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Spin wave stiffness and damping in a frustrated chiral helimagnet Co8Zn8Mn4 as measured by small-angle neutron scattering
Multiple intriguing low-temperature phenomena have recently been discovered in the family of chiral cubic
Co-Zn-Mn compounds with a β-Mn-type structure. In particular, Co8Zn8Mn4 displays a reduction of the
helical spiral pitch on cooling along with lattice shape transformations of metastable skyrmions and the
manifestation of peculiar magnetic textures due to strong magnetocrystalline anisotropy. Here we report on
temperature-dependent measurements of helimagnon excitations in the field polarized regime Co8Zn8Mn4
using the spin-wave (SW) small-angle neutron-scattering technique. By applying a new analytical expression
to interpret the data, quantitative estimates for both SW stiffness and damping are extracted across a wide
temperature range between 70 and 250 K. We speculate that their nontrivial temperature dependencies arise
due to the effects of magnetic frustration arising from Mn magnetic moments, which is further reflected in
continuous variations of both exchange and Dzyaloshinskii-Moriya interactions.