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You searched for subject:( Acoplamento bilinear). Showing records 1 – 3 of 3 total matches.

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Universidade do Rio Grande do Norte

1. Silva, Edimilson Félix da. Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático .

Degree: 2012, Universidade do Rio Grande do Norte

In this work, we investigated the magnetic properties of a monocrystalline Fe thin film and of Fe(80 Å)/Cr(t)/Fe(80 Å) tri-layers, with the nonmagnetic metallic Cr spacer layer thickness varying between 9 Å < t < 40 Å. The samples were deposited by the DC Sputtering on Magnesium Oxide (MgO) substrates, with (100) crystal orientation. For this investigation, experimental magneto-optical Kerr effect (MOKE) magnetometry and ferromagnetic resonance (FMR) techniques were employeed. In this case, these techniques allowed us to study the static and dynamical magnetization properties of our tri-layers. The experimental results were interpreted based on the phenomenological model that takes into account the relevant energy terms to the magnetic free energy to describe the system behavior. In the case of the monocrystalline Fe film, we performed an analytical discussion on the magnetization curves and developed a numerical simulation based on the Stoner-Wohlfarth model, that enables the numerical adjustment of the experimental magnetization curves and obtainment of the anisotropy field values. On the other hand, for the tri-layers, we analyzed the existence of bilinear and biquadratic couplings between the magnetizations of adjacent ferromagnetic layers from measurements of magnetization curves. With the FMR fields and line width angular dependencies, information on the anisotropy in three layers was obtained and the effects of different magnetic relaxation mechanisms were evidenced. It was also possible to observe the dependence of the epitaxy of the multilayers with growth and sputtering parameters. Additionally it was developed the technique of AC magnetic susceptibility in order to obtain further information during the investigation of magnetic thin films Advisors/Committee Members: Oliveira, Alexandre Barbosa de (advisor), CPF:03187557422 (advisor).

Subjects/Keywords: Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático; Magneto-optical Kerr effect; Ferromagnetic resonance; Bilinear coupling; Biquadratic coupling

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Silva, E. F. d. (2012). Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático . (Masters Thesis). Universidade do Rio Grande do Norte. Retrieved from http://repositorio.ufrn.br/handle/123456789/16605

Chicago Manual of Style (16th Edition):

Silva, Edimilson Félix da. “Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático .” 2012. Masters Thesis, Universidade do Rio Grande do Norte. Accessed July 23, 2019. http://repositorio.ufrn.br/handle/123456789/16605.

MLA Handbook (7th Edition):

Silva, Edimilson Félix da. “Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático .” 2012. Web. 23 Jul 2019.

Vancouver:

Silva EFd. Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático . [Internet] [Masters thesis]. Universidade do Rio Grande do Norte; 2012. [cited 2019 Jul 23]. Available from: http://repositorio.ufrn.br/handle/123456789/16605.

Council of Science Editors:

Silva EFd. Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático . [Masters Thesis]. Universidade do Rio Grande do Norte; 2012. Available from: http://repositorio.ufrn.br/handle/123456789/16605


Universidade do Rio Grande do Norte

2. Silva, Edimilson Félix da. Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático .

Degree: 2012, Universidade do Rio Grande do Norte

In this work, we investigated the magnetic properties of a monocrystalline Fe thin film and of Fe(80 Å)/Cr(t)/Fe(80 Å) tri-layers, with the nonmagnetic metallic Cr spacer layer thickness varying between 9 Å < t < 40 Å. The samples were deposited by the DC Sputtering on Magnesium Oxide (MgO) substrates, with (100) crystal orientation. For this investigation, experimental magneto-optical Kerr effect (MOKE) magnetometry and ferromagnetic resonance (FMR) techniques were employeed. In this case, these techniques allowed us to study the static and dynamical magnetization properties of our tri-layers. The experimental results were interpreted based on the phenomenological model that takes into account the relevant energy terms to the magnetic free energy to describe the system behavior. In the case of the monocrystalline Fe film, we performed an analytical discussion on the magnetization curves and developed a numerical simulation based on the Stoner-Wohlfarth model, that enables the numerical adjustment of the experimental magnetization curves and obtainment of the anisotropy field values. On the other hand, for the tri-layers, we analyzed the existence of bilinear and biquadratic couplings between the magnetizations of adjacent ferromagnetic layers from measurements of magnetization curves. With the FMR fields and line width angular dependencies, information on the anisotropy in three layers was obtained and the effects of different magnetic relaxation mechanisms were evidenced. It was also possible to observe the dependence of the epitaxy of the multilayers with growth and sputtering parameters. Additionally it was developed the technique of AC magnetic susceptibility in order to obtain further information during the investigation of magnetic thin films Advisors/Committee Members: Oliveira, Alexandre Barbosa de (advisor), CPF:03187557422 (advisor).

