Diffuse phase transition and relaxation behavior

in hydrothermally processed PLZT ceramics

N. S. Echatoui1,2, T. Lamcharfi1,2, S. Sayouri1*, L. Hajji3, A. Alimoussa3

1LPTA, Département de Physique, Faculté des Sciences-DM, B.P. 1796, Fès-Atlas, Maroc.

2 LSSC Département de Génie Electrique, FST, Route d’Immouzer, Fès, Maroc.

3LPSCM, Faculté des Sciences Semlalia, B.P. 2390, Marrakech, Maroc.

4LESEO Département de Physique, FST Guiliz, Marrakech, Maroc.

* Corresponding author. E-mail: ssayouri@yahoo.com

Received: 14 April 2005; revised version accepted: 13 October 2005

 

Abstract

(Pb1-yLay)(Zr0.52Ti0.48)O3 (PLZTy) powders were prepared using hydrothermal process and their dielectric properties were investigated. In particular, the thermal variation of the dielectric permittivity shows that a diffuse character of the ferroelectric to paraelectric transition clearly takes place at y = 0.08, and that relaxation occurs for y = 0.10. A quadratic law in temperature was used to study the temperature dependence of the dielectric constant of the samples showing the relaxation phenomenon and values of the fitting parameters such as the diffuseness parameter were calculated and discussed. Moreover, as expected for relaxor ferroelectrics, the temperature corresponding to the maximum of the dielectric constant follows the empirical Vogel-Fulcher law.

Keywords: PLZT; Diffuse Phase Transition (DPT); Relaxation; Diffuseness parameter.

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