Control of the resonance frequency of soft ferromagnetic amorphous thin films by strip patterning

Abstract

Amorphous nearly zero-magnetostrictive soft ferromagnetic thin films with an in-plane uniaxial anisotropy exhibit a gyromagnetic resonance with frequency generally lower than 2 GHz. A convenient way to increase this frequency is to take the advantage of controlled demagnetizing effects: a periodic pattern of metal strips of width w, parallel to the easy axis, separated by a gap of width e is etched in the amorphous layer of thickness h. By playing with the geometrical parameters w, e, h, it is possible to adjust the resonance frequency. In this article, we demonstrate this principle for amorphous CoZrNb and CoFeMoMnSiB films.