Диэлектрические и сегнетоэлектрические свойства тонких гетероэпитаксиальных пленок SBN-50

The phase transformations and ferroelectric characteristics of thin heteroepitaxial barium-strontium niobate SBN-50 films grown by RF cathode sputtering in an oxygen atmosphere were studied using dielectric spectroscopy and scanning probe microscopy (in the modes of force microscopy of the piezoresponse and Kelvin modes). It is shown that the films are characterized by a low surface roughness, an average size of ferroelectric domains of ~ 100 nm, and spontaneous polarization directed from the substrate to the film surface. Differences in the magnitude of the surface potential signal and its relaxation for the regions polarized at +10 V and –10 V were established. The nature of the change in the dielectric parameters in the temperature range T = 275–500 K indicates that the material belongs to ferroelectric relaxors. The reasons for the established regularities are discussed.

Turing Patterns in Ferroelectric Domains: Nonlinear Instabilities

This chapter outlines how ferroelectric domain patterns link to various, cross-disciplinary, fundamental instabilities. It starts by highlighting the startling resemblance between Turing patterns and the ‘labyrinthine’ polar nanoregHions associated with ferroelectric relaxors. The chapter goes on to look at patterns arising out of the Landau-Ginzburg approach and links these to experimentally observed domain patterns. The link between Turing patterns and those from Landau-Ginzburg is particularly noteworthy as the terms, and considerations, of the two approaches differ: yet both can describe ferroic domain configurations in lead based ferroelectrics in different boundary conditions. This chapter considers other fundamental situations, such as Zhabotinskii-Belousov patterns and Richtmyer-Meshkov instabilities, before looking at the evolution of these patterns with increasing. It concludes by looking at the dimensionality of PbTiO3. Because many of these processes require diffusion, they should be absent (or qualitatively different) near Quantum Critical points.

Piezoelectric and elastic properties of relaxor-like PZT:Ba ceramics

The solid solutions of PbZr1-xTixO3 (PZT) are the most known and widely applicable piezoelectric ceramic materials. The influence of different dopants on PZT properties has been studied for many years. Some of such compositions have revealed a behavior typical for ferroelectric relaxors. In the case of Pb0.75Ba0.25Zr0.70Ti0.30O3 ceramics (abbreviation PBZT 25/70/30), prepared by mixed-oxide processing technique elastic, it was found that macroscopic piezoelectric activity is present far above the temperature at which structural changes and maximum of permittivity occur in unpoled samples (~ 200 °C). Anomalies of the elastic and piezoelectric properties have been observed very clearly near the temperature of 152 °C. Within the temperature range of 152–220 °C, unstable piezoelectric properties have been detected due to the existence of polar micro/nano-clusters and non-trivial elastic-electric interactions between them, through the non-polar paraelectric matrix. The origin of such interactions could be lattice instabilities, dynamic change in polar cluster sizes, and fluctuations in chemical composition. Based on the results of the research, it can be said that PZT ceramics of such composition is a relaxor-like material and it is not a ferroelectric relaxor.

Dielectric properties of Co(CO3)(H2O)2(C3H4N2)2 and [Co(C3H3N2)2]n

Dielectric relaxation phenomenon with non-Debye dynamics in Co(CO3)(H2O)2(C3H4N2)2 and [Co(C3H3N2)2]n, resembling the behaviour of ferroelectric relaxors is presumably connected with the charge carriers.