MONTE-CARLO INVESTIGATION OF THE ROLE OF INITIAL CONDITIONS ON OXYGENDIFFUSION IN PLANAR YBA2CU3O6+C

We investigate the role played by initial preparation of the system on the diffusion of oxygen ions in YBa2Cu3O6+c superconductors. We use t he asymmetric, next-nearest-neighbors Ising model and standard Monte C arlo simulations. When initially only one sublattice is populated with oxygen ions, the system is in a one-domain state and the diffusion co efficient has, for all temperatures, a minimum when c=1. When the oxyg en ions are initially put on both sublattices, two or more domains may form. This leads to the appearance of an additional diffusion mechani sm and the tracer diffusion coefficient has a maximum at low temperatu res and c=1.