Properties of high-frequency granular magnetic materials

Soft magnetic materials, i.e. materials with a high permeability, are used in various devices for power, RF, and microwave applications. It is particularly important to engineer high-mu and low-loss magnetic materials. Permeability of a material is an extrinsic property, i.e. it is determined not only by intrinsic bulk parameters but also by the material composition. Granular magnetic materials are comprised of randomly hard magnetic grains that are exchanged coupled to result in soft properties. These materials combine the ability to have a high permeability with low conductivity. Generally, these materials are characterized by non-reciprocal dispersive tensors and identifying their properties can be a complicated task.