In superlattices and heterostructures, superconductivity is induced in non-superconducting materials through the proximity effect. This occurs when a superconducting layer is brought into close proximity with a non-superconducting layer, allowing the Cooper pairs from the superconducting layer to penetrate into the non-superconducting layer.

All of the mentioned types of superlattices are commonly used in superconductivity research. Metal-insulator superlattices exhibit proximity-induced superconductivity, semiconductor-superconductor superlattices explore the interplay of superconductivity and semiconductor properties, and ferromagnet-superconductor superlattices investigate the interplay of superconductivity and magnetism.

The Josephson effect refers to the flow of supercurrent through a weak link between two superconductors. This weak link can be a thin insulating layer, a normal metal layer, or a constriction in a superconducting wire.

The coherence length is a crucial parameter in superlattices and heterostructures. It determines the maximum thickness of a superconducting layer for proximity-induced superconductivity. If the superconducting layer is thicker than the coherence length, the proximity effect becomes negligible.

All of the mentioned experimental techniques are commonly used to study the superconducting properties of superlattices and heterostructures. STM provides atomic-scale resolution, AFM allows for surface characterization, and TEM enables the analysis of structural properties.

Superconductivity in superlattices and heterostructures has a wide range of potential applications. These include superconducting electronics, quantum computing, energy-efficient power transmission, and other emerging technologies.