Superconducting transition

Superconductivity is the absence of resistivity below some critical temperature. It was discovered after Helium liquification.

The measure of resistivity as a function of temperature is shown in Fig. 1.1.

The absolute absence of resistivity combined with general quantum-mechanical principles and lead to informative conclusions on the properties of the superconducting state.

The most striking properties of superconductors such as their ideal diamagnetism, macroscopic quantum nature of superconductivity including phase coherence which leads to zero resistivity, to quantization of magnetic flux and to formation of quantized vortices.