Dielectric behaviour of CuCr ferrites

Abstract

Samples of the system CuFe 2− x Cr x O 4 where x = 0.0, 0.2, 0.4, 0.6 and 0.8 were prepared. The dielectric constant and dielectric loss were measured at different frequencies and temperatures from room temperature to 600 K. The dielectric constant was measured using the phase detector technique (lock-in amplifier). The results showed that the dielectric loss decreases with increasing frequency and Cr substitution. The dielectric constant decreases with both increasing frequency and Cr substitution at room temperature. At moderate temperatures, the dielectric constant shows a dispersion peak ε′ max, and this peak shifted to higher frequency with increasing temperature. The results are explained in the light of the fact that the dielectric polarization process is similar to that of conduction. The appearance of the dispersion peak is related to the contribution of two types of charge carriers.