Made available in DSpace on 2014-12-17T15:15:04Z (GMT). No. of bitstreams: 1 AnnaCDM_DISSERT.pdf: 3464816 bytes, checksum: 8d617feb92fa3c439455f7c50d0cdd96 (MD5) Previous issue date: 2014-05-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The study and fabrication of nanostructured systems composed of magnetic materials has been an area of great scientific and technological interest. Soft magnetic materials, in particular, have had great importance in the development of magnetic devices. Among such materials we highlight the use of alloys of Ni and Fe, known as Permalloy. We present measurement results of structural characterization and magnetic films in Permalloy (Ni81Fe19), known to be a material with high magnetic permeability, low coercivity and small magneto- crystalline anisotropy, deposited on MgO (100) substrates. The Magnetron Sputtering technique was used to obtain the samples with thicknesses varying between 9 150 nm. The techniques of X- ray Diffraction at high and low angle were employed to confirm the crystallographic orientation and thickness of the films. In order to investigate the magnetic properties of the films the techniques of Vibrant Sample Magnetometry (VSM), Ferromagnetic Resonance (FMR) and Magnetoimpedance were used. The magnetization curves revealed the presence of anisotropy for the films of Py/MgO (100), where it was found that there are three distinct axis - an easy-axis for ?H = 0?, a hard-axis for ?H = 45? and an intermediate for ?H = 90?. The results of the FMR and Magnetoimpedance techniques confirm that there are three distinct axes, that is, there is a type C2 symmetry. Then we propose, for these results, the interpretation of the magnetic anisotropy of Py/MgO ( 100 ) is of type simple C2, ie a cubic magnetic anisotropy type ( 110 ) / O estudo e obten??o de sistemas nanoestruturados compostos por materiais magn?ticos tem se mostrado uma ?rea de grande interesse cient?fico e tecnol?gico. Materiais magn?ticos macios, em especial, tem tido grande import?ncia no desenvolvimento de dispositivos magn?ticos. Entre esses tipos de materiais cabe-nos destacar o uso de ligas de Ni e Fe, conhecidas como Permalloy. Neste trabalho apresentamos resultados de medidas de caracteriza??o estrutural e magn?tica em filmes nanom?tricos de Permalloy (Ni81Fe19), conhecido por ser um material com alta permeabilidade magn?tica, baixa coercividade e pequena anisotropia magneto-cristalina, depositado em substratos de MgO(100). A t?cnica de Magnetron Sputtering foi utilizada na obten??o das amostras com espessuras variando entre 9 150nm. As t?cnicas de Difratometria de Raios-X em alto e baixo ?ngulo foram empregadas para confirmar a orienta??o cristalogr?fica e a espessura dos filmes. Com o intuito de investigar as propriedades magn?ticas dos filmes foram usadas as t?cnicas de Magnetometria de Amostra Vibrante (VSM), Resson?ncia Ferromagn?tica (FMR) e Magnetoimped?ncia. As curvas de magnetiza??o revelaram a presen?a de anisotropia para os filmes de Py/MgO(100), verificando-se a ocorr?ncia de tr?s eixos distintos um eixo-f?cil para ?H=0?, um eixo-duro para ?H=45? e um eixo intermedi?rio para ?H=90?. Os resultados obtidos usando as t?cnicas de FMR e Magnetoimped?ncia confirmaram que h? tamb?m tr?s eixos distintos, isto ?, h? uma simetria tipo C2. Propomos ent?o, para esses resultados, a interpreta??o de que a anisotropia magn?tica do Py/MgO(100) seja do tipo C2 simples, isto ?, uma anisotropia magn?tica c?bica tipo (110)