[en] Full text: Increase in magnetic storage capabilities inevitably requires miniaturization of magnetic bits. Two solutions for this problem have been proposed: the assembly of magnetic vortexes, where the competition between exchange and dipolar interactions stabilizes a specific magnetic configuration and the modification of magnetic properties of nanoclusters due to change in structural properties, leading to an enhancement of their orbital momentum, especially in 3D transition metals. Since nanoclusters inevitable exhibit superparamagnetism, the determination of the orbital momentum of nanoclusters suffers from the need of high magnetic fields and extremely low temperatures. Therefore, even the search for enhanced magnetic materials is jeopardized by this limitation. In the present work, we have grown cobalt nanoclusters on Au(110) by electron beam deposition under ultra-high vacuum conditions. Scanning tunneling microscopy and low energy electron diffraction confirmed the preparation of a clean Au surface as well as the formation of pure Co nanoclusters in the range of the equivalent of 1-4 monolayers. The magnetization of Cobalt clusters was confirmed by X-ray Magnetic Circular Dichroism (XMCD) measured at the new PGM beamline at the Brazilian Synchrotron Radiation Laboratory (LNLS). A reasonably low magnetic field (1.1 Tesla) was used and the measurements were done at room temperature. By fixing the spin momentum and determining the average angle between the incident X-ray photon and the total magnetic moment, we clearly observe the enhancement of Co orbital momentum as coverage decreases down to approximately 1.5 monolayers. The procedure of determination of the orbital momentum a low magnetic fields will be discussed in detail. (author)

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