Unit 5 - Elements of superconductivity

<!--HTML--><p>This unit belongs to the third part of the course, which is focussed on&nbsp;providing some elements of superconductivity. The theory would deserve a whole course by itself, and its&nbsp;roots lay in quantum mechanics: so this unit is limited&nbsp;to give&nbsp;a general outlook of the main theories and ideas about superconductivity developed in the past 100 years.</p> <p>After a introduction to the discovery of superconductivity,&nbsp;we will outline&nbsp;&nbsp;the Meissner effect, and discuss&nbsp;how superconductivity is destroyed above a given magnetic field, temperature and current density.&nbsp; We will then introduce the concept of penetration length through the London theory, and the coherence length of the Ginzburg Landau theory. These two concepts will allow introducing the difference between type I and type II superconductors, the second type allowing the penetration of magnetic field and being the only type that can be used to build superconducting magnets.</p> <p>We will conclude by a phenomenological review of the main features of Nb-Ti,&nbsp;Nb3Sn, and HTS critical surfaces.</p> <p>&nbsp;</p>