An introduction to superconductivity phenomenon

Cryogenics, study and use of materials at very low temperatures. The upper limit of cryogenic temperatures has not been agreed on, but the American National Institute of Standards and Technology has suggested that the term cryogenics be applied to all temperatures below -150° C. Cryogenic temperatures are achieved either by the rapid evaporation of volatile liquids or by the expansion of gases confined initially at pressures of 150 to 200 atmospheres. In this work basic idea behind this science and its applications are discussed.