  Single crystals of the single Kagome layer compound FeSn are investigated
using x-ray and neutron scattering, magnetic susceptibility and magnetization,
heat capacity, resistivity, Hall, Seebeck, thermal expansion, thermal
conductivity measurements and density functional theory (DFT). FeSn is a planar
antiferromagnet below TN = 365 K and exhibits ferromagnetic magnetic order
within each Kagome layer. The in-plane magnetic susceptibility is sensitive to
synthesis conditions. Resistivity, Hall and Seebeck results indicate multiple
bands near the Fermi energy. The resistivity of FeSn is about 3 times lower for
current along the stacking direction than in the plane, suggesting that
transport and the bulk electronic structure of FeSn is not quasi 2D. FeSn is an
excellent metal with Rho(300K)/Rho(2K) values about 100 in both directions.
While the ordered state is antiferromagnetic, high temperature susceptibility
measurements indicate a ferromagnetic Curie-Weiss temperature of 173 K,
reflecting the strong in-plane ferromagnetic interactions. DFT calculations
show a 3D electronic structure with the Dirac nodal lines along the K-H
directions in the magnetic Brillouin zone about 0.3 eV below the Fermi energy,
with the Dirac dispersions at the K points gapped by spin-orbit coupling except
at the H point. The magnetism, however, is highly 2D with
Jin-plane/Jout-of-plane = 10. The predicted spin-wave spectrum is presented.
