ION-BEAM CHANNELING YIELDS OF HOST AND IMPURITY ATOMS IN LINBO3 - COMPUTER-SIMULATIONS

A Monte Carlo program for the simulation of channeling phenomena in LiNbO3 crystals is described. Results of the program are compared with experimental yields for Nb, Li, and O from angular scans through the [0001], [0221BAR], [0441BAR], and [1120BAR] axial directions and through the (0001) planar direction obtained with 1.6-MeV He+ and proton beams. A set of calculated angular scans for different axial and planar directions, and different impurity locations in LiNbO3, is presented. The program has been applied to identify the lattice location of Nd, Eu, and Hf in LiNbO3, and that of Lu and Hf in Mg-doped LiNbO3 by comparing the experimental data with the simulated angular scans. The results confirm that the Hf atoms occupy substitutional Li sites and Eu and Nd atoms lie at a position shifted by almost-equal-to 0.4 angstrom from the regular Li site along the c axis and towards the nearest oxygen plane in LiNbO3. The Hf and Lu atoms occupy the Nb and Li sites respectively if the LiNbO3 is codoped with Mg atoms.