Element?specific visualization of dynamic magnetic coupling in a Co/Py bilayer microstructure
Sprache des Titels:
Englisch
Original Kurzfassung:
We present the element?specific and time resolved visualization of uniform ferromagnetic resonance
excitations of a Permalloy (Py) disk?Cobalt (Co) stripe bilayer microstructure. The transverse high
frequency component of the resonantly excited magnetization is sampled in the ps regime by a
combination of ferromagnetic resonance (FMR) and scanning transmission X?ray microscopy (STXM?
FMR) recording snapshots of the local magnetization precession of Py and Co with nanometer spatial
resolution. The approach allows us to individually image the resonant dynamic response of each
element, and we find that angular momentum is transferred from the Py disk to the Co stripe and
vice versa at their respective resonances. The integral (cavity) FMR spectrum of our sample shows an
unexpected additional third resonance. This resonance is observed in the STXM?FMR experiments
as well. Our microscopic findings suggest that it is governed by magnetic exchange between Py and
Co, showing for the Co stripe a difference in relative phase of the magnetization due to stray field
influence.
Forschungs-