Multifunctional structural, optical, magnetic, and electrical properties of sol–gel-derived SmFeO3 nanoparticles

SmFeO 3 nanoparticles were prepared through a sol–gel synthesis route to explore their crystal structure, optical response, magnetic characteristics, and electrical behavior. Powder X-ray diffraction (XRD) results confirm the formation of a single-phase orthorhombic perovskite structure with Pbnm symmetry, and the average crystallite size estimated from peak broadening lies in the 35–40 nm range. Field-emission scanning electron microscopy (FESEM) reveals aggregated nanograins, while BET surface analysis indicates a mesoporous framework, suggesting a relatively good surface-to-volume ratio. Optical absorption measurements show a direct optical band gap (E g = 2.11 eV) within the visible region, demonstrating the semiconducting nature of the material. The photoluminescence spectrum recorded under 398 nm excitation exhibits emission bands at ∼572, 600, 644, and 705 nm, which originate from the 4 G 5/2 → 6 H J (J = 5/2–11/2) transitions of Sm 3+ ions, indicating efficient radiative recombination through intra-4f electronic states. Magnetic measurements reveal a narrow M–H hysteresis loop, indicating weak ferromagnetism arising from spin canting in the antiferromagnetic Fe 3+ lattice, consistent with the Dzyaloshinskii–Moriya interaction. Mössbauer spectroscopy further verifies that iron ions exist predominantly in the Fe 3+ high-spin state within octahedral FeO₆ coordination. Electrical characterization shows a frequency-dependent dielectric response governed by the Maxwell–Wagner interfacial polarization mechanism, while impedance spectroscopy demonstrates thermally activated semiconducting conduction dominated by grain contributions. The collective structural, optical, magnetic, and dielectric properties confirm that SmFeO 3 nanoparticles exhibit multifunctional behavior, highlighting their potential for photocatalytic systems, spintronic devices, magnetoelectric components, optoelectronic technologies, and advanced energy-related applications.