AVS 52nd International Symposium
    Magnetic Interfaces and Nanostructures Wednesday Sessions
       Session MI-WeM

Paper MI-WeM8
Spin-Resolved Core Level Photoemission of the Ni/Co/Cu(001) System Using Circularly Polarized X-Rays

Wednesday, November 2, 2005, 10:40 am, Room 204

Session: Magnetic Imaging and Spectroscopies
Presenter: T. Komesu, University of Missouri-Rolla
Authors: T. Komesu, University of Missouri-Rolla
G.D. Waddill, University of Missouri-Rolla
M.T. Butterfield, Lawrence Livermore National Laboratory
S.-W. Yu, Lawrence Livermore National Laboratory
J.G. Tobin, Lawrence Livermore National Laboratory
Correspondent: Click to Email
We present spin-resolved 2p core level photoemission results for Co/Cu(001) and for Ni/Co/Cu(001). For the former we have collected the core level spectra by reversing the magnetization of the Co film emphasizing exchange effects in the spin-polarization as well as by reversing the helicity of the incident x-rays on an unmagnetized sample which isolates spin-orbit effects in the observed spin-polarization. For the exchange effects we observe strong spin polarization in the main peaks and a weaker spin polarization effect in the controversial satellite peak at ~4 eV higher binding energy than the main peaks. The spin-orbit spectrum shows strong spin-polarization throughout the spectral region that changes sign between the 2p3/2 and 2p1/2 peak consistent with its sensitivity to the core-hole spin-orbit coupling. Finally, we have studied the effects of charge transfer for the Ni/Co/Cu(001) system using spin-resolved photoemission where we see changes in the spin polarization of the main peaks and satellite features of both Ni and Co 2p core levels that can be understood in terms of charge transfer from the Co to the Ni as a function of Ni film thickness. These results establish that spin-resolved core level photoemission is a sensitive probe of electron correlation effects in thin magnetic films and surfaces. This work was performed under the auspices of the U.S. DOE by University of California Lawrence Livermore National Laboratory under contract W-7405-Eng-48.