Revealing optical and magnetic transitions in mo-doped CoFe₂O₄ via spectroscopic analysis

Spinel ferrites are a class of multifunctional materials known for their distinctive structural, magnetic, and optical characteristics, making them promising candidates for diverse technological applications such as biomedicine, catalysis, environmental remediation, spintronics, and optoelectronics. In this study, we explore the impact of partially substituting Fe³⁺ ions with Mo⁶⁺ in cobalt ferrite, forming the composition CoFe₂₋ₓMoₓO₄ (x = 0, 0.4). This substitution is anticipated to alter the electron density in the conduction band, thereby influencing the material’s optical and magnetic behavior. The polycrystalline samples were synthesized via a chemical method using ethylene glycol as a complexing agent. Optical absorption measurements reveal a slight red shift in the absorption edge, a narrowing of the optical band gap, and a notable increase in Urbach energy with increasing Mo content — indicating enhanced structural disorder. Overall, these findings demonstrate the compositional tunability of spinel ferrite properties and underscore the potential of Mo-doped cobalt ferrites in advanced applications, including sensors, optoelectronic devices, and energy storage technologies.