  The dielectric response in a magnetic field is routinely used to probe the
existence of coupled magnetic and elastic order in the multiferroics. However,
here we demonstrate that magnetism is not necessary to produce a
magnetocapacitance when the material is inhomogeneous. By considering a
two-dimensional, two-component composite medium, we find a characteristic
dielectric resonance that depends on magnetic field. We propose this as a
possible signature of inhomogeneities and we argue that this behavior has
already been observed in nanoporous silicon and some manganites.
