Dresden 2009 – scientific programme
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MA: Fachverband Magnetismus
MA 14: Poster Ib: Magnetic Materials (1-14); Micro Magnetism/Computational Mag. (15-17); Surface Magnetism (18-22); Spin Structures/Phase Transitions (23-25)
MA 14.22: Poster
Tuesday, March 24, 2009, 10:15–13:00, P1B
Bcc Co/Fe(110) measured by spin-polarized scanning tunneling spectroscopy — •Torsten Methfessel and Hans-Joachim Elmers — Johannes Gutenberg-Universität Mainz, Institut für Physik, Staudingerweg 7, D-55099 Mainz
Highly spin polarized metals are of great interest e.g. for the application in spin-valves. Recently observed large tunneling magnetoresistance (TMR) effect values of 410 % at room temperature for Co/Fe(100) electrodes indicate a high spin-polarization at the Fermi energy of bcc Co [1]. Using STM and STS we have recently shown that two monolayer of undistorted bcc Co grow on Fe(110) [2]. By covering the STM tip with 5 ML Fe we perfom spin-polarized scanning tunneling microscopy on the Co(110) surface. The magnetization of the Co layers follow the magnetization of the Fe buffer layer with an easy axis along the the [11 0] axis. Spin-polarized spectroscopy reveals an asymmetry of the differential conductivity for the first Co layer with a maximum value of 5 % at 0.1 eV below EF in close agreement with the data measured for the Fe(110) surface. The second layer shows a maximum of ca. 4 % of the opposite sign at 0.1 eV above EF. The experimental results are compared with theoretical calculations.
[1] S. Yuasa et. al., Appl.Phys.Lett. 89 (2006) 042505.
[2] T. Methfessel, and H.J. Elmers, Surf.Sci. (accepted).