Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 12: Elektronentheorie

MA 12.1: Vortrag

Samstag, 5. März 2005, 09:00–09:15, TU EMH225

Direct Observation of Orbital Magnetism in Cubic Solids    — •H. Wende¹, W.D. Brewer¹, A. Scherz¹, C. Sorg¹, K. Baberschke¹, P. Bencok², and S. Frota-Pessôa³ — ¹Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin-Dahlem, Germany — ²European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France — ³Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo, S.P. Brazil

We present X-ray magnetic circular dichroism (XMCD) measurements of the orbital/spin magnetic moment ratios of dilute 3d-series impurities (Cr,Mn,Fe,Co) in fcc Au and Cu host matrices [1]. These dilute 3d impurities in noble metal hosts represent an intermediate case between the nearly atomic configuration and a bulk 3d-metal environment, where the usual description includes strong hybridization and crystal field effects. We show the first direct measurement of considerable orbital moments in cubic symmetry for a localized impurity in a bulk metal host. This confirms previous hyperfine structure measurements. Here, it is shown that the unquenching of orbital magnetism depends on a delicate balance of hybridization effects between the local impurity with the host and the filling of the 3d states of the impurity. The results are accompanied by ab initio calculations that support our experimental findings.
Supported by BMBF (05 KS4 KEB 5).

[1] W.D. Brewer et al., Phys. Rev. Lett. 93, 077205-1 (2004).