Silva, ArielPaschoal, Carlos William2024-12-132012https://deposita.ibict.br/handle/deposita/721In this work we investigated the vibrational and dielectric properties of the ceramic Bi₃Fe₀ ₅Nb₁ ₅O₉(BFN) at room temperature by using the Raman and infrared spectroscopic techniques along with classical lattice dynamics calculations. Concerning the Raman modes, fifteen vibrational modes at room temperature, were observed and classified based on performed lattice dynamics calculations. The temperature dependent Raman spectra showed clearly the ferroelectric phase transition in BFN at around 250 ° C, as discussed in the literature. The dielectric properties as well as Longitudinal (LO) and Transverse (TO) optical modes were obtained by adjusting the reflectivity spectrum of BFN at room temperature. We calculated static dielectric constant as εs = 30, which is relatively larger than the minimum value required for passive devices used in microwave electronics (εs > 10). Finally, we determined the dielectric loss in the microwave region yielding a quality factor Q = 2040 (10 GHz).application/pdfopenAccessEspectroscopia RamanInfravermelhoPropriedades vibracionais da cerâmicaRaman spectroscopInfrared Vibrational properties of ceramicsCNPQ::CIENCIAS EXATAS E DA TERRA::FISICADissertação