DIELECTRIC PROPERTIES OF COMPLEX PEROVSKITE PZBT-PMNT CERAMIC UNDER COMPRESSIVE STRESS

Abstract

Effects of compressive stress on the dielectric properties of complex perovskite PZBT-PMNT ceramic were investigated. The dielectric properties measured under stress-free condition showed a composite nature with two distinct temperatures of dielectric maximum associated with PZBT and PMNT end members. The dielectric properties under the compressive stress were observed at stress levels up to 230 MPa using a home-built compressometer. The results clearly showed that the compression load significantly reduced both the dielectric constant and the dielectric loss tangent in every measuring frequency. The change of the dielectric constant with stress was attributed to competing influences of the intrinsic contribution of non-polar matrix and the extrinsic contributions of re-polarization and growth of micro-polar regions, while the clamping of the domain walls contributed to the stress-dependent changes of the dielectric loss tangent. Finally, a large drop of the dielectric constant after a stress cycle was likely caused by the stress induced decrease in switchable part of spontaneous polarization.