Magnetoelectric Properties of Reciprocal Bi-Anisotropic Materials with Focus on the Polarizability of Chiro-Omega Spheres

Abstract

This paper concentrates on magnetoelectric characteristics of bianisotropic materials using the concept of reciprocity as a criterion of classification. A dyadic matrix representation is followed, and the complementary operation for dyadic matrices is introduced which is shown to be a very useful operation in treating material parameters of bianisotropic media. The analysis goes further to treat the polarizability properties of bianisotropic spheres. The polarizability matrix, containing four dyadic elements, is derived in compact matrix form. The distinction between two types of reciprocal magnetoelectric coupling is interpreted in terms of helical and omega-type elements. These account for the symmetric and antisymmetric parts, respectively, of the magnetoelectric material dyadic in the bianisotropic constitutive relations. The components of the polarizability dyadics are calculated for an omega sphere and also for a chiro-omega sphere. It is found that the components of the material parameter dyadics ∊, μ, ζ η become coupled in the polarizability components. The coupling details are described and these are shown to be different for the chiral magnetoelectric effects and the omega effects.