Current induced chiral domain wall motion in CuIr/CoFeB/MgO thin films with strong higher order spin-orbit torques

Abstract

We investigate the Dzyaloshinskii-Moriya interaction (DMI) and spin-orbit torque effects in cuir/cofeb/mgo heterostructures. to this end, harmonic hall measurements and current induced domain wall motion experiments are performed. the motion of domain walls at zero applied field due to current demonstrates the presence of dmi in this system. we determine the strength of the dmi to be d= 5 /- 3 mu j/m2 and deduce right-handed chirality in domain walls showing a partial neel type spin structure. to ascertain the torques, we perform a second harmonic measurement to quantify the damping- and field-like current induced effective fields as a function of the magnetization direction. from the angular dependent analysis, we identify non-negligible higher order terms for polar magnetization angles theta>0, which need to be included when considering the effective manipulation of spins by current.