  In the present work, we address the question of an impurity-related origin of
the colossal magnetocapacitive effect in the spinel system CdCr2S4. We
demonstrate that a strong variation in the dielectric constant below the
magnetic transition temperature or in external magnetic fields also arises in
crystals prepared without chlorine. This excludes that an inhomogeneous
distribution of chlorine impurities at the surface or in the bulk material
gives rise to the unusual effects in the spinel multiferroics. In addition, we
show that colossal magnetocapacitive effects can be also generated in
chlorine-free ceramic samples of CdCr2S4, doped with indium.
