Magnetic anomalies and canting effects in nanocrystalline spinel copper ferrites CuxFe3−xO4
| Autor: | R. E. Vandenberghe, R. B. Scorzelli, Roberto C. Mercader, G. Cernicchiaro, S. J. Stewart |
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| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 97:054304 |
| ISSN: | 1089-7550 0021-8979 |
| Popis: | The magnetic behavior of nanocrystalline copper spinel ferrites CuxFe3−xO4 (0.42⩽x⩽1) exhibiting different degrees of crystallinity, have been investigated by means of in-field Mossbauer and dc magnetic measurements. The samples were obtained by a coprecipitation method and were subsequently high-energy ball milled for different times, which induced a progressive improvement of the ferrite crystallinity and cation redistribution. Their magnetism shows some peculiar features; at 5K, the virgin magnetization curves remain outside the main hysteresis loop for applied fields of ≈1T and display an S-shaped form. Below 60K, the field-cooled hysteresis loops are shifted toward the negative field direction. In addition, in the same temperature range, the field-cooled magnetization of the samples with poorest crystallinity decreases sharply due to the spin freezing at the surface. The in-field Mossbauer spectra at 4.2K show that the magnetic moments of the Fe3+ ions are in a canted spin state for both the tetrahed... |
| Databáze: | OpenAIRE |
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