Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 19: Poster Surface Magnetism

O 19.2: Poster

Monday, March 17, 2025, 18:00–20:00, P2

Design of a STM/ nc-AFM head to quantify the magnetic exchange interaction between individual atoms — •Karoline Oetker, Zhengyuan Liu, Henning von Allwörden, Alexander A. Khajetoorians, and Nadine Hauptmann — IMM, Radboud University, Nijmegen, The Netherlands

STM methods are highly powerful tools to quantify the magnetic coupling between single adatoms and with the atom at the tip [1,2]. These current-based methods prohibit to probe the atomic-scale magnetic properties of adatoms on thick insulating layers. However, it was shown that thicker insulating layers with a 4-fold symmetry, as MgO, can prohibit single-electron induced ground state transitions and only allow higher-order excitation processes, which stabilizes the magnetic moment of the adatom [3]. Therefore, a force-based method, such as magnetic exchange force microscopy (MExFM), is a promising tool to quantify the different magnetic coupling mechanisms between individual adatoms on thick insulating layers. We present the design of a 1K STM/nc-AFM setup dedicated for MExFM measurements in magnetic fields up to 9T, based on the tuning fork design. Our goal is to quantify the different distance-dependent magnetic interactions between different magnetic atoms, e.g. 3d and 4f elements. We will utilize functionalized tips with different magnetic atoms, to probe the distance-dependent magnetic exchange force between the tip and adatoms on thick insulating layers. 1.Meier, F. et al., Science 320, 82-86 (2008), 2. Baumann, S. et al., Science 350, 417-420 (2015). 3.Donati, F. et al., Science 352, 318-321 (2016).

Keywords: nc-AFM; single atoms; 4f elements; STM; magnetic interaction