Investigação dos efeitos do campo magnético no transporte no supercondutor (Hg,Re)-1223

• Autor(a) principal: Rocha, Jefferson Rodrigues
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/7437
• topic: Física; Supercondutividade; Irreversibilidade; Corrente crítica; Magnetismo terrestre; Física aplicada; 53

Samples of the superconducting ceramics Hg0.82Re0.18Ba2Cu3O8+d were prepared bysolid vapor technique . Firstly , the praparation of the ceramic percursor started with amixture of Ba2Ca2Cu3OXand ReO2 powders with molar ratio 1:0.18.Thepercursor ma-terial was submited to a anealing under three diferent partial pressuresof oxigen using amixture of oxygen/argon at ratios :5/95(sample A ), 10/90 (sampleB) and 15/85 (sampleC).Secondly the percursors prepared with diferent O2 partial pressure were blended withHgO at molar relationship 1:82.the synthesis was done at 8650C at 72 h. Moreover ,X-ray powder difraction scaning electron microscopy (SEM) images, and energy disper-sion X-ray spectra(EDS) analysis were done .the results have shown that the samples thesamples have similar morphology of the grains . Using the SEM images , ahistogramof the grain –boundary size were made where the average junctions sizes is representedby a gamma density distribuition function .Finally, the samples were submited to ACeletrical resistivity r(T) under low applied magnetic field (up 400 Oe).These measure-ments were performanced by four probe technique and bars of approximately 7x1x1 mm3were cut .The zero resistance critical temperature (TZ) were determined from r(T) curves.the resultsare compared and qualitatively explained in the framework of flux trappin bysuperconductin grains .