Critical spin-flip scattering at the helimagnetic transition of MnSi

Abstract

We report spherical neutron polarimetry (SNP) and discuss the spin-flip scattering cross sections as well as the chiral fraction $\eta$ close to the helimagnetic transition in MnSi. For our study, we have developed a miniaturised SNP device that allows fast data collection when used in small angle scattering geometry with an area detector. Critical spin-flip scattering is found to be governed by chiral paramagnons that soften on a sphere in momentum space. Carefully accounting for the incoherent spin-flip background, we find that the resulting chiral fraction $\eta$ decreases gradually above the helimagnetic transition reflecting a strongly renormalised chiral correlation length with a temperature dependence in excellent quantitative agreement with the Brazovskii theory for a fluctuation-induced first order transition.

arXiv comment5 pages, 3 figures

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Cited by in corpus (9)

• Uniaxial pressure dependence of magnetic order in MnSi
• Topological magnon band structure of emergent Landau levels in a skyrmion lattice
• Weak crystallization of fluctuating skyrmion textures in MnSi
• MIEZE Neutron Spin-Echo Spectroscopy of Strongly Correlated Electron Systems
• Kinetic small angle neutron scattering of the Skyrmion lattice in MnSi
• Evolution of magneto-crystalline anisotropies in Mn${}_{1-x}$Fe${}_x$Si and Mn${}_{1-x}$Co${}_x$Si as inferred from small-angle neutron scattering and bulk properties
• Effect of Dzyaloshinski-Moriya interaction on spin-polarized neutron scattering
• Anisotropic magneto-crystalline coupling of the skyrmion lattice in MnSi
• Dipolar effects on the critical fluctuations in Fe: Investigation by MIEZE