Atomistic simulation was used to study screw dislocations, grain boundaries, thin films and surfaces. The results showed that a/2(110) screw dislocations in the bulk oxides were more stable than a(100) dislocations, although the latter were stabilized by vacancies. The adsorption of MgO units at the a(100) spiral dislocations exhibited a complicated 2-layer growth mechanism. Self-diffusion through MgO grain boundaries was shown to be faster than in the bulk crystal; with pipe diffusion being the energetically most favourable route. The study of thin Fe3O4 films on MgO showed that the most stable MgO/Fe3O4 (001)/(00l) interface was an open structure with closely-matched spacings between the substrate Mg ions and the O atoms of the film. The predominance of the MgO{100} surfaces was reflected by faceting of the less stable {110} and {111} surfaces. The low-coordination surface sites which were formed in this way were the most reactive with regard to the adsorption of water and dissolution. In the same way, α-quartz surfaces with dangling bonds were more reactive towards H2O and NaOH than were the fully-coordinated {0001} surface sites.

Atomistic Simulation of Oxide Dislocations and Interfaces. S.C.Parker, H.H.De Leeuw, D.J.Harris, F.M.Higgins, P.M.Oliver, S.E.Redfern, G.W.Watson: Radiation Effects and Defects in Solids, 1999, 151[1-4], 997-1007