FORMATION OF COPPER CRYSTALLITES ON A CU FE/CU(100) SANDWICH/

The formation of copper microcrystallites on a Cu/Fe/Cu(100) sandwich due to annealing at temperatures between 500 K and 600 K was studied. For the crystallites to form, the iron film thickness must be more tha n 10 monolayers (bcc-Fe) and the copper film thickness must be in the range of 3-10 monolayers. The formation process of the crystallites wa s investigated using a newly developed apparatus allowing scanning ele ctron, scanning Auger and scanning tunneling microscopy on the same sa mple position and repeated repositioning to a given position. The crys tallites were found to form mainly at step bunches and predominantly o riented along the [110] directions of the copper substrate. A large nu mber of screw dislocations are visible on top of the crystallites. The growth of the crystallites was observed by sequential measuring/annea ling cycles. The results are discussed in terms of the structural tran sformation of the Cu/Fe/Cu sandwich.