Large linear high-frequency strain by interlocked monoclinic polar nanoregions

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Ferroelectric films are vital for microactuators, requiring large and linear strains, especially at high frequencies.
• Current methods struggle to enhance strain response under high-frequency and temperature conditions due to limitations in frequency- and temperature-dependent dynamics.

Purpose of the Study:

• To develop ferroelectric films with enhanced, stable, and linear strain response at high frequencies.
• To explore a novel approach using promoted local strain fluctuation to achieve specific polar configurations.

Main Methods:

• Fabrication of spin-coated epitaxial (K,Na)NbO3-based ferroelectric films.
• Induction of an interlocked polar configuration through promoted local strain fluctuation.
• Characterization of strain response at high frequencies (up to 10^5 Hz).

Main Results:

• Achieved high-frequency strains exceeding 1.1% with remarkable linearity and stability at 10^5 Hz.
• Demonstrated that interlocked monoclinic and tetragonal polar nanoregions enhance piezoelectric response across a broad frequency range.
• Identified mutual compensation between two distinct polarization switching mechanisms contributing to overall linearity.

Conclusions:

• The developed interlocked polar configuration in ferroelectric films significantly boosts high-frequency strain performance.
• This facile strategy offers a promising route for creating reliable ferroelectric films with large, linear strain for advanced microactuator applications.
• The findings pave the way for next-generation precision devices operating at high frequencies.