Growth and magnetism of self-organized Co nanoplatelets on Si(111) surface

Magnetic nanodots have great potential for applications in ultrahigh-density information storage, quantum computing and many other fields. In this work, Co nanoplatelets with uniform size, height and shape were fabricated by ultrahigh vacuum metal evaporation on the Si(111)-(7 x 7) surface, using a two-dimensional identical Al cluster array as the template and spacer. The Al clusters reduce Si dangling bonds significantly and prevent the reaction between Si and the ferromagnetic metal Co. Almost all Co nanoplatelets appear as equilateral triangles with a side length of 5.4 nm and a magic thickness of 2 ML, pointing in the [211] direction. In situ scanning tunneling microscopy (STM) was used to determine the atomic structure and atomistic formation process of the Co nanoplatelets. Magnetic properties of the Co platelets were measured by SQUID at 5 K. Such quantum dots exhibit unusually high perpendicular magnetic anisotropy. The present study demonstrates a promising pathway to directly integrate magnetic nanostructures with Si-based electronic devices. Copyright (C) 2006 John Wiley & Sons, Ltd.