Sub-micron mapping of GHz magnetic susceptibility using scanning transmission x-ray microscopy

摘要

We report submicron imaging (∼0.75 μm resolution) of complex magnetic susceptibility in a micron-size ferromagnetic heterostructure using time-resolved scanning transmission x-ray microscopy. The real and imaginary parts of the susceptibility are extracted from the phase and amplitude of the small-angle (<20°) rotational response of the local magnetization under microwave excitation. Frequency-dependent response patterns were observed in an incompletely saturated bilayer element. The technique is extensible to higher frequencies (to ∼10 GHz), better spatial resolution, and layer-specific measurement.