Micromagnetic Modeling of a Magnetically Unstable Zone and Its Geological Significances
[1];
[1];
[2];
[4];
[5];
[6];
- School of Geophysics and Measurement‐control Technology East China University of Technology Nanchang China
- School of Geosciences University of Edinburgh Edinburgh UK
- School of Water Resources and Environmental Engineering East China University of Technology Nanchang China
- Paleomagnetism and Planetary Magnetism Laboratory School of Geophysics and Geomatics China University of Geosciences Wuhan China
- School of Environmental Sciences University of Liverpool Liverpool UK
- Division of Geosciences Research Scripps Institution of Oceanography La Jolla CA USA
Abstract Recent micromagnetic simulations have found that particles in the transitional zone between the single domain (SD) and single vortex (SV) zone are prone to thermal and external magnetic field instabilities that could adversely affect the accuracy of interpretations of paleomagnetic recordings. In this study, we attempt to evaluate the internal magnetization characteristics of these magnetically unstable (MU) particles and the influence on paleomagnetic observations by simulating the magnetic behavior of 68–104 nm truncated octahedral magnetite particles using the MERRILL modeling software. We found that: (a) The size region of the “MU zone” for grains of truncated octahedron shape is different from cubic octahedrons and spheres, indicating that the zone may be controlled by the geometry and shape of particles; (b) The MU zone has a range of 79–97 nm region, which is dominated by a hard‐axis aligned single vortex (HSV); and (c) MU particles are unstable as a function of temperature and have low coercive fields. Finally, the numerical fitting of hysteresis parameters for experimental data suggests that the influence of such MU particles in samples should not be ignored, especially for samples with fine‐grained magnetic minerals as the primary magnetic recording carriers. This research has extended our understanding of the behavior of the “MU zone” and its significance on paleomagnetic records.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1886692
- Journal Information:
- Journal of Geophysical Research. Solid Earth, Journal Name: Journal of Geophysical Research. Solid Earth Journal Issue: 9 Vol. 127; ISSN 2169-9313
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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