CoB/Ni-Based Multilayer Nanowire with High-Speed Domain Wall Motion under Low Current Control

The spin-transfer torque motion of magnetic domain walls (DWs) in a CoB/Ni-based nanowire driven by a low current density of (1.12 +/- 0.8) x 10(11) Am-2 has been observed indirectly by magnetotransport measurements. A high DW velocity of 85 +/- 4 m/s at zero field was measured at the threshold current density. Upon increasing the current density to 2.6 x 10(11) Am-2, the DW velocity increases to 197 +/- 16 m/s before decreasing quickly in the high-current-density regime attributed to nonadiabatic spin-transfer torque at a low damping factor and weak pinning. The addition of B atoms to the Co layers decreased the magnitude of saturation magnetization, Gilbert damping factor, and density of pinning sites, making the CoB/Ni multilayer nanowire favorable for practical applications. (C) 2012 The Japan Society of Applied Physics