Oxygen diffusion at 1400 to 1500K was studied using molecular dynamics simulation with Born model potentials (table 23). The diffusion was found to occur mainly within the Cu(1)-O basal plane, via a vacancy mechanism, and the oxygen diffusivity was given by:

D(cm2/s) = 1.4 x 10-4exp[-0.98(eV)/kT]

This was in good agreement with experiment. Details of the oxygen migration mechanisms were deduced from particle trajectories; analyzed using molecular graphics techniques. The oxygen vacancies were found to migrate between O(1), O(4) and O(5) sites, but not to O(2) or O(3) sites. The possible oxygen-ion jump-paths were observed to be O(1)-O(5), O(1)-O(4) and O(4)-O(5).

Molecular-Dynamics Study of Oxygen Diffusion in YBa2Cu3O6.91. Zhang, X., Catlow, C.R.A.: Physical Review B, 1992, 46[1], 457-62

Table 23

Diffusivity of O in YBa2Cu3O6.91