Morphology and magnetism of Fe on vicinal W(110) surfaces with different step orientation

Nanostructures of monolayer height of single-crystalline Fel(1 1 0) films were grown on stepped W(1 1 0) surfaces. The growth mode strongly depends on the step orientation of the substrate. Continuous stripes are formed at steps along the [1 0 0] direction whereas triangular shaped islands grow on substrates with [1 - 10]-oriented step edges. No ferromagnetic order was found in submonolayer films grown on [1 - 10]-steps. The nanostripe array on [1 0 0] steps shows a ferromagnetic phase-transition with a critical behavior different from the Ising-like phase transition observed for submonolayer films grown on smooth W(1 1 0). The magnetic easy axis in the samples is oriented parallel to the him plane along [1 - 10], i.e. perpendicular to the step orientation. Magnetostatic interactions induce ferromagnetic interstripe coupling which drives the transition to ferromagnetic order. (C) 2000 Elsevier Science B.V. All rights reserved.