Effect of Mn addition on the structural and magnetic properties of Zn-ferrite nanoparticles

Abstract

Abstract Super-paramagnetic, mono-dispersed and single-phased Mn-substituted Zn-ferrite nanoparticles (NPs) with a narrow size distribution were synthesized by a one-step citric acid-assisted hydrothermal method. X-ray diffraction (XRD), Scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier-transform infrared spectroscopy (FTIR) techniques were utilized to determine characteristics of the NPs. The as-prepared Zn0.3Fe2.7O4 NPs were highly crystalline with uniform size (14.5 ± 2.65) and good stability in an aqueous medium. The effects of Mn concentration (x = 0.25, 0.5, 0.75 and 1) and pH on the formation of Zn0.3MnxFe2.7−xO4 NPs were thoroughly studied. The maximum saturation magnetization of 55 emu/g was obtained for the Zn-ferrite sample substituted with x = 0.5 of Mn. Increasing x firstly resulted in an increased saturation magnetization from 47.1 emu/g (x = 0.25) to 55 emu/g (x = 0.5), followed by a decrease to 37 emu/g (x = 1). The variation of saturation magnetization was correlated with the distribution of Mn2+ ions in tetrahedral and octahedral sites.