Experimental investigation on the dielectric behavior of nanostructured rutile-phase titania

In this work, the nanostructured rutile-phase titania with mean grain size of 8.5 nm was synthesized by PEPVD (plasma-enhanced physical vapor deposition) method, the measurements on frequency spectra of capacities and dielectric loss for corresponding bulk and film specimens have been conducted by using ac LRC method, and the conductivity and the polarization relaxation time have also been calculated from the frequency spectra of real and imaginary parts of the dielectric constants. It has been found that there exist abnormal dielectric behaviors in the bulk and film specimens. In low-frequency range, the dielectric constants of nanostructured specimens increase dramatically with decreasing frequency and are 10∼102 times higher than that of the corresponding coarse-grained counterpart. The aforementioned anomalous dielectric behaviors imply the existence of new polarization mechanism caused by the defects and the dangling bonds within the numerous interfaces.