Effect of Cr3+ substitution on magnetic and electrical properties of (Ni0.3Cu0.7) Fe2O4 spinel ferrites

摘要

Chromium substituted copper base spinel ferrites (Ni0.3Cu0.7)CrXFe2?XO4 were prepared by Sol-gel method. Structural, magnetic and electrical properties were studied by utilizing an X-ray diffractometer, vibrating-sample magnetometer, and precision LCR-meter using labtracer software. The X-ray diffraction analysis con?rmed the formation of single phase fcc structure of the samples. The lattice constant and crystallite size decreased from 8.37-8.23 ?A and 53.09-35.36 nm, respectively with increasing content of Cr3+ ions. From Magnetization Vs Applied ?eld loops it was observed that the saturation magnetization decreased and coercivity increased with increasing content of Cr3+ ions. Dc resistivity increased with increase of Cr3+ concentration and decreased with increase in temperature which shows the semiconducting behavior of ferrites. The dielectric constant, dielectric loss, and tangent loss decreased with increase of Cr3+ concentration. The dielectric constant follows bilayer Maxwell Wagner model and Koop’s phenomenological theory while ac conductivity increased with increasing frequency following Jonscher’s power law.