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 depositi on) method, the measurements on frequency spectra of capacities and dielect ric loss for corresponding bulk and film specimens have been conducted by u sing ac LRC method, and the conductivity and the polarization relaxation ti me have also been calculated from the frequency spectra of real and imagina ry parts of the dielectric constants. It has been found that there exist ab normal dielectric behaviors in the bulk and film specimens. In low-frequenc y range, the dielectric constants of nanostructured specimens increase dram atically with decreasing frequency and are 10 similar to 10(2) times higher than that of the corresponding coarse-grained counterpart. The aforementio ned anomalous dielectric behaviors imply the existence of new polarization mechanism caused by the defects and the dangling bonds within the numerous interfaces. (C) 2000 Elsevier Science S.A. All rights reserved.