Effect of Mg substitution on structure and magnetic properties of Ni0·25Cu0·3Zn0·45Fe2O4 ferrites synthesised by NaOH coprecipitation method

Abstract

Ni0·25−xMgxCu0·3Zn0·45Fe2O4 (for x = 0, 0·05, 0·1, 0·2 and 0·25) ferrites have been synthesised by NaOH coprecipitation method. The X-ray diffraction patterns of these ferrites confirmed the formation of the single phase spinel structure. The lattice constant was found to increase with Mg content obeying Vegard’s law. The crystallite size of these samples varies from 13·2 to 16·4 nm. The bulk density ρB decreases with increasing Mg concentration. And scanning electron microscopy images show no obvious differences among all samples with different Mg concentration. With increasing Mg content, the initial permeability monotonously increases while the cutoff frequency fr gradually decreases, which agrees well with Snoek’s law. Moreover, saturation magnetisation Ms and the Curie temperature Tc continuously decrease with increasing Mg content but no noticeable variation in quality factor Q with Mg content is observed.