Domain wall chirality reversal by interfacial engineering in Pt/Co/Pt based perpendicularly magnetized systems

Abstract

Heavy metal/ferromagnet interfaces in systems with perpendicular magnetic anisotropy (PMA) hosts chiral Néel wall with the assistance of interfacial Dzyaloshinskii–Moriya interaction (iDMI). We have investigated field induced domain wall motion in the creep regime to estimate the effective iDMI strength, Deff of sputter-deposited Ta/Pt/Co/Pt and Ta/Pt/Co/Au/Pt thin films that exhibit PMA. Two similar Pt/Co interfaces on either side of the Co layer in the Ta/Pt/Co/Pt system lead to a small Deff with a negative sign that supports the Néel type domain wall of right-handed chirality. Ultrathin Au layers of different thicknesses have been deposited at the top Co/Pt interface to introduce asymmetry around the Co layer and control the Deff. Here, two interfaces (Pt/Co and Au/Co) of opposite iDMI polarity have been chosen to invert the domain wall chirality to the left-handed chirality instead of the right-handed chirality found in the Ta/Pt/Co/Pt system.