Impurezas magnéticas em ferromagnetos de Ising com campo transverso
| Ano de defesa: | 2005 |
|---|---|
| Autor(a) principal: | |
| Orientador(a): | |
| Banca de defesa: | |
| Tipo de documento: | Tese |
| Tipo de acesso: | Acesso aberto |
| Idioma: | por |
| Instituição de defesa: |
Não Informado pela instituição
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| Programa de Pós-Graduação: |
Não Informado pela instituição
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| Departamento: |
Não Informado pela instituição
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| País: |
Não Informado pela instituição
|
| Palavras-chave em Português: | |
| Link de acesso: | http://www.repositorio.ufc.br/handle/riufc/12930 |
Resumo: | A Green function formalism is used to calculate the spectrum of excitations associated with magnetic impurities implanted in a ferromagnetic thin film described by the transverse Ising model. Using the equations of motion method, explicit expressions for the Green function are determined for a ferromagnetic without impurities. The Green’s functions for a ferromagnetic film containing impurities are obtained through Dyson equation. We consider only the “defect” modes that appear below the bulk band of the pure material. In order to assess the influence of the position of the impurities in the film on the excitations spectra, we consider three different geometrical arrangement for the impurities: impurities line perpendicular to the surface film, four impurities in a plane paralel to the surface, and four impurities in a plane perpendicular to the surfaces of the film. We obtain results for the frequencies localized modes as a function of the exchange parameter between two impurities neighborings, of the exchange parameter between the impurities and their neighborings, and the effective field parameter at the impurities. |
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Leite Filho, Raimundo ValmirCosta Filho, Raimundo Nogueira da2015-06-23T21:06:50Z2015-06-23T21:06:50Z2005LEITE FILHO, R. V. Impurezas magnéticas em ferromagnetos de Ising com campo transverso. 2005. 109 f. Tese (Doutorado em Física) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2005.http://www.repositorio.ufc.br/handle/riufc/12930A Green function formalism is used to calculate the spectrum of excitations associated with magnetic impurities implanted in a ferromagnetic thin film described by the transverse Ising model. Using the equations of motion method, explicit expressions for the Green function are determined for a ferromagnetic without impurities. The Green’s functions for a ferromagnetic film containing impurities are obtained through Dyson equation. We consider only the “defect” modes that appear below the bulk band of the pure material. In order to assess the influence of the position of the impurities in the film on the excitations spectra, we consider three different geometrical arrangement for the impurities: impurities line perpendicular to the surface film, four impurities in a plane paralel to the surface, and four impurities in a plane perpendicular to the surfaces of the film. We obtain results for the frequencies localized modes as a function of the exchange parameter between two impurities neighborings, of the exchange parameter between the impurities and their neighborings, and the effective field parameter at the impurities.O formalismo de funções de Green é usado para calcular o espectro de excitações associados a impurezas magnéticas implantadas em um filme ferromagnético descrito pelo modelo de Ising com campo transverso. Através do método da equação de movimento expressões explícitas para as funções de Green são determinadas para um ferromagneto sem impurezas. A função de Green