Depinning of Transverse Domain Walls from Notches in Magnetostatically Coupled Nanostrips

The separation-dependent interaction between domain walls (DWs) in two Permalloy nanostrips containing a double notch is studied by means of micromagnetic simulations. We show that the DW configuration and the relative chirality affect the field required for depinning from the notch. In the case of repulsive interaction, the DW configuration can become unstable at small separation distances, where DWs can depin even without applying external fields. The effect of the magnetostatic interaction on the stability is quantified by calculating the energy barrier connected to the depinning mechanism. (C) 2011 The Japan Society of Applied Physics