Structural and Magnetic Characterizations of Coprecipitated Ni–Zn and Mn–Zn Ferrite Nanoparticles

摘要

Two mixed ferrite systems, namely Ni$_0.65$Zn$_0.35$Fe$_2 $O$_4$(Ni–Zn) and Mn$_0.75$Zn$_0.18 $Fe$_2.07 $O$_4$(Mn–Zn) have been prepared by coprecipitation method, and then the resulting ultrafine powders were heat treated at different temperatures from 200 to 800$^circ$C for improved crystallinity and magnetic properties. The samples were characterized by X-ray diffraction, vibrating sample magnetometry, and ferromagnetic resonance spectrometry. As a result of the heat treatment, the average particle size has been found to increase from 9.9 to 15.7 nm for Ni–Zn ferrites and from 2.4 to 10.2 nm for Mn–Zn ferrites, and the corresponding magnetization values have increased from 9.1 to 23 emu/g for Ni–Zn ferrites and from 7.9 to 11.7 emu/g for Mn–Zn ferrites, respectively. The results are discussed in the light of changes in particle size and inversion degree parameter for cationic distribution at nanoscales.