A study was made of diffusion and ordering in monocrystals as a function of time after O was ejected from the surface by a strong laser pulse. Features in the Raman spectra that were sensitive to O concentration and disorder were monitored by means of time-resolved spectroscopy. The data clearly showed that room-temperature diffusion occurred from bulk Cu3Ba2YO7 and into the O-depleted Cu3Ba2YO6+x surface. There appeared to be fast (less than 5ms) and relatively slow (more than 60s) lifetime components of the observed features. It was suggested that diffusion in Cu3Ba2YO6+x, which was shown to involve the hopping of O along vacancy positions, could be aided by anharmonic features of the lattice as well as by the chemical potential gradient at the Cu3Ba2YO6+x/Cu3Ba2YO7 interface.

I.Poberaj, D.Mihailovic, S.Bernik: Physical Review B, 1990, 42[1], 393-8