Uranium magnetism tuned to the limits

Advisor: Ladislav Havela (MFF UK)

Funding: Fully funded.

Contact: havela@mag.mff.cuni.cz

Actinides are an important part of any technologically advanced society. Besides nuclear technologies there is an ongoing intense research to utilize the potential of depleted uranium in chemical technologies. Numerous possibilities are offered by strong spin-orbit interaction, providing enormous magnetic anisotropy and giant magnetoresistance effects at U-based compounds. The problem has been week exchange interactions and hybridization of the 5f electronic states, responsible for magnetism, with other electronic states. As a result, the temperatures of magnetic ordering are typically below ambient temperature.

Besides conventional tuning using modifications of U-U distances, the possibility to use the potential of polar bonding with ligands, decoupling the 5f states from hybridization, has been articulated. Such phenomenon, bringing stronger 5f magnetism, was first observed in compounds with hydrogen [1]. Research or other materials is under way.

We seek students keen to invest effort into materials synthesis and low-temperature studies, to undertake thin film synthesis and spectroscopic studies, as well as to interact with theorists performing ab-initio computations and simulations. The goal is to understand mechanisms and limits of 5f magnetism in U-based compounds.

Literature:

[1] L. Havela, M. Paukov, M. Dopita, L. Horak, M. Cieslar, D. Drozdenko, P. Minarik, I. Turek, M. Divis, D. Legut, L. Kyvala, T. Gouder, F. Huber, A. Seibert, E. Tereshina-Chitrova: XPS, UPS, and BIS study of pure and alloyed β-UH3 films: Electronic structure, bonding, and magnetism, Journal of Electron Spectroscopy and Related Phenomena 239 (2020) 146904.