Using the conventional sol-gel process, the series of non-stoichiometric oxygen lanthanum ferrites with the formula ${\mathit{La}}_{0.75}{\mathit{Ba}}_{0.10}{\mathit{Sr}}_{0.15}Fe{O}_{2.875-\delta }$ (δ = 0.00, 0.125 and 0.25) were prepared. X-ray diffraction analysis confirmed the formation of the orthorhombic structure with Pnma space group. In the present work, we confirm the potential of ${\mathit{La}}_{0.75}{\mathit{Ba}}_{0.10}{\mathit{Sr}}_{0.15}Fe{O}_{2.875-\delta }$ (δ = 0.00, 0.125 and 0.25) as an efficient dielectric material. All samples show high absorbance in the visible region with wavelength above 300 nm. The optical band gaps are found to increase from 3.25 to 4.1 with increasing oxygen vacancy concentration. The dielectric constant, dielectric loss and loss factor were carried out as a function of oxygen vacancy concentration and frequency (10²–10⁶ Hz) at room temperature. The variation of dielectric constant with frequency indicates dispersive behavior and giant dielectric response (more than 10⁴) at low frequencies for compounds deficient in oxygen. Such value of ${\epsilon }^{\text{'}}$ makes these samples an interesting material to be used in applications namely the reduction of electronic components size. To summarize, incorporating vacancy oxygen enhances the dielectric properties. Thus, the interesting dielectric constant and weak loss strengthen the use for potential applications.

使用常规的溶胶-凝胶工艺，一系列具有以下化学式的非化学计量氧镧铁氧体 ${\mathit{啦}}_{0.75}{\mathit{巴}}_{0.10}{\mathit{r}}_{0.15}FË{Ø}_{2.875--\delta }$ 制备（δ＝ 0.00、0.125和0.25）。X射线衍射分析证实具有Pnma空间群的正交结构的形成。在目前的工作中，我们确认了${\mathit{啦}}_{0.75}{\mathit{巴}}_{0.10}{\mathit{r}}_{0.15}FË{Ø}_{2.875--\delta }$（δ  = 0.00、0.125和0.25）作为有效的介电材料。所有样品在波长大于300 nm的可见光区域均显示出高吸收率。发现随着氧空位浓度的增加，光学带隙从3.25增加到4.1。介电常数，介电损耗和损耗因数是室温下氧空位浓度和频率（10 ² –10 ⁶ Hz）的函数。介电常数随频率的变化表明，对于缺乏氧的化合物，在低频下的色散行为和巨大的介电响应（大于10 ⁴）。这样的价值${\epsilon }^{\text{'}}$使这些样品成为一种有趣的材料，可用于应用，即减小电子元件的尺寸。总而言之，引入空位氧可增强介电性能。因此，令人感兴趣的介电常数和微弱损耗增强了其在潜在应用中的用途。