Effect of Gd and Co contents on the microstructural, magneto-optical and electrical characteristics of cobalt ferrite (CoFe2O4) nanoparticles

Abstract Rare earth oxides with a trivalent nature play a pivotal role in reinforcing the magneto-optical attributes of spinel ferrite nanoparticles by replacing Fe3+ ions. In this study, rare earth Gd oxide doped with CoFe2O4 NPs with a composition of Co1+xGdxFe2-2xO4 (x = 0, 0.05, 0.10, and 0.15) were synthesized using sol-gel auto-combustion. The outcome of Gd cations on the physical, magneto-optical and electrical characteristics of the cobalt ferrite NPs were reported. X-ray diffraction (XRD), and Fourier transform infrared (FTIR) investigations confirmed the single-phase cubic crystalline nature and metal ion stretching in the cobalt ferrite synthesized samples. Decreasing drift in the average crystallite and grain sizes (estimated from the XRD patterns and SEM micrographs) and magnetic saturation ( M s ) were examined with the increasing content of Gd oxide and Co ions in the CoFe2O4 NPs. The optical bandgap of the synthesized samples explains the semiconducting nature of the prepared NPs due to the presence of an E g from 2.13 eV to 2.45 eV in the semiconductor region. The electrical properties of the co-doped samples exhibit a conducting trend in the presence of Gd3+ ions with the increase of temperature from 298 K to 973 K. DC measurements of the synthesized NPs demonstrated DC conductivity values from 0.1087 S/cm to 0.2676 S/cm at 973 K.