Interferência quântica na corrente crítica macroscópica de cerâmicas policristalinas com uma intrínseca solução sólida de duas fases supercondutoras

• Autor(a) principal: Bolzan, Márcio de Sousa
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/7495
• topic: Superconductivity; Ceramic Superconductors; Josephson Effect; Critical current; Electrical conductivity; Supercondutividade; Supercondutores cerâmicos; Efeito Josephson; Corrente crítica; Condutividade elétrica; Física; 53

The scattering of the superconducting current in the passage between grains in a polycrystalline ceramic has been studied by several researchers especially in recent 20 years. In this study we used the knowledge of the structure between the grains found in the superconducting ceramics based on mercury carefully produced in UFES, associated with a macroscopic quantum interference modeling to very precisely describe the behavior of the critical current when the sample is submited at presence of magnetic fields. Associating the pinning energy of the vortex, it is possible to model with more detail the grain boundary, and find a better description of the behavior of the critical current measured experimentally. The proposed model here adds new insight into the correlation between the critical current and the description of the grain boundary, highlighting the role of parameters relevant as size distribution of the junctions between grains and the pinning potential of vortex in the correct description of the measured values of the critical current as a function of the applied field. Therefore, we conclude that this paper proposing a model that describes with good quality the critical current behavior circulating in polycrystalline ceramic samples based on mercury, when the sample is subjected to an external magnetic field.