Temperature dependence of critical field

When the superconducting materials are subjected to a strong magneticfield, it will result in the destruction of the superconductingproperty. I.e. they return to the normal state. The minimum magneticfield required to destroy the superconducting property is called thecritical field (Hc). The variation of Hc with temperature is shown inthe figure. The dependence of critical field on temperature isgoverned by the following relationHc(T) = Hc(0)[1-(T/Tc)2]Where Hc(0) is the critical field at 0 K.