Magnetic Exchange Force Microscopy and Spectroscopy

Over that past 10 years, my coworkers and I developed a new versatile tool to study magnetic phenomena with atomic resolution, i.e., magnetic exchange force microscopy (MExFM) [1]. In contrast to magnetic force microscopy (MFM), which probes the long-range dipolar magnetostatic interaction, it is sensitive to the electron-mediated short-range magnetic exchange interaction between neighboring spins [2]. As a force microscopy based technique, it can - unlike spin-polarized scanning tunneling microscopy (SP-STM) - also be applied to nonconductive surfaces.

In my presentation, I will review MExFM results obtained on the antiferromagnetic bulk insulator NiO(001) [1], the antiferromagnetic Fe monolayer on W(001) [3] and the noncollinear skyrmionic spin texture of the Fe monolayer on Ir(111) [4]. Finally, I will show how magnetic exchange force spectroscopy (MExFS) can be performed in a very elegant fashion to obtain quantitative information about the magnetic exchange interaction [5].

[1] U. Kaiser, A. Schwarz, and R. Wiesendanger, “Magnetic exchange force microscopy with atomic resolution” Nature 446, 522 (2007).

[2] A. Schwarz and R. Wiesendanger, “Magnetic sensitive force microscopy“ Nano Today 3, 28 (2008).

[3] R. Schmidt, C. Lazo, H. Hölscher, U. H. Pi, V. Caciuc, A. Schwarz, R. Wiesendanger, and S. Heinze, “Probing the Magnetic Exchange Forces of Iron on the Atomic Scale” Nano Lett. 9, 200 (2009).

[4] J. Grenz, A. Köhler, A. Schwarz, and R. Wiesendanger “Probing the Nano-Skyrmion Lattice on Fe/Ir(111) with Magnetic Exchange Force Microscopy” Phys. Rev. Lett. 119, 047205 (2017).

[5] R. Schmidt, U. Kaiser, C. Lazo, A. Schwarz, R. Wiesendanger, and S. Heinze, “Quantitative Measurement of the Magnetic Exchange Interaction across a Vacuum Gap” Phys. Rev. Lett. 106, 257202 (2011).