Electrochemical room temperature reduction and reoxydation of thin films and pellets of YBa₂Cu₃O_7-x

YBa₂Cu₃O₇ (1237) was reduced and reoxydated quantitatively, in a controlled manner, at room temperature (RT), by way of extraction or insertion of oxygen, using an electrochemical set-up. RT reduction and reoxygenation of thin films, which led to homogeneous products, as judged by X ray diffraction. Since reduction leads to loss of superconductivity and re-oxidation restores it, this method allows room temperature control over superconducting properties of (parts of) films. This