Subjects/Keywords: Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático; Magneto-optical Kerr effect; Ferromagnetic resonance; Bilinear coupling; Biquadratic coupling

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Silva, E. F. d. (2012). Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático . (Thesis). Universidade do Rio Grande do Norte. Retrieved from http://repositorio.ufrn.br/handle/123456789/16605

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Silva, Edimilson Félix da. “Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático .” 2012. Thesis, Universidade do Rio Grande do Norte. Accessed July 23, 2019. http://repositorio.ufrn.br/handle/123456789/16605.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Silva, Edimilson Félix da. “Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático .” 2012. Web. 23 Jul 2019.

Vancouver:

Silva EFd. Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático . [Internet] [Thesis]. Universidade do Rio Grande do Norte; 2012. [cited 2019 Jul 23]. Available from: http://repositorio.ufrn.br/handle/123456789/16605.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Silva EFd. Efeito Kerr magneto-óptico; Ressonância ferromagnética; Acoplamento bilinear; Acoplamento biquadrático . [Thesis]. Universidade do Rio Grande do Norte; 2012. Available from: http://repositorio.ufrn.br/handle/123456789/16605

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Universidade do Rio Grande do Norte

3. Bandeira, Analine Pinto Valeriano. Propriedades estáticas e dinâmicas de super-redes e multicamadas quasiperiódicas .

Degree: 2018, Universidade do Rio Grande do Norte

In this thesis, we investigate the static and dynamic properties of magnetic multilayer and thin film systems, respectively. The propagation of spin waves was investigated in a quasiperiodic superlattice which structure was built according to the so-called Octonacci sequence, composed by two simple cubic ferromagnetic materials interacting through bilinear and biquadratic exchange couplings at their interfaces. The ferromagnetic materials are described by the Heisenberg model, and a transfer matrix treatment is employed, with the calculations performed for the exchange-dominated regime, taking into account the random phase approximation (RPA) to obtain the allowed bands and transmittance spectra. In addition, the influence of the biquadratic coupling on the band and transmittance spectra is discussed. We also performed an investigation of the static magnetic properties of nanometric films, with low symmetry crystallographic growth directions ([211] and [321]), by using two quasiperiodic models. For the model 1, the magnetic thin films are stacked quasiperiodically, with the nonmagnetic spacers having the same thickness, while for the model 2, the non-magnetic spacers follows the quasiperiodicity, with different thicknesses. For both models the quasiperiodicity is according to the Fibonacci and Octonacci quasiperiodic sequences. The theoretical modelling is based on a realistic magnetic energy taking into account the Zeeman, cubic and uniaxial anisotropy terms, besides the bilinear and biquadratic couplings. From the equilibrium configurations, magnetization, magnetoresistance and phase diagrams are obtained. Advisors/Committee Members: Bezerra, Claudionor Gomes (advisor), 60992565472 (advisor).

Subjects/Keywords: Ondas de spin; Acoplamento bilinear; Acoplamento biquadrático; Transmitância; Propriedades estáticas; Fases; Diagramas de fases 3D

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bandeira, A. P. V. (2018). Propriedades estáticas e dinâmicas de super-redes e multicamadas quasiperiódicas . (Doctoral Dissertation). Universidade do Rio Grande do Norte. Retrieved from http://repositorio.ufrn.br/handle/123456789/26517

Chicago Manual of Style (16th Edition):

Bandeira, Analine Pinto Valeriano. “Propriedades estáticas e dinâmicas de super-redes e multicamadas quasiperiódicas .” 2018. Doctoral Dissertation, Universidade do Rio Grande do Norte. Accessed July 23, 2019. http://repositorio.ufrn.br/handle/123456789/26517.

MLA Handbook (7th Edition):

Bandeira, Analine Pinto Valeriano. “Propriedades estáticas e dinâmicas de super-redes e multicamadas quasiperiódicas .” 2018. Web. 23 Jul 2019.

Vancouver:

Bandeira APV. Propriedades estáticas e dinâmicas de super-redes e multicamadas quasiperiódicas . [Internet] [Doctoral dissertation]. Universidade do Rio Grande do Norte; 2018. [cited 2019 Jul 23]. Available from: http://repositorio.ufrn.br/handle/123456789/26517.

Council of Science Editors:

Bandeira APV. Propriedades estáticas e dinâmicas de super-redes e multicamadas quasiperiódicas . [Doctoral Dissertation]. Universidade do Rio Grande do Norte; 2018. Available from: http://repositorio.ufrn.br/handle/123456789/26517

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