Superconductivity

Temperature dependence of resistivity in superconducting materialsThe electrical resistivity of many metals and alloys drops suddenly tozero when their specimens are cooled to a sufficiently lowtemperature, often a temperature in the liquid Helium range (4 K).This phenomenon is known as superconductivity. Materials which showsuperconductivity property are called superconducting materials.Superconductivity was first observed by Kamerlingh Onnes in 1911 whilemeasuring the resistivity of mercury at low temperatures.The temperature at which the resistivity of the material suddenlychanges to zero is called critical temperature or superconductingtransition temperature (Tc). The transition temperature of mercury is4.15 K.