After cooling to below 223 K, a thicker and better-ordered CoO(100) film was prepared by further reactive deposition of cobalt in O2 (7 x 10 -7 mbar) for 18 min. Finally, the CoO(100) film was annealed at 1073 K for 5 min. The quality of the resulting CoO(100) surface was verified by a sharp (1×1) LEED pattern. A ball model of the surface structure is depicted in Figure .