AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Thursday Sessions
       Session MI+NS-ThA

Invited Paper MI+NS-ThA5
Spin-Polarized Scanning Tunneling Spectroscopy: Magnetic Domain Imaging and Beyond

Thursday, October 28, 1999, 3:20 pm, Room 618/619

Session: Magnetic Imaging
Presenter: R. Wiesendanger, University of Hamburg, Germany
Authors: R. Wiesendanger, University of Hamburg, Germany
M. Bode, University of Hamburg, Germany
M. Getzlaff, University of Hamburg, Germany
Correspondent: Click to Email
Spin-polarized vacuum tunneling from ferromagnetic thin film probe tips into exchange-split surface states of rare-earth thin films is demonstrated and applied to magnetic domain imaging with a spatial resolution below 20 nm. The bias dependence of the spin polarization extracted from tunneling spectroscopy data is found to be in surprisingly good agreement with results from spin-resolved (inverse) photoemission indicating that spin-dependent density-of-states effects dominate over matrix element effects. It is also shown that spin-polarized electronic states can yield high tunneling magnetoresistance. On the other hand, surface contamination leads to a strong decrease of the measured spin-polarisation by impurity-assisted scattering which influences strongly the vacuum-TMR effect as well as the contrast in spatially resolved magnetic imaging applications.