Domains and hysteresis in patterned soft magnetic elements

We study the magnetization reversal in rectangular ferromagnetic thin film elements using the magneto-optical Kerr effect for magnetometry and domain observation. The aim of this study is to support the global simulation of magnetic materials such as by the Preisach concept by microscopic investigations. As we are able to study in these samples the whole domain structure as a function of an applied field in real time, we can investigate in detail the question of reproducibility of magnetization processes starting with an identical initial configuration. We observe an obviously intrinsic irreproducibility of the main domain rearrangement process characteristic for these samples. This property of an unpredictable magnetization process can be influenced by a superimposed alternating field.