Structural and Magnetic Characterization of Ni-Co Mixed Ferrite Nanopowders Synthesized via Coprecipitation and Sol-Gel Methods

Abstract

Ni 0.5 Co 0.5 Fe 2 O 4 nanoparticulate powders were synthesized using coprecipitation and sol-gel methods. The crystalline structure of the nanocompounds was determined through X-ray diffraction analysis. The chemical composition of the synthesized nanopowders was analyzed using infrared spectroscopy measurements. The size, morphology, and aggregation of the nanoparticles were determined from electron microscopy images. The magnetic properties of the nanocompounds were studied through magnetization measurements as a function of temperature and applied magnetic field. The synthesized powders consist of aggregates of nanoparticles with mean particle sizes of 24 nm and 43 nm, with those synthesized using the coprecipitation method being smaller. The compounds exhibited a single crystalline phase corresponding to the cubic spinel structure, with a unit cell parameter of approximately 8.35 Å and an inversion parameter with values of 0.94 and 0.95. The synthesized Ni-Co mixed ferrites presented an ordered magnetic behavior below 320 K, with the nanoparticles being in the blocked magnetic regime.