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MO: Fachverband Molekülphysik

MO 20: Atomic clusters (with A)

MO 20.6: Vortrag

Donnerstag, 15. März 2012, 15:45–16:00, V57.05

Spin Coupling and Orbital Momentum Quenching in Small Iron and Cobalt Clusters — •Andreas Langenberg^1,2, Konstantin Hirsch^1,2, Vicente Zamudio-Bayer^1,2, Markus Niemeyer^1,2, Arkadiusz Lawicki², Marlene Vogel², Kazuhiro Egashira³, Thomas Möller², Akira Terasaki³, Bernd von Issendorff⁴, and Tobias Lau¹ — ¹Helmholtz-Zentrum Berlin für Materialien und Energie, Albert Einstein Str. 15, 12489 Berlin — ²Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin — ³Cluster Research Laboratory, Toyota Technological Institute, Ichikawa 272-0001, Japan — ⁴Universität Freiburg, Fakultät für Physik, 79104 Freiburg, Germany

X-ray magnetic circular dichroism (XMCD) spectroscopy was performed on free and size selected iron and cobalt clusters in a linear penning trap giving direct access to spin and orbital resolved magnetic moments (m_s, m_l). For iron clusters a quenching of the orbital magnetic moments for already very small clustersizes and an antiferromagnetic coupling of Fe₁₃⁺ [1] can be observed. Moreover the measured total magnetic moments of the clusters (m_j=m_l+m_s) are in good agreement with results from Stern-Gerlach experiments [2,3]. High resolution XMCD spectra as well as magnetization curves of cobalt and iron clusters will be discussed in detail.

[1] P. Bobadova-Parvanova, K. A. Jackson et.al., Phys. Rev. B 66, 195402 (2002)

[2] X. Xu, S. Yin et.al., Phys. Rev. Lett. 95, 237209 (2005)

[3] M. Knickelbein, Chem. Phys. Lett. 353, 221-225 (2002)