Abstract: A material formed as a film comprised of monomolecular layers (2,3,4,5) stacked on a substrate (1), wherein said film includes at least one first set (R) of layers which form an electric charge reservoir, and a second set (S) of layers which form a conductive cell and which contain a number of conductive copper oxide layers (4), separated from each other by intermediate layers (5), the reservoir and the conductive cell being adjacent in the layer stack. There are at least four conductive copper oxide layers, and the intermediate layers have the chemical formula Ca.sub.1-x M.sub.x and are free of strontium, wherein x is a real number between 0 and 0.2, M is a component with an ionic radius close to that of the Ca.sup.2+ ion, and the intermediate layers may be complete or not.