Investigation on Optical, Dielectric, and Magnetic Properties of CoAl2-xFexO4 Nanoparticles

In this study, Fe3+ doped cobalt aluminate, CoAl2-xFexO4, x = 0.00, 0.05, 0.10, 0.15, and 0.20, nanoparticles are synthesized via an efficient co-precipitation method. X-ray powder diffraction (XRD) is used to confirm the formation of single-phase cubic spinel structure. Some important optical parameters such as optical band gap E-opt, Urbach energy E-u, and refractive index n are estimated using UV-visible spectra, and their variations with Fe3+ content are discussed. Dielectric studies are carried out for the pelletized samples of CoAl2-xFexO4 nanoparticles at room temperature in the frequency range 50 kHz to 5 MHz. Several important dielectric parameters such as dielectric permittivity (epsilon '), dielectric loss (tan delta), and ac conductivity (sigma(ac)) of the samples are determined as a function in both frequency and Fe3+ content. The obtained Cole-Cole diagram shows one semicircle corresponding to grain conductions. The magnetic hysteresis (M-H) loop shows ferromagnetic behavior of the samples. The results show that the variation of magnetic parameters depends strongly on Fe3+ content and particle size. Saturation magnetization, magnetic moment, and remnant magnetization increase as the Fe3+ content increases.