| Autor: |
Zhandun, Vyacheslav S., Kazak, Natalia V., Kupenko, Ilya, Vasiukov, Denis M., Li, Xiang, Blackburn, Elizabeth, Ovchinnikov, Sergei G. |
| Předmět: |
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| Zdroj: |
Dalton Transactions: An International Journal of Inorganic Chemistry; 2/7/2024, Vol. 56 Issue 5, p2242-2251, 10p |
| Abstrakt: |
The magnetic and electronic structures of Fe4O5 have been investigated at ambient and high pressures via a combination of representation analysis, density functional theory (DFT+U) calculations, and Mössbauer spectroscopy. A few spin configurations corresponding to the different irreducible representations have been considered. The total-energy calculations reveal that the magnetic ground state of Fe4O5 corresponds to an orthogonal spin order. Depending on the magnetic propagation vector k, two spin-ordered phases with minimal energy differences are realized. The lowest energy magnetic phase is related to k = (0, 0, 0) and is characterized by ferromagnetic ordering of iron magnetic moments at prismatic sites along the b-axis and antiferromagnetic ordering of iron moments at octahedral sites along the c-axis. For the k = (1/2, 0, 0) phase, the moments in the prisms are antiferromagnetically ordered along the b-axis and the moments in the octahedra are still antiferromagnetically ordered along the c-axis. Under high pressure, Fe4O5 exhibits magnetic transitions with the corresponding electronic transitions of the metal–insulator type. At a critical pressure PC ∼ 60 GPa, the Fe ions at the octahedral sites undergo a high-spin to low-spin state crossover with a decrease in the unit-cell volume of ∼4%, while the Fe ions at the prismatic sites remain in the high-spin state up to 130 GPa. This site-dependent magnetic collapse is experimentally observed in the transformation of Mössbauer spectra measured at room temperature and high pressures. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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