Growth modes of Fe(110) revisited: A contribution of self-assembly to magnetic materials

Abstract

We have revisited the epitaxial growth modes of Fe on W(110) and Mo(110), and propose an overview or our contribution to the field. We show that the Stranski-Krastanov growth mode, acknowledged for a long time in these systems, is in fact characterized by a bimodal distribution of islands for a growth temperature in the range ∼250-700 °C. We observe firstly compact islands whose shape is determined by Wulff-Kaischev's theorem, and secondly thin and flat islands that display a preferred height, i.e. are independent of nominal thickness and deposition procedures (1.4 nm for Mo, and 5.5 nm for W on the average). We used this effect to fabricate self-organized arrays of nanometres-thick stripes by step decoration. Self-assembled nanoties are also obtained for nucleation of the flat islands on Mo at fairly high temperature, i.e. ∼800 °C. Finally, using interfacial layers and solid solutions we separate two effects on the preferred height, first that of the interfacial energy, and second that of the continuously varying lattice parameter of the growth surface. © IOP Publishing Ltd.