Effect of a Platinum Buffer Layer on the Magnetization Dynamics of Sputter Deposited YIG Polycrystalline Thin Films

The present investigation deals with the effect of thickness and a platinum (Pt) buffer layer on the dynamic magnetic properties of polycrystalline yttrium iron garnet (YIG) films fabricated after post-annealing to recrystallize from the amorphous state. The dynamic magnetic properties of films without a buffer layer deteriorate as the thickness decreases as indicated by the increased line-widths in the ferromagnetic resonance spectra. On the other hand, a strong rejuvenation in the static and dynamic magnetic properties of the films is observed when a Pt buffer layer is used. The Pt buffer layer decreases the Gilbert damping parameter from 11.4×10^-4 and 3.5×10^-4 for a 100 nm-thick YIG film. These observations mainly originate from controlling the microstructure or the surface morphology of the films.