Structural and Magnetic Properties of Cu2+ Substituted Co–Zn Ferrite Nanoparticles, Synthesized by Sol–Gel Combustion Method

Abstract

In this work, the effect of Cu content on structural and magnetic properties of Cobalt–Zinc Ferrite nanoparticles synthesized by sol–gel combustion method have been investigated. All the samples exhibit cubic spinel structure and the lattice constant decreases linearly with increasing Cu-content. Average crystallite sizes calculated from Debye–Scherrer formula are in the range of 51–100 nm. The broadening of X-ray diffraction peaks decrease with increasing Cu content ‘x’ suggest that crystallite size increases with increasing ‘x’. Cation distribution estimated form X-ray line intensity calculations show that Cu ions simultaneously occupy tetrahedral (A) and octahedral (B) sites with different ratio and Zn and Co ions occupies A and B sites respectively. With increasing Cu content a fraction of Co ions migrate to A site when x >0.2. Grain sizes estimated from SEM are found to be increase with increasing Cu content. Particle size calculated using TEM for the undoped Co–Zn ferrites is about 55 nm. Saturation magnetization (Ms), Coercivity (Hc) and remanent magnetization (Mr) that varies significantly with Cu-Content. Saturation magnetization decreases from 90.7 emu/g (x = 0.0) to 51 emu/g (x = 0.4). The proposed cation distribution supports the variation in saturation magnetization and Coercivity with increasing Cu content.