Demonstration of edge roughness effect on the magnetization reversal of spin valve submicron wires

We prepared submicron wide trilayer spin valve wires designed with periodic spikes as artificial roughness. The height and the pitch of the spikes were varied systematically. No obvious dependence was found between the roughness and the domain wall velocity when the spikes were smaller than a threshold of 30 nm for NiFe. The average velocity was slowed down when the height of the spikes were larger than the threshold. In-plane transverse magnetic fields help to reduce the critical current density for current induced domain-wall motion. Our results could be attributed to the space modulation of the local magnetization. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3463459]