000156001 001__ 156001
000156001 005__ 20210308100441.0
000156001 0247_ $$2Handle$$a2128/7939
000156001 0247_ $$2ISSN
000156001 020__ $$a978-3-89336-983-6
000156001 037__ $$aFZJ-2014-04916
000156001 041__ $$aEnglish
000156001 1001_ $$0P:(DE-Juel1)130503$$aAndreas, Christian$$b0$$eCorresponding Author$$gmale$$ufzj
000156001 245__ $$aMultiscale Multimodel Simulation of Micromagnetic Singularities
000156001 260__ $$aJülich$$bForschungszentrum Jülich GmbH Zentralbibliothek, Verlag$$c2014
000156001 300__ $$aXIX, 188 S.
000156001 3367_ $$0PUB:(DE-HGF)11$$2PUB:(DE-HGF)$$aDissertation / PhD Thesis$$bphd$$mphd$$s156001
000156001 3367_ $$02$$2EndNote$$aThesis
000156001 3367_ $$2DRIVER$$adoctoralThesis
000156001 3367_ $$2BibTeX$$aPHDTHESIS
000156001 3367_ $$2DataCite$$aOutput Types/Dissertation
000156001 3367_ $$2ORCID$$aDISSERTATION
000156001 4900_ $$aSchriften des Forschungszentrums Jülich. Reihe Schlüsseltechnologien / Key Technologies$$v88
000156001 502__ $$aUniversité de Srasbourg, Diss., 2014$$aUniversität Duisburg-Essen, Diss., 2014$$bDr.$$cUniversität Duisburg-Essen$$cUniversité de Strasbourg$$d2014
000156001 500__ $$3POF3_Assignment on 2016-02-29
000156001 520__ $$aDuring the last decades, the research on fundamental magnetic structures, like domain walls, spinwaves and vortices, resulted in a detailed understanding of the magnetization dynamics in ferromagnetic materials, without which the development of modern storage devices would not have been possible. On the pathway to this level of understanding micromagnetic simulations played an important role due to their ability to reproduce experimental results in great detail and, especially, to predict magnetic patterns and their dynamic properties. An example of the predictive power is the research field of vortex dynamics. Another fundamental magnetic structure is the Bloch point, which is particularly complex since the description of the processes and energy terms responsible for its formation lie within the scope of the continuum theory of micromagnetism, but the study of its detailed properties requires a different framework. In terms of topology and concerning the exchange energy density, the Bloch point displays a point singularity in the theory of micromagnetism. Bloch points are not a marginal phenomenon; they play, e.g., an important role as transient structures during the switching of vortex cores and reside inside of the archetypal example of vortex domain walls in solid cylindrical nanowires. In the 1960s, E. Feldtkeller and W. Döring described and characterized Bloch points with the then available methods, yet their dynamics eluded a detailed description, since on one hand a large volume is necessary to stabilize a Bloch point structure and on the other hand an atomistic description of its center is required. To solve this problem we developed a multiscale multimodel simulation framework in the context of this thesis, which is able to detect automatically Bloch points as well as other micromagnetically critical structures. In that simulation kit we apply a classical Heisenberg model to the critical regions, while using the framework of micromagnetism for the remaining sample, which is discretized with finite elements. The program allows not only for a static examination of Bloch points residing in a localized Heisenberg approximated region, but also for dynamic simulations due to its ability to detect regions of interest automatically as well as to track them with the multimodel region. The simulations within this thesis focus on ferromagnetic cylindrical nanowires with vortex domain walls. The simulations describe the depinning field necessary to trigger a propagation of the domain wall with the Bloch point in its center and the impact of the relative orientation of the lattice to the Bloch point propagation direction. In addition, we could identify different propagation patterns of the structure consisting of domain wall and Bloch point. In addition to regimes with a continuous domain wall movement, this thesis highlights and discusses several complex modes of domain wall/Bloch point propagation. In particular, we find a propagation regime in which the Bloch point and domain wall propagate with constant velocity above the minimum spin wave phase velocity. This velocity remains constant within a broad interval of external field strength. Using analytic calculations we could ascribe this maximum velocity, which is a feature of potential interest from a technological perspective, to an intrinsic property of the Bloch point. [...]
000156001 773__ $$y2014
000156001 8564_ $$uhttps://juser.fz-juelich.de/record/156001/files/FZJ-2014-04916.pdf$$yOpenAccess
000156001 8564_ $$uhttps://juser.fz-juelich.de/record/156001/files/FZJ-2014-04916.jpg?subformat=icon-144$$xicon-144$$yOpenAccess
000156001 8564_ $$uhttps://juser.fz-juelich.de/record/156001/files/FZJ-2014-04916.jpg?subformat=icon-180$$xicon-180$$yOpenAccess
000156001 8564_ $$uhttps://juser.fz-juelich.de/record/156001/files/FZJ-2014-04916.jpg?subformat=icon-640$$xicon-640$$yOpenAccess
000156001 909CO $$ooai:juser.fz-juelich.de:156001$$pdnbdelivery$$pVDB$$pdriver$$popen_access$$popenaire
000156001 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess
000156001 9141_ $$y2014
000156001 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)130503$$aForschungszentrum Jülich GmbH$$b0$$kFZJ
000156001 9132_ $$0G:(DE-HGF)POF3-529H$$1G:(DE-HGF)POF3-520$$2G:(DE-HGF)POF3-500$$aDE-HGF$$bKey Technologies$$lFuture Information Technology - Fundamentals, Novel Concepts and Energy Efficiency (FIT)$$vAddenda$$x0
000156001 920__ $$lyes
000156001 9201_ $$0I:(DE-Juel1)PGI-6-20110106$$kPGI-6$$lElektronische Eigenschaften$$x0
000156001 980__ $$aphd
000156001 980__ $$aVDB
000156001 980__ $$aFullTexts
000156001 980__ $$aI:(DE-Juel1)PGI-6-20110106
000156001 980__ $$aUNRESTRICTED
000156001 9801_ $$aFullTexts