Effect of zinc doping on structural, bonding nature and magnetic properties of co-precipitated magnesium–nickel ferrites

This paper describes the electronic structure, bonding nature and magnetic properties of Mg 0.5 Ni 0.5− x Zn x Fe 2 O 4 ( x  = 0.1, 0.2, 0.3, 0.4) nano-spinel ferrite samples synthesized by the co-precipitation method. Spinel structure with Fd3̄$\bar{3}$m space group is confirmed by XRD analysis with trace amounts of hematite. The results of XRD and FTIR confirm the formation of spinel structure. The estimated average crystallite size ranges from 35 to 59 nm by different methods. The FESEM analysis revealed that the samples have a generally porous aspect. Particle size analysis indicates that the average particle size is approximately 150 nm. Covalent bond exists between the tetrahedral A site – oxygen atom (A–O) and ionic nature exists between the octahedral B site – oxygen atom (B–O) in the two sub lattices of the ferrite unit cell, as determined by the maximum entropy method. Mg 0.5 Ni 0.3 Zn 0.2 Fe 2 O 4 demonstrates high A–O covalency and B–O covalency/ionic boundary based on MEM electron density analysis.