Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

O 31: Surface and Interface Magnetism I (jointly with MA)

O 31.3: Talk

Tuesday, March 12, 2013, 11:00–11:15, H33

Detecting and Interpreting Spin-Dependent Dissipation Observed with Magnetic Exchange Force Microscopy and Spectroscopy — •Alexander Schwarz, Rene Schmidt, Elena Y. Vedmedenko, and Roland Wiesendanger — Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg

Magnetic exchange force microscopy (MExFM) and spectroscopy (MExFS) can resolve magnetic surfaces and probe the distance dependence of the magnetic exchange interaction with atomic resolution [1,2]. In both cases the frequency shift of an oscillating cantilever due to conservative tip-sample interactions is detected. By recording the amplitude and the excitation amplitude required to keep the amplitude of the cantilever oscillation constant, the energy loss due to dissipative processes can be determined. It turns out, that this signal can be spin-dependent as well [2,3]. The possible origin of this signal will be discussed in terms of spin-excitations [4] and spin-dependent adhesion-hysteresis [3]. Additionally, it will be shown how the dissipation signal can be used to characterize the tip, which is very important to correctly evaluate force spectroscopy data quantitatively.

[1] U. Kaiser, A. Schwarz and R. Wiesendanger, Nature 446, 522 (2007).

[2] R. Schmidt, A. Schwarz, and R. Wiesendanger, Phys. Rev. Lett. 106, 257202 (2011).

[3] E. Y. Vedmedenko et al., Phys. Rev. B 85, 174410 (2012).

[4] F. Pellegrini, G. E. Santoro, and E. Tosatti, Phys. Rev. Lett. 105, 146103 (2010).