Tailoring Structural and Magnetic Properties of Fe-Based Epitaxial Thin-Film Alloys Grown by Sputter Beam Epitaxy

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dc.contributor Mewes, Tim
dc.contributor Kaminski, Matthias
dc.contributor Schwiete, Georg
dc.contributor Allred, Jared
dc.contributor.advisor Hauser, Adam
dc.contributor.author Budhathoki, Sujan
dc.date.accessioned 2022-02-04T20:16:51Z
dc.date.available 2022-02-04T20:16:51Z
dc.date.issued 2021
dc.identifier.other http://purl.lib.ua.edu/181757
dc.identifier.other u0015_0000001_0004047
dc.identifier.other Budhathoki_alatus_0004D_14672
dc.identifier.uri http://ir.ua.edu/handle/123456789/8322
dc.description Electronic Thesis or Dissertation
dc.description.abstract Thin films are an excellent option to realize new materials for scientific discovery, newmaterial properties, and applications development. Amongst thin film deposition techniques, magnetron sputter deposition boasts scalability, flexibility in elemental choice and material access, lower cost compared to most physical vapor depositions techniques, and deposition speed range, particularly the ability for high-rate deposition. A modified version of off-axis magnetron sputtering, sputter beam epitaxy (SBE) is flexible, employs both DC and RF sputtering, utilizes a wide range of elements and materials for both alloy and oxide growth, and flux monitoring and beam controls results in stoichiometric, phase-pure, and significantly improved crystalline thin films. The successful fabrication and characterization of high-quality iron-based alloys, grown as epitaxial thin films by ultra-high vacuum SBE, are presented in this dissertation as proof of concept. High-quality epitaxial Fe81Ga19 thin films of thickness 16 and 24 nm grown onMgO(100) substrates show a low residual linewidth, ∆H0 = 13±1 Oe and ∆H0 = 71±1 Oe respectively. Similarly, a very low effective damping parameter,αef f = 0.0065+0.0005 −0.0001 and αef f = 0.0039+0.0028 −0.0007 are observed for 16 and 24 nm thick films respectively. Another binary compound FeGe lacks inversion symmetry and hosts Skyrmions close to room temperature. The epitaxial FeGe thin films grown on Ge(111) substrates reveal a strain-induced enhancement of transition temperature to 350 K. The Skyrmionic signatures are revealed by strong topological Hall (TH) resistivity values between 10 and 330 K. Further, the maximum magnitude of TH resistivity values occurs just below transition temperature consistent with the onset of the SkX phase in bulk FeGe. Epitaxial Heusler alloy thin films of Co2FeTi0.5Al0.5 grown on MgO(100), MAO(100), and Al2O3(110) substrates exhibit a very low linewidth and damping parameter. A total damping parameter of αeff = 0.00202± 0.0001 and a residual linewidth term ∆H0 = 0.0011 ± 0.0001 T are observed for 10 nm film grown on Al2O3(110) substrate. Four-fold manetocrystalline anisotropy is observed in films grown on MgO and MAO substrates, whereas a pronounced uniaxial anisotropy is observed in films grown on Al2O3(110) substrate is observed.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.title Tailoring Structural and Magnetic Properties of Fe-Based Epitaxial Thin-Film Alloys Grown by Sputter Beam Epitaxy
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Department of Physics and Astronomy
etdms.degree.discipline Physics
etdms.degree.grantor The University of Alabama
etdms.degree.level doctoral
etdms.degree.name Ph.D.

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