Atomic-scale origin of interfacial Dzyaloshinskii–Moriya interaction in Pt/Fe/Au

Recent results show remarkable interfacial-Dzyaloshinskii-Moriya interaction (i-DMI) effect in magnetic heterostructures composed of relatively thick Fe thin films ( $$\gg 1\, \text {nm}$$ ). To investigate its origin, we present a thorough magnetic characterization of the SiO2/57Fe(t)/Au and SiO2/Pt/57Fe(t)/Au heterostructures (t = 1.6–2.2 nm). An i-DMI constant $${D}_{s}^{Pt}=0.43\pm 0.02 \ {\text{mJ}/\text{m}}^{2}$$ is extracted for the Pt/Fe/Au system, as probed by wavevector-resolved Brillouin light scattering spectroscopy. Ferromagnetic resonance and conversion electron Mössbauer spectroscopy provide evidence that significant surface anisotropy is present in Pt/Fe/Au and an interfacial Fe fraction (~ 18%) exhibits tilted magnetization (~ 25° out of plane) and enhanced hyperfine field, correlating with the stronger i-DMI.