Control of domain wall pinning by switchable nanomagnet state

We report on a novel approach to establish switchable pinning of magnetic domain walls in a nanowire with perpendicular magnetic anisotropy by a single in-plane magnetized single-domain nanomagnet positioned on top of the wire. Devices were prepared by depositing a permalloy nanomagnet on top of a nanowire formed from a Co/Ni multilayer with their long axes parallel, separated by a nonmagnetic layer. We show by electrical measurements that the domain wall pinning strength depends critically on the state of the bistable nanomagnet and can differ by more than 10¿mT. We also performed micromagnetic calculations that show that the difference in pinning strength is caused by the interaction of the forced Néel wall with the nanomagnet's magnetostatic field.