Magnetodynamic properties of ultrathin films of Fe₃Sn₂-a topological kagome ferromagnet

Fe ₃ 3 Sn ₂ 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 3 Sn ₂ 2 have not yet been explored. Here, we report, for the first time, the measurements of the intrinsic Gilbert damping constant ( α ᵢnt α int ), and the effective spin mixing conductance (g ₑff↑ ↓ eff ↑ ↓ ) of Pt/Fe ₃ 3 Sn ₂ 2 bilayers for Fe ₃ 3 Sn ₂ 2 thicknesses down to 2 nm, for which α ᵢnt α int is (3.8 ± 0.2) × 10⁻² ( 3.8 ± 0.2 ) × 10 - 2 , and g ₑff↑ ↓ eff ↑ ↓ is (11.7 ± 0.6)~nm⁻² ( 11.7 ± 0.6 ) nm - 2 . The films have a high saturation magnetization, MS=620~emu~cm⁻³ M S = 620 emu cm - 3 , and large anomalous Hall coefficient, RS=4.6× 10⁻¹⁰~Ω ~ cm~G⁻¹ R S = 4.6 × 10 - 10 Ω cm G - 1 . The large values of g ₑff↑ ↓ eff ↑ ↓ , together with the topological properties of Fe ₃ 3 Sn ₂ 2 , make Fe ₃ 3 Sn ₂ 2 /Pt bilayers useful heterostructures for the study of topological spintronic devices.