The static and dynamic properties of magnetic Pd/Fe(001) ultrathin film crystalline structures prepared on GaAs(001) templates were
investigated by ferromagnetic resonance (FMR) from 10 to 73 GHz. It
will be shown that the formation of a self-assembled nanoscale network
of misfit dislocations in crystalline structures can be detected during
the growth by fan-out diffraction features in reflection high electron
energy diffraction. This network of defects leads to a strong extrinsic
magnetic damping. The out-of-plane measurements of the FMR linewidth
have revealed that the extrinsic damping is caused by two-magnon
scattering. The contribution to the FMR linewidth from two-magnon
scattering is strongly anisotropic and follows the rectangular symmetry
of the glide planes of the misfit dislocation network. It will be shown
that the observed strong anisotropy in two-magnon scattering can be
interpreted by Fourier components of magnetic defects. The angular
dependence of the Fourier components results in an effective
channelling of scattered spin waves.