Two solid solution series were studied in the binary system La 2 BaZnO 5 -Eu 2 BaZnO 5 . In the present work we report the fluorescence spectra of the Eu 3+ ion embedded in La 2Àx Eu x BaZnO 5 (0 6 x 6 1.4) and Eu 2Ày La y BaZnO 5 (0 6 y 6 0.3) solid solutions; there are important structural modifications due to changes in oxygen coordination that take place in the La and Eu compounds. This effect is made evident through the analysis of the typical europium ion transitions: the magnetic dipole 5 D 0 ! 7 F 1 transition, and the forced electric dipole 5 D 0 ! 7 F 2 and 5 D 0 ! 7 F 4 transitions which are usually very sensitive to the local crystal environment.
The excitation and emission spectra of Eu 3+ in both types of solid solutions were analyzed for different stoichiometry values (x and y). The emission, obtained with 398 nm excitation light, and excitation spectra were recorded at 17 K in order to have a good spectral resolution. As the Eu/La concentration changed in the La/Eu solid solutions, a larger splitting of the Stark crystal field components was observed as well as large intensity changes in the emission line spectra. In particular for x = 1 in La 2Àx Eu x BaZnO 5 and y = 0.2 in Eu 2Ày La y BaZnO 5 , the excitation and emission spectra show the largest line resolution. These results manifest the influence of the different Eu 3+ oxygen environments in each one of the structures.