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

摘要

Heavy metal/ferromagnet interfaces in systems with perpendicular magnetic anisotropy (PMA) hosts chiral Neel 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, D eff 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 D eff with a negative sign that supports the Neel 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 D eff. 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.