Influence of grain size on the soft mode and the phase transition in the nanocrystalline PbTi1− xZrxO3 system

• Published in: The Journal of physics and chemistry of solids Vol. 55; no. 5; pp. 427 - 432
• Main Authors: Jinfang, Meng, Guangtian, Zou, Qiliang, Cui, Jiangping, Li, Xlaohui, Wang, Muyu, Zhao
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.1994; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Ferroelectricity and antiferroelectricity; high pressure; high temperature; Lattice dynamics; Nanocrystalline materials; Phase transitions and curie point; Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Physics; Raman spectra; soft mode phase transition; Raman spectra; Nanocrystalline materials; soft mode phase transition; high temperature; high pressure; Grain size; Temperature dependence; Inorganic compounds; Pressure effects; Ferroelectric phase transformations; Transition element compounds; Lead oxides; Experimental study; Soft modes; Titanium oxides; Zirconium oxides; Quaternary compounds; Nanocrystal
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/0022-3697(94)90168-6

The Raman spectra of nanocrystalline PbTi 0.75Zr 0.25O 3 show that its perovskite phase occurred at a higher crystallization temperature during its sol-gel process than the perovskite PbTiO 3 phase. The effects of grain size on the ferroelectric phase transition and the soft mode have been investigated. The phase transition temperature T c is shifted to a lower temperature with decreasing grain size. The possibility that the additional mode occurring in the low frequency Raman spectra might be due to zone boundary transverse acoustical phonons which couple to the q ∼ 0 soft TO phonon mode is confirmed. The Raman spectra, as a function of pressure, reveal that the phase transition may be correlated with Diffuse Phase Transition (DPT).