Interaction of magnetostatic excitations with 90° domain walls in micrometer-sized permalloy squares

We investigate the magnetic excitations in soft magnetic squares and in particular the role of domain walls in such Landau flux-closure structures. For this we combine synchrotron-based photoemission electron microscopy and simulations using the Landau-Lifshitz-Gilbert equation. We show that the 90°Néel walls in such squares act as efficient barriers for magnetic excitations that absorb the incoming energy. Because of the finite elasticity, the absorbed energy leads to oscillations of the domain walls, which subsequently cause emission of sharp wave fronts.