Neuvième colloque sur les lasers et l'optique quantique
C. Chardonnet et G. Millot
J. Phys. IV France 135 (2006) 345-348
DOI: 10.1051/jp4:2006135114

Second harmonic generation and Yb³⁺ cooperative emission as unusual ways to probe phase transitions in BaTiO₃ sol-gel nanocrystals

J. Amami¹, Y. Guyot¹, C. Goutaudier¹, G. Boulon¹, M. Ayadi², D. Hreniak³, R. Pazik³ and W. Strek<sup>3

1</sup>  Physical Chemistry of Luminescent Materials, UMR 5620 CNRS, Claude Bernard/Lyon 1 University, 69622 Villeurbanne, France
²  Physical Chemistry of Mineral Materials, Bizerte University, Tunisia
³  Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland
    e-mail: georges.boulon@pcml.univ-lyon1.fr

(Published online 23 November 2006)

Abstract
Nanocrystalline powders of 1% Yb³⁺-doped BaTiO₃ sintered at different temperatures were obtained by the sol-gel method. The structure of the powders covering crystallite-sizes from 25 to 60 nm depending on the annealing temperature ( C) was determined from the Scherrer's equation. Second Harmonic Generation (SHG) intensity magnitude is compared in each samples of the tetragonal BaTiO₃ whereas the isotropic cubic phase is detected by the absence of the SHG signal. Cooperative emission, indicating the Yb³⁺ ions pairs, was easily detected in the cubic phase and not seen in the ferroelectric tetragonal structure.

© EDP Sciences 2006