  The correlation between colossal magnetocapacitance (CMC) and colossal
magnetoresistance (CMR) in CdCr2S4 system has been revealed. The CMC is induced
in polycrystalline Cd0.97In0.03Cr2S4 by annealing in cadmium vapor. At the same
time, an insulator-metal transition and a concomitant CMR are observed near the
Curie temperature. In contrast, after the same annealing treatment, CdCr2S4
displays a typical semiconductor behavior and does not show magnetic field
dependent dielectric and electric transport properties. The simultaneous
occurrence or absence of CMC and CMR effects implies that the CMC in the
annealed Cd0.97In0.03Cr2S4 could be explained qualitatively by a combination of
CMR and Maxwell-Wagner effect.
