Multidomain hematite: A source of planetary magnetic anomalies?
Thermoremanent magnetization (TRM) in hematite is larger than TRM in magnetite for grain sizes ≥10 µm. We show that hematite's weak spontaneous magnetization Ms causes its strong TRM, since the self‐demagnetizing field Hd opposing large domain wall displacements is proportional to Ms. In hemati...
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Published in | Geophysical research letters Vol. 28; no. 17; pp. 3345 - 3348 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
Blackwell Publishing Ltd
01.09.2001
American Geophysical Union |
Subjects | |
Online Access | Get full text |
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Summary: | Thermoremanent magnetization (TRM) in hematite is larger than TRM in magnetite for grain sizes ≥10 µm. We show that hematite's weak spontaneous magnetization Ms causes its strong TRM, since the self‐demagnetizing field Hd opposing large domain wall displacements is proportional to Ms. In hematite, Hd is comparable to the Earth's magnetic field but in magnetite, Hd is 1000 times larger. As a result, Earth's field TRM of MD hematite (≈ 0.3 Am²/kg) outweighs TRM and induced magnetization of MD magnetite (≈0.01–0.02 Am²/kg and rivals TRM of single‐domain and PSD magnetite as a source of magnetic anomalies on Earth and perhaps on Mars. |
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Bibliography: | ark:/67375/WNG-7XPGRGKL-V ArticleID:2001GL013125 istex:45CD81BA4204B260F0557BF09D0BDB708326FA09 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1029/2001GL013125 |