Colossal permittivity and multiple effects in (Zn + Ta) codoped TiO₂ceramics

Abstract

Colossal permittivity (CP) materials are potential for the important applications of device miniaturization and energy storage. In this work, (Zn 2+ 1/3 Ta 5+ 2/3) x Ti 1-x O 2 ceramics were fabricated by conventional solid-state method. Large dielectric permittivity (>10 4) and low tanδ (<0.06) have been attained. This dielectric property shows a high stability in wide temperature (30-200°C) and frequency (20-10 6 Hz) range. The crystalline structure, microstructure and dielectric properties of ZTTO ceramics were systematically investigated. XPS reveals the formation of electron-pinned defect-dipoles (EPDD) model. In addition, combined with impedance spectroscopy and frequency dependent dielectric constant under DC bias results reveal that colossal permittivity are mainly caused by EPDD model, internal barrier layer capacitance (IBLC) effect, and electrode effect. This work would provide guidance to further researching the colossal permittivity materials.

Pioneering dielectric materials of Sn-doped Nb0.025Ti0.975O2 ceramics with excellent temperature and humidity stability for advanced ceramic capacitors

“…19 In contrast, when doping TiO 2 with A 2+/3+ such as Cr 3+ , Zn 2+ , and In 3+ , it is generally expected to create oxygen vacancies for charge compensation. 8,15,23 To conrm the presence of only Sn 4+ state (without Sn 2+ state) in the structure of the 5% Sn-NTO sample, the Sn 3d prole was observed in detail with binding energies of 486.48 and 494.92 eV, corresponding exclusively to the existence of Sn 4+ , as shown in Fig. 2(c).…”

“…JCPDS 21-1276). 15,23 In other words, no impurity phases were detected. Complementing the XRD results, the SEM-EDS mapping images demonstrate a uniform distribution of all constituent elements in the 5% Sn-NTO ceramic, which represents the highest doping concentration of Sn 4+ .…”

“…1(b), the 2q of (110) diffraction peaks, the strongest peak, shied toward lower angles when Sn 4+ concentrations increased, which is similar to other works. 14,23,24 The results were attributed to the increasing lattice parameters (a and c) and bond lengths of the crystal. Additionally, it is important to note that the apparent splitting of the (110) peak at higher 2q values can be attributed to the Ka 2 component of the Cu radiation source used in the XRD analysis.…”