Yb3+ distribution in LiNbO3 :(MgO) studied by cooperative luminescence

This work presents a study of the distribution of Yb3+ ions in LiNbO3 and L iNbO3:MgO using cooperative luminescence as a probe. The cooperative rate i s measured as a function of Yb3+ concentration in the samples. After compar ing the experimental results with simple possibilities for rare earth distr ibution, a model for the distribution of Yb3+ ions is proposed, in which a fraction of the dopant ions forms pairs with an Yb3+ ion placed at Li+ site and the other one at Nb5+ site, while the rest of the ions are randomly pl aced at Li+ sites. Moreover, the codoping with MgO enhances the cooperative emission and this is discussed in terms of a more efficient redistribution of Yb3+ ions to Nb5+ sites. (C) 2001 American Institute of Physics.