From Dublin to Berlin as a Humboldt Research Fellow

Dr. Katarzyna Siewierska joins the group of Prof. Alexander Föhlisch as a postdoctoral Humboldt Research fellow.

Dr. Katarzyna Siewierska joins the group of Prof. Alexander Föhlisch as a postdoctoral Humboldt Research fellow. © Privat

Dr. Katarzyna Siewierska joins the group of Prof. Alexander Föhlisch as a postdoctoral Humboldt Research fellow. She has earned her PhD at Trinity College in Dublin, Ireland, and plans in the next two years to explore the electronic structure and spin dynamics of half-metallic thin films at BESSY II.  Understanding these spintronic materials better may pave the way for more energy efficient data storage technologies.


Katarzyna Siewierska describes her project herself very clearly:

A dream material for spintronics would have low/zero net moment, no stray fields, high resonance frequency, low damping and be 100 % spin polarised, combining the best features of a metallic ferromagnet and an antiferromagnet. Such materials have the potential to revolutionise magnetic data storage and data transfer. They are called zero moment half-metals (ZMHM). This new material class was theoretically predicted in 1995, but it took almost 20 years before the first member, Mn2RuxGa, was demonstrated in 2014.

Up to now, the few other examples of ZMHMs are all Mangan-based Heusler alloys, revealing the critical role of Mangan for obtaining the uniquely desirable combination of properties. It is of great research interest to understand why this is so.

Synchrotron radiation-based techniques provide important insights into the electronic and magnetic properties of spintronic materials due to their sensitivity to spin and crystal structure, coupled with element specificity.

In this work we will combine the expertise of researchers at BESSY II in resonant inelastic X-ray scattering (RIXS) with the high quality ZMHM thin films I fabricated and studied at Trinity College Dublin (TCD) during my thesis. The goal is to confirm the half-metallic band structure of MRG, explore the spin-lattice relaxation and investigating magnon excitations to obtain information about their dispersion and the energy of ferrimagnetic resonance modes.

 

red.

  • Copy link

You might also be interested in

  • What vibrating molecules might reveal about cell biology
    Science Highlight
    16.10.2025
    What vibrating molecules might reveal about cell biology
    Infrared vibrational spectroscopy at BESSY II can be used to create high-resolution maps of molecules inside live cells and cell organelles in native aqueous environment, according to a new study by a team from HZB and Humboldt University in Berlin. Nano-IR spectroscopy with s-SNOM at the IRIS beamline is now suitable for examining tiny biological samples in liquid medium in the nanometre range and generating infrared images of molecular vibrations with nanometre resolution. It is even possible to obtain 3D information. To test the method, the team grew fibroblasts on a highly transparent SiC membrane and examined them in vivo. This method will provide new insights into cell biology.
  • Prashanth Menezes awarded prestigious VAIBHAV Fellowship by Government of India
    News
    09.10.2025
    Prashanth Menezes awarded prestigious VAIBHAV Fellowship by Government of India
    The Ministry of Science and Technology, Government of India, has announced the recipients of the Vaishvik Bhartiya Vaigyanik (VAIBHAV) Fellowship, a flagship initiative aimed at fostering collaboration between the Indian STEMM (Science, Technology, Engineering, Mathematics, and Medicine) diaspora and leading research institutions in India. Among the 2025 awardees is Dr. Prashanth W. Menezes, Head of the Department of Materials Chemistry for Catalysis at Helmholtz-Zentrum Berlin (HZB).
  • Sasol and HZB deepen collaboration with strategic focus on digitalisation
    News
    08.10.2025
    Sasol and HZB deepen collaboration with strategic focus on digitalisation
    Sasol Research & Technology and Helmholtz Zentrum Berlin (HZB) are expanding their partnership into the realm of digitalisation, building on their joint efforts in the CARE-O-SENE project and an Industrial Fellowship launched earlier this year. This new initiative marks a significant step forward in leveraging digital technologies to accelerate catalyst innovation and deepen scientific collaboration.