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AM: Magnetismus

AM 20: Spektroskopie, Dichroismus III

AM 20.9: Talk

Thursday, March 20, 1997, 12:45–13:00, F5

Spin-resolved photoemission in ferromagnetic fcc Fe-Co alloys on Cu(100) — •M. Zharnikov^1,2, A. Dittschar¹, W. Kuch¹, C. M. Schneider¹, and J. Kirschner¹ — ¹Max-Planck-Institut f"ur Mikrostrukturphysik, Weinberg 2, D-06120 Halle — ²present address: Angewandte Physikalische Chemie, Universit"at Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg

The electronic properties of ferromagnetic fcc Fe-Co alloys on Cu(100) were investigated by spin-resolved photoelectron spectroscopy. The photon energies were varied from 14 eV to 35 eV; the measurements were carried out at normal light incidence and normal emission. At a fixed concentration a dispersion of the majority 3d band with Δ₅ symmetry towards higher binding energy along the Δ axis of the Brillouin zone could be followed upon increasing photon energy. The corresponding minority band lies above E_F and crosses the Fermi edge between 17 eV and 21 eV photon energy. Upon variation of the concentration the spectra for the alloy films reveal a gradual shift of the Δ₅ minority band through the Fermi level, and a change of the sign of the polarization at the Fermi level. Both such a behaviour and the observed value of the exchange splitting imply that the electronic properties of the fcc Fe-Co alloys on Cu(100) are in between of the analogous properties of pure fcc Co and the high-spin phase of fcc Fe. This finding agrees with both a simple mixture of the Fe and Co electronic properties in a randomly mixed alloy film and a chemical separation (clustering) of both constituents.