The Effect of Cationic Disorder on Low Temperature Magnetic Properties of MnZn Ferrite Nanoparticles

Abstract

MnZn ferrite nanoparticles (NPs) with MnxZn1−xFe2O4 (x = 0 and 0.6) compositions have been synthesized by sol–gel process. As prepared (AP) particles were annealed at 1200 °C in air to compare the physical properties of NPs with their bulk counterparts. The crystallite sizes of AP samples were estimated to be 18 nm for x = 0 and 11 nm for x = 0.6. The cationic disorder was evaluated from the Rietveld analysis of X-ray diffraction (XRD) data, which decreases with increasing annealing temperature. The average particle size of the AP samples is observed to be below 20 nm and transform into single-phase spinel structure of ∼500 nm long cylindrical rods of 60 nm-diameter for x = 0.6, when annealed at 1200 °C in air. The magnetic properties of AP NPs show ferrimagnetic behavior below the blocking temperature (TB) and superparamagnetic behavior above the TB. The observed magnetic characteristics corroborate well with the structural parameters obtained from the Rietveld analysis of the XRD data.