Exchange coupling and natural ferromagnetic resonance phenomena in Fe40Co37Zr11N12/ZrN/Ni80Fe20 film systems with in-plane uniaxial anisotropy

Abstract Ferromagnetic Fe40Co37Zr11N12/ZrN/Ni80Fe20 film systems with a uniaxial anisotropy in the film plane were synthesised by reactive magnetron sputtering and by post annealing in a static magnetic field. Investigation on the energy exchange interaction between the ferromagnetic layers without and with an interface layer were carried out. This exchange impacts the static magnetisation properties as well as the natural resonance frequency behaviour and its damping features caused by spin current generated damping and/or anti-damping effects. As static polarisation loops are slightly but distinguishably different dependent on the interface thickness, the films definitely exhibit a distinct variation in their frequency spectra. By means of the interface layer with different thickness, various dynamic behavioural patterns could be observed. This can be assumed because the observed ferromagnetic resonance dual lines show remarkable changes in their full width at half maxima (FWHM) at frequencies of around 600 MHz attributed to the Ni80Fe20 layers and 2.3 GHz attributed to the Fe40Co37Zr11N12 layers if interface layer are applied.