Influence of ion beam mixing on the structure and magnetic properties of multilayered Co–B thin films

Multilayered Co–B films with various bilayer periods (BP=TCo+TB, TCo=4×TB) and ratios of bilayer thickness were ion beam mixed with 150 keV 1016 Ar ions/cm2. The morphologies of both the as-deposited and the ion beam mixed films changed with BP. The ion beam mixed films exhibited amorphous structures, and the morphologies differed as a function of layer thickness in the as-deposited state. The morphological differences appeared to influence magnetic properties such as in-plane anisotropy and coercivity. Magnetization measurements revealed that the compositional inhomogeneities resulted in the anomalous extension of ferromagnetic composition range compared to melt-quenched films.