Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 24: Particles and clusters
O 24.8: Vortrag
Dienstag, 23. März 2010, 12:15–12:30, H34
Magnetic coupling and anisotropy of Fe nanoclusters deposited onto Cu(111) — •Christian Praetorius1, Greg A. Ballentine2,4, Armin Kleibert3,5, Norman Wilken3, Andris Voitkans3, Karl-Heinz Meiwes-Broer3, and Kai Fauth1,2 — 1Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2MPI für Metallforschung, Heisenbergstr. 3, 70689 Stuttgart, Germany — 3Physikalisches Institut, Universität Rostock, 18051 Rostock, Germany — 4Dpt. of Physics, Brandon University, 270 18th street, Brandon, Canada R7A 6A9 — 5Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
Magnetization and magnetic response of Fe nanoclusters is studied by temperature and density dependent in situ X-ray magnetic circular dichroism after deposition onto Cu(111). At particle diameters of 6 nm, ferromagnetic response is obtained at ambient temperature for nanocluster densities well below percolation threshold. Both, enhanced intrinsic magnetic anisotropy energy (MAE) density as well as collective effects contribute to this effect. This enhancement of MAE is not accompanied by enhanced orbital magnetic moments. At elevated cluster densities we observe sizeable macroscopic magnetic in plane anisotropy. This anisotropy can quantitatively be understood as the effect of a demagnetizing field, and thus the average effect of diplar interactions of the nanoclusters.