Understanding the ultrahigh dielectric permittivity response in titanium dioxide ceramics

Abstract

Dielectric materials with ultrahigh permittivity have attracted intensive interest due to the increasing demand of microelectronics and energy storage applications. In this work, for the first time we successfully synthesized zinc/magnesium and tungsten co-doped TiO2 dielectric ceramics with giant permittivity (εr ≈ 104) via ordinary mixed-oxide technique. The obtained ceramics are of pure homogenous rutile phase structure as verified by XRD and Raman spectroscopy; scanning electron microscopy studies indicate the very dense microstructure of them. Our detailed studies on dielectric performances imply that the partial substitution of Ti4+ by W6+ inhibits the generation of defect dipole and enhances the interface Maxwell-Wagner polarization, making the latter a dominant factor for the obtained giant permittivity. Our findings in this work might help to understand the physical origin of ultrahigh dielectric permittivity in (M0.5W0.5)xTi1-xO2-type (M = Mg or Zn) and other TiO2-based dielectric materials.