Dispositivo de Variação de Campo Magnético DC, Usado na Caracterização da Magneto-Resistência em Materiais Magnéticos

• Ano de defesa: 2008
• Autor(a) principal: Costa, Carlos Cesar
• Orientador(a): FEITOSA, Carlos Chesman de Araújo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Maranhão
• Programa de Pós-Graduação: PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA/CCET
• Departamento: FISICA
• País: BR
• Palavras-chave em Português: campo magnético; magneto-resistência; materiais magnéticos
• Palavras-chave em Inglês: magnetic field; magneto-resistance; magnetic materials
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: http://tedebc.ufma.br:8080/jspui/handle/tede/714

In the present work of dissertation of the master's degree course, we studied the magnetic properties of films simple nanometric's as: iron on oxide of magnesium (F/MgO) and permalloy (Fe Ni) in room temperature, obtained by the eltro-deposition process by sputtering. The experimental results were interpreted in agreement with the models phenomenological that take into account the most relevant terms of the magnetic free energy of the system. We made an approach in accordance with the literature on the main mechanisms that originate the electric resistance in magnetic metallic films, such as: resistance electric ohm's, effects hall, anisotropic magnetoresistance (AMR). it is made a description of the main experimental techniques used in the characterization of films nanometric's, as the Magnetometer Optical for Kerr Effect (MOKE), Ferromagnetic Resonance (FMR) and Magnetoresistance (MR). This last technique, that it uses the method of the four tips, it is used to obtain the magnetoresistance curves. In this work, we studied the effect of the anisotropic magnetoresistance in simple films, where the magnetoresistance curves are associated to the competitions enter the energies Zeeman and of anisotropic magnetic. The effect of AMR was verifies for the samples of films nanometric's through numeric simulation. For the development of the research, we set up a Device of Variation of Magnetic Field DC (DVCM DC) and the experimental data are obtained through virtual instrumentation. The magnetoresistance curves were interpreted in agreement with the model phenomenological and we still used the hysteresis loop obtained by MOKE as parameters.