Europhys. Lett.
Volume 63, Number 3, August 2003
Page(s) 388 - 393
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00534-y
Europhys. Lett., 63 (3) , pp. 388-393 (2003)

Brillouin scattering study of $\chem{La}$-modified lead zirconate titanate relaxor

G. Shabbir and S. Kojima

Institute of Materials Science, University of Tsukuba Tsukuba, Ibaraki 305-8573, Japan

(Received 9 April 2003; accepted in final form 2 June 2003)

Elastic properties of $\chem{La}$-modified ( $\chem{Pb}$ 1-x $\chem{La}$ x)( $\chem{Zr_{0.65}Ti_{0.35}}$) $\chem{O_{3}}$ (lead zirconate titanate) with x = 10 (PLZT 10/65/35) relaxor ferroelectric ceramic were studied by high-resolution Brillouin scattering technique in a wide temperature range from 90 to 1033 $\un{K}$. The Brillouin frequency shift ( $\nu$) and sound velocity of the acoustic phonon modes, showed deviation from the high-temperature linear behaviour and a broad softening on cooling towards the dielectric maximum temperature $T_{\ab{m}}$. The temperature dependence of the maximum relaxation time was obtained from the Vögel-Fulcher relationship by combining the Brillouin scattering and dielectric data. The onset of the acoustic mode frequency dispersion from paraelectric to the relaxor ferroelectric state can be explained by the concept of freezing of the relaxation time spectrum of PLZT at a finite temperature.

62.20.Dc - Elasticity, elastic constants.
78.35.+c - Brillouin and Rayleigh scattering; other light scattering.
77.84.Dy - Niobates, titanates, tantalates, PZT ceramics, etc.

© EDP Sciences 2003