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Cycloidal magnetic structure of BiFe1−xCoxO3 (x = 0.05, 0.1, 0.15) studied by 57Fe Mössbauer spectroscopyтезисы доклада
- Авторы: Соболев Алексей Валерьевич, Русаков Вячеслав Серафимович, Гапочка Алексей Миайлович, Глазкова Яна Сергеевна, Губайдулина Татьяна Валиевна, Мацнев Михаил Евгеньевич, Белик Алексей Александрович, Пресняков Игорь Александрович
- Сборник: BOOK OF ABSTRACTS ICAME 2021
- Тезисы
- Год издания: 2021
- Место издания: Brasov, Romania
- Первая страница: 126
- Аннотация: We have carried out a detailed 57Fe Mössbauer study of Co-substituted BiFeO3, BiFe1-xCoxO3 with x = 0.05, 0.1, and 0.15, performed in a wide temperature range including the magnetic transition point (TN). At low temperatures T << TN, the 57Fe Mössbauer spectra are composed of several Zeeman patterns originating from different configurations of the nearest-neighbor arrangements of Fe3+ and Co3+ ions. The line broadening and sizeable spectrum asymmetry were shown to be consistent with the space-modulated cycloidal magnetic structure of easyplane type with high values of the anharmonicity parameter m = 0.47 – 0.92 (at 4.7 K). The experimental spectra were analyzed assuming the anisotropy of the magnetic hyperfine field Hhf at the 57Fe nuclei. The m parameter increases with increasing temperature and reaches its maximum value (m ≈ 1) for x = 0.10 and 0.15 near 200 K and 150 K, respectively, corresponding to a transition to a collinear antiferromagnetic structure with μFe⊥ch. Such an unusual trend of the anharmonicity parameter m(T) was well reproduced by the molecular field model in which the low-spin to intermediate-spin transition of Co3+ is assumed. At the low cobalt content in BiFe0.95Co0.05O3, the cycloidal structure is retained but with a very high degree of anharmonicity, corresponding to the nearly collinear spin order except for small regions of domain walls.
- Добавил в систему: Гапочка Алексей Михайлович