Superconductivity was discovered 1911 by Kamerlingh Onnes. During the last century, the history of superconductivity has been full of theoretical challenges and practical developments. In 1986, the discovery of Bednorz and Müller of an oxide superconductor with critical temperature (Tc) approximately equal to 35 K, has given a novel impetus to this fascinating subject. Since this discovery, there are a great number of laboratories all over the world involved in research of superconductors with high Tc values, the so-called “high-Tc superconductors”
