AVS 56th International Symposium & Exhibition
    Magnetic Interfaces and Nanostructures Thursday Sessions
       Session MI-ThM

Paper MI-ThM6
Isolation of Exchange- and Spin-orbit- Driven Effects via Manipulation of the Axis of Quantization

Thursday, November 12, 2009, 9:40 am, Room C1

Session: Magnetization Dynamics, Imaging and Spectroscopy
Presenter: G.D. Waddill, Missouri University of Science and Technology
Authors: T. Komesu, Missouri University of Science and Technology
G.D. Waddill, Missouri University of Science and Technology
S.W. Yu, Lawrence Livermore National Laboratory
M.T. Butterfield, Lawrence Livermore National Laboratory
J.G. Tobin, Lawrence Livermore National Laboratory
Correspondent: Click to Email
Double Polarization Photoelectron Spectroscopy (DPPS), using circularly polarized xrays and true spin detection, has been performed using the 2p core levels of ultra-thin films of Fe and Co. This includes both the separation into magnetization- and spin- specific spectra and an Instrumental Asymmetry analysis. By simply by choosing different axes of quantization it is possible to selectively manipulate the manifestation of exchange and spin-orbit effects. Furthermore, the underlying simplicity of the results can be confirmed by comparison to a simple yet powerful single-electron picture.
The interplay of spin-orbit and exchange effects is of crucial importance to the understanding of complex electronic structure. For example, in the highly relativistic 5f systems, this interplay may be the key to understanding electron correlation. [1] One way to address this crucial issue is via photon-helicity- specific and spin-polarized photoemission from core levels, which is strongly dependent upon each of the two effects. [2] In fact, it is possible to observe strongly spin polarized photoemission from completely “non-magnetic” systems. [3] Here, using circularly polarized x-rays and true spin detection, it will be demonstrated how each of the effects, exchange and spin-orbit, can be isolated and quantified, simply by choosing different axes of quantization within the same overall experimental geometry. Moreover, the underlying simplicity of the results will be illustrated by the utilization of separate magnetization- and spin-specific spectra, as well as a simple but powerful single-electron model.
Takashi Komesu: Present address: Spring8,  Japan Synchrotron Radiation Research Institute, Japan
Corresponding Author, Tobin1@LLNL.Gov
Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344. This work was supported by the DOE Office of Basic Energy Science and Campaign 2/WCI/LLNL.  The  APS has been built and operated under funding from the Office of Basic Energy Science at DOE.  We would like to thank the scientific and technical staff of Sector 4 of the Advanced Photon Source for their technical assistance in supporting this work.  TK would like to thank Prof. Peter A. Dowben at University of Nebraska-Lincoln for valuable scientific discussions.
References
1.    S.-W. Yu et al, J. Phys. Cond. Mat. 20, 422202 (2008) and ref’s therein.
2.    J.G. Tobin and F.O. Schumann, Surface Science 478, 211 (2001).
3.    S.W. Yu et al, Phys. Rev. B 73, 075116 (2006); J.G. Tobin et al, EuroPhysics Lett. 77, 17004 (2007).