Multi-segmented Magnetic Nanowires Fabrication and Characterization

Handle URI:
http://hdl.handle.net/10754/609176
Title:
Multi-segmented Magnetic Nanowires Fabrication and Characterization
Authors:
Moreno Garcia, Julian ( 0000-0002-9320-7574 )
Abstract:
In this work, nickel-gold multi-segmented magnetic nanowires were grown by electrodeposition in anodized alumina templates. The templates were fabricated by a two step anodization process of aluminum disks in an aqueous solution of oxalic acid. In this process, ordered pores grew in an alumina oxide layer at the exposed aluminum area. Each disk was electropolished before the anodization process and the features at its surface were characterized to assess the effect on the pore ordering. Nickel Watts and gold cyanide electrolyte baths were prepared to electrodeposit pure nickel and gold in the templates. Both solutions response to a range of externally applied voltages was characterized and a threshold voltage above which deposition occurs is reported. Single nanowires were isolated by chemically dissolving the template and dispersed in ethanol. Devices were fabricated with these isolated nanowires in which gold contacts were deposited to measure the resistance. A current pulse setup was implemented in a magnetoresistance system allowing to send current pulses with amplitude as low as 2nA and 50μs width. Magneto resistance measurement were carried out on the single nanowires devices and the effect of current pulses was studied. It was found that distinct resistance states can be achieved by applying a determined current pulse at a constant applied field and that the initial state can be recovered by removing excess charge from the nanowire. Finally, the effect of annealing the nanowires in an air atmosphere at 150°C for 24 hours is studied showing that the nickel sections oxidize and the gold sections remain unchanged.
Advisors:
Kosel, Jürgen ( 0000-0002-8998-8275 )
Committee Member:
Manchon, Aurelien ( 0000-0002-4768-293X ) ; Di Fabrizio, Enzo ( 0000-0001-5886-4678 )
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program
Program:
Materials Science and Engineering
Issue Date:
28-Apr-2016
Type:
Thesis
Appears in Collections:
Theses; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.advisorKosel, Jürgenen
dc.contributor.authorMoreno Garcia, Julianen
dc.date.accessioned2016-05-12T12:24:05Zen
dc.date.available2016-05-12T12:24:05Zen
dc.date.issued2016-04-28en
dc.identifier.urihttp://hdl.handle.net/10754/609176en
dc.description.abstractIn this work, nickel-gold multi-segmented magnetic nanowires were grown by electrodeposition in anodized alumina templates. The templates were fabricated by a two step anodization process of aluminum disks in an aqueous solution of oxalic acid. In this process, ordered pores grew in an alumina oxide layer at the exposed aluminum area. Each disk was electropolished before the anodization process and the features at its surface were characterized to assess the effect on the pore ordering. Nickel Watts and gold cyanide electrolyte baths were prepared to electrodeposit pure nickel and gold in the templates. Both solutions response to a range of externally applied voltages was characterized and a threshold voltage above which deposition occurs is reported. Single nanowires were isolated by chemically dissolving the template and dispersed in ethanol. Devices were fabricated with these isolated nanowires in which gold contacts were deposited to measure the resistance. A current pulse setup was implemented in a magnetoresistance system allowing to send current pulses with amplitude as low as 2nA and 50μs width. Magneto resistance measurement were carried out on the single nanowires devices and the effect of current pulses was studied. It was found that distinct resistance states can be achieved by applying a determined current pulse at a constant applied field and that the initial state can be recovered by removing excess charge from the nanowire. Finally, the effect of annealing the nanowires in an air atmosphere at 150°C for 24 hours is studied showing that the nickel sections oxidize and the gold sections remain unchanged.en
dc.language.isoenen
dc.subjectCylindrical Nanowiresen
dc.subjectMagnetoresistanceen
dc.subjectCurrent Pulsesen
dc.titleMulti-segmented Magnetic Nanowires Fabrication and Characterizationen
dc.typeThesisen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMaterials Science and Engineering Programen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberManchon, Aurelienen
dc.contributor.committeememberDi Fabrizio, Enzoen
thesis.degree.disciplineMaterials Science and Engineeringen
thesis.degree.nameMaster of Scienceen
dc.person.id132569en
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