Obtaining strong magnetoelectric couplings in bulk materials and heterostructures is an ongoing challenge. We demonstrate that manganite heterostructures of the form (Insulator)/(LaMnO3)n/(CaMnO3)n/(Insulator) show strong multiferroicity in magnetic manganites where ferroelectric polarization is realized by charges leaking from LaMnO3 to CaMnO3 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.
@article{arxiv.1702.06302,
title = {Giant magnetoelectric effect in pure manganite-manganite heterostructures},
author = {Sanjukta Paul and Ravindra Pankaj and Sudhakar Yarlagadda and Pinaki Majumdar and Peter B. Littlewood},
journal= {arXiv preprint arXiv:1702.06302},
year = {2017}
}