para um filme ferromagnético contendo impurezas é obtida através da equação de Dyson. O espectro de ondas de spin relativo ás impurezas é obtido para freqüências abaixo do limite inferior da banda de volume para um material puro. Com o objetivo de avaliar a influência da posição das impurezas no filme no espectro de excitações, consideramos três diferentes disposições geométricas para as impurezas: linha de impurezas perpendicular á superfície do filme, quatro impurezas em um plano paralelo `as superfícies e quatro impurezas em um plano perpendicular `as superfícies do filme. Obtemos resultados para a freqüência dos modos localizados como função do parâmetro de troca entre duas impurezas vizinhas, do parâmetro de troca entre as impurezas e seus vizinhos e do parâmetro de campo efetivo nas impurezas.Ondas de SpinFerromagnetismoImpurezas magnéticas em ferromagnetos de Ising com campo transversoinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisporreponame:Repositório Institucional da Universidade Federal do Ceará (UFC)instname:Universidade Federal do Ceará (UFC)instacron:UFCinfo:eu-repo/semantics/openAccessLICENSElicense.txtlicense.txttext/plain; charset=utf-81786http://repositorio.ufc.br/bitstream/riufc/12930/2/license.txt8c4401d3d14722a7ca2d07c782a1aab3MD52ORIGINAL2005_tese_rvleitefilho.pdf2005_tese_rvleitefilho.pdfapplication/pdf673288http://repositorio.ufc.br/bitstream/riufc/12930/3/2005_tese_rvleitefilho.pdf4f978de2d3b21f2a763a3781d88663b5MD53riufc/129302019-07-31 13:53:46.491oai:repositorio.ufc.br:riufc/12930w4kgbmVjZXNzw6FyaW8gY29uY29yZGFyIGNvbSBhIGxpY2Vuw6dhIGRlIGRpc3RyaWJ1acOnw6NvIG7Do28tZXhjbHVzaXZhLAphbnRlcyBxdWUgbyBkb2N1bWVudG8gcG9zc2EgYXBhcmVjZXIgbm8gUmVwb3NpdMOzcmlvLiBQb3IgZmF2b3IsIGxlaWEgYQpsaWNlbsOnYSBhdGVudGFtZW50ZS4gQ2FzbyBuZWNlc3NpdGUgZGUgYWxndW0gZXNjbGFyZWNpbWVudG8gZW50cmUgZW0KY29udGF0byBhdHJhdsOpcyBkZTogcmVwb3NpdG9yaW9AdWZjLmJyIG91ICg4NSkzMzY2LTk1MDguCgpMSUNFTsOHQSBERSBESVNUUklCVUnDh8ODTyBOw4NPLUVYQ0xVU0lWQQoKQW8gYXNzaW5hciBlIGVudHJlZ2FyIGVzdGEgbGljZW7Dp2EsIG8vYSBTci4vU3JhLiAoYXV0b3Igb3UgZGV0ZW50b3IgZG9zIGRpcmVpdG9zIGRlIGF1dG9yKToKCmEpIENvbmNlZGUgw6AgVW5pdmVyc2lkYWRlIEZlZGVyYWwgZG8gQ2VhcsOhIG8gZGlyZWl0byBuw6NvLWV4Y2x1c2l2byBkZQpyZXByb2R1emlyLCBjb252ZXJ0ZXIgKGNvbW8gZGVmaW5pZG8gYWJhaXhvKSwgY29tdW5pY2FyIGUvb3UKZGlzdHJpYnVpciBvIGRvY3VtZW50byBlbnRyZWd1ZSAoaW5jbHVpbmRvIG8gcmVzdW1vL2Fic3RyYWN0KSBlbQpmb3JtYXRvIGRpZ2l0YWwgb3UgaW1wcmVzc28gZSBlbSBxdWFscXVlciBtZWlvLgoKYikgRGVjbGFyYSBxdWUgbyBkb2N1bWVudG8gZW50cmVndWUgw6kgc2V1IHRyYWJhbGhvIG9yaWdpbmFsLCBlIHF1ZQpkZXTDqW0gbyBkaXJlaXRvIGRlIGNvbmNlZGVyIG9zIGRpcmVpdG9zIGNvbnRpZG9zIG5lc3RhIGxpY2Vuw6dhLiBEZWNsYXJhIHRhbWLDqW0gcXVlIGEgZW50cmVnYSBkbyBkb2N1bWVudG8gbsOjbyBpbmZyaW5nZSwgdGFudG8gcXVhbnRvIGxoZSDDqSBwb3Nzw612ZWwgc2FiZXIsIG9zIGRpcmVpdG9zIGRlIHF1YWxxdWVyIG91dHJhIHBlc3NvYSBvdSBlbnRpZGFkZS4KCmMpIFNlIG8gZG9jdW1lbnRvIGVudHJlZ3VlIGNvbnTDqW0gbWF0ZXJpYWwgZG8gcXVhbCBuw6NvIGRldMOpbSBvcwpkaXJlaXRvcyBkZSBhdXRvciwgZGVjbGFyYSBxdWUgb2J0ZXZlIGF1dG9yaXphw6fDo28gZG8gZGV0ZW50b3IgZG9zCmRpcmVpdG9zIGRlIGF1dG9yIHBhcmEgY29uY2VkZXIgw6AgVW5pdmVyc2lkYWRlIEZlZGVyYWwgZG8gQ2VhcsOhIG9zIGRpcmVpdG9zIHJlcXVlcmlkb3MgcG9yIGVzdGEgbGljZW7Dp2EsIGUgcXVlIGVzc2UgbWF0ZXJpYWwgY3Vqb3MgZGlyZWl0b3Mgc8OjbyBkZSB0ZXJjZWlyb3MgZXN0w6EgY2xhcmFtZW50ZSBpZGVudGlmaWNhZG8gZSByZWNvbmhlY2lkbyBubyB0ZXh0byBvdSBjb250ZcO6ZG8gZG8gZG9jdW1lbnRvIGVudHJlZ3VlLgoKU2UgbyBkb2N1bWVudG8gZW50cmVndWUgw6kgYmFzZWFkbyBlbSB0cmFiYWxobyBmaW5hbmNpYWRvIG91IGFwb2lhZG8KcG9yIG91dHJhIGluc3RpdHVpw6fDo28gcXVlIG7Do28gYSBVbml2ZXJzaWRhZGUgRmVkZXJhbCBkbyBDZWFyw6EsIGRlY2xhcmEgcXVlIGN1bXByaXUgcXVhaXNxdWVyIG9icmlnYcOnw7VlcyBleGlnaWRhcyBwZWxvIHJlc3BlY3Rpdm8gY29udHJhdG8gb3UKYWNvcmRvLgoKQSBVbml2ZXJzaWRhZGUgRmVkZXJhbCBkbyBDZWFyw6EgaWRlbnRpZmljYXLDoSBjbGFyYW1lbnRlIG8ocykgc2V1IChzKSBub21lIChzKSBjb21vIG8gKHMpIGF1dG9yIChlcykgb3UgZGV0ZW50b3IgKGVzKSBkb3MgZGlyZWl0b3MgZG8gZG9jdW1lbnRvIGVudHJlZ3VlLCBlIG7Do28gZmFyw6EgcXVhbHF1ZXIgYWx0ZXJhw6fDo28sIHBhcmEgYWzDqW0gZGFzIHBlcm1pdGlkYXMgcG9yIGVzdGEgbGljZW7Dp2EuCg==Repositório InstitucionalPUBhttp://www.repositorio.ufc.br/ri-oai/requestbu@ufc.br || repositorio@ufc.bropendoar:2019-07-31T16:53:46Repositório Institucional da Universidade Federal do Ceará (UFC) - Universidade Federal do Ceará (UFC)false |
