X-band characterization of anisotropic magnetic materials: application to ferrofluids

A simple, fast method of characterization of anisotropic magnetic materials uses a nonreciprocal X-band rectangular cell. The material may be a solid, powder, or magnetic liquid. A network analyzer measures the scattering parameters, and an original numerical processing routine computes the permeability tensor components. Two anisotropic magnetic materials have been characterized: a ferrofluid made with magnetite particles suspended in a hydrocarbon and a barium iron oxide powder. The knowledge of permeability behavior of magnetic liquids is important in designing specific nonreciprocal microwave devices. Experimental results are in good agreement with the proposed theoretical simulated model