MURPHYS-HSFS-2014 - 7th International Workshop on Multi-Rate Processes & Hysteresis, 2nd International Workshop on Hysteresis and Slow-Fast Systems, April 7-11, 2014 - Abstract

Otto, Felix

Domain pattern in ferromagnets: energy landscape and hysteresis

We study the behavior of the magnetization of a ferromagnetic sample in form of an elongated thin film under an external field in direction of the long axis. Despite the small sample size, the magnetization reversal proceeds in several stages. Intermediate configurations display a fairly complex domain structure (“concertina”). We argue how this hysteresis behavior can be explained in the framework of a variational model in terms of a cascade of bifurcations and marginal stability. The understanding arises from a combination of the rigorous derivation of suitably reduced model, and numerical simulation and qualitative analysis of this more tractable reduced model. This is joint work with Jutta Steiner and Rudolf Schäfer et. al. (for the experiments).