Cr <sup>3+</sup> substituted aluminum cobalt ferrite nanoparticles: influence of cation distribution on structural and magnetic properties
A. M. Faramawy, G. Mattei, Carlo Scian, Hamada Elsayed, M.I.M. Ismail
Abstract
Abstract Nanoparticles Cr x Al 0.5–x CoFe 1.5 O 4 (x = 0.1, 0.25 and 0.4) spinel ferrites were synthesized by co-precipitation technique, aiming to study the relationship between cation distribution of the substitution of chromium and aluminum ions on the structure, morphology, magnetic properties, permeability, Curie temperature and AC loss. X-ray diffraction (XRD) analysis used with Rietveld refinement revealed nanocrystalline single-phase of the spinel ferrites. The calculated average crystallite size is between 40 and 45 nm. The obtained results show, that both lattice constant and total porosity increased by increasing Cr 3+ concentration. It was found that Al 3+ occupied tetrahedral (A) and octahedral (B) sites whereas, Cr 3+ preferred to occupy only octahedral (B) sites. The magnetization M s, coercivity H c and the magneto-crystalline constant k 1 decreased with increasing Cr 3+ content. Likewise, Curie temperature T C decreased from 670 K to 585 K with increasing Cr 3+ concentration. Magnetic loss has further been observed and increased with increasing Cr 3+ concentration in all investigated samples.