Controlled nucleation of Co clusters on Au(111): towards spin engineering

The morphology and distribution of Co clusters on Au(111) can be controlled : from very small (a few atoms) randomly distributed clusters to bigger (se veral 100 atoms) self-organized clusters on a regular network. The substrat e temperature imposed during growth turns out to be the leading parameter, deciding for spontaneous organization of adsorbed metal atoms. From a detai led variable temperature scanning tunneling microscopy (STM) study, it is s uggested that this way of organizing matter at the nanoscale may be used to achieve new material properties. In particular, from in situ magnetic meas urements on the example of Co on Au(111), it is shown that the direction of the magnetization can be adjusted from in-plane to out-of-plane, depending on the growth condition. (C) 2000 Elsevier Science B.V. All rights reserve d.