Nanoscale polarization switching mechanisms in multiferroic BiFeO$_3$ thin films

TL;DR

This study investigates nanoscale polarization switching mechanisms in BiFeO$_3$ thin films with different domain structures, revealing how local electric fields influence polarization reversal and domain configurations.

Contribution

It provides detailed insights into how intrinsic domain structures affect polarization switching in multiferroic BiFeO$_3$ thin films using piezoresponse force microscopy.

Findings

Complete polarization control in bubble-like samples.

In-plane reversal can occur without out-of-plane change in stripe-like samples.

Switching behavior correlates with local electric field components.

Abstract

Ferroelectric switching in BiFeO$_3$ multiferroic thin films with intrinsic ``stripe-like'' and ``bubble-like'' polydomain configurations was studied by piezoresponse force microscopy. Using the local electric field applied by a scanning probe microscope tip, we observe reversal of both out-of-plane and in-plane components of the polarization, with the final domain state depending on the tip sweeping direction. In ``bubble-like'' samples, complete control of the polarization is achieved, with in-plane polarization change mediated and stabilized by out-of-plane polarization reversal. In ``stripe-like'' samples the intrinsic domain structure influences polarization switching and in-plane reversal may occur without out-of-plane change. The observed switching behaviour can be well correlated with the radial and vertical components of the highly inhomogeneous electric field applied by the tip.