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Understanding magnetic field reversal mechanisms in mesoscopic magnetic multilayer ring structures

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dc.contributor.advisor Caroline A. Ross. en_US
dc.contributor.author Ng, Bryan en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Materials Science and Engineering. en_US
dc.date.accessioned 2009-04-29T17:35:25Z
dc.date.available 2009-04-29T17:35:25Z
dc.date.copyright 2008 en_US
dc.date.issued 2008 en_US
dc.identifier.uri http://hdl.handle.net/1721.1/45395
dc.description Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008. en_US
dc.description Includes bibliographical references. en_US
dc.description.abstract Patterned pseudo spin-valve rings show great promise for device applications due to their non-volatility and variety of stable magnetic states. However, the magnetic reversal of these elements under an applied field is complex due to the magnetostatic coupling between the two ferromagnetic layers. Elliptical rings are electrically probed using highly symmetric Wheatstone bridges in conjunction with traditional four-point electrical measurements and micromagnetic simulations. New insight into domain wall nucleation and propagation events are elucidated. The resulting behavior is found to yield large signals at very low fields, making these devices ideal for device applications in data storage and computer logic. 360° domain walls are found to be extremely stable until fields as high as 10000e, but are positionally uncontrollable in elliptical rings. Rhombic rings were investigated as a geometry that can nucleate, propagate and pin domain walls more easily. Measurements and simulations confirm that the same reversal mechanisms exist and domain walls are more systematically positioned. The control over 3600 domain walls is valuable since reversals can occur without nucleation by decoupling the wall into a reverse domain. As a result, rhombic rings are useful as devices that can perform device functions at extremely low fields. en_US
dc.description.statementofresponsibility by Bryan Ng. en_US
dc.format.extent 96 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri http://dspace.mit.edu/handle/1721.1/7582 en_US
dc.subject Materials Science and Engineering. en_US
dc.title Understanding magnetic field reversal mechanisms in mesoscopic magnetic multilayer ring structures en_US
dc.type Thesis en_US
dc.description.degree M.Eng. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Materials Science and Engineering. en_US
dc.identifier.oclc 317404502 en_US


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