Structural and dielectric characterisation of lanthanum-modified lead titanate Pb1-xLaxTi1-x/4O3 with x = 0.14

 

Y. Guaaybess1,2, M. Moussetad2, A. El Mesbahi3, S. Sayouri1*,

M. Maanan2, R. Adhiri2, L. Hajji4, O. Azaroual1

1 Laboratoire de Physique Théorique et Appliquée (LPTA) faculté des sciences Dhar Mehraz BP 1796 Atlas –Fès, Maroc

2Laboratoire d’élaboration et d’analyse des matériaux et des couches minces, FS, Département de Physique,

Ben M’Sik, Casablanca, Maroc

3 Ecole Supérieure de Technologie route d'Immouzer BP 2427 –Fès, Maroc

4LESEO, FSTG Guéliz  Marrakech, Maroc

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

Received : 10 March 2009; revised version accepted: 17 July 2009

 

Abstract

     Dielectric study of lanthanum-modified lead titanate Pb1-xLaxTi1-x/4O3 (x=14 % refereed to as PLT14), prepared by a sol-gel process, shows a decrease of the transition temperature Tc and diffuseness of the Curie point peak. Although the diffuseness of the Curie point peak, the paraelectric behaviour of this sample is still governed by the ideal Curie-Weiss law. Curie-Weiss temperature of 229 °C is clearly lower than Tc equal to 293 °C. Curie-Weiss constant value is found to be equal to 1.13 105. These results suggest that the phase transition of PLT14 is of the first order type with displacive nature similar to that observed in pure lead titanate.

 

Keywords: sol-gel; Dielectric properties; La-doped PbTiO3.

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