Influência de uma fenda na dinâmica de vórtices utilizando a teoria de Ginzburg-Landau dependente do temp

• Ano de defesa: 2013
• Autor(a) principal: Duarte, Elwis Carlos Sartorelli [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Supercondutividade; Supercondutores; Euquação de Ginzburg-Landau; Supercondutivity
• Link de acesso: http://hdl.handle.net/11449/110394

The study of superconducting samples in a mesoscopic scale is of scientific and technological great interest due to their confinement effects. As a consequence, this fact led to an intensification of works focused in this category of materials in the last decades. Such scale lies in the fundamental superconducting lengths, i.e., the coherence length k = 5,and the penetration depth (T). In this work, we use Time Dependent Ginzburg-Landau theory, TDGL, to describe the order parameter and the magnet field inside superconducting samples of square cross section and infinite length, in the z axis, under a constant external magnetic field. In such samples was inserted a long slit-like defect, and thus, we focused our studies on the influence of this slit, positioned in several positions of the border of the sample, in the properties of the material. It is important to emphasize that the TDGL model allows us to describe the metastable states of the vortex configuration and the equilibrium state is obtained by leaving the system rich the stationary state. The discretization of the TDGL equations was obtained by the variable link method. Thus, the computational simulations were carried out and we analyzed the influence of a slit, in several positions, in the first vortex penetrations as well as in the and .critical fields. It were simulated type II superconducting samples, , with mesoscopic dimensions of . The external applied magnet field was changed in steps of = 10-3, for several values of temperature. It was also analyzed the conditions for which the first penetration of the vortex occur by the slit. In this interim, we carried out simulations for samples with lateral sizes of 20 (0) x 20 (0) e (30) (0)