Studies of the doping process can provide a better understanding of the superconducting mechanisms in cuprous oxide materials. In this work, we studied the doping effects on the crystal structure, electric, morphologic and magnetic properties of the BSCCO system with the nominal composition Bi1.6Pb0.4Sr(2-x)RExCa2Cu3O(10-δ). Here, the rare earth element (RE) was replaced by La in the sites of Sr. The x was ranged from 0.0 to 2.0, in steps of 0.5. The samples were prepared based on Pechini's method. The resulting powder was pressed at room temperature and the pellets were submitted to several heat treatments. The characterizations confirm the La in the sites of Sr however; the superconducting properties of the sample were not improved.

A homemade Josephson junction was successfully obtained using a superconductor thin film of the BSCCO system. The film was deposited on a lanthanum aluminate, produced from a commercial powder with a nominal composition Bi1.8Pb0.4Sr2CaCu2Ox, was thermally treated by a domestic microwave oven. The XRD analysis of the film indicated the coexistence of Bi-2212 and Bi-2223 phases and SEM images revealed that a typical superconductor plate-like morphology was formed. From the electrical characterization, performed using DC four probes technique, it was observed an onset superconducting transition temperature measured around 81K. At the current-voltage characteristics curve, a step of electric current at zero-voltage could be observed, an indicative that the tunneling Josephson occurred.

<p>Em meados da década de 1980, os ditos supercondutores cerâmicos foram descobertos. Estes materiais se destacam por possuírem temperaturas de transição superiores à do nitrogênio líquido (<italic>T</italic> = 77 K). Este líquido criogênico possui um custo e facilidade de obtenção muito mais vantajosos se comparado com o hélio líquido (<italic>T</italic> = 4, 2 K). Assim, as possibilidades de aplicações desses materiais se ampliaram. Tais aplicações se adequam, em geral, aos esforços por buscas de fontes de energia limpas e a estruturação de uma sociedade sustentável por conta das propriedades dos supercondutores (por exemplo, resistividade nula e diamagnetismo perfeito). Neste trabalho apresentaremos a montagem de um experimento de levitação supercondutora que pode ser usado em problematizações a alunos do ensino médio além de incentivá-los a optarem por uma carreira científica.</p>

<p>In the middle of 1980’s, the ceramic superconductors were novel materials that exhibit superconductivity at temperatures larger than that of liquid nitrogen (<italic>T</italic> = 77 K). This cryogenic liquid is easier to be obtained and cheaper than liquid helium (<italic>T</italic> = 4.2 K). Thus, the possibility of applications of such materials increased and they are suited to the efforts to search clean energy sources and the growth of a sustainability society. This is possible due to the properties of the superconductors as zero resistivity and perfect diamagnetism. In this work we will present the arrangement of a superconducting levitation experiment that can be used as a motivation for high school students and also to encourage them to choose a scientific career.</p>