  Mn4N thin film is one of the potential magnetic mediums for spintronic
devices due to its ferrimagnetism with low magnetization, large perpendicular
magnetic anisotropy (PMA), thermal stability, and large domain wall velocity. A
recent experiment confirmed the existence of tunable magnetic skyrmions in
MgO/Mn4N/CuxPt1-x(x=0,0.5,0.9,0.95), and density functional theory (DFT)
calculation provided a large theoretical value of the interfacial
Dzyaloshinskii-Moriya Interaction (iDMI) of Mn4N/Pt, which is consistent with
the predicted chemical trend of DMI in transition metal/Pt films. So far,
measured DMI has not been reported in Mn4N which is needed in order to support
the predicted large DMI value. This paper reports the average DMI of
MgO/Mn4N(17nm)/CuxPt1-x(3nm), extracted from the anomalous Hall effect with
various tilted angles, based on magnetic droplet theory with DMI effects. The
DMI decreases from 0.267 mJ/m2 to 0.011 mJ/m2 with non-linear tendencies as Cu
concentration in the CuxPt1-x capping layer increases from 0 to 1,
demonstrating the control of DMI through CuxPt1-x capping layer. Furthermore, a
solid solution model is developed, based on X-ray photoelectron spectroscopy
(XPS) compositional depth profile, to analyze the possible effects on DMI from
the mixing layers at the surface of Mn4N. After taking into account the mixing
layers, the large DMI in Mn4N film with Pt capping is consistent with the
predicted DMI.
