Non-stoichiometric ferrite magnetic nanoparticles Mg_0.5+xLi_1−2xFe₂O₄ (x = 0, 0.15, 0.35) were prepared using low-cost sol–gel method and annealed at temperature 700 °C. Thermal analysis measurement confirms that there is a decrease in weight with an increase in temperature which becomes thermally stable till 600 °C. The XRD study confirms that prepared nanoparticles are a cubic spinel structure having Fd3m space group. The crystallite size lies in the range of 26.41–31 nm. Lattice parameter was found to increase with decreasing molar ratio of Li ion. The FTIR spectroscopy confirms the spinel nature of ferrite nanomaterial having characteristics absorption peaks at 588 and 435 cm^−1. HRTEM and SEM image confirms the cubic spinel structure and porosity in the material. The indirect energy band gap was evaluated for all samples using tauc plot and found to be 2.25, 1.89 and 2.03 eV respectively for x = 0, 0.15 and 0.35. The energy band gap was found function of crystallite size. Strong luminescence was observed in the visible range of 580–610 nm. The non-molar ratio of Li = 0, 0.15 and 0.35 mol leads to a systematic increase in all the magnetic parameters. The magnetization increases from 15.53 to 33.75 emu/g, retentivity from 2.66 to 7.11 emu/g and coercivity increases 116.56–161.37 Gauss, respectively. Prepared nanomaterial possesses pure phase porous crystal with luminescent property in the visible range, energy band gap in the range of 2.03–2.25 eV and uniform increase in the magnetic parameter. Hence, materials may be potential candidate for magneto-optical device, humidity sensor, hydroelectric cell applications and some other realted fields.

非化学计量的铁素体的磁性纳米粒子的Mg _{0.5 + X}栗_1-2倍的Fe ₂ ø ₄（X  = 0，0.15，0.35），使用低成本的溶胶-凝胶方法制备的并在温度700退火℃。热分析测量结果表明，随着温度的升高，重量有所减轻，直到600°C时才保持热稳定性。XRD研究证实所制备的纳米颗粒是具有Fd3m空间群的立方尖晶石结构。晶粒尺寸在26.41–31 nm之间。发现晶格参数随着Li离子摩尔比的降低而增加。FTIR光谱证实了在588和435cm ^-1处具有特征吸收峰的铁氧体纳米材料的尖晶石性质^。HRTEM和SEM图像证实了材料中的立方尖晶石结构和孔隙率。使用tauc图评估了所有样品的间接能带隙，发现x分别为2.25、1.89和2.03 eV = 0、0.15和0.35。发现能带隙是微晶尺寸的函数。在580-610 nm的可见光范围内观察到强发光。Li ＝ 0、0.15和0.35mol的非摩尔比导致所有磁参数的系统性增加。磁化强度分别从15.53增加到33.75 emu / g，保持力从2.66增加到7.11 emu / g，矫顽力增加了116.56–161.37高斯。制备的纳米材料具有纯相多孔晶体，在可见光范围内具有发光性能，能带隙在2.03–2.25 eV范围内，并且磁参数均匀增加。因此，材料可能是磁光设备，湿度传感器，水力电池应用和其他一些实际领域的潜在候选者。