We report resonant elastic X-ray scattering (REXS) of long-range magnetic order in EuPtSi3, combining different scattering geometries with full linear polarization analysis to unambiguously identify magnetic scattering contributions. At low temperatures, EuPtSi3 stabilizes type A antiferromagnetism featuring various long-wavelength modulations. For magnetic fields applied in the hard magnetic basal plane, well-defined regimes of cycloidal, conical, and fan-like superstructures may be distinguished that encompass a pocket of commensurate type A order without superstructure. For magnetic field applied along the easy axis, the phase diagram comprises the cycloidal and conical superstructures only. Highlighting the power of polarized REXS, our results reveal a combination of magnetic phases that suggest a highly unusual competition between antiferromagnetic exchange interactions with Dzyaloshinsky--Moriya spin--orbit coupling of similar strength.
@article{arxiv.2305.07653,
title = {Resonant elastic X-ray scattering of antiferromagnetic superstructures in EuPtSi$_{3}$},
author = {Wolfgang Simeth and Andreas Bauer and Christian Franz and Aisha Aqeel and Pablo J. Bereciartua Perez and Jennifer A. Sears and Sonia Francoual and Christian H. Back and Christian Pfleiderer},
journal= {arXiv preprint arXiv:2305.07653},
year = {2023}
}