On 06/10/2026 at 1:15 PM, in room 2011 of the Faculty of Physics, University of Białystok, Mgr Paweł Butkiewicz, from the Doctoral School of University of Bialystok, Faculty of Physics, University of Bialystok will give a lecture entitled:
„Determination of the Hyperfine Structure of ⁵⁷Fe Nuclear Levels in GaFeO₃ and FeB Single Crystals”
Tomasz Karpiuk
Andrzej Maziewski
„Determination of the Hyperfine Structure of ⁵⁷Fe Nuclear Levels in GaFeO₃ and FeB Single Crystals ”
Paweł Butkiewicz
Doctoral School of University of Bialystok
Faculty of Physics, University of Bialystok
Mössbauer spectroscopy enables the investigation of local hyperfine interactions in solids, in particular the electric quadrupole interaction associated with the electric field gradient (EFG) and the magnetic dipole interaction associated with the hyperfine magnetic field (HMF). In the case of single crystals, directional measurements provide additional information on the spatial orientation of these interactions.
This work presents investigations of the hyperfine structure of ⁵⁷Fe nuclear levels in GaFeO₃ and FeB single crystals, with particular emphasis on the velocity moments formalism (VMF) [1,2].
For GaFeO₃, directional Mössbauer measurements were performed and the influence of crystallographic symmetry on the observed EFG tensor was analyzed. The analysis was generalized to all 230 space groups, determining the symmetry-imposed constraints on the tensor components accessible experimentally. The results for GaFeO₃ were compared with ab initio calculations. The studies of GaFeO₃ also included structural and magnetic characterization as well as analysis of cation disorder [3–5].
FeB was used as a system in which the magnetic dipole and electric quadrupole interactions coexist at room temperature. Directional measurements were performed on ⁵⁷Fe-enriched single crystals using a synchrotron Mössbauer source at the BL11XU beamline at SPring-8. Analysis of the velocity moments was used to investigate the possibility of separating the contributions of the two interactions and to identify the experimental limitations of the method [6].
The obtained results demonstrate the potential of directional Mössbauer spectroscopy and the velocity moments formalism for investigating the spatial orientation of hyperfine interactions in single crystals.
Selected publications related to the dissertation:
