Adjustment of Demagnetizing Field in Permalloy Nanowires to Control Domain Wall Motion

The domain wall motion in permalloy nanowires has been investigated widely due to its potential for a new type of memory. In this paper. we use the LLG Simulator based on the Landau-Lifshitz-Gilbert (LLG) equation to investigate the field-driven domain-wall motion in a long, straight ferromagnetic strip. An injection field of 60 Oe is applied to inject a domain wall from an extended disk into the nanowire. We found a dependence of nanowire dimensions with the velocity of domain wall. By increasing the width of the nanowire, the velocity of the domain wall motion also increases, while the Walker breakdown field ( HWB) decreases. On the other hand, increasing the thicknesses of the nanowire, the domain wall velocity, HWB, and demagnetizing field all decrease. By applying a vertical field from 0 to 1000 Oe in order to enhance the demagnetizing field, it is found the HWB is increased from 16 to 20 Oe.