Current-induced magnetization switching in asymmetric necked wires

The authors have studied the current-induced domain wall movement mechanism in Ni80Fe20 wires patterned with a nanoconstriction and asymmetric arm widths using transport and focused magneto-optic Kerr effect (MOKE) measurements. Using dc current, the trapped domain wall is removed from the constriction at a current density greater than 1011 A/m2 and the direction of domain wall displacement is detected using focused MOKE measurements. At zero field, the current-induced domain wall displacement is in the direction of the current carriers while at the nucleation field of the domain wall the displacement direction is set by the direction of the applied field, independent of the current direction.