Superconductivity: 100th anniversary of its discovery and its future

The past and prospects of the superconducting technology are discussed as a systematic wide technology from the aspects of energy, transport and telecommunication. Superconductivity has unique characteristics, perpetual current, diamagnetism and Josephson effect. Since its discovery 100 years ago, it had taken nearly half a century to elucidate its mechanism and its application has still been restricted only to fields of extreme needs in the technical level. The major reason for the delay has apparently been the 'penalty of cooling', however, it is also due to the fact that a superconducting wire has to be a complex composite in a nanotechnology-processed structure. Also, owing to the discovery of high-temperature superconductors, it has recently become feasible to forecast a promising future of the superconducting technology in a long term. (author)