Business card Dr. Katarzyna Siewierska

• Beamline Scientist
• Institute Methods and Instrumentation for Synchrotron Radiation Research
• (030) 8062 - 14633
• (030) 8062 - 14987
• 0000-0001-5673-8504
• Email

Dr Katarzyna Siewierska is an experimental condensed-matter physicist specialising in synchrotron-based spectroscopy and the electronic and magnetic properties of quantum materials. She received her PhD in Physics from Trinity College Dublin, the University of Dublin, in 2021. Her doctoral research focused on the development and characterisation of zero-moment half-metallic Mn₂RuₓGa thin films for spintronic applications. This work combined thin-film fabrication with magnetotransport, magnetometry, magneto-optical Kerr-effect microscopy and X-ray magnetic circular dichroism.

She subsequently joined Helmholtz-Zentrum Berlin, initially as an Alexander von Humboldt Research Fellow and later as a beamline scientist at BESSY II. Her current work centres on resonant inelastic X-ray scattering and X-ray absorption spectroscopy, including the development and application of high-resolution methods. She also supports external users in planning, performing and analysing synchrotron experiments.

Her research interests include spintronic and correlated-electron materials, low-energy excitations, interfacial and thin-film phenomena, and the use of element- and orbital-selective X-ray techniques to investigate electronic structure, magnetism, lattice dynamics and chemical bonding. Her work spans materials such as Heusler compounds, transition-metal oxides, cuprates and two-dimensional materials.

Recent publications

2025

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  Hu, Z.; Jha, A.; Siewierska, K.; Lenne, S.; le Berre, P.; Dempsey, N. M.; Stamenov, P.; Rode, K.; Coey, J. M. D.: Magnetism of sperimagnetic amorphous RCo3 thin films with R = Dy, Tb, and Tm. Physical Review B 112 (2025), p. 014441/1-13
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  Kühn, D.; Sinha, S.; Johansson, F. O. L.; Siewierska, K.; Tebano, A.; Mårtensson, N.; Lindblad, A.; Di Castro, D.; Föhlisch, A.: Direct observation of the on-site oxygen 2p two-hole Coulomb energy in La₂CuO₄. Nature Communications 16 (2025), p. 9748/1-9
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  Smith, R.; Gercsi, Z.; Zhang, R.; Siewierska, K. E.; Smekhova, A.; Rode, K.; Coey, J. M. D.: Corrigendum : Effects of disorder on the magnetic properties of the Heusler alloy V₂FeAl. Acta Materialia 267 (2025), p. 120489/1

2024

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  Hu, Z.; Besbas, J.; Siewierska, K.; Smith, R.; Stamenov, P.; Coey, J.M.D.: Magnetism, transport, and atomic structure of amorphous binary Y_xCo_1-x alloys. Physical Review B 109 (2024), p. 014409/1-9
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  Liu, C.-Y.; Celiberti, L.; Decker, R.; Ruotsalainen, K.; Siewierska, K.; Kusch, M.; Wang, R.-P.; Kim, D. J.; Olaniyan, I.I.; Di Castro, D.; Tomiyasu, K.; van der Minne, E.; Birkhölzer, Y.A.; Kiens, E.M.; van den Bosch, I.C.G.; Patil, K.N.; Baeumer, C.; Koster, G.; Lazemi, M.; de Groot, F.M.F.; Dubourdieu, C.; Franchini, C.; Föhlisch, A.: Orbital-overlap-driven hybridization in 3d-transition metal perovskite oxides LaMO₃ (M = Ti-Ni) and La₂CuO₄. Communications Physics 7 (2024), p. 156/1-7
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  Smith, R.; Gercsi, Z.; Zhang, R.; Siewierska, K.E.; Rode, K.; Coey, J.M.D.: Effects of disorder on the magnetic properties of the Heusler alloy V₂FeAl. Acta Materialia 267 (2024), p. 119733/1-9

2023

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  Liu, C.-Y.; Feng, P.; Ruotsalainen, K.; Bauer, K.; Decker, R.; Kusch, M.; Siewierska, K.; Pietzsch, A.; Haase, M.; Lu, Y.; de Groot, F.; Föhlisch, A.: Role of La 5p in bulk and quantum-confined solids probed by the La 5p⁵4f^{1 3}D₁ excitonic final state of resonant inelastic x-ray scattering. The Journal of Physical Chemistry C 127 (2023), p. 11111-11118