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  • Single Particle Multipole E...
    Cortés‐Ortuño, David; Fabian, Karl; de Groot, Lennart V.

    Geochemistry, geophysics, geosystems : G3, April 2021, 2021-Apr, 2021-04-00, 20210401, 2021-04-01, Letnik: 22, Številka: 4
    Journal Article

    Micromagnetic tomography aims at reconstructing large numbers of individual magnetizations of magnetic particles from combining high‐resolution magnetic scanning techniques with micro X‐ray computed tomography (microCT). Previous work demonstrated that dipole moments can be robustly inferred, and mathematical analysis showed that the potential field of each particle is uniquely determined. Here, we describe a mathematical procedure to recover higher orders of the magnetic potential of the individual magnetic particles in terms of their spherical harmonic expansions (SHE). We test this approach on data from scanning superconducting quantum interference device microscopy and microCT of a reference sample. For particles with high signal‐to‐noise ratio of the magnetic scan we demonstrate that SHE up to order n = 3 can be robustly recovered. This additional level of detail restricts the possible internal magnetization structures of the particles and provides valuable rock magnetic information with respect to their stability and reliability as paleomagnetic remanence carriers. Micromagnetic tomography therefore enables a new approach for detailed rock magnetic studies on large ensembles of individual particles. Key Points Micromagnetic Tomography uniquely recovers higher‐order multipole terms for several individual grains in a sample Higher order multipole moments are an expression of the internal domain structure of magnetic grains Ultimately, this enables to select individual grains for rock‐ and paleomagnetic studies based on domain configuration