| dc.title.pt_BR.fl_str_mv |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso |
| title |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso |
| spellingShingle |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso Leite Filho, Raimundo Valmir Ondas de Spin Ferromagnetismo |
| title_short |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso |
| title_full |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso |
| title_fullStr |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso |
| title_full_unstemmed |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso |
| title_sort |
Impurezas magnéticas em ferromagnetos de Ising com campo transverso |
| author |
Leite Filho, Raimundo Valmir |
| author_facet |
Leite Filho, Raimundo Valmir |
| author_role |
author |
| dc.contributor.author.fl_str_mv |
Leite Filho, Raimundo Valmir |
| dc.contributor.advisor1.fl_str_mv |
Costa Filho, Raimundo Nogueira da |
| contributor_str_mv |
Costa Filho, Raimundo Nogueira da |
| dc.subject.por.fl_str_mv |
Ondas de Spin Ferromagnetismo |
| topic |
Ondas de Spin Ferromagnetismo |
| description |
A Green function formalism is used to calculate the spectrum of excitations associated with magnetic impurities implanted in a ferromagnetic thin film described by the transverse Ising model. Using the equations of motion method, explicit expressions for the Green function are determined for a ferromagnetic without impurities. The Green’s functions for a ferromagnetic film containing impurities are obtained through Dyson equation. We consider only the “defect” modes that appear below the bulk band of the pure material. In order to assess the influence of the position of the impurities in the film on the excitations spectra, we consider three different geometrical arrangement for the impurities: impurities line perpendicular to the surface film, four impurities in a plane paralel to the surface, and four impurities in a plane perpendicular to the surfaces of the film. We obtain results for the frequencies localized modes as a function of the exchange parameter between two impurities neighborings, of the exchange parameter between the impurities and their neighborings, and the effective field parameter at the impurities. |
| publishDate |
2005 |
| dc.date.issued.fl_str_mv |
2005 |
| dc.date.accessioned.fl_str_mv |
2015-06-23T21:06:50Z |
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2015-06-23T21:06:50Z |
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info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
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publishedVersion |
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LEITE FILHO, R. V. Impurezas magnéticas em ferromagnetos de Ising com campo transverso. 2005. 109 f. Tese (Doutorado em Física) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2005. |
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http://www.repositorio.ufc.br/handle/riufc/12930 |
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LEITE FILHO, R. V. Impurezas magnéticas em ferromagnetos de Ising com campo transverso. 2005. 109 f. Tese (Doutorado em Física) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2005. |
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por |
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por |
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