Supercondutividade, um estudo sobre os seus 100 anos: elementos para sua Divulgação Científica

Abstract

In 2011 the scienti c community celebrated the 100th anniversary of the discovery of the phenomenon of superconductivity. In 1911 H. K. Onnes observed for the rst time that the electrical resistance of mercury drops abruptly to zero when cooled below 4.2 K . From that moment the scientists began to look for new materials that exhibit the above characteristic at higher temperatures. Superconductors, however, are not a simple ideal conductor because it presents a characteristic known as the Meissner E¤ect, which is the expulsion of the magnetic ux from the material. The rst few attempts to explain this phenomenon were phenomenological: theory of London and theory of Ginsburg-Landau, but the microscopic theory that satisfactorily explained the superconductivity was the theory developed by Bardeen, Cooper and Schrie¤er (BCS). However, very recently in 1986, superconductivity was discovered in compounds made of ceramic oxides of barium and lanthanum. Moreover, the BCS theory can not satisfactorily explain the mechanism responsible for superconductivity in high temperature superconductors. Hence the de- velopment of a microscopic theory is essential that explains the new superconductors. Scientists today seek to nd superconductors at room temperature, which experts say would bring a new industrial revolution, with high impacts in electronics, generation and storage of electrical energy, among others. Therefore, it is of utmost importance to propagate the above knowledge to the students and the physics community in general. Hence, we employ the means of learning that have been a very important tool in revealing science and technology.