Effects of Fe2+ substitution on magnetic and dielectric properties of CdCr2S4

The magnetic and dielectric properties of polycrystalline Cd1-xFexCr2S4 (0 <= x <= 0.9) are investigated. Upon substitution of Cd by Fe, the Curie temperature (T-C) is increased while the saturation magnetization is decreased. A low doping level of Fe increases the permittivity, while a high doping level decreases the permittivity, which is explained by the internal barrier layer capacitor model. Kinks are observed in the temperature-dependent permittivity and loss tangent near T-C for the samples with x = 0.5, 0.7, 0.9, implying the existence of the magnetodielectric effect. Furthermore, with the increase of Fe content, a decrease of anomaly deviation rate induced by internal molecular field is revealed in the permittivity, while an increase is observed for the loss tangent.