Superconductivity in Randomly Stacked Superconducting and Normal Layers

The proximity effect in a randomly stacked superconducting and normal layers, has been investigated theoretically. The superconducting transition in such a multilayer has been shown to acquire width δTc, because of the presence of varying length segments of the superconducting regions sandwiched by normal regions. The superconducting transition temperature is found to decrease monotonically, while δTc goes through a maximum as the fraction of the normal layers is increased from 0 to 1.