Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 2: Spin-Dynamics / Spin-Torque I
MA 2.1: Vortrag
Montag, 23. März 2009, 11:00–11:15, HSZ 04
Magnon dispersion and life times of thin Ni films studied with inelastic scanning tunneling spectroscopy — •Toyo Kazu Yamada1, Nicolai Urban1, Timofey Balashov1, Albert Takács1, Pawel Buczek2, Leonid Sandratskii2, Arthur Ernst2, and Wulf Wulfhekel1 — 1Physikalisches Institut, Universität Karlsruhe, Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany — 2Max-Plank-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
Ni films of thickness between 4 and 12 monolayers were grown epitaxially on a Cu(100) substrate. Using inelastic scanning tunneling spectroscopy at 4 K magnons in the Ni film were studied. In the thin films, the magnons are confined and thus quantized along the surface normal. For a film of n momolayres, n magnon modes normal to the surface are expected. In the experiments these modes appear as peaks in the inelastic tunnelling spectra. By measuring the peak position and widths the magnon energies and lifetimes can be obtained. The observed lifetimes strongly depend on the momentum of the magnons in agreement with non-adiabatic dynamic susceptibility calculations.