Adjustable resonance frequency and linewidth by Zr doping in Co thin films

Abstract

Co 100 − x Zr x (40 nm) thin films with different Zr compositions were grown on silicon substrates by radio frequency magnetron sputtering. The coercivity decreased with an increase in the Zr composition. A uniaxial anisotropy existed in the Co100−xZrx films, and the anisotropy field of the films decreased from 55 to 40 Oe with the increase of Zr composition. The resonance frequency and linewidth were decreased with the increase of the Zr composition during the permeability measurements. For samples with x=0 and 9, the magnetic anisotropy effective field and saturated field were obtained by fitting the external magnetic field dependent resonance frequency with Landau–Lifschitz–Gilbert equation. Therefore, it is an effective way to get the adjustable anisotropy field and linewidth, which is desirable for obtaining the high resonance and high permeability ferromagnetic film materials for high frequency application.