Suppressed pinning field of a trapped domain wall due to direct current injection

We investigate the influence of the dc current injection on trapped domain walls in magnetic nanostructures designed for high precision anisotropy magnetoresistance measurements. The results obtained for a simple strip with no trapped domain wall are compared with those for the strip with the trapped domain wall. The depinning field of the domain wall decreases significantly when the electron current is applied along the direction of the domain wall propagation. On the other hand, the switching field only shows a small reduction when the electron current is opposed to the domain wall propagation. The origin of this behavior can be explained by considering Joule heat as well as an additional pressure exerted on the domain wall due to the transfer of the spin angular momentum from the spin-polarized current to the local magnetic moment. (C) 2003 American Institute of Physics.