Magnetoelectric phase control at domain-wall-like epitaxial oxide multilayers

TL;DR

This paper demonstrates the creation of stable, domain-wall-like structures in oxide multilayers that enable electric control of magnetic properties, advancing potential applications in oxide-based nanoelectronics.

Contribution

It introduces a method to engineer robust, artificial domain-wall-like objects in epitaxial oxide heterostructures with controllable magnetoelectric functionalities.

Findings

Interfacial electron/hole accumulation controls LSMO conductivity.

Charged junctions exhibit distinct magnetoelectric responses.

Artificial domain walls can be designed in oxide multilayers.

Abstract

Ferroelectric domain walls are nanoscale objects that can be created, positioned, and erased on demand. They often embody functional properties that are distinct from the surrounding bulk material. Enhanced conductivity, for instance, is observed at charged ferroelectric domain walls. Regrettably, domain walls of this type are scarce because of the energetically unfavorable electrostatics. This hinders the current technological development of domain-wall nanoelectronics. Here we overcome this constraint by creating robust domain-wall-like objects in epitaxial oxide heterostructures. We design charged head-to-head (HH) and tail-to-tail (TT) junctions with two ferroelectric layers (BaTiO$_{3}$ and BiFeO$_{3}$) that have opposing out-of-plane polarization. To test domain-wall-like functionalities, we insert an ultrathin ferromagnetic La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ layer into the junctions. The interfacial electron or hole accumulation at the interfaces, set by the HH and TT polarization configurations, respectively, controls the LSMO conductivity and magnetization. We thus propose that trilayers reminiscent of artificial domain walls provide magnetoelectric functionality and may constitute an important building block in the design of oxide-based electronic devices.