Domain wall roughness and creep in nanoscale crystalline ferroelectric polymers

TL;DR

This study investigates the static and dynamic properties of domain walls in nanoscale crystalline ferroelectric polymers, revealing a consistent effective dimensionality and insights into ferroelectric behavior relevant for nanoscale applications.

Contribution

It provides new measurements of domain wall roughness and creep in thin ferroelectric polymer films, highlighting an unexpected effective dimensionality of ~1.5.

Findings

Domain wall roughness exponent ranges from 0.39 to 0.48.

Domain wall creep exponent varies from 0.20 to 0.28.

Effective dimensionality of ~1.5 is independent of film thickness.

Abstract

We report piezo-response force microscopy studies of the static and dynamic properties of domain walls (DWs) in 11 to 36 nm thick films of crystalline ferroelectric poly(vinylidene-fluoride-trifluorethylene). The DW roughness exponent {\zeta} ranges from 0.39 to 0.48 and the DW creep exponent {\mu} varies from 0.20 to 0.28, revealing an unexpected effective dimensionality of ~1.5 that is independent of film thickness. Our results suggest predominantly 2D ferroelectricity in the layered polymer and we attribute the fractal dimensionality to DW deroughening due to the correlations between the in-plane and out-of-plane polarization, an effect that can be exploited to achieve high lateral domain density for developing nanoscale ferroelectrics-based applications.