Polycrystalline thin film, method for producing the same and oxide superconductor

摘要

An object of the invention is to provide a polycrystalline thin film which includes an intermediate layer that is made thinner while keeping high crystal orientation so as to prevent warpage of a substrate resulting from internal stress of the film. A polycrystalline thin film according to the invention includes an intermediate layer formed by a first layer and a second layer laminated in this order and provided on a metal substrate. The first layer has a rock-salt crystal structure and the second layer has a fluorite crystal structure.