Structural characterization, electrical and dielectric relaxations in Dy-doped zirconia

Abstract

Optically active 2 mol% dysprosium doped zirconia, Zr0.98Dy 0.02O2, was synthesised by conventional solid state route. Rietveld analysis of XRD data of this composition revealed that monoclinic phase dominates at room temperature. SEM micrograph depicted the presence of spherical grains with average grain size of 200 nm. The FTIR spectrum of this system indicated a homogeneous distribution of Dy particles among the zirconia structure. The Raman and UV spectra of the system showed various peaks corresponding to different phases present in the system. The electrical conductivity and dielectric properties of this system were measured in temperature range 573-1073 K and in the frequency range 20 Hz-1 MHz. The real part of conductivity spectra was found to follow Jonscher power law. The temperature dependent total conductivity was found to show three different regions, with different activation energy in the entire temperature range. The scaling behaviour of the conductivity spectra also confirms the observed temperature dependence. The temperature and frequency dependence of real part of permittivity and tangent loss indicated the presence of orientational and space charge polarization processes in the system. © 2012 Elsevier B.V. All rights reserved.