Surface Roughness Effects on Magnetic Properties and Switching Mechanism in Iron Nanowires

Abstract

Nanowires fabricated with experimental techniques are never perfect and possess structural imperfections. The effect of the resulting surface roughness on magnetic properties of iron nanowires has been simulated here with the use of numerical technique involving atomistic-resolved software Vampire. A two-regime or a power-law decrease in the coercive field has been found for the roughness amplitude up to 30% of the perfect radius of the wire. The roughness of the surface of the side face of cylindrical wire makes the ends of the cylinder inequivalent as far as the switching mechanism is concerned. As a result, the switching becomes dominated by a transverse domain wall arising at one specific end only. Both the coercive field and the switching mechanism are essential in designing magnetic devices, e.g., for memory storage.