Abstract
Geometrically frustrated systems play an important role in studying new physical phenomena and unconventional thermodynamics. Charge ordered defect pyrochlores AM2+M3+F6 offer a convenient platform for probing the interplay between electron distribution over M2+ and M3+ sites and structural distortions; however, they are limited to compounds with M2+/3+ = V, Fe, Ni, and Cu due to difficulties in the simultaneous stabilization of other 3d elements in the +2 and +3 oxidation states. Herein, we employ Cl- anions under hydrothermal conditions for the mild reduction of Mn2O3 in concentrated HF to obtain the CsMn2+Mn3+F6 composition as a phase pure sample and study its properties. The magnetism of CsMn2F6 was characterized by measuring the magnetic susceptibility and isothermal magnetization data, and a magnetic transition to a canted antiferromagnet state was found at 24.1 K. We determined the magnetic structure of CsMn2F6 using powder neutron diffraction, which revealed successive long-range ordering of the Mn2+ and Mn3+ sites that is accompanied by a second transition. The role and strength of magnetic exchange interactions were characterized using DFT calculations.
Original language | English |
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Pages (from-to) | 11554-11567 |
Number of pages | 14 |
Journal | Journal of the American Chemical Society |
Volume | 143 |
Issue number | 30 |
DOIs | |
State | Published - Aug 4 2021 |
Funding
Financial support for this work was provided by the National Science Foundation under award DMR-1806279 and is gratefully acknowledged. This research used resources at the High Flux Isotope Reactor and the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. D.S.P (first-principles calculations) was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division.