A new electron diffraction approach for structure refinement applied to Ca.sub.3./sub.Mn.sub.2./sub.O.sub.7./sub.

0542910 - FZÚ 2022 RIV GB eng J - Journal Article
Beanland, R. - Smith, K. - Vaněk, Přemysl - Zhang, H. - Hubert, A. - Evans, K. - Römer, R.A. - Kamba, Stanislav
A new electron diffraction approach for structure refinement applied to Ca₃Mn₂O₇.
Acta Crystallographica Section A-Foundation and Advances. Roč. 77, May (2021), s. 196-207. ISSN 2053-2733. E-ISSN 2053-2733
R&D Projects: GA MŠMT(CZ) EF16_019/0000760; GA ČR GA18-09265S
Grant - others:OP VVV - SOLID21(XE) CZ.02.1.01/0.0/0.0/16_019/0000760
Institutional support: RVO:68378271
Keywords : digital diffraction * electron diffraction * Ca₃Mn₂O₇ * CBED * LACBED
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 2.331, year: 2021
Method of publishing: Open access
https://doi.org/10.1107/S2053273321001546

The digital large-angle convergent-beam electron diffraction (D-LACBED) technique is applied to Ca3Mn2O7 for a range of temperatures. Bloch-wave simulations are used to examine the effects that changes in different parameters have on the intensity in D-LACBED patterns, and atomic coordinates, thermal atomic displacement parameters and apparent occupancy are refined to achieve a good fit between simulation and experiment. The sensitivity of the technique to subtle changes in structure is demonstrated. Refined structures are in good agreement with previous determinations of Ca3Mn2O7 and show the decay of anti-phase oxygen octahedral tilts perpendicular to the c axis of the A21am unit cell with increasing temperature, as well as the robustness of oxygen octahedral tilts about the c axis up to 400 C. The technique samples only the zero-order Laue zone and is therefore insensitive to atom displacements along the electronbeam direction.
Permanent Link: http://hdl.handle.net/11104/0320243