Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 13: Surface Magnetism
MA 13.9: Vortrag
Dienstag, 26. Februar 2008, 12:30–12:45, EB 301
Magnetic Anisotropy of a single Fe atom on Pt(111) — •Tobias Schuh1, Timofey Balashov1, Albert F. Takacs1, Arthur Ernst2, Sergey Ostanin2, Jürgen Henk2, Patrick Bruno2, Toshio Miyamachi3, Shigemasa Suga3, and Wulf Wulfhekel1 — 1Physikalisches Institut, Universität Karlsruhe (TH), Wolfgang- Gaede Str. 1, 76131 Karlsruhe — 2MPI für Mikrostrukturphysik, Weinweg 2, 06108 Halle — 3Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
The storage of data in modern hard disks relies on the stability of the magnetization of magnetic bits. Reducing the size of the bits allows higher storage density. The smallest bit can be realized by a single atom and its stability by the magnetic anisotropy of the atom.
We used a scanning tunneling microscope to image single Fe atoms on Pt(111) at 4 K. With inelastic tunneling spectroscopy the spin excitations of individual Fe atoms were measured. The excitations were detected in the second derivative of the tunneling current exhibiting a peak and a dip symmetric with respect to the Fermi energy. From the position of the extrema the excitation energy was determined. Assuming a spin of S=1ℏ for the Fe atom, the excitation energy is found to be identical to the uniaxial magnetic anisotropy.
We determined the magnetic anisotropy to 5.7±0.1 meV per atom in good agreement to XMCD measurements of single Co atoms on Pt(111) [1]. The experimental energy is compared with theoretical calculations.
[1] P. Gambardella et al., Science 300 1130 (2003)