Efeitos de deformações controladas em fitas amorfas magnetostrictivas estudados por Espectroscopia Mössbauer do 57Fe

• Ano de defesa: 2011
• Autor(a) principal: Loyola, Gustavo Viali
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Física; Centro de Ciências Exatas; UFES; Programa de Pós-Graduação em Física
• Palavras-chave em Português: Magnetic Materials; Condensed Matter; Materiais Magnéticos; Matéria Condensada; Física; 53
• Link de acesso: http://repositorio.ufes.br/handle/10/7422

In this work, we have study the effect of magnetization reorientation induced by stress (curvature) in , Al x/ Metglas, bilayers, where is the Fe78B13Si9 magnetostrictive amorphous ribbon (Metglas 2605S2), is the material deposited layer and its thickness (~microns). Additionally we estimated the ribbon anisotropies, out-of-plane, from the Mössbauer experiments as a function of the applied magnetic field in Ni x/ FINEMET/Ni x , trilayers, where is the Fe73.5Cu1Nb3Si13.5B9 magnetostrictive amorphous ribbon, is the material deposited layer. We induced stress by coupling of different materials and we study the effect of the magnetic reorientation by Mössbauer spectroscopy, since the relative absorption line intensities of a magnetic phase, measured by Mössbauer spectroscopy, mainly depend on the angle between incident gamma rays and the sample magnetization directions. We held Mössbauer measurements with the gamma rays direction has been set perpendicular to the ribbons planes; consequently we obtained information the average distribution of magnetization in the ribbons. The main results we conclude that: there is a line stress null which moves according to the curvature result in making non-zero mean stress; the magnetic reorientation occurs mainly due curvature effect; 95% of the fraction with perpendicular anisotropy to FINEMET magnetostrictive amorphous ribbon has values from 0 to 3kJ m 3 ; about 5% anisotropies has more than 12kJ m 3 associated with defects and irregularities from de production process; perpendicular bulk increased substantially due to stress-induced deposited of Ni layer.