Magnetoelectric coupling without electric and magnetic response?

Abstract

We theoretically consider electrically small reciprocal particles, which show bianisotropic magneto-electric coupling. We study how strong the magneto-electric effect can be in comparison with the electric and magnetic polarizations induced directly by the corresponding electric and magnetic incident fields. In particular, we prove that it is not possible to realize a passive reciprocal particle, which would have exactly zero electric or magnetic polarizability but still exhibit magneto-electric coupling effects. On the other hand, we prove that magnetoelectric coupling coefficient can be very large as compared to both electric and magnetic polarizabilities of the same particle, in contrast to some claims found in the literature.