The impact of spin-polarized current on the excitations of interface pinned domain walls

We report a theoretical study of the impact of spin-polarized currents on the excitation spectrum of a periodic sequence of domain walls in a Py™(Ni ₈₀Fe ₂₀ ) nanowire exchange coupled to a two-sublattices vicinal antiferromagnetic substrate. At low spin current densities, there are only minor changes in the magnetic equilibrium configuration. However, one may find relevant effects on the domain wall excitations spectrum. Our results show a low-frequency mode determined by the restoring force resonance mode related to the interface’s exchange field strength. Therefore, the spectrum of the domain walls only shows the low-frequency mode up to 1 0 8 A/m 2 . However, for large spin currents densities ( 1 0 8 A/m 2 < J < 1 0 11 A/m 2 ), the domain wall excitations spectrum extends up to 6.6 GHz.