EUROPIUM DIFFUSION IN Y-CUT AND Z-CUT LINBO3 PRE-IRRADIATED BY GEV URANIUM IONS

Single crystals of LiNbO3 with y- and z-cut orientations were irradiat ed at GANIL with 3.37 MeV/amu U-238 ions at a fluence ranging from 1.0 x 10(11) to 4.0 x 10(11) ions.cm(-2). The damage resulting from these irradiations at high electronic stopping powers (> 10 KeV/nm) consist s mainly of amorphous tracks. After irradiation the samples were impla nted with europium ions of 70 keV energy at a fixed fluence of 5 x 10( 16) ions. Subsequent annealings in air, in the range 700-1100 degrees C, were applied to investigate the influence of the pre-irradiation da mage on the thermal evolution of Eu implanted LiNbO3 crystals. Rutherf ord Backscattering Spectrometry (RES) results clearly show that the ex istence of the amorphous tracks enhances the europium diffusion. An an isotropy effect has been observed in the diffusion process.