Around half the metallic elements (and many compounds) become superconducting at sufficiently low temperatures. This should not be a surprise - one expects their electrons to adopt an orderly arrangement at low temperatures, and as this module will show, one such possibility is the superconducting state. I shall discuss the observed phenomena of superconductivity, including zero resistance, perfect diamagnetism, lack of entropy, and electron interference effects. These will be used to support the macroscopic theoretical understanding of superconductivity, and will lead to a description of key elements of the BCS microscopic theory of superconductivity. As well as discussing features of superconductors that are important in applications, such as high-field electromagnets, radio-frequency filters, SQUID magnetometers and superconducting electronics, I shall describe some important experiments in superconductivity research, several of which have been performed in Birmingham.

By the end of the module the student should be able to:

• Be familiar with the basic phenomena of superconductivity and be able to explain how these are related to the macroscopic theory;
• Have an understanding of some ideas contained in the BCS theory and how these are revealed in the behaviour of superconductors;
• Be familiar with some key experiments in superconductivity;
• Be aware of some technical applications of superconductors, and how these are supported by the properties of superconducting materials and our theoretical understanding.