Formation of a narrow domain wall by using a local interlayer exchange coupled system

Formation of a narrow magnetic domain wall is demonstrated by using micromagnetic simulations. It is found that the domain wall width can be shrunk in a local interlayer exchange coupled system. A local interlayer exchange coupled system means that only part of a ferromagnetic layer has an interlayer exchange coupling with another ferromagnetic layer. The system can be considered as two parts with respect to the lateral dimensions: one is an exchange coupled region, and the another is a free region. Since the two regions have quite different local switching fields, the domain wall will be formed at the interface between the two regions at moderate fields. Furthermore, the transport between the two domains might be more ballistic, so a larger domain wall magnetoresistance would be expected.