Publication

Phenomenological model of dynamic nonlinear response of relaxer ferroelectrics

Alexander Tagantsev
2000
Journal Articles

Abstract

A phenomenological model was proposed which describes frequency dispersion of nonlinear dielectric response of relaxer ferroelectrics (relaxors) as a result of dispersion of their linens dielectric permittivity. The model was applied to Pb(Mg1/3Nb2/3)O-3 (PMN) relaxer. It provided a good qualitative description of temperature and frequency dependence of the third harmonics of PMN. Analysis within the model yielded a frequency independent nonlinear coefficient corresponding: to static nonlinear dielectric susceptibility. The model explained the recently reported for PMN data on the Vogel-Fulcher law for frequency dependence of the temperature at which the third harmonics passes a maximum.

Official source

https://infoscience.epfl.ch/entities/publication/ef04fb03-6976-4079-b565-92acc8f31f0e

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Alexander Tagantsev
2000
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/ef04fb03-6976-4079-b565-92acc8f31f0e

About this result

Related concepts (32)

Dielectric

In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation.

Nonlinear optics

Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in nonlinear media, that is, media in which the polarization density P responds non-linearly to the electric field E of the light. The non-linearity is typically observed only at very high light intensities (when the electric field of the light is >108 V/m and thus comparable to the atomic electric field of ~1011 V/m) such as those provided by lasers. Above the Schwinger limit, the vacuum itself is expected to become nonlinear.

Relative permittivity

The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insulator measures the ability of the insulator to store electric energy in an electrical field. Permittivity is a material's property that affects the Coulomb force between two point charges in the material. Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum.