Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 13: Surface Magnetism

MA 13.1: Vortrag

Dienstag, 26. Februar 2008, 10:30–10:45, EB 301

Advances in Magnetic Exchange Force Microscopy — •Schwarz Alexander, Kaiser Uwe, Schmidt Rene, and Wiesendanger Roland — Department Physik, Institut für Angewandte Physik, Universität Hamburg, Jungíusstr. 11, 20355 Hamburg

Recently, the feasibility of magnetic exchange force microscopy (MExFM), which allows to visualize magnetic structures with atomic resolution, has been demonstrated [1]. This novel technique utilizes a force microscopy set-up to detect the short-ranged magnetic exchange interaction between two atomic magnetic moments (spins) residing on an atomically sharp tip as well as on the probed surface. Atomically resolved data obtained with an iron coated tip on two very different antiferromagnetic systems are compared: (i) a 3D insulator with localized spins that are coupled via superexchange and (ii) a 2D metallic bandferromagnet with delocalized spins coupled via itinerant exchange. In (i) latter case, a direct exchange between tip and sample spins at small separations seems to be necessary to observe a magnetic signal. For system (ii) the magnetic signal appears to be stronger and detectable at larger separations. Both systems exhibit a peculiar interplay of chemical and magnetic interactions, because they are approximately of the same range.
 
[1] U. Kaiser, A. Schwarz, R. Wiesendanger, Nature 446, 522 (2007).