Structural and Optical Properties of the Ruddlesden-Popper La1.4(Sr0.95Ca0.05)1.6Mn2O7 Sample Prepared by a Sol-Gel Method

The polycrystalline sample of the Ruddlesden-Popper La-1.4(Sr0.95Ca0.05)(1.6)Mn2O7 phase was synthesized using a sol-gel method. To determine the structural and optical properties as a function of photon energy for this sample, we can use the various techniques of characterization such as X-ray diffraction, SEM, and ellipsometric spectroscopy. Based on structural analysis by Rietveld profile fitting, a single-phase sample with tetragonal I4/mmm space group was obtained. The optical properties were investigated by spectroscopic ellipsometry at room temperature in the spectral range of 300-800 nm. The optical constants: refractive index n and extinction coefficient k were also studied. These measurements revealed that the optical absorption is obtained around 590 nm and the sample has a direct transition corresponding to the energy gap which was equal to 2.25 eV.