Seminario de Física Aplicada
Fecha: Jueves 24 de Ene. de 2013, 2 pm
Lugar: ICIMAF, Calle E eq. a 15, Vedado
Ponente: Yanela Méndez
Título: Estudio por difracción de rayos-X de la evolución microestructural y estructural en el sistema PbTiO3 modificado con tierras raras
Abstract.
The work presents a study concerning the microstructure evolution of the Pb1-3x/2LnxTiO3 ferroelectric ceramic system as function of lanthanide ions, where Ln = La, Sm, Eu, Gd and Dy, on the basis of the degree of broadening and asymmetry that exhibit the maxima of the X - ray diffraction patterns of these compounds. The diffraction patterns show an anisotropic broadening (dependent on hkl) of the integral breath, while the asymmetry effect appear on those peaks which are splitted in doublets and triplets when the system goes from the high symmetry P m3m to the lower P 4mm symmetry. The observed behaviors are known to be typical for all ferroelectric materials, in which ferroelectric domains microstructures evolve during a phase transformation. A model is used for fitting anisotropic and asymmetric diffraction profiles of the studied samples within the Rietveld method.