Ferroelectricity and strain effects in orthorhombic YMnO3 thin films

TL;DR

This study investigates how epitaxial strain influences ferroelectricity and magnetic properties in orthorhombic YMnO3 thin films, revealing strain-dependent suppression of ferroelectric order and associated magnetic changes.

Contribution

It provides new insights into strain-induced tuning of multiferroic properties in YMnO3 thin films, linking structural distortions to ferroelectric and magnetic behavior.

Findings

Weakly strained films are ferroelectric with switchable polarization.

Increasing strain suppresses ferroelectricity and induces net magnetization.

Structural changes correlate with the suppression of ferroelectric order.

Abstract

We report on the dielectric properties of epitaxial [001] and [100]-textured thin films of antiferromagnetic orthorhombic YMnO3 and their variation under compressive epitaxial strain. It is found that weakly strained YMnO3 films are ferroelectric with a polarization along c-axis switchable by 90 degrees by an external magnetic field. When reducing film thickness and increasing epitaxial strain, the ferroelectric order is progressively suppressed. Analysis of structural, dielectric and magnetic data indicates that suppression of ferroelectricity when reducing thickness is accompanied by an enlarged ratio a/b of the in-plane cell parameters of the orthorhombic structure and the appearance of a net magnetization. All results can be well described by considering the multiferroic phase diagram of orthorhombic manganites.