Modelagem computacional da corrente crítica em supercondutores policristalinos do tipo HgRe-1223

• Ano de defesa: 2010
• Autor(a) principal: Bolzan, Marcio de Sousa
• 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: Supercondutores; Condutividade elétrica; Modelagem de dados; Josephson, Efeito; Física; 53
• Link de acesso: http://repositorio.ufes.br/handle/10/7421

There are many applications of superconductors for use where it is important to know the behavior of critical current density as a function of magnetic field in the sample, for both it was developed and analyzed a model to describe such behavior in polycrystalline samples of high superconducting critical temperature. The idea was to capture all or part of this behavior as accurately as possible. The theory is based on assumptions that the grains that form polycrystalline superconducting samples are connected by Josephson junctions where it is observed macroscopic quantum interference effects between superconductors separated by a junction crossed by a tunneling current with a dependence on the flow of applied magnetic field, the Cooper pairs tunneling junctions with such a type Fraunhofer diffraction pattern so that the critical current in weak joints is influenced by the first application of magnetic field, thus in a certain field and temperature regime close to critical, critical current in the sample is given by the superposition of Josephson currents influenced by the field at each junction. Finally, the model was be adjusted with the aid of experimental data, the critical current density as a function of applied magnetic field, obtained from polycrystalline samples of superconducting ceramic HgRe-1223 with 5% oxygen doping