Reversible and irreversible current induced domain wall motion in CoFeB based spin valves stripes

Abstract

The authors present results on current induced domain wall motion in Co∕Cu∕CoFeB trilayered stripes. The threshold current densities are around 106A∕cm2 at zero field, i.e., about two orders of magnitude smaller than in single NiFe stripes. The domain wall motion is assisted when the field torque acts in the same direction as the spin torque. When the field torque is opposed to the spin transfer one and above a threshold field, the authors observe a reversible displacement of the domain wall (peak in the dV∕dI measurements). This can be ascribed to the onset of domain wall fluctuations, which is confirmed by micromagnetic simulations.