Abstract We investigate the structural and optical properties of ZnFe2-xLaxO4 spinel ferrite (0 ≤ x ≤ 0.015) prepared using sol-gel route. The lattice parameter increases and the crystallite size decreases by La3+ replacements as was demonstrated by X-ray diffraction. UV–visible spectroscopy was used to study the optical properties. The optical band gap increases from 1.8714 to 1.9557 eV, with the increase in La3+ concentration up to x = 0.015. On the contrary, Urbach energy (band tail width), EU was found to be decreased from 0.6027 to 0.4247 eV. In addition, different optical parameters were extracted and associated with the change of La amount such as the absorption coefficient, refractive index, the extinction coefficient, real and imaginary dielectric constant, conductivity optical and electrical conductivity. Finally, the dependency of the refractive index to the wavelength was fitted to Wemple-DiDomenico single oscillator model and the parameters like dispersion energy, single oscillator energy, oscillator length strength, and average oscillator wavelength were also determined.

中文翻译：

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La掺杂尖晶石锌铁氧体ZnFe2-xLaxO4的合成、结构、光学和色散参数（x = 0.00、0.001、0.005、0.01和0.015）

摘要 我们研究了使用溶胶-凝胶法制备的 ZnFe2-xLaxO4 尖晶石铁氧体 (0 ≤ x ≤ 0.015) 的结构和光学性质。正如 X 射线衍射所证明的那样，通过 La3+ 置换，晶格参数增加，晶粒尺寸减小。紫外-可见光谱用于研究光学性质。光学带隙从 1.8714 eV 增加到 1.9557 eV，La3+ 浓度增加到 x = 0.015。相反，发现 Urbach 能量（带尾宽度），EU 从 0.6027 降低到 0.4247 eV。此外，提取了不同的光学参数，并将其与 La 量的变化相关联，例如吸收系数、折射率、消光系数、实部和虚部介电常数、电导率、光导率和电导率。最后，