Magnetodynamic properties of ultrathin films of Fe _3 Sn _2 -a topological kagome ferromagnet

Fe _3 Sn _2 is a topological kagome ferromagnet that possesses numerous Weyl points close to the Fermi energy, which can manifest various unique transport phenomena such as chiral anomaly, anomalous Hall effect, and giant magnetoresistance. However, the magnetodynamic properties of Fe _3 Sn _2 have not yet been explored. Here, we report, for the first time, the measurements of the intrinsic Gilbert damping constant ( α _int ), and the effective spin mixing conductance (g _eff^↑↓ ) of Pt/Fe _3 Sn _2 bilayers for Fe _3 Sn _2 thicknesses down to 2 nm, for which α _int is (3.8 ± 0.2) × 10^-2 , and g _eff^↑↓ is (11.7 ± 0.6) nm^-2 . The films have a high saturation magnetization, M_S=620 emu cm^-3 , and large anomalous Hall coefficient, R_S=4.6× 10^-10 Ω cm G^-1 . The large values of g _eff^↑↓ , together with the topological properties of Fe _3 Sn _2 , make Fe _3 Sn _2 /Pt bilayers useful heterostructures for the study of topological spintronic devices.