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

Abstract Recent results show remarkable interfacial-Dzyaloshinskii-Moriya interaction (i-DMI) effect in magnetic heterostructures composed of relatively thick Fe thin films ( $$\gg 1\, \text {nm}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>≫</mml:mo> <mml:mn>1</mml:mn> <mml:mspace/> <mml:mtext>nm</mml:mtext> </mml:mrow> </mml:math> ). To investigate its origin, we present a thorough magnetic characterization of the SiO 2 / 57 Fe(t)/Au and SiO 2 /Pt/ 57 Fe(t)/Au heterostructures (t = 1.6–2.2 nm). An i-DMI constant $${D}_{s}^{Pt}=0.43\pm 0.02 \ {\text{mJ}/\text{m}}^{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>Pt</mml:mi> </mml:mrow> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mn>0.43</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.02</mml:mn> <mml:mspace/> <mml:msup> <mml:mrow> <mml:mtext>mJ</mml:mtext> <mml:mo>/</mml:mo> <mml:mtext>m</mml:mtext> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> 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. Graphic Abstract