LaMnO3 (LMO) nanoparticles were synthesized using the reverse micelle route and thoroughly characterized to determine their structural, morphological, optical, electrical, and magnetic properties. The single-phase formation of a cubic deformed perovskite structure with good crystallinity was confirmed by X-ray diffraction (XRD) and Rietveld refinement. Irregularly shaped nanoparticle agglomeration with a porous morphology was observed by scanning electron microscopy (SEM), and a homogeneous elemental distribution and phase purity were confirmed through energy-dispersive X-ray spectroscopy (EDS). Fourier-transform infrared (FTIR) spectroscopy complemented the characteristic Mn–O vibrational modes, allowing the stabilization of the well-defined MnO6 octahedra. UV–visible spectroscopy indicated a direct optical bandgap of approximately 1.96 eV, suggesting its potential for use in visible-light-driven electronics. Electrical resistivity measurements exhibited thermally activated behavior with an activation energy of 0.21 eV, which is compatible with small polaron hopping in perovskite oxide semiconductors. Magnetic measurements at room temperature revealed that the size-induced surface effects and oxygen vacancies caused weak ferromagnetism.
