Effect of sintering temperature on re-distribution of cations, electronic structure and tuning of optical band gap and ferromagnetism in Mn0.1Co0.9Fe2O4 spinel ferrites

Abstract Manganese-ion doped cobalt ferrite with the composition Mn 0.1 Co 0.9 Fe 2 O 4 was synthesized by the self-combustion method and sintered at 800 °C, 900 °C and 1000 °C, represented as MCF-800, MCF-900 and MCF-1000, respectively. X-ray methods observed a single-phase cubic spinel formation. XPS analysis revealed the distribution of Mn 3+ and Mn 2+ ions in the tetrahedral A and octahedral B sites. Optical absorption studies confirmed an energy bandgap of 1.2505 eV for the sample MCF-1000, corresponding to near IR absorption useful for catalytic and water-splitting applications. The VSM measurements revealed a maximum magnetization ( Ms ) of 79.612 emu/g for the sample MCF-1000. The maximum entropy method (MEM) electron density distribution studies revealed different strengths of electron density for the cation tetrahedral site A and octahedral site B depending on sintering temperature variation. The sample sintered at 1000 °C with the A–O covalent and B–O ionic bonds with mid-bond densities of 1.903 e/Å 3 and 0.381 e/Å 3 may be useful for ferromagnetic applications. The magnetic, optical, and electronic analyses confirm that the sample MCF-1000 may be best suited for low-cost catalytic, water splitting and ferrite applications.