Intrinsic anomalous Hall effect in thin films of topological kagome ferromagnet Fe3Sn2

Abstract

Fe₃Sn₂, a kagome ferromagnet, is a potential quantum material with intriguing topological features. Despite substantial experimental work on the bulk single crystals, the thin film growth of Fe₃Sn₂ remains relatively unexplored. Here, we investigate the effect of two different seed layers (Ta and Pt) on the growth of Fe₃Sn₂ thin films. We demonstrate the growth of polycrystalline Fe₃Sn₂ thin films on Si/SiO₂ substrates by room temperature sputter deposition, followed by in situ annealing at 500 °C. Our structural and magnetic measurements indicate that a pure ferromagnetic phase is formed for the Pt/Fe₃Sn₂ thin films with higher saturation magnetization of M_s = 464 emu cc⁻¹, while a mixed-phase (consisting of ferromagnetic, Fe₃Sn₂ and antiferromagnetic, FeSn) is formed for the Ta/Fe₃Sn₂ thin films with a lower M_s of 240 emu cc⁻¹. The Pt/Fe₃Sn₂ thin films also exhibit an anomalous Hall coefficient, R_s ≈ 2.6 × 10⁻¹⁰ Ω cm⁻¹ G⁻¹ at room temperature, which is two order of magnitude higher compared to 3d-transition metal ferromagnets. A non-zero temperature-independent anomalous Hall conductivity σ^int_xy = (23 ± 11) Ω⁻¹ cm⁻¹ indicates an intrinsic mechanism of anomalous Hall effect originating from Berry curvature. These results are important for realizing novel topological spintronic devices on a CMOS-compatible substrate.