Conferencias, I Congreso Internacional de Ciencias Naturales y Aplicadas

Por defecto: 
Probe of the Second Harmonic Generation Response Multiferroic Iron—Doped Lithium Niobate Powders
Oswaldo Sánchez Dena, Mónica Janeth García Rodríguez, José Rurik Farías Mancilla

Construir: Centro Cultural Universitario
Sala: Teatro Gracia Pasquel
Fecha: 2023-11-28 03:40 PM – 04:00 PM
Última modificación: 2023-11-19


Solid solutions of lithium niobate (LiNbO3) are synthetic bimetallic oxides with high chemical stability and melting points, insoluble in water and other organic solvents. Intrinsically, LiNbO3 adopts a crystalline ferroelectric phase for a wide temperature range, room temperature to approximately 1200 °C. Its high electro-optical coefficients are attributed to this phase. Likewise, ferroelectric LN has high nonlinear optical coefficients. In single crystal form, the knowledge of spatial symmetry and different experimental configurations are used to optimize the Second Harmonic Generation (SHG). In the case of polycrystals, the coherence of the second harmonic generation response is lost due to the intrinsic randomization of the material. However, this could be changed if some degree of order is induced using external stimuli, such as the application of an external magnetic field. LiNbO3 powders are being tested because they exhibit important ferromagnetic properties at room temperature when suitably doped with Fe ions and post-thermally treated in a reducing atmosphere. The objective of this work is to analyze the response of the SHG with and without magnetic field to observe if there is a magneto-optical coupling. For this purpose, iron-doped LN samples were synthesized at variable concentrations of 0.8-6.0 wt.% Fe2O3 , then subjected to oxidation and reduction treatments so that a total of 21 samples are available for analysis, also counting the untreated samples. The characterization detailed of the samples was carried out using X-ray diffraction (XRD) and Raman spectroscopy. For the analysis of the SHG, a representative set of samples was studied in the presence and absence of an external magnetic field of constant amplitude. In conclusion, the SHG response can be tailored by controlling the number of intrinsic and extrinsic point defects within the pristine structure. This can be done in reduced LN:Fe powders by adjusting their magnetization to an optimal value, using doping concentration rates between 0.8 and 2.2 wt.% Fe2O3. . The present results might find application in other fields, such as seismic measurements and characterization of cathodic materials new generation lithium ion-batteries (LIBs) or spent LIBs.