Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 84: Electronic Structure of Surfaces I: Spectroscopy, Surface States

O 84.3: Vortrag

Donnerstag, 21. März 2024, 11:00–11:15, MA 144

Control of the asymmetric band structure in Mn₂Au by a ferromagnetic driver layer — •Y. Lytvynenko^1,2, O. Fedchenko¹, S. Chernov^1,3, S. Babenkov¹, D. Vasilyev¹, O. Tkach¹, A. Gloskovskii³, T. R. F. Peixoto³, C. Schlueter³, V. Grigorev¹, M. Filianina^1,4, S. Sobolev¹, A. Kleibert⁵, M. Kläui¹, J. Demsar¹, G. Schönhense¹, M. Jourdan¹, and H.-J. Elmers¹ — ¹JGU Mainz, Germany — ²Institute of Magnetism of the NAS and MES of Ukraine — ³DESY, Germany — ⁴Stockholm University, Sweden — ⁵SLS, PSI, Switzerland

In this work, the hard X-ray angle-resolved photoemission spectroscopy (HARPES) reveals the momentum-resolved band structure in an epitaxial Mn₂Au(001) film capped by a 2 nm thick ferromagnetic Permalloy (Py) layer. By magnetizing the Py layer, the exceptionally strong exchange bias aligns the Néel vector (NV) in the Mn₂Au film leading to changes in the electronic properties. Uncompensated Mn interfacial magnetic moments in Mn₂Au are identified as the origin of the exceptional exchange bias using XMCD in combination with PEEM. Using time-of-flight momentum microscopy, we measure the asymmetry of the band structure in Mn₂Au resulting from the homogeneous orientation of the NV. Comparison with theory shows that the NV, determined by the magnetic moment of the top Mn layer, is oriented antiparallel to the Py magnetization. Our experimental results demonstrate that HARPES can measure the band structure of epitaxial layers beneath a metallic capping layer. We thus confirm that the ferromagnetic capping layer controls the bulk band structure of the AFM film.

Keywords: HARPES; band structure; momentum microscopy; Néel vector