Different stochastic behaviors for magnetic field and current in domain wall creep motion

Magnetic domain wall (DW) creep motions driven by a magnetic field and by the spin Hall (SH) torque are investigated in perpendicularly magnetized Co/Ni nanowires with structural inversion asymmetry. It is found that the DW arrival time distribution becomes wider when a DW is driven by the SH torque compared with that driven by a magnetic field. Our results indicate that the SH torque and a magnetic field drive a DW in different ways in the DW creep regime, although the SH torque is generally considered to induce an effective field. (C) 2014 The Japan Society of Applied Physics