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Please use this identifier to cite or link to this item: http://hdl.handle.net/1843/38455
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dc.contributor.advisor1Roberto Magalhães Paniagopt_BR
dc.contributor.advisor1Latteshttp://lattes.cnpq.br/4301975699820809pt_BR
dc.contributor.referee1Edmar Avellar Soarespt_BR
dc.contributor.referee2Luis Eugênio Fernandez Outonpt_BR
dc.creatorMatheus Felipe de Souza Barbosapt_BR
dc.creator.Latteshttp://lattes.cnpq.br/5542973406791390pt_BR
dc.date.accessioned2021-10-21T12:59:53Z-
dc.date.available2021-10-21T12:59:53Z-
dc.date.issued2021-05-05-
dc.identifier.urihttp://hdl.handle.net/1843/38455-
dc.description.resumoThe use of thin films, and more recently of nanostructures, to optimize physical and chemical properties of materials is ubiquitous nowadays. In this context, the deposition of ultrathin films on vicinal surfaces has been an area of great scientific curiosity, given that the periodic arrangement of substrate steps in nanometric scale can lead to the ordered growth of nanostructures, and such self-organization has great technological appeal. In particular, low dimensional ferromagnetic systems have received great attention due to promising applications in magnetic memory devices and spintronics. In order to improve the understanding of these systems, here we investigate the effects of the growth temperature on the structural and magnetic properties of ultrathin iron (Fe) and cobalt (Co) ferromagnetic films on vicinal Ag(977). A few monolayers (ML) were slowly deposited by molecular beam epitaxy (MBE) between 0.5 ML and 5.0 ML. In-situ analysis techniques were used, such as low energy electron diffraction (LEED), scanning tunneling microscopy (STM) and magneto-optical Kerr effect (MOKE). For Fe/Ag(977) grown at room temperature, in the 2.0 ML to 5.0 ML range, we observe the formation of elongated nanostructures (“nanowires”) of Fe aligned with the step edges of the vicinal surface. At 500 K, between 1.0 ML and 3.0 ML, the growth of triangular structures was observed, most probably with surface alloy formation among the thin film and the substrate. For Co/Ag(977) samples grown at 500 K, for lower thickness, we observe the formation of triangular structures, suggesting Co stacking fault (FCC) on the Ag(111) terraces, and hexagonal structures due to Co-HCP stacking for higher thickness. From the point of view of magnetic properties, which were investigated by MOKE, we have observed from a thickness of 3.0 ML Fe on Ag(977) the presence of a distinguished ferromagnetic signal, when compared to the substrate diamagnetic signal. Nevertheless, for Co/Ag(977) a ferromagnetic signature was already present from 2.0 ML. Both systems have shown strong anisotropies and the experimental results indicate that the easy magnetization axis is in-plane and aligned with the steps, while the hard axis is out-of-plane. Furthermore, the coercive field strength has a dependence with the in-plane angle (φ) of the applied magnetic field, with a minimum value when aligned to the steps, which is in line with the nano-structured arrangement observed by STM.pt_BR
dc.description.sponsorshipCNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológicopt_BR
dc.description.sponsorshipCAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorpt_BR
dc.languageengpt_BR
dc.publisherUniversidade Federal de Minas Geraispt_BR
dc.publisher.countryBrasilpt_BR
dc.publisher.departmentICX - DEPARTAMENTO DE FÍSICApt_BR
dc.publisher.programPrograma de Pós-Graduação em Físicapt_BR
dc.publisher.initialsUFMGpt_BR
dc.rightsAcesso Restritopt_BR
dc.subjectCondensed matterpt_BR
dc.subjectAg(977) Vicinal surfacept_BR
dc.subjectPhysics of surfaces and interfacespt_BR
dc.subjectMagnetism and matterpt_BR
dc.subject.otherMatéria condensadapt_BR
dc.subject.otherFísica de superfíciept_BR
dc.subject.otherMagnetismopt_BR
dc.titleGrowth temperature effects on the structural and magnetic properties of ferromagnetic nanostructures self-assembled on vicinal surface Ag(977)pt_BR
dc.typeDissertaçãopt_BR
dc.description.embargo2022-05-05-
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