Colossal magnetocapacitive effect in differently synthesized and doped   CdCr2S4
  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. 
S. Krohns, F. Schrettle, P. Lunkenheimer, V. Tsurkan, A. Loidl