Investigation of structural changes in la2-xyxmo2o9 (0≤x≤0,2) using raman spectroscopy

Investigation of Structural Changes in La2-xYxMo2O9 (0≤x≤0,2) Using Raman Spectroscopy The aim of the bachelor thesis is to investigate the changes in the structure of yttrium-substituted lanthanum molybdate gels and polycrystalline compounds using the Raman spectrometry method. The following tasks have been implemented: 1. To review the literature on research of lanthanum molybdate and its compounds by vibrational spectroscopy and other methods. 2. To register the Raman spectra of the yttrium-substituted lanthanum molybdate gels and polycrystalline compounds after annealing in different temperatures. 3. To determine the structural changes of the samples from the degree of lanthanum substitution, the temperature of annealing, and the cooling time of the samples using Raman spectroscopy. According to the 27 works reviewed, methods of vibrational spectrometry are less commonly used, but effective and complementary to other methods for investigating family of lanthanum molybdate-based ion conductors. The Raman spectra of the yttrium-substituted lanthanum molybdate gels and polycrystalline compounds were recorded. The analysis of spectra has shown that changing the substitution rate of lanthanum with yttrium changes the parameters of vibration bands that can be linked to the changes caused by the phase transition of the samples from the monoclinic to the cubic structure. After analyzing the dependence of spectral parameters on the annealing temperature, it was found that the annealing temperature is not significantly influencing the vibrational bands of the polycrystalline compounds. It was found that vibrational band parameters in different cooling methods of the samples correlate with the substitution rate of yttrium