Journal of Nanomedicine & Nanotechnology

Role of antiferroelectric nanoregions in enhancement of piezoelectric properties of morphotropic coarsegrained ceramics

19^th International Conference on Nanotechnology and Expo

November 13-14, 2017 | Atlanta, USA

V L Sobolev

South Dakota School of Mines and Technology, USA

Keynote: J Nanomed Nanotechnol

Abstract:

The talk presents a review of results of investigations of inhomogeneous states caused by the coexistence of dipole-ordered phases in solid solutions of complex oxides with perovskite crystal structure. Lead zirconate titanate (PZT) based solid solutions are considered as an example. Distinguishing feature of solid solutions of complex oxides with perovskite crystal structure is a small difference in the free energies of the ferroelectric and antiferroelectric states. Physical effects caused by the coexistence of phases have been studied in detail. The local decomposition of the solid solutions the vicinity of the interphase boundaries separating the domains of coexisting phases is responsible for the formation of the mesoscopic system segregates near these interphase boundaries. Special attention has been paid to investigations of the kinetics of formation of the mesoscopic segregate structures and the mechanisms controlling this kinetics. Manifestation of the presence of the mesoscopic segregate structure in the inhomogeneous state of coexisting phases in piezoelectric and other properties of the abovementioned compounds has been studied. Influences of thermoelectric treatment and external electric field on the system of segregates have been studied. Importance of considering this decomposition phenomenon in PZT-based solid solutions with compositions belonging to the morphotropic boundary region of the temperature-composition. The proper thermoelectric treatment of samples containing these segregates can give substantially higher values of piezoelectric parameters in the PZTbased compounds that have been observed so far.

Biography :

V L Sobolev has completed his PhD in Physical and Mathematical Sciences in 1974 from Donetsk Physics and Technology Institute of the Academy of Sciences of Ukrainian SSR; obtained his Habilitation Degree of Doctor of Physical and Mathematical Sciences in 1984 from The Supreme Attestation Committee of the USSR. He is a Professor at the Physics Department of the South Dakota School of Mines and Technology. Main research interests are in wide range of properties of ferroelectric, magnetic, magnetoelectric and high-temperature superconducting materials. Results of his research have been published in more than 300 articles and several invention patents on methods of measurements of thin magnetic films parameters.