Effective demagnetizing factors of complicated particle mixtures

Demagnetizing factors have been calculated for hierarchical mixtures and dispersions of magnetic particles, such as columns of plate-like particles in a matrix and clusters of spherical particles. The theory involves a number of shape and density parameters describing particles, aggregates, and matrix. It approximates distant particles by a homogeneous medium and yields closed and easy-to-use expressions for the effective demagnetizing factor.