Two-magnon scattering in a self-assembled nanoscale network of misfit dislocations

Abstract

The static and dynamic properties of magnetic Pd/Fe͑001͒ ultrathin film crystalline structures prepared on GaAs͑001͒ templates were investigated by ferromagnetic resonance ͑FMR͒ 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.

Scattering of spin current injected in Pd(001)

“…The presence of a self-assembled network of misfit dislocation half loops was observed by plan view transmission electron microscopy ͑TEM͒. 12 Above a Pd thickness of 100 ML the network of self-assembled misfit dislocations leads to strong two magnon scattering. Therefore, the study of intrinsic damping had to be carried out for the Pd films thinner than 100 ML ͑20 nm͒.…”

“…Therefore, the study of intrinsic damping had to be carried out for the Pd films thinner than 100 ML ͑20 nm͒. 12 The damping was investigated by ferromagnetic resonance ͑FMR͒ at 24 and 36 GHz.…”

Ferromagnetic resonance and magnetic damping in C-doped Mn5Ge3

“…At 300K and 250K ( figure 5(b)), the FMR linewith has the same six-fold symmetry as the angular dependence of H r ( figure 2(e)). If the scattering centres are given by lattice defects (dislocation lines), the azimuthal dependence should reflect the lattice symmetry [32,20]. The angular dependence of the scattering was fitted with Γ i f (ϕ i ) = Γ 0 + Γ 2 cos 2 (ϕ − ϕ 2 ) + Γ 6 cos 6(ϕ − ϕ 6 ) at 250K and 300K and with Γ i f (ϕ i ) = Γ 0 + Γ 2 cos 2 (ϕ − ϕ 2 ) + Γ 4 cos 4(ϕ − ϕ 4 ) at 150K and 100K.…”

Spin Pumping at the Magnetic Insulator (YIG)/Normal Metal (Au) Interfaces

“…The zero frequency offset did not disappear in the perpendicular FMR (the field perpendicular to the film surface) and therefore was not caused by two magnon scattering indicating that the films were accompanied by long range magnetic inhomogeneities [10], see Fig.2. The FMR line position and ∆H(f ) did not change by depositing a thin Au film over YIG.…”