Multijump Magnetic Switching in In-Plane Magnetized Ultrathin Epitaxial Ag/Fe/Ag(001) Films

We predict and verify experimentally using magneto-optics a new magnetic switching mechanism involving three irreversible transitions in in-plane magnetized ultrathin epitaxial films. These transitions are mediated by the sweeping of 90\ifmmode^\circ\else\textdegree\fi{} and 180\ifmmode^\circ\else\textdegree\fi{} domain walls at three distinct applied field strengths. The prediction and observation of this new phenomenon shows that the complex domain processes which determine magnetic switching in such films can be accurately modeled by a single parameter which corresponds physically to the maximum pinning pressure that defects can exert on a domain wall.