A study of size effects in PbTiO3 nanocrystals by Raman spectroscopy

2019-10-21 06:15:15

effects size nanocrystals PbTiO3 phonon

责任者: Ma Wenhui;Zhang Mingsheng;Lu Zuhong 单位: Lab. of Molecular & Biomolecular Electron., Southeast Univ., Nanjing, China 来源出处: Physica Status Solidi A(Phys. Status Solidi A (Germany)),1998/04/16,166(2):811-15 摘要: PbTiO3 nanocrystals were investigated by using Raman spectroscopy. The phonon modes in the nanocrystals exhibited an obvious frequency downshift as compared with bulk single crystals, and the mode frequencies in nanocrystalline PbTiO3 shifted up with annealing treatment. Size dependence of phonon modes in the nanocrystals was observed and attributed to the internal stress arising from surface tension effects. A relation between the frequency (ωR) of the E1(1TO) mode and the crystallite size (R) was established to be ωR=89-440/R, and the critical size for PbTiO3 was estimated to be 11.6 nm from the equation 关键词: annealing;crystallites;ferroelectric materials;internal stresses;lead compounds;nanostructured materials;particle size;phonon spectra;Raman spectra;surface tension;transmission electron microscopy;size effects;nanocrystals;Raman spectroscopy;phonon modes;annealing;internal stress;surface tension effects;crystallite size;TEM;transmission electron microscopy;ferroelectric materials;sol gel method;400 to 700 C;40 to 100 nm;PbTiO3