Structural and magnetic properties of self-assembled nanoscale Fe islands on Cu(100)

We have grown nanoscale Fe islands on the c(2x2)N/Cu(100) surface at room temperature. Previous scanning tunneling microscopy studies have shown that adsorption of atomic N at subsaturation coverage forms periodic arrays of c(2x2) N islands each with a size of about 5x5 nm. At room temperature these islands can channel the growth of other transition metals such as Fe onto the remaining clean Cu areas. The result is a regular array of Fe islands separated by N-covered islands. The size and shape of the Fe islands depends both on Fe and N coverage. We have studied the structural properties of the Fe islands by means of low energy electron diffraction and Fe K-edge surface extended X-ray absorption fine structure. From these data we estimate that we are able to produce Fe column-like islands thicker than 10 atomic layers. The Fe atoms are arranged in an fee lattice with tetragonal distortion as observed in Fe/Cu(100) films. The magnetic properties of the Fe islands have been probed by means of magnetic linear dichroism in the angular distribution and magnetic circular dichroism of photoelectrons from the Fe 3p core levels. Our data from Fe islands shows that they can be remanently magnetised parallel or perpendicular to the surface after applying a field of B=0.3 T, indicating cubic anisotropy.