Magnetocapacitance without magnetism

Abstract

A substantial magnetodielectric effect is often an indication of coupled magnetic and elastic order, such as is found in the multi-ferroics. However, it has recently been shown that magnetism is not necessary to produce either a magnetoresistance or a magnetocapacitance when the material is inhomogeneous. Here, we will investigate the characteristic magnetic-field-dependent dielectric response of such an inhomogeneous system using exact calculations and numerical simulations of conductor-dielectric composites. In particular, we will show that even simple conductor-dielectric layers exhibit a magneto-capacitance, and thus random bulk inhomogeneities are not a requirement for this effect. Indeed, this work essentially provides a natural generalization of the Maxwell-Wagner effect to finite magnetic field. We will also discuss how this phenomenon has already been observed experimentally in some materials. © 2014 The Author(s).