Synthesis of nanocrystalline nickel-zinc ferrite by the sol-gel method

Abstract

Ni0.5Zn0.5Fe2O4 crystals having dimensions varying from 13 to 35 nm have been synthesized within a silica glass matrix by a sol-gel method. Particle sizes in the above range can be controlled by a suitable heat treatment schedule at temperatures varying from 973 to 1323 K. The coercivity values for different heat-treated samples are found to be in the range 20-95 Oe, which are significantly larger than that for samples having grain sizes of the order of a few microns. The Mössbauer spectra of the samples show the presence of ultrafine particles exhibiting superparamagnetic relaxation. © 1993.