Room-Temperature Electronically-Controlled Ferromagnetism at the LaAlO3/SrTiO3 Interface

TL;DR

This study demonstrates room-temperature ferromagnetism at the LaAlO3/SrTiO3 interface controlled by electrical gating, revealing potential for oxide-based spintronic devices through direct magnetic domain observation.

Contribution

It provides the first direct magnetic imaging of electrically controlled ferromagnetism at oxide interfaces, highlighting a new method to manipulate emergent magnetic phases.

Findings

In-plane ferromagnetic domains observed at room temperature.

Electrical gating modulates magnetic order and domain structure.

Electrons influence magnetic alignment, enabling control over magnetism.

Abstract

Reports of emergent conductivity, superconductivity, and magnetism at oxide interfaces have helped to fuel intense interest in their rich physics and technological potential. Here we employ magnetic force microscopy to search for room-temperature magnetism in the well-studied LaAlO3/SrTiO3 system. Using electrical top gating to deplete electrons from the oxide interface, we directly observe an in-plane ferromagnetic phase with sharply defined domain walls. Itinerant electrons, introduced by a top gate, align antiferromagnetically with the magnetization, at first screening and then destabilizing it as the conductive state is reached. Subsequent depletion of electrons results in a new, uncorrelated magnetic pattern. This newfound control over emergent magnetism at the interface between two non-magnetic oxides portends a number of important technological applications.