Lepidagathis ananthapuramensis Leaf Extract Stabilized Co₃O₄ Nanoparticles and its Structural, Optical and Magnetic Properties

The present work focusses on the green synthesis of Co₃O₄ nanoparticles (NPs) using Lepidagathis ananthapuramensis leaf extract and to investigate its structural, optical, morphological and magnetic properties. The structural information confirmed the formation of spinel type polycrystalline cubic symmetry with space group Fd-3 m. The Fourier transform infrared spectroscopic studies revealed the sharp doublet peak in the finger print region pertaining to the Co²⁺ and Co³⁺ ions. The X-ray photoelectron spectroscopy further confirmed the presence of Co³⁺ and Co²⁺ ions in which Co³⁺ ions are present more than Co²⁺ ions. The UV–Visible spectroscopic studies indicate that there are two characteristic absorptions of Co₃O₄ NPs indicating the ligand to metal charge transfer. The morphological analysis of Co₃O₄ NPs using field emission scanning microscope and high-resolution transmission electron microscopy, showed irregular shapes of different sizes with Co mostly at surface than the core. The magnetic data revealed the existence of antiferromagnetic nature co-hosting weak ferromagnetism. The detailed explanations of a straightforward and affordable method for creating spinel type Co₃O₄ and their structural and magnetic properties were explained.