Um modelo para defeitos estruturais em nanomagnetos

• Autor(a) principal: Apolônio, Felipe Andrade
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4244
• topic: Nanodiscos magnéticos; Vórtice; Defeitos estruturais; Nanodisks magnetic; Vortex; Structural defects; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::FISICA DA MATERIA CONDENSADA

Nanoestructured ferromagnetic materials, with several shapes and sizes, have been intensively investigated because of their potential application in magnetoeletronic devices. Ferromagnets may have a number of stable magnetization configurations. In nanodisks with thickness L > 15 nm and radius R > 100 nm, vortex configuration appears as the ground-state, in the absence of external magnetic field. For more careful you are when preparing samples, impurities and structural defects (in the crystal structure, for example) will always be present, to a greater or lesser amount, and they are generally pointlike (or tiny structures) and randomly distributed throughout the material. It is experimentally known that these defects may deeply modify the vortex dynamics, notably their equilibrium position, among others aspects like their gyrotropic motion. Here, we present a proposal for modeling such defects as they were pointlike, using a potential like λδ3 (x - x0), λ being a real constant. This model yields, actually, to consider only the local interaction between the defect and the vortex core. We developed a relatively simple analytical model, which was able to describe some aspects of such interaction, agreeing, qualitatively well, with results observed experimentally.