The diffusion of Ti in MgO(100) pre-bombarded by Ar+, Cl+ and Cr+ was studied by secondary ion mass spectroscopy under conditions for non steady-state radiation-enhanced diffusion. The Ti diffusion behaviors of these samples were different, although the ballistic behaviors of the implanting ions were similar. For short annealing periods, the Ti diffusion enhancements follow the order Cr+>Ar+>Cl+, while for long annealing periods the order was Cl+>Ar+>Cr+. A model based on a vacancy clustering mechanism during thermal relaxation of the energetic cascade was proposed to explain these trends.

Vacancy Clustering Model for Ti Non Steady-State Radiation-Enhanced Diffusion in MgO (100). M.Lu, C.Lupu, J.W.Rabalais: Applied Physics Letters, 2002, 81[26], 5033-5