Model of FeCr2S4 as a true semiconductor in a strong Weiss field

We propose the simple model for the colossal magnetoresistance in FeCr(2)S(4). The material is considered a classical semiconductor with parabolic density of states that is affected by both the external magnetic field and the strong Weiss exchange field that arises from the magnetic order in the substance. The resulting effective field shifts the conducting bands and hence causes the change in the number of thermoactivated carriers. This change is presumed to be responsible for the magnetoresistance. Surprisingly this apparently oversimplified model describes well both the temperature and magnetic-field dependences of the resistivity in this material employing the minimal set of the adjusted parameters. The role of the critical phenomena above Curie temperature appears to be important.