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dc.contributor.authorFabian, Karl
dc.contributor.authorShcherbakov, Valera P.
dc.date.accessioned2018-09-03T06:45:52Z
dc.date.available2018-09-03T06:45:52Z
dc.date.issued2018-07-17
dc.description.abstractA first-principle micromagnetic and statistical calculation of viscous remanent magnetization (VRM) in an ensemble of cubic magnetite pseudo-single domain (PSD) particles is presented. The theoretical methods developed apply to all magnetic particle sizes, from single domain to multidomain. The numerical implementation is based on a fast relaxation algorithm for finding optimal transition paths between micromagnetic local energy minima. The algorithm combines a nudged-elastic-band technique with action minimization. Initial paths are obtained by repetitive minimizations of modified energy functions. For a cubic PSD particle, 60 different local energy minima are identified, and all optimal energy barriers between them are numerically calculated for the case of zero external field. These results are used to estimate the energy barriers in weak external fields. Based on these, time-dependent transition matrices are constructed, which fully describe the continuous homogeneous Markov processes of VRM acquisition and decay. By spherical averaging, the acquisition of remanent magnetization in an isotropic PSD ensemble is calculated from laboratory to geological timescales. The modelled particle ensemble shows a physically meaningful overshooting of magnetization during VRM acquisition. The results also clarify why VRM acquisition in PSD particles can occur much faster than VRM decay, and therefore explain occurrence of extremely stable VRM as found in some palaeomagnetic studies.en_US
dc.description.sponsorshipState assignment of IPE RASen_US
dc.descriptionThis article has been accepted for publication in <i>Geophysical Journal International</i> © 2018. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Source at <a href=https://doi.org/10.1093/gji/ggy285> https://doi.org/10.1093/gji/ggy285</a>.en_US
dc.identifier.citationFabian, K. & Shcherbakov, V.P. (2018). Energy barriers in three-dimensional micromagnetic models and the physics of thermoviscous magnetization. Geophysical Journal International, 215, 314-324. https://doi.org/10.1093/gji/ggy285en_US
dc.identifier.cristinIDFRIDAID 1604555
dc.identifier.doi10.1093/gji/ggy285
dc.identifier.issn0956-540X
dc.identifier.issn1365-246X
dc.identifier.urihttps://hdl.handle.net/10037/13626
dc.language.isoengen_US
dc.publisherOxford University Press (OUP)en_US
dc.relation.journalGeophysical Journal International
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/en_US
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450en_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450en_US
dc.subjectRock and mineral magnetismen_US
dc.subjectNumerical modellingen_US
dc.subjectMagnetic propertiesen_US
dc.titleEnergy barriers in three-dimensional micromagnetic models and the physics of thermoviscous magnetizationen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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