High density nanoparticle Mn-Zn ferrite synthesis, characterisation and magnetic properties

Abstract

The amazing magnetic properties exhibited by nanoparticles Mn-Zn ferrites and their promising technological and medical applications have attracted much interest in recent years. Nanoparticle Mn-x Zn(1-x) Fe2O4 spinel ferrites with x = 0.6/0.63/0.65/0.67/0.7 were synthesised by the nitrilotriacetate precursor method employing microwave combustion synthesis. Powder X-ray diffractometry (XRD) confirmed the formation of the ferrite phase in all samples. IR analysis was done to verify formation of spinel structure. Elemental analysis using EDS confirmed the nanoparticle composition. The crystallite size was calculated from peak widths using the Scherrer formula, yielding a size in the range of 10-25 nm. Transmission electron microscopy was also performed on the samples to testify formation of nanosized crystallites in the sample. Saturation magnetisation (Mr), retentivity (Ms) and coercivity (He) measurements were carried out on the samples using standard hysteresis loop tracer equipment. The saturation magnetisation values were found to be in the range of 58.6-63.2 emu/g with very low values for (Mr/Ms). Variation of specific magnetisation with temperature and Curie temperature measurements were carried out using pulse field AC susceptibility measuring equipment. These measurements indicated formation of single domain (SD) material with dependence of Curie temperature on Zn concentration. The density of the samples was found to be high.