Interface Spin-orbit Coupling Induced Room-temperature Ferromagnetic Insulator

TL;DR

This paper demonstrates a novel method to create room-temperature ferromagnetic insulators by engineering (111)-oriented 3d/5d interfaces, significantly advancing spintronic device materials.

Contribution

It introduces a new interface engineering strategy to induce ferromagnetic insulating phases at room temperature using epitaxial synthesis.

Findings

Enhanced spin-orbit coupling at (111) interfaces suppresses metallicity in LSMO.

A tunable ferromagnetic insulating phase is achieved by controlling LSMO thickness.

The approach offers a pathway for dissipation-free quantum and spintronic devices.

Abstract

Fabricating room-temperature ferromagnetic insulators, which are crucial candidates for next-generation dissipation-free quantum and spintronic devices, remains a significant challenge. In this Letter, we report on the epitaxial synthesis of novel room-temperature ferromagnetic insulating thin films created through the precise construction of (111)-oriented 3d/5d interfaces. Our analysis indicates that, unlike conventional doping methods, the (111)-oriented SrIrO3/La2/3Sr1/3MnO3 (SIO/LSMO) interfaces exhibit markedly enhanced spin-orbit coupling. This enhanced interfacial spin-orbit coupling strengthens the electron-phonon coupling in LSMO, thereby shortening the electronic mean free path. As a result, the intrinsic metallicity of LSMO is suppressed, giving rise to a new ferromagnetic insulating phase that emerges between the ferromagnetic metal and paramagnetic insulator regimes of the LSMO phase diagram. Furthermore, the temperature window of the ferromagnetic insulating phase can be tuned by precisely controlling the thickness of the LSMO layers. Our Letter reveals a new strategy for developing ferromagnetic insulators by engineering 3d/5d interfaces and orientations, paving a way for the development of novel dissipation-free quantum and spintronic devices.