Emergent exchange-driven giant magnetoelastic coupling in a correlated itinerant ferromagnet

TL;DR

This study uncovers a giant magnetoelastic coupling in Sr$_4$Ru$_3$O$_{10}$, showing how electronic correlations lead to strong electron-lattice interactions and influence magnetic and structural properties at the surface level.

Contribution

It demonstrates a significantly enhanced magnetoelastic coupling in a correlated itinerant ferromagnet, linking electronic correlations to strong electron-lattice interactions.

Findings

Giant magnetostriction observed in Sr$_4$Ru$_3$O$_{10}$ surface layers.

Electronic structure varies with magnetic alignment between layers.

Exchange interactions strongly influence surface structural relaxation.

Abstract

The interaction between the electronic and structural degrees of freedom is central to several intriguing phenomena observed in condensed-matter physics. In magnetic materials, magnetic interactions couple to lattice degrees of freedom, resulting in magnetoelastic coupling, which is typically small and only detectable in macroscopic samples. Here we demonstrate a giant magnetoelastic coupling in the correlated itinerant ferromagnet Sr$_4$Ru$_3$O$_{10}$. We establish an effective control of magnetism in the surface layer and utilize it to probe the impact of magnetism on its electronic and structural properties. By using scanning tunnelling microscopy, we reveal subtle changes in the electronic structure dependent on ferromagnetic or antiferromagnetic alignment between the surface and subsurface layers. We further determine the consequences of the exchange force on the relaxation of the surface layer, which exhibits giant magnetostriction. Our results provide a direct measurement of the impact of exchange interactions and correlations on structural details in a quantum material, revealing how electronic correlations result in a strong electron-lattice coupling.