Influence of chromium ion substitution on the structure and properties of zinc ferrite synthesized by the sol–gel auto-combustion method

Nanocrystalline powders of chromium substituted zinc ferrites with the general formula ZnFe2−xCrxO4 (0 ⩽ x ⩽ 2) were obtained by the sol–gel auto-combustion method, using tartaric acid as a combustion-complexing agent. The solid phase chemical reactions were monitored using infrared spectroscopy, finally indicating the absence of organic phases. The XRD results confirmed the spinel mono-phase formation in the 24–36 nm crystallite size range. Nanosized particle formation was confirmed through scanning electron microscopy. The cation distribution in the samples was estimated theoretically and the results showed that all the compounds had a mixed ionic distribution. The magnetic properties of the samples were studied using a vibrating sample magnetometer and showed that the increase in Cr3+ concentration in the Zn ferrite caused a reduction in the hysteresis losses and a non-linear reduction in the saturation magnetization. The electrical analysis showed very low values of dielectric loss at frequencies over 1 MHz.

The relationship between the structure and electrical properties of a sintered powder.Figure optionsDownload as PowerPoint slide