Rapid Domain Wall Motion in Permalloy Nanowires Excited by a Spin-Polarized Current Applied Perpendicular to the Nanowire

We study domain wall dynamics in Permalloy nanowires excited by alternating spin-polarized current applied perpendicular to the nanowire. Spin torque ferromagnetic resonance measurements reveal that domain wall oscillations at a pinning site in the nanowire can be excited with velocities as high as 800 m/s at current densities below 10(7) A/cm(2).