Annealing effects on the structural and dielectric properties of (Nb + In) co-doped rutile TiO2 ceramics

Abstract

Density functional theory calculations were conducted to investigate the electronic structures of rutile Ti₁₆O₃₂, Ti₁₃Nb₂InO₃₂, and Ti₁₃Nb₂InO₃₁ systems. High density (Nb + In) co-doped rutile TiO₂ ceramics were successfully prepared by one modified solid state method. XRD, XPS, Raman scattering and FT-IR measurements were performed to investigate the structural properties of the (Nb + In) co-doped rutile TiO₂ ceramics annealed in different atmospheres. The lattice parameters for the (Nb + In) co-doped rutile TiO₂ ceramics were enlarged slightly after they were annealed in air and oxygen. Raman scattering results indicate that the E_g modes are quite sensitive to oxygen vacancy in comparison with the other Raman active modes. The ceramics annealed in oxygen at 873 K exhibit the best dielectric performance with giant dielectric permittivity (>14 000) and small dielectric loss (<0.2) over the frequency range from 40 Hz to 1 MHz.