We report the structural and magnetic properties of high-quality bulk single crystals of the kagome ferromagnet Fe3Sn. The dependence of magnetisation on the magnitude and orientation of the external field reveals strong easy-plane type uniaxial magnetic anisotropy, which shows a monotonous increase from K1=−0.99×106J/m3 at 300\,K to −1.23×106J/m3 at 2\,K. Our \textit{ab initio} electronic structure calculations yield the value of total magnetic moment of about 6.9 μB/f.u. and a magnetocrystalline anisotropy energy density of 0.406\,meV/f.u. (1.16×106J/m3) both being in good agreement with the experimental values. The self-consistent DFT computations for the components of the spin/orbital moments indicate that the small difference between the saturation magnetisations measured along and perpendicular to the kagome layers results from the subtle balance between the Fe and Sn spin/orbital moments on the different sites. In zero field, magnetic force microscopy reveals micrometer-scale magnetic vortices with weakly pinned cores that vanish at ∼3\,T applied perpendicular to the kagome plane. Our micromagnetic simulations, using the experimentally determined value of anisotropy, well reproduce the observed vortex-domain structure. The present study, in comparison with the easy-axis ferromagnet Fe3Sn2, shows that varying the stacking of kagome layers provides an efficient control over magnetic anisotropy in this family of Fe-based kagome magnets.
@article{arxiv.2302.13810,
title = {Large ordered moment with strong easy-plane anisotropy and vortex-domain pattern in the kagome ferromagnet Fe$_3$Sn},
author = {Lilian Prodan and Donald M. Evans and Sinéad M. Griffin and Andreas Östlin and Markus Altthaler and Erik Lysne and Irina G. Filippova and Serghei Shova and Liviu Chioncel and Vladimir Tsurkan and István Kézsmárki},
journal= {arXiv preprint arXiv:2302.13810},
year = {2023}
}