Domain wall pinning in ferromagnetic structures fabricated by focused ion beam

We present an experimental study of different methods to fabricate small magnetic wire structures with notches and their use to study domain wall pinning at constrictions. Direct patterning of continuous Co films with focused ion beam is shown to cause severe damage to the material, which alters the magnetic properties significantly. Patterning silicon substrates and subsequent film deposition yields well defined devices, which are used to show how domain walls can be controllably injected into wires and then pinned at constrictions. The pinning strength is then deduced by the field needed to depin the domain wall. (C) 2004 Elsevier B.V. All rights reserved.