Business card Dr. Katarzyna Siewierska
Dr. Katarzyna Siewierska completed her PhD in Physics in 2021 at University of Dublin, Trinity College. Her thesis title was `Development and Characterisation Zero-moment Half-metal'. The research involved fabrication and characterisation of Mn2RuxGa thin films using a variety of techniques including magneto-transport, magnetometry, magneto-optical Kerr effect microscopy and x-ray magnetic circular dichroism. Her main research interests are novel spintronic materials and synchrotron techniques.
Brief project summary: 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 Mn-based Heusler alloys, revealing the critical role of Mn 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 HZB/BESY 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.Publications