Show simple item record

dc.contributor.advisorFalco, Charles M.en_US
dc.contributor.authorEickmann, James Thomas, 1970-
dc.creatorEickmann, James Thomas, 1970-en_US
dc.date.accessioned2013-04-18T09:55:38Z
dc.date.available2013-04-18T09:55:38Z
dc.date.issued1998en_US
dc.identifier.urihttp://hdl.handle.net/10150/282634
dc.description.abstractI have investigated the influence of an ultra-thin Au interface layer on the magnetic anisotropy of Co-Pd and Co-Cu structures. Sandwich structures of the form X/Co/Y/Cu/Si(111), with (X, Y) = (Pd, Pd), (Au, Pd), (Pd, Au), (Cu, Cu), (Au, Cu), and (Cu, Au) were studied. For each structure, a Au layer of systematically varied thickness (t(Au)) was inserted at one Co interface. I also investigated Co/Pd and Co/Cu multilayer systems. For each Co-Pd sandwich structures a maximum is observed in the magnetic anisotropy for t(Au) = 1 to 1.5 atomic monolayer (ML). For the Co/Pd multilayer system, a maximum in coercivity occurs with tAu = 0.5 ML. For each Co-Cu sandwich structure except (X, Y) = (Cu, Au), a minimum in magnetic anisotropy is observed at t(Au) = 1 ML. For the Co/Cu multilayer system, a decrease in magnetoresistance was seen with increased tAu except in multilayers with a relatively thin Co layer thickness (∼3 ML) which display a peak in magnetoresistance is seen at tAu = 1 ML. I have also investigated the strain, surface alloying, and surface (interface) roughness of these systems using RHEED, XPS, and LAXD. Analysis of these measurements reveals some correlation between magnetic anisotropy and both strain and surface roughness. Based on my investigations, I conclude that the most likely cause for the non-monotonic changes seen in anisotropy is changes in the surface magnetocrystalline anisotropy. While strain and surface roughness may also play a role, I believe that the influence of the ultra-thin Au interlayer on the orbital hybridization and electronic environment at the interface is dominant.
dc.language.isoen_USen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectPhysics, Electricity and Magnetism.en_US
dc.subjectPhysics, Condensed Matter.en_US
dc.titleInfluence of ultra-thin Au interface layers on the structure and magnetic anisotropy of Co filmsen_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.identifier.proquest9829374en_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineOptical Sciencesen_US
thesis.degree.namePh.D.en_US
dc.description.noteDigitization note: p. 101 missing from paper original.
dc.identifier.bibrecord.b38554604en_US
refterms.dateFOA2018-07-01T01:08:05Z
html.description.abstractI have investigated the influence of an ultra-thin Au interface layer on the magnetic anisotropy of Co-Pd and Co-Cu structures. Sandwich structures of the form X/Co/Y/Cu/Si(111), with (X, Y) = (Pd, Pd), (Au, Pd), (Pd, Au), (Cu, Cu), (Au, Cu), and (Cu, Au) were studied. For each structure, a Au layer of systematically varied thickness (t(Au)) was inserted at one Co interface. I also investigated Co/Pd and Co/Cu multilayer systems. For each Co-Pd sandwich structures a maximum is observed in the magnetic anisotropy for t(Au) = 1 to 1.5 atomic monolayer (ML). For the Co/Pd multilayer system, a maximum in coercivity occurs with tAu = 0.5 ML. For each Co-Cu sandwich structure except (X, Y) = (Cu, Au), a minimum in magnetic anisotropy is observed at t(Au) = 1 ML. For the Co/Cu multilayer system, a decrease in magnetoresistance was seen with increased tAu except in multilayers with a relatively thin Co layer thickness (∼3 ML) which display a peak in magnetoresistance is seen at tAu = 1 ML. I have also investigated the strain, surface alloying, and surface (interface) roughness of these systems using RHEED, XPS, and LAXD. Analysis of these measurements reveals some correlation between magnetic anisotropy and both strain and surface roughness. Based on my investigations, I conclude that the most likely cause for the non-monotonic changes seen in anisotropy is changes in the surface magnetocrystalline anisotropy. While strain and surface roughness may also play a role, I believe that the influence of the ultra-thin Au interlayer on the orbital hybridization and electronic environment at the interface is dominant.


Files in this item

Thumbnail
Name:
azu_td_9829374_sip1_m.pdf
Size:
2.670Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record