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MA: Fachverband Magnetismus
MA 25: Surface Magnetism / Magnetic Imaging I
MA 25.9: Vortrag
Donnerstag, 25. März 2010, 12:15–12:30, H23
Lifetime information of excited states in magnetic single atoms and clusters studied by STM — •Toshio Miyamachi1,2, Tobias Schuh1, Timofey Balashov1, Albert. F. Takács1, Shigemasa Suga2, and Wulf Wulfhekel1 — 1Physikalisches Institut, Karlsruher Institut für Technologie, Karlsruhe, Germany — 2Graduate School of Engineering Science, Osaka University, Toyonaka, Japan
The magnetic stability of bits in a hard disk relies on the energetic barrier to reverse the magnetization, which is governed by magnetic anisotropy energy (MAE). Recent x-ray magnetic circular dichroism study has revealed a giant MAE of Co atoms on Pt(111) of 9.3 meV [1], raising hope for realizing ultimate miniaturization of bits. This technique, however, cannot extract information about the magnetization dynamics, which also plays an important role for the stability of bits. Here we demonstrate that inelastic tunneling spectroscopy using scanning tunneling microscopy (STM) can investigate the lifetimes of magnetically excited states in addition to MAE [2]. By virtue of atomic manipulation capabilities of the STM, these properties are determined with the highest precision for single atoms, dimers and trimers of Fe and Co on Pt(111). The estimated short lifetimes of the order of femtoseconds are explained from efficient electron-electron scattering processes induced by the strong hybridization of the impurity state and the substrate.
[1] P. Gambardella et al., Science 300, 1130 (2003)
[2] T. Balashov et al., PRL 102, 257203 (2009)