Orbital control of noncollinear magnetic order in nickelate heterostructures

TL;DR

This study demonstrates how the magnetic order in nickelate heterostructures can be controlled through orbital manipulation using strain and quantum confinement, revealing a tunable spiral magnetic state.

Contribution

It provides a detailed experimental analysis of orbital-controlled magnetic order in nickelate heterostructures, confirming theoretical predictions.

Findings

Identification of a spiral magnetic state in LaNiO3 superlattices

Control of magnetic polarization plane via orbital occupation

Correlation between strain, confinement, and magnetic order

Abstract

We have used resonant x-ray diffraction to develop a detailed description of antiferromagnetic ordering in epitaxial superlattices based on two-unit-cell thick layers of the strongly correlated metal LaNiO3. We also report reference experiments on thin films of PrNiO3 and NdNiO3. The resulting data indicate a spiral state whose polarization plane can be controlled by adjusting the Ni d-orbital occupation via two independent mechanisms: epitaxial strain and quantum confinement of the valence electrons. The data are discussed in the light of recent theoretical predictions.