Magnetodielectric effects at magnetic ordering transitions

The dielectric constant in many insulating magnets exhibits pronounced changes at magnetic ordering temperatures or with the application of external magnetic fields. As the dielectric response is sensitive to materials properties at non-zero wavevectors, dielectric spectroscopy provides additional insight into spin structures in these insulators beyond what can be determined using bulk magnetization measurements alone. We present illustrative examples of intrinsic magnetodielectric coupling in non-polar ferro- and antiferromagnets, SeCuO₃ and TeCuO₃ respectively, and of magnetodielectric coupling in a polar system, specifically Ni₃V₂O₈. We also show an example of how spurious magnetocapacitive effects can significantly modify the magnetodielectric response of a system. We include with some general comments on how the magnetodielectrics may be useful for device applications and how the coupling may be enhanced by modifying the materials.