Giant magnetoelectric effect in pure manganite-manganite heterostructures

TL;DR

This paper demonstrates a giant magnetoelectric effect in manganite heterostructures, where strong multiferroicity arises from charge leakage and electron-phonon interactions, enabling electric control of magnetic properties.

Contribution

It introduces a novel heterostructure design that achieves strong magnetoelectric coupling through charge leakage and electron-phonon interactions, a significant advancement over previous bulk material approaches.

Findings

Strong multiferroicity observed in heterostructures

Giant magnetoelectric effect induced by electric field

Charge leakage from LaMnO3 to CaMnO3 enhances coupling

Abstract

Obtaining strong magnetoelectric couplings in bulk materials and heterostructures is an ongoing challenge. We demonstrate that manganite heterostructures of the form ${\rm (Insulator)/(LaMnO_3)_n/(CaMnO_3)_n/(Insulator)}$ show strong multiferroicity in magnetic manganites where ferroelectric polarization is realized by charges leaking from ${\rm LaMnO_3}$ to ${\rm CaMnO_3}$ due to repulsion. Here, an effective nearest-neighbor electron-electron (electron-hole) repulsion (attraction) is generated by cooperative electron-phonon interaction. Double exchange, when a particle virtually hops to its unoccupied neighboring site and back, produces magnetic polarons that polarize antiferromagnetic regions. Thus a striking giant magnetoelectric effect ensues when an external electrical field enhances the electron leakage across the interface.