Structural, electronic, and magnetic properties of lithium-doped magnesium ferrite nanoparticles

Abstract

This study investigates the structural, microstructural, electronic, and magnetic properties of lithium-doped magnesium ferrite nanoparticles (Mg_1-xLi_xFe₂O₄) with varying lithium concentrations (x = 0, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03). Samples were synthesized via solution combustion synthesis and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and Mössbauer spectroscopy. XRD results confirm the formation of a single-phase spinel cubic structure, with a decrease in lattice parameters and crystallite size observed as lithium content increases. SEM analysis reveals uniform and homogeneous particle distribution, with a slight refinement in grain size with higher lithium doping. EDX confirms the presence of magnesium, iron, and oxygen, but lithium detection is limited due to its low atomic number and associated X-ray energy. XPS analysis indicates the chemical surface states of the composites, showing major photoemission peaks for Mg, Fe, and O, with a weak lithium signal due to low photoemission cross sections. Mössbauer spectra indicate superparamagnetic behavior at room temperature, transitioning to Zeeman splitting at 15K, providing insights into the local environments of Fe³⁺ ions. The findings highlight the impact of lithium doping on the structural, electronic, and magnetic properties of MgFe₂O₄, suggesting potential applications in magnetic storage devices and catalysis.