Abstract
Optical properties of a La0.57Nd0.1Sr0.13Ag0.2MnO3 polycrystalline sample prepared by solid-state reaction were investigated. The FTIR spectra confirmed the formation of the structure of orthorhombic perovskite. Tauc method, spectra diffuse reflectance (DRS) spectroscopy and first derivative methods were used to found and confirm exactly the value of optical band gap energy (E-g) of La0.57Nd0.1Sr0.13Ag0.2MnO3. Results show an indirect bandgap energy of E-gTau = 3.20 eV,E-gDRS = 3.59 eV, E-gdrivAbso= 3.29 eV and E-gdrivRefel= 3.594 eV.This shift in E-g value between Tauc method and spectra diffuse reflectance (DRS) spectroscopy is related to the lack of precision of Tauc's method. Urbach energy, optical extinction coefficient and skin depth in function of the wavelength of the incident photon were determined and discussed based on the absorption and reflectance spectrum. The Refractive index (n), the dispersion energy (E-0 and E-d), zero-frequency refractive index (n(0)), oscillator strength (S-0) and the oscillator wavelength (lambda(0)) values were found using Wemple-DiDomenico single-effective-oscillator model. Besides, the interband transition strength (J(cv)), surface (SELF) and volume (VELF) energy loss function were evaluated from dielectric constant data of the La0.57Nd0.1Sr0.13Ag0.2MnO3 sample In addition, the dielectric properties (epsilon*, sigma*, tg delta, M* and Z*) and optical conductivity (sigma(op)) has been optically studied and discussed clearly. Finally, the obtained values by the three methods are compared and discussed. These analysis of La0.57Nd0.1Sr0.13Ag0.2MnO3 compound may be a good candidate for optical devices.