Field- and current-induced domain-wall motion in permalloy nanowires with magnetic soft spots

We study field- and current-induced domain-wall motion in permalloy nanowires containing a square-shaped magnetically softened region. Implantation of chromium ions is used to induce pinning sites via a local reduction in the saturation magnetization. Micromagnetic simulations, magnetic transmission soft x-ray microscopy, and electrical measurements are employed to characterize the pinning potential which significantly differs for transverse and vortex walls. Reliable domain-wall depinning from a so-called magnetic soft spot by single current pulses is observed. This demonstrates the suitability of these pinning sites for applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3590267]