The optical and dielectric properties of the ZnFe₂O₄–Al₂O₃ nanocomposite are investigated and compared with the ZnFe₂O₄–SiO₂ nanocomposite and ZnFe₂O₄ nanoparticles. The nanocomposite is prepared by simple sol–gel auto-combustion method. The prepared samples are annealed at 800 °C for 6 h. The samples are characterized by infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The formation of single phase cubic spinel structure for ZnFe₂O₄ nanoparticles is confirmed by X-ray diffraction analysis and the average crystallite size is 52.09 nm. In nanocomposite form the reduction in the crystallite size is observed. Studies on infrared spectroscopy confirm the presence of Al₂O₃ and SiO₂ along with ZnFe₂O₄ nanoparticles. Transmission electron microscopy observations reveal that ZnFe₂O₄ nanoparticles are well dispersed in alumina as well as in silica matrix and not highly agglomerated. From UV–visible spectroscopy, the calculated band gap of ZnFe₂O₄ is 2.89 eV where in presence of alumina matrix the band gap of nanocomposite increases to 2.97 eV. In presence of SiO₂, a decrease in the band gap of ZnFe₂O₄ nanoparticles is observed (2.75 eV). Dielectric properties such as dielectric constant, dielectric loss of synthesized nanocomposites are studied as a function of frequency. The dielectric study reveals that ZnFe₂O₄–Al₂O₃ exhibits a significantly enhanced dielectric constant and dielectric loss as compared to that of ZnFe₂O₄–SiO₂ as well as ZnFe₂O₄ nanoparticles. At lower frequencies, the value of dielectric constant is in the order of 10⁴ for ZnFe₂O₄ nanoparticles and in presence of alumina, it enhances to the order of 10⁵. The composite structure exhibits a significantly enhanced ac conductivity with respect to ZnFe₂O₄ as well as ZnFe₂O₄–SiO₂ nanocomposite. The above results suggest that ZnFe₂O₄–Al₂O₃ nanocomposite can be a promising candidate for the development of optoelectronic devices.

研究了ZnFe ₂ O ₄ -Al ₂ O ₃纳米复合材料的光学和介电性能，并将其与ZnFe ₂ O ₄ -SiO ₂纳米复合材料和ZnFe ₂ O ₄纳米颗粒进行了比较。纳米复合材料是通过简单的溶胶-凝胶自燃方法制备的。制备的样品在800°C退火6 h。通过红外光谱，X射线衍射，场发射扫描电子显微镜和透射电子显微镜对样品进行表征。ZnFe ₂ O ₄的单相立方尖晶石结构的形成通过X射线衍射分析证实了纳米颗粒，平均微晶尺寸为52.09nm。以纳米复合物形式观察到微晶尺寸的减小。红外光谱研究证实了Al ₂ O ₃和SiO ₂以及ZnFe ₂ O ₄纳米颗粒的存在。透射电子显微镜观察表明，ZnFe ₂ O ₄纳米颗粒很好地分散在氧化铝以及二氧化硅基质中，并且没有高度聚集。通过紫外可见光谱，计算出的ZnFe ₂ O ₄带隙为2.89eV，其中在存在氧化铝基质的情况下，纳米复合材料的带隙增加至2.97eV。在存在SiO _2的情况下，观察到ZnFe ₂ O ₄纳米粒子的带隙减小（2.75 eV）。研究介电常数，如合成纳米复合材料的介电常数，介电损耗与频率的关系。介电研究表明，与ZnFe ₂ O ₄ -SiO ₂和ZnFe ₂ O ₄相比，ZnFe ₂ O ₄ -Al ₂ O _3的介电常数和介电损耗显着提高。纳米粒子。在较低的频率下，ZnFe ₂ O ₄纳米粒子的介电常数值约为10 ⁴，而在氧化铝的存在下，介电常数的值提高至10 ^5数量级。相对于ZnFe ₂ O ₄以及ZnFe ₂ O ₄ -SiO ₂纳米复合材料，复合材料的交流电导率显着提高。以上结果表明，ZnFe ₂ O ₄ -Al ₂ O ₃纳米复合材料可以作为光电子器件开发的有前途的候选者。