Competing charge and magnetic order in the candidate centrosymmetric skyrmion host EuGa2Al2

DOI: 10.1103/PhysRevB.108.L100404

Authors: A. M. Vibhakar (Diamond Light Source) , D. D. Khalyavin (ISIS Facility) , J. M. Moya (Rice University) , P. Manuel (ISIS Facility) , F. Orlandi (ISIS Facility) , S. Lei (Rice University) , E. Morosan (Rice University) , A. Bombardi (Diamond Light Source; University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 108

State: Published (Approved)
Published: September 2023
Diamond Proposal Number(s): 30799 , 34149

Abstract: Eu ( Ga 1 − x Al x ) 4 are centrosymmetric systems that have recently been identified as candidates to stabilize topologically nontrivial magnetic phases, such as skyrmion lattices. In this Letter, we present a high-resolution resonant x-ray and neutron scattering study on EuGa 2 Al 2 that provides new details of the complex coupling between the electronic ordering phenomena. Our results unambiguously demonstrate that the system orders to form a spin density wave with moments aligned perpendicular to the direction of the propagation vector below 19.5 K, and upon further cooling below 15 K, a cycloid with moments in the a b plane, in contrast to what has been reported in the literature. We show that concomitant with the onset of the spin density wave is the suppression of the charge density wave order, indicative of a coupling between the localized 4 f electrons and itinerant electron density. Furthermore, we demonstrate that the charge density wave order breaks the fourfold symmetry present in the I 4 / m m m crystal structure, thus declassifying these systems as square-net magnets.

Journal Keywords: Charge density waves; Skyrmions; Spin density waves; Topological materials; Topological phases of matter; Noncollinear magnets; Neutron diffraction; Resonant elastic x-ray scattering; X-ray resonant magnetic scattering

Diamond Keywords: Skyrmions

Subject Areas: Materials, Physics


Instruments: I16-Materials and Magnetism

Added On: 18/10/2023 11:28

Documents:
PhysRevB.108.L100404.pdf

Discipline Tags:

Quantum Materials Physics Magnetism Materials Science

Technical Tags:

Scattering Resonant Elastic X-ray Scattering (REXS)