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 Eg 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 (>14000) and small dielectric loss (<0.2) over the frequency range from 40 Hz to 1 MHz.