Dresden 2006 – scientific programme

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MA: Magnetismus

MA 32: Magnetic Particles / Clusters

MA 32.4: Talk

Thursday, March 30, 2006, 16:00–16:15, HSZ 401

Magnetic spin and orbital moments of mass-filtered Fe nanoparticles deposited on Co/W(110) — •Armin Kleibert¹, Joachim Bansmann², and Karl-Heinz Meiwes-Broer¹ — ¹Institut für Physik, Universität Rostock, Universitätsplatz 3, D-18051 Rostock — ²Abteilung Oberflächenchemie und Katalyse, Universität Ulm, Albert-Einstein-Allee 47, D-89069 Ulm

In this contribution we focus on the magnetic spin and orbital moments of large Fe nanoparticles with diameters between 6-10nm (i.e. 15.000-50.000 atoms per cluster) deposited on ultrathin Co films on W(110). The moments have been obtained from in situ measurements of the XMCD (X-ray magnetic circular dichroism) via TEY (total electron yield) and are corrected for self-saturation effects. HRTEM (high resolution transmission electron microscopy) images yield structural and morphological properties of the Fe nanoparticles. The particles show bulk-like magnetic spin moments being nearly independent of the particle size. However, the orbital moments are strongly enhanced when compared to the bulk and exhibit a pronounced increase when reducing the size of the particles. Analysing the data reveals that the enhancement of the orbital moments is most probably not restricted to the surface of the particles. Thus, even the inner parts of the particles may possess properties being different from the bulk. As possible mechanisms we suggest size- and shape-dependent surface strain as well as surface relaxations, both being able to modify the crystal lattice as well as the symmetry. Moreover, we expect a significant influence of the substrate on the properties of the particles.