Paraelectric in a Strong High-Frequency Field

TL;DR

This paper investigates how strong high-frequency fields alter the effective permittivity of ferroelectric films in the paraelectric phase, emphasizing effects far from resonance and using both phenomenological and microscopic models.

Contribution

It provides a comparative analysis of permittivity changes under high-frequency fields using phenomenological and microscopic approaches.

Findings

Effective permittivity is most affected far from resonance.

Permittivity varies with high-frequency field amplitude.

Microscopic and phenomenological models show consistent results.

Abstract

A change in the effective permittivity of a ferroelectric film in the paraelectric phase under the action of a strong high-frequency field (nonequilibrium soft mode heating) is considered. It is shown that this effect must be most clearly pronounced far from the resonance (\omega_0 << \omega_sm), rather than for the external field frequency \omega_0 close to the soft mode frequency \omega_sm. The effective permittivity as a function of the high-frequency field amplitude is calculated using the phenomenological approach and within the microscopic theory based on the simple model of a displacement-type ferroelectric.