.
Figure 1 Sb delta layers in Si (Dr. C. Mc Conville, Warwick University)
Two delta layers of Sb were grown on Si by MBE techniques and capped with 80 angstroms of amorphous Si. The MEIS results clearly show the Sb delta layers and provide information on the amount of Si recrystallisation, the lattice location of the Sb and any diffusion and/or segregation of the Sb.
Figure 2 Fe/Au magnetic multilayers (DR. P.K. Hucknall Leeds University)
The 2 dimensional data set relates to a 2 Å Fe layer sandwiched between two Au layers each of thickness 15 Å. Multilayer structures of this type exhibit the giant magnetoresistance (GMR) effect . Analysis of the data shows that the Au layers are fcc(111) with twinned domains and that the Fe is fcc(111) rather than bcc. There is a substantial decrease in the crystal quality of the Fe layer as the thickness increases from to 2 to 16 Å, with 8 Å being an approximate limit for fcc Fe growth. Some surface segregation of Fe is seen.
Figure 2 Reconstruction of crystal surfaces - Ni(100)c(2x2)-O (Prof. D.P. Woodruff, Warwick University)
The adsorption of c. 0.5 ML of oxygen on Ni(100) induces two main effects; an outward movement of the top layer of Ni atoms and a rumpling of the second layer Ni atoms. Second layer Ni atoms lying directly beneath oxygen atoms are attracted outwards whilst Ni atoms having no oxygen above them are contracted inwards towards the third layer. Two incidence geometries have been used. The (310) incidence illuminates (nominally) a single layer and gives the best surface specificity. The (210) incidence illuminates (nominally) two layers and gives the best information about the rumpling which occurs between the first and second layers. Comparison between experiment and simulation for the two geometries gives structural values of: oxygen height = 0.84 Å Ni first layer expansion = 3.5% Ni peak to peak rumpling = 0.2 Å
