Does the surface layer of an itinerant ferromagnet change its magnetization direction at the same field as the bulk? Not always – at least not in Sr4Ru3O10. Domain wall pinning allows us to precisely control the magnetic configuration of surface and bulk. Using scanning tunneling microscopy at ultra-low temperatures, Carolina Marques found how the electronic states change between ferromagnetic and antiferromagnetic alignment of the surface layer and bulk magnetizations. Intriguingly, through control of the magnetic configuration, we were able to detect the tiny structural change that accompanies the change in magnetic configuration. While tiny in the grand scheme of things, our measurements reveal a giant magnetoelastic coupling that is driven by exchange interactions, qualitatively as expected from the Bethe-Slater curve sketched almost a century ago. Our results highlight the coupling between electronic, magnetic and structural degrees of freedom, and how these effects are enhanced through electronic correlations.
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- Carolina A. Marques, Luke C. Rhodes, Weronika Osmolska, Harry Lane, Izidor Benedičič, Masahiro Naritsuka, Siri A. Berge, Rosalba Fittipaldi, Mariateresa Lettieri, Antonio Vecchione, and Peter Wahl, Emergent exchange-driven giant magnetoelastic coupling in a correlated itinerant ferromagnet, Nature Physics (2025). DOI: 10.1038/s41567-025-02893-x