Multicamadas de NiFe/FeMn com potencial de aplicação como sensores a altas frequências

• Autor(a) principal: Poerschke, Julia Grasel
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Manancial - Repositório Digital da UFSM
• Texto Completo: http://repositorio.ufsm.br/handle/1/9259
• topic: Magnetoimpedância; Multicamadas; Exchange bias; Magnetoimpedance; Multilayers; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA

In this work we investigated the magnetization process and the magnetoimpedance in samples exhibiting exchange bias. Ni81Fe19=Fe50Mn50=T a bilayers and multilayers where grown onto glass substrates. The exchange bias was induced during growth by a 2 kOe static magnetic field. Structural, magnetic and impedance characterization was carried out. In the hysteresis curves from all samples a shift was observed. This shifting was also observed in the magnetoimpedance curves, and it had the same magnitude observed in the magnetic hysteresis curve. This displacement caused the impedance versus magnetic field curve to be approximately linear in the region near to H = 0. It is possible to use these systems as a magnetic field sensor with a linear response. The sensitivity, defined as the rate of change of the real part of the impedance with the magnetic field, reached values above 200 m =Oe at frequencies below 1 GHz.