Electric field induced metal-insulator transition and colossal magnetoresistance in CdCr$_{2}$S$_{4}$

Multiferroic ordering existing in a single material is a recent hot topic in the field of condensed matter physics due to its potential application in device control. The chromium chalcogenide spinel CdCr$_{2}$S$_{4}$ is one of the attractive materials investigated by Hemberger \textit{et al.} recently.[1] Based on the electrical measurement, there is no discontinuity through the ferromagnetic ordering at $T_{C} \quad \sim $ 85K.[2] We measure the temperature dependent resistance under various electric fields to investigate the electrical properties of the present material. To our knowledge, we first observe the electric field induced metal-insulator transition in this material around $T_{C}$. Moreover, a colossal magnetoresistance (CMR), which is comparable to that of manganese-based CMR material, is also observed near $T_{C}$. The origin for these properties is discussed. [1] J. Hemberger, P. Lunkenheimer, R. Fichtl, H.-A. Krug von Nidda, V. Tsurkan, A. Loidl, Nature 434, 364 (2006). [2] P. K. Baltzer, H. W. Lehmann, and M. Robbins, Phys. Rev. Lett. 15, 493 (1965).