Mechanisms of enhanced performance in Zr/Ta codoped rutile-TiO ceramics via broadband dielectric spectroscopy.

Aliovalent dopant codoped rutile-TiO materials have garnered attention due to their excellent performance properties, characterized by low loss tangent (tanδ), high dielectric permittivity (ε'), and stable ε' over a broad temperature range. This performance is primarily due to the electron-pinned defect-dipoles (EPDDs) of the complex defects [Formula: see text]Ti-[Formula: see text]TiB. Notably, the excellent dielectric properties in ZrTaTiO (Zr-TTO) ceramics can be achieved using the traditional mixed oxide method without the EPDDs, due to the absence of A (acceptor doping ions). Instead, the existence of localized free electrons and oxygen vacancies ([Formula: see text]) in Zr-TTO structures, due to doping ions and the sintering process, was confirmed by X-ray photoelectron and Raman spectroscopies. These ceramics exhibited ε'~ 2 × 10 and tanδ < 0.03 at 1 kHz and 25 °C in the 2.5-10%Zr-TTO samples. Moreover, all ceramics demonstrated a maximum ε' change (∆ε') of less than ±15% over the temperature range suitable for X7R and X8R type ceramic capacitors. Significantly, the change in ε' related to relative humility was calculated to be less than ±0.5% over the range of 50-95% RH, indicating the environmental stability of the dielectric properties, which is essential for capacitor applications. Investigations suggested that at least four mechanisms contributed to this system: the intrinsic effect of ionic polarization, Ti · e -[Formula: see text]- Ti · e and Ti · e - [Formula: see text] defects, interfacial polarization at insulating grain boundaries, and non-Ohmic contact between the surface sample and the metal electrode.