Atomic-scale Modulation of Synthetic Magnetic Order in Oxide Superlattices

TL;DR

This paper demonstrates atomic-scale control of synthetic spiral spin order in oxide superlattices with nonmagnetic insulator layers, advancing spintronic device development beyond metallic heterostructures.

Contribution

It introduces a method to modulate spin order across insulating layers at atomic precision, expanding the scope of spintronic materials and device concepts.

Findings

Oscillatory magnetic behavior observed in superlattices.

Modulated spiral spin structures confirmed by neutron reflectometry.

Atomic-scale customization of spin states achieved.

Abstract

Atomic-scale precision control of magnetic interactions facilitates a synthetic spin order useful for spintronics, including advanced memory and quantum logic devices. Conventional modulation of synthetic spin order has been limited to metallic heterostructures that exploit RKKY interaction through a nonmagnetic metallic spacer; however, they face problems arising from Joule heating and/or electric breakdown. The practical realization and observation of a synthetic spin order across a nonmagnetic insulating spacer would lead to the development of spin-related devices with a completely different concept. Herein, we report the atomic-scale modulation of the synthetic spiral spin order in oxide superlattices composed of ferromagnetic metal and nonmagnetic insulator layers. The atomically controlled superlattice exhibit an oscillatory magnetic behavior, representing the existence of a spiral spin structure. Depth-sensitive polarized neutron reflectometry evidences modulated spiral spin structures as a function of the nonmagnetic insulator layer thickness. Atomic-scale customization of the spin state could lead the field one step further to actual spintronic applications.