Large ordered moment with strong easy-plane anisotropy and vortex-domain pattern in the kagome ferromagnet Fe3Sn

We report the structural and magnetic properties of high-quality bulk single crystals kagome ferromagnet Fe$_3$Sn. The dependence magnetisation on magnitude orientation external field reveals strong easy-plane type uniaxial anisotropy, which shows a monotonous increase from $K_1=-0.99\times 10^6 J/m^3$ at 300\,K to $-1.23\times10^6 2\,K. Our \textit{ab initio} electronic structure calculations yield value total moment about 6.9 $\mu_B$/f.u. magnetocrystalline anisotropy energy density 0.406\,meV/f.u. ($1.16\times10^6 J/m^3$) both being in good agreement with experimental values. self-consistent DFT computations for components spin/orbital moments indicate that small difference between saturation magnetisations measured along perpendicular layers results subtle balance Fe Sn different sites. In zero field, force microscopy micrometer-scale vortices weakly pinned cores vanish $\sim$3\,T applied plane. micromagnetic simulations, using experimentally determined well reproduce observed vortex-domain structure. present study, comparison easy-axis Fe$_3$Sn$_2$, varying stacking provides an efficient control over this family Fe-based magnets.