Transition metals (Zn,Co) interplay in structural modifications of ferrites followed by low temperature magnetic features and optoelectronic trends

Zn and Co incorporated with Fe 2 O 4 show different magnetic behaviors, the former can be adjusted between ferromagnetic and antiferromagnetic while the later one displays ferromagnetic ordering. This work presents a mixed system of Co–Zn with Fe 2 O 4 for its potential applications in optical communication, data storage, and magneto-optical devices. Zn x Co 1- x Fe 2 O 4 ( x = 0.00, 0.25, 0.50, 0.75, 1.00) nanostructures were prepared through Sol–Gel method followed by annealing at 800 °C. XRD results showed the cubic nature of all samples with grain sizes of 14–21 nm having high values of specific surface area (71–81 m 2 g −1 ). A linear increase in lattice constant from 8.3934 to 8.4322 Å is reported with the increase in Zn +2 concentration from 0 to 1, i.e., following Vegard’s law. Magnetic properties for x = 0.5 sample studied up to 5 K, and an improvement has been reported, e.g., M s from 40 to 88 emu.g −1 , H c up to 2236 Oe, n B from 1.72 to 3.75 μ B , H ex up to 32.44 Oe, and α Y - K ranged from 50° to 16°. Switching is reported in direct B.G for x = 0.25, x = 0.50, and in indirect B.G for x = 0.75. Prepared nanostructures have long ranged nonlinear refractive index (0.48–5.34) and metallization criterion from 0.37 to 0.45. Increased Zn +2 content in CoFe 2 O 4 resulted a decrease in Urbach energy from 318 to 141 meV. High values of lattice dielectric constant, direct B.G and large values of activation energies, optical and electrical conductivities suggested that prepared samples (especially with x = 0.50) have potential for use in efficient electronic devices such as sensors, photoconductors, solar cells and high-capacity energy storage devices such as supercapacitors. Dielectric and optoelectronic properties for Zn x Co 1- x Fe 2 O 4 surpassed all the previous work.