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

A Monte Carlo program for the simulation of channeling phenomena in Li NbO3 crystals is described. Results of the program are compared with e xperimental yields for Nb, Li, and O from angular scans through the [0 001], [0221BAR], [0441BAR], and [1120BAR] axial directions and through the (0001) planar direction obtained with 1.6-MeV He+ and proton beam s. A set of calculated angular scans for different axial and planar di rections, and different impurity locations in LiNbO3, is presented. Th e 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 compari ng the experimental data with the simulated angular scans. The results confirm that the Hf atoms occupy substitutional Li sites and Eu and N d 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 p lane in LiNbO3. The Hf and Lu atoms occupy the Nb and Li sites respect ively if the LiNbO3 is codoped with Mg atoms.