Magnetic properties of step-decorated Fe nanostripes and dots grown on Mo(1 1 0)

Abstract

Arrays of epitaxial Fe(1 1 0) nanostripes 1–5 nm thick and ∼100 nm wide are fabricated under UHV by pulsed laser deposition on a stepped Mo(1 1 0) surface. This step decoration process results from surface diffusion limitations at 500 K, or alternatively from the occurrence of a metastable 6-atomic-layer thickness upon annealing a continuous film grown at room temperature. The stripe orientation and spacing are uniform over the whole sample as controlled by the 0.05° miscut of the substrate. Room temperature magnetic properties are investigated by vibrating sample magnetometry. In the case of steps parallel to Fe[0 0 1], all sources of anisotropy contribute to align the magnetization parallel to the step direction, yielding a rather square hysteresis loop with a coercive field of 70 mT. Average single particle behavior is extracted by differentiating the reversible and the irreversible magnetic contributions deduced from a series of minor hysteresis loops. A model with no interaction between the particles well reproduces the experimental results.