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dc.contributor.authorHiggs, Thomas David Charles
dc.date.accessioned2018-09-11T08:43:11Z
dc.date.available2018-09-11T08:43:11Z
dc.date.issued2018-10-20
dc.date.submitted2017-12-21
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/280118
dc.description.abstractThe antiferromagnetic coupling between a rare-earth (RE) and a tran- sition metal (TM) ferromagnet can be exploited to engineer normal state and superconducting functional devices. RE/TM ferromagnetic multi- layers were previously used as spin-mixers to generate spin-triplet su- percurrents. This was possible due to magnetic inhomogeneity present in the devices, however the precise nature of the inhomogeneity was not understood. Here we present a comprehensive study of the Ni/Gd/Ni system using a powerful element-specific measurement technique: x-ray magnetic circular dichroism. In order to analyse the experimental results we present a novel model based on the Stoner-Wohlfarth model, which shows that significant inhomogeneity exists at the Ni/Gd interfaces due to the competition between the exchange energies within the system and the Zeeman energy of the applied magnetic field. The experiment and model together provide a complete overview of the Ni/Gd/Ni system due to the breadth of temperatures and thicknesses studied. The knowledge gained from this work is then applied to designing and test- ing new spin valves based on the intrinsic inhomogeneity at the RE/TM interface, and both Ni/Gd- and Gd/Ho-based devices show reversible magnetic switching behaviour which alters the superconducting critical temperature.
dc.description.sponsorshipEPSRC
dc.language.isoen
dc.rightsAttribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.rights.urihttps://creativecommons.org/licenses/by-nc-sa/4.0/
dc.subjectmagnetism
dc.subjectsuperconductivity
dc.subjectthin-film
dc.subjectxmcd
dc.subjectproximity effect
dc.subjectferromagnet
dc.subjectantiferromagnet
dc.subjectpython
dc.subjectrare-earth
dc.subjecttransition metal
dc.subjectholium
dc.subjectgadolinium
dc.subjectnickel
dc.subjectniobium
dc.subjectexchange bias
dc.titleMagnetic structures and proximity effects in rare-earth / transition metal ferromagnetic and superconductor systems
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)
dc.publisher.institutionUniversity of Cambridge
dc.publisher.departmentMaterials Science and Metallurgy
dc.date.updated2018-09-10T17:24:50Z
dc.identifier.doi10.17863/CAM.27483
dc.publisher.collegeQueens'
dc.type.qualificationtitlePhd in Physics
cam.supervisorRobinson, Jason
cam.thesis.fundingtrue


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Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
Except where otherwise noted, this item's licence is described as Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)