The magnetic properties of amorphous thin films are shaped by inherent composition variations and magnetic proximity effects. Their magnetic properties can be tuned precisely with composition over a continuous range and their high resistance reduces shunting in spintronic systems. We examine the static and dynamic magnetic properties of amorphous magnetic thin films of Cox(Al0.7Zr0.3)1−x in the range \(0.60\le x<0.87\) , with and without a purposely modulated composition. The Gilbert damping is very low but increases dramatically with decreasing Co content. Damping is also studied in a CoAlZr multilayer with alternating intrinsically paramagnetic and ferromagnetic layers, and a film with a continuously modulated composition, both showing low damping. The structural and magnetic depth profiles of the heterostructures are measured with XRR and PNR, where proximity-induced magnetization is observed in the paramagnetic constituents. The enhancement in magnetization and reduction in damping is equivalent to an increase in mean Co content of approximately 3.4 at% and 1.9 at% for the multilayer and continuously modulated film, respectively. The results demonstrate how composition modulations affect the static and dynamic properties of thin films and how the magnetic proximity effect reduces the impact of such variations in composition.
