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You searched for subject:(Permanent micromagnet array). One record found.

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1. Ponomareva, Svetlana. Développement et caractérisation avancée de matériaux magnétiques durs de haute performance : Development and advanced characterization of high performance hard magnetic materials.

Degree: Docteur es, Nanophysique, 2017, Grenoble Alpes; Université polytechnique de Tomsk (Russie)

L'auteur n'a pas fourni de résumé en français

Nowadays in medicine and biotechnology a wide range of applications involves magnetic micro/nano-object manipulation including remote control of magnetic beads, trapping of drug vectors, magnetic separation of labelled cells and so on. Handling and positioning magnetic particles and elements functionalized with these particles has greatly benefited from advances in microfabrication. Indeed reduction in size of the magnet while maintaining its field strength increases the field gradient. In this context, arrays made of permanent micromagnets are good candidates for magnetic handling devices. They are autonomous, suitable for integration into complex systems and their magnetic action is restricted to the region of interest.In this thesis we have elaborated an original approach based on AFM and MFM for quantitative study of the magnetic force and associated force gradients induced by TMP micromagnet array on an individual magnetic micro/nano-object. For this purpose, we have fabricated smart MFM probes where a single magnetic (sub)micronic sphere was fixed at the tip apex of a non-magnetic probe thanks to a dual beam FIB/SEM machine equipped with a micromanipulator.Scanning Force Microscopy conducted with such probes, the so-called Magnetic Particle Scanning Force Microscopy (MPSFM) was employed for 3D mapping of TMP micromagnets. This procedure involves two main aspects: (i) the quantification of magnetic interaction between micromagnet array and attached microsphere according to the distance between them and (ii) the complementary information about micromagnet array structure. The main advantage of MPSFM is the use of a probe with known magnetization and magnetic volume that in combination with modelling allows interpreting the results ably.We conducted MPSFM on TMP sample with two types of microparticle probes: with superparamagnetic and NdFeB microspheres. The measurements carried out with superparamagnetic microsphere probes reveal attractive forces (up to few tens of nN) while MFM maps obtained with NdFeB microsphere probes reveal attractive and repulsive forces (up to one hundred of nN) for which the nature of interaction is defined by superposition of microsphere and micromagnet array magnetizations. The derived force and its gradient from MFM measurements are in agreement with experiments on microparticle trapping confirming that the strongest magnetic interaction is observed above the TMP sample interfaces, between the areas with opposite magnetization. Thanks to 3D MFM maps, we demonstrated that intensity of magnetic signal decays fast with the distance and depends on micromagnet array and microsphere properties.Besides the magnetic interaction quantification, we obtained new information relevant to TMP sample structure: we observed and quantified the local magnetic roughness and associated fluctuations, in particular in zones of reversed magnetization. The variation of detected signal can reach the same order of magnitude as the signal above the micromagnet…

Advisors/Committee Members: Marchi, Florence (thesis director), Khasanov, Oleg (thesis director).

Subjects/Keywords: Réseau de micro-aimants permanents; Microscopie à force atomique et à force magnétique; Fabrication de la sonde à microparticule; Quantification et cartographie d'interaction à nano-Échelle; Modélisation micromagnétique; Micromagnétisme; Permanent micromagnet array; Atomic and Magnetic Force Microscopy; Microparticle probe fabrication; Nano-Scale interaction quantification and mapping; Micromagnetic modelling; Micromagnetism; 530

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APA (6th Edition):

Ponomareva, S. (2017). Développement et caractérisation avancée de matériaux magnétiques durs de haute performance : Development and advanced characterization of high performance hard magnetic materials. (Doctoral Dissertation). Grenoble Alpes; Université polytechnique de Tomsk (Russie). Retrieved from http://www.theses.fr/2017GREAY035

Chicago Manual of Style (16th Edition):

Ponomareva, Svetlana. “Développement et caractérisation avancée de matériaux magnétiques durs de haute performance : Development and advanced characterization of high performance hard magnetic materials.” 2017. Doctoral Dissertation, Grenoble Alpes; Université polytechnique de Tomsk (Russie). Accessed March 09, 2021. http://www.theses.fr/2017GREAY035.

MLA Handbook (7th Edition):

Ponomareva, Svetlana. “Développement et caractérisation avancée de matériaux magnétiques durs de haute performance : Development and advanced characterization of high performance hard magnetic materials.” 2017. Web. 09 Mar 2021.

Vancouver:

Ponomareva S. Développement et caractérisation avancée de matériaux magnétiques durs de haute performance : Development and advanced characterization of high performance hard magnetic materials. [Internet] [Doctoral dissertation]. Grenoble Alpes; Université polytechnique de Tomsk (Russie); 2017. [cited 2021 Mar 09]. Available from: http://www.theses.fr/2017GREAY035.

Council of Science Editors:

Ponomareva S. Développement et caractérisation avancée de matériaux magnétiques durs de haute performance : Development and advanced characterization of high performance hard magnetic materials. [Doctoral Dissertation]. Grenoble Alpes; Université polytechnique de Tomsk (Russie); 2017. Available from: http://www.theses.fr/2017GREAY035

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