Carbon encapsulation of magnetic metal nanoparticles: correlation between nanoscale structure of carbon matrix and electromagnetic properties

The dependence between the variation of microwave losses by $a$ - $C:H(Co)$ films measured at 10 $GHz$ and alteration of Co content in the film was investigated. It was shown that microwave losses attain maximal value at approximately 33at.% of cobalt. This dependence may be explained in terms of the formation of Co-containing clusters having various shapes. Because of property of conductive flakes to absorb microwaves, fragments of graphene modified with Co are considered as candidates for the microwave absorption. Estimations of the flake size using Raman and transmission electron microscopy data allow reproduce initial conditions for mathematical simulation of physical properties of the flakes.