| Автор | Dunlop, David J. |
| Автор | Argyle, Kenneth S. |
| Автор | Bailey, Monika E. |
| Дата выпуска | 1990 |
| dc.description | We describe three useful techniques for investigating magnetic microstructure and granulometry, high‐temperature alternating‐field (AF) demagnetization, thermal fluctuation analysis (TFA), and determination of the demagnetizing factor N, and give examples of their use. For synthetic magnetite samples, thennoremanent magnetization and anhysteretic rémanent magnetization are shown to differ in their AF demagnetization spectra at all temperatures up to the blocking range. Moreover, various coercivity fractions of either spectrum evolve differently with temperature than does the bulk coercive force. TFA of high‐temperature coercive force data for dispersed magnetite crystals with mean sizes of 215, 390 and 540 run indicate that ≈200 nm regions are thermally activated in each case. These regions may be responsible for pseudo‐single‐domain behaviour. A crude estimate of N for multidomain grains at any temperature is the ratio between bulk coercive force and saturation remanence. The 215–540 nm magnetites appear to contain two or three domains between −100°C and 400°C; new domains may nucleate at higher temperatures. |
| Формат | application.pdf |
| Копирайт | Copyright 1990 by the American Geophysical Union. |
| Тема | Application of Optical and Magnetic Techniques in Rock Magnetism |
| Тема | Geomagnetism and Paleomagnetism |
| Тема | Geomagnetism and Paleomagnetism: Instruments and techniques |
| Тема | Geomagnetism and Paleomagnetism: Rock and mineral magnetism |
| Тема | Geomagnetism and Paleomagnetism: Biomagnetism |
| Тема | Geomagnetism and Paleomagnetism: Paleomagnetism applied to tectonics |
| Название | High‐temperature techniques for measuring microcoercivity, crystallite size, and domain state |
| Тип | article |
| DOI | 10.1029/GL017i006p00767 |
| Electronic ISSN | 1944-8007 |
| Print ISSN | 0094-8276 |
| Журнал | Geophysical Research Letters |
| Том | 17 |
| Первая страница | 767 |
| Последняя страница | 770 |
| Аффилиация | Dunlop, David J.; Geophysics Laboratory, Department of Physics, University of Toronto |
| Аффилиация | Argyle, Kenneth S.; Geophysics Laboratory, Department of Physics, University of Toronto |
| Аффилиация | Bailey, Monika E.; Geophysics Laboratory, Department of Physics, University of Toronto |
| Выпуск | 6 |
| Библиографическая ссылка | Argyle, K. S.D. J.Dunlop, Low‐temperature and high‐temperature hysteresis of small multidomain in magnetites (215‐540 nm), J. Geophys. Res., 95, 1990 |
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