (Zn + Ta) co-doped TiO2 Ceramics

Abstract

<jats:title>Abstract</jats:title> <jats:p>The search for giant dielectric constant materials is imperative because of their potential for important applications for the areas of device miniaturization and energy storage. In this work, we report a (Zn + Ta) co-doped TiO<jats:sub>2</jats:sub> (ZTTO) ceramics that manifests high dielectric permittivity (&gt;10<jats:sup>4</jats:sup>) and low dielectric loss. This dielectric property shows a high stability in wide temperature range (25-200℃) and frequency range(20-10<jats:sup>6</jats:sup>Hz). The crystalline structure, microstructure and dielectric properties of ZTTO ceramics were systematically investigated. XPS, Impedance spectroscopy and frequency dependent dielectric constant under DC bias results reveal that the colossal dielectric properties of (Zn<jats:sup>2+</jats:sup><jats:sub>1/3</jats:sub>Ta<jats:sup>5+</jats:sup><jats:sub>2/3</jats:sub>)<jats:sub>x</jats:sub>Ti<jats:sub>1-x</jats:sub>O<jats:sub>2</jats:sub> ceramics were mainly caused by electron-pinned defect-dipoles (EPDD) model, internal barrier layer capacitance (IBLC) effect and electrode effect. This work would provide a guidance to further researching the colossal permittivity CP materials.</jats:p>

High dielectric performance and multifarious polarizations in (Lu + Ta) co-doped TiO2ceramics

“…As the amount of doping increases, Ta ions release more free electrons, resulting in a decrease in breakdown field strength and nonlinear coefficient. This phenomenon is similar to the Nb+Gd, Sb+Ga and Ta+Zn systems [26,30,38]. Figure 4(c) shows the impedance spectrum for LTTO ceramics (x = 0.01) at high temperature.…”

“…As x increases to 0.04, the grain size of co-doped ceramics gradually increases to 4.32um. This is also found in Sb +Ga, Ta+Zn and Tl+Nb ceramics [15,26,38]. Usually, grain growth is associated with the liquid-phase sintering mechanism, which refers to the diffusive mass transfer of ions or atoms at the grain boundaries.…”

“…The O 1s profile in Figure 6 [38]. The formation of Ti 3+ can be explained by the following equations [38]:…”