| Summary: | 碩士 === 國立交通大學 === 光電工程所 === 91 === For using powder X-ray diffraction explains ferroelectric phase transition in polycrystalline Pb1-xSrxTiO3 and contrasts to the decreasing giant LO-TO splitting [Appl. Phys. Lett. 81, 3019, (2002)], a direct observation of the variation of displacement in Pb is larger than Ti, used Rietveld refinement, and Pb-O bonding length calculated differs greatly from Ti-O.
In view of XRD theories, the intensity of Bragg peaks represents atomic position and atomic scattering factor. Simultaneously, the electronic densities in atom are reflected by atomic scattering factor. Therefore, the extent of displacement in Pb differing from Ti doped Sr atom can be proposed that the Pb-O interaction is more hybridized than Sr-O, reduces the effect of long-range Coulomb interaction. Furthermore, Pb-O interaction may play important role than Ti-O in Pb1-xSrxTiO3 system.
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