Effect of rapid thermal annealing on microstructural, magnetic, and microwave properties of FeGaB alloy films

We have performed rapid thermal annealing (RTA) experiments on crystalline and amorphous [formula omitted] films in order to understand and reduce the linewidth of ferromagnetic resonance (FMR). In the absence of cubic anisotropy in amorphous films, the effective anisotropy is small, resulting in a narrow FMR linewidth. The FMR linewidth in both crystalline and amorphous films can be further reduced by RTA. In crystalline films, a minimum FMR linewidth can be achieved by annealing the samples at a relatively high temperature for a short time. The effect is attributed to the reduction in the uniaxial anisotropy. In amorphous films, the reduction in FMR linewidth is achieved at low temperature and short annealing time. Elevated temperatures and prolong time may crystallize the amorphous structure and introduce a much large cubic anisotropy, resulting in a large FMR linewidth.