Characterization of Al-Substituted Ni-Zn Ferrites by XRD and FTIR Techniques

Abstract

Ni0.5Zn0.5AlxFe2-xO4 (x = 0.00 to 0.50 in increments of 0.05) was prepared by the auto combustion sol-gel method, and the resulting nanopowder was subjected to calcination at three temperatures: 400, 600, and 800 °C. The structure of ferrite was characterized by XRD, and it was found that all the prepared Ni-Zn samples possess a single-phase cubic spinel structure, corresponding to the Fd-3m space group. The crystal lattice constant, a(Å), was calculated based on the resulting XRD patterns and it was found within the range of 8.312 to 8.386 Å, as the value of a(Å) decreases with increasing Al content, and increases with increasing temperature when the aluminum content (x) is constant. The Scherrer equation was used to calculate the crystalline size (D), with all samples in the range of 14.64 to 39.75 nm, and the crystalline size increases with increasing calcination temperature at a constant concentration, and increases with increasing aluminum content when the calcination temperature is constant. It was also found that the theoretical density, ρx, decreases with increasing aluminum content, and increases with increasing calcination temperature. The lengths of ionic jumps were calculated and it was found that the lengths of ionic jumps decrease with increasing Al content at a constant temperature. As FTIR spectroscopy analyzes showed the formation of Al-Ni-Zn Ferrite with a spinel structure, the increase in bond lengths in all samples leading to a decrease in the absorption frequency. The infrared absorption peaks become stronger and clearer, indicating an increase in the crystallinity of the samples, as the calcination temperature increases.