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| Auteurs principaux: | , , , , |
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| Format: | Preprint |
| Publié: |
2024
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| Sujets: | |
| Accès en ligne: | https://arxiv.org/abs/2404.07769 |
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| _version_ | 1866913310374363136 |
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| author | Bellon, Ualisson Donardelli Williams, Wyn Trindade, Ricardo Ivan Ferreira Diaz, Ana Galante, Douglas |
| author_facet | Bellon, Ualisson Donardelli Williams, Wyn Trindade, Ricardo Ivan Ferreira Diaz, Ana Galante, Douglas |
| contents | The recording of planetary magnetic fields is often attributed to uniformly-magnetised nanoscopic iron oxides, called single-domain (SD). Yet, the main magnetic constituents of rocks are more complex, non-uniformly magnetised grains in single or multi-vortex states. We know little about their behaviour due to limitations in defining their precise shape and internal magnetic structure. We propose a novel approach combining non-destructive synchrotron-based ptychographic nanotomography with micromagnetic modelling to explore the magnetic stability of remanence-bearing minerals. Applied to a microscopic rock sample, we identified hundreds of nanoscopic grains of magnetite/maghemite with diverse morphologies. For some grains, shape irregularities near the transition from SD to the single-vortex state allow for multiple domain states, some unstable and unable to record the field for significant periods. Additionally, some other grains exhibit temperature-dependent occupancy probabilities, potentially hampering experiments to recover the intensity of past magnetic fields. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_07769 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Coupling nanoscopic tomography and micromagnetic modelling to assess the stability of geomagnetic recorders Bellon, Ualisson Donardelli Williams, Wyn Trindade, Ricardo Ivan Ferreira Diaz, Ana Galante, Douglas Geophysics The recording of planetary magnetic fields is often attributed to uniformly-magnetised nanoscopic iron oxides, called single-domain (SD). Yet, the main magnetic constituents of rocks are more complex, non-uniformly magnetised grains in single or multi-vortex states. We know little about their behaviour due to limitations in defining their precise shape and internal magnetic structure. We propose a novel approach combining non-destructive synchrotron-based ptychographic nanotomography with micromagnetic modelling to explore the magnetic stability of remanence-bearing minerals. Applied to a microscopic rock sample, we identified hundreds of nanoscopic grains of magnetite/maghemite with diverse morphologies. For some grains, shape irregularities near the transition from SD to the single-vortex state allow for multiple domain states, some unstable and unable to record the field for significant periods. Additionally, some other grains exhibit temperature-dependent occupancy probabilities, potentially hampering experiments to recover the intensity of past magnetic fields. |
| title | Coupling nanoscopic tomography and micromagnetic modelling to assess the stability of geomagnetic recorders |
| topic | Geophysics |
| url | https://arxiv.org/abs/2404.07769 |