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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Propriedades estruturais e magnéticas do isolante topológico Bi2Se3 com aglomerados de FexSey

Vasconcelos, Hugo Menezes do Nascimento 29 March 2016 (has links)
Submitted by Livia Mello (liviacmello@yahoo.com.br) on 2016-10-11T19:57:49Z No. of bitstreams: 1 TeseHMNV.pdf: 4404722 bytes, checksum: 1983a667805c061a711a3694028b17b0 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T12:45:43Z (GMT) No. of bitstreams: 1 TeseHMNV.pdf: 4404722 bytes, checksum: 1983a667805c061a711a3694028b17b0 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-21T12:45:59Z (GMT) No. of bitstreams: 1 TeseHMNV.pdf: 4404722 bytes, checksum: 1983a667805c061a711a3694028b17b0 (MD5) / Made available in DSpace on 2016-10-21T12:46:06Z (GMT). No. of bitstreams: 1 TeseHMNV.pdf: 4404722 bytes, checksum: 1983a667805c061a711a3694028b17b0 (MD5) Previous issue date: 2016-03-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In this work, we discuss the growth of Fe containing Bi2 Se3epilayers on the GaAs(111) substrate by molecular beam epitaxy (MBE) with Fe contents of in the 8- 20% range. It is shown that Bi2 Se3 film thin are grown with quality and the Fe form a phase segregation of Fe x Sey material that may have different stoichiometries possibity, leading to magnetic and superconducting results. Despite the composite structure, the surface state of Bi2 Se3 is preserved as shown with persistence of Dirac Cone of the Γ point by Angle-Resolved Photoemission Spectroscopy (ARPES). It was observed that higher Fe content deposited is increased formation of compound responsible for ferrimagnetic layers together with the superconducting phase supposed. The Fe3Se 4 was the most abundant type of segregation in all samples, with the results ferrimagnetic these samples at temperatures around 315 K. / Neste trabalho, abordamos o crescimento de Bi2 Se3 com adição de Fe em substrato de GaAs(111) por meio de epitaxia de feixe molecular (MBE), variando o teor de Fe depositado de 8% até 20%. É mostrado que os filmes de Bi2 Se3 são crescidos com qualidade e o Fe juntamente com o Se formam uma segregação de fases Fex Sey , material que pode ter diferentes estequiometrias levando a resultados magnéticos e possivelmente supercondutor. Apesar da estrutura compósita, a estrutura superficial do Bi2 Se3 é preservada como mostrado pela persistência do cone de Dirac no ponto Γ nas medidas de espectroscopia de fotoemissão de resolução angular (ARPES). Foi possível observar que quanto maior o teor de Fe depositado, ocorre uma maior formação de compostos responsável pela fase ferrimagnética em conjunto com a fase supostamente supercondutora. O Fe3Se 4 foi o tipo de segregação mais abundante em todas as amostras, levando a resultados ferrimagnéticos nessas amostras em temperaturas em torno de 315 K.

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