Domain wall transformations and hopping in La_(0.7)Sr_(0.3)MnO_3 nanostructures imaged with high resolution x-ray magnetic microscopy

摘要

We investigate the effect of electric current pulse injection on domain walls in La_(0.7)Sr_(0.3)MnO_3 (LSMO) half-ring nanostructures by high resolution x-ray magnetic microscopy at room temperature. Due to the easily accessible Curie temperature of LSMO, we can employ reasonable current densities to induce the Joule heating necessary to observe effects such as hopping of the domain walls between different pinning sites and nucleation/annihilation events. Such effects are the dominant features close to the Curie temperature, while spin torque is found to play a small role close to room temperature. We are also able to observe thermally activated domain wall transformations and we find that, for the analyzed geometries, the vortex domain wall configuration is energetically favored, in agreement with micromagnetic simulations.