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MA: Fachverband Magnetismus

MA 5: Spin Structures and Magnetic Phase Transitions

MA 5.10: Vortrag

Montag, 26. März 2012, 12:00–12:15, H 0112

Atomic Scale Magnetic Dissipation from Spin-Dependent Adhesion Hysteresis — •Elena Y. Vedmedenko, Q. Zhu, U. Kaiser, A. Schwarz, and R. Wiesendanger — Institute of Applied Physics, University of Hamburg Jungiusstr. 11, 20355 Hamburg, Germany

The experimental observation of atomic scale magnetic dissipation by magnetic exchange force microscopy [1] on NiO(001) with an Fe-coated tip is reported. The origin of the dissipation signal has been investigated using Monte-Carlo energy minimization techniques and compared with experimental results. The calculations predict that the Caldeira-Leggett-type dissipation proposed previously [2] is a special case of the general phenomenon of adhesive hysteresis. According to our calculations the adhesion hysteresis is distance as well as spin dependent and should be measurable not only above magnetic Ni but also on paramagnetic O atoms. The energy released during binding or the unbinding process may then be dissipated via spin flips or phonons. Considering the simplicity of our theoretical model, the calculated energy dissipation agrees surprisingly well with the measured energy dissipation.
U. Kaiser, A. Schwarz, R. Wiesendanger, Nature, 446, (522), (2007) [2] F. Pellegrini, G. E. Santoro, E. Tosatti, Phys. Rev. Lett. 105, (146103), (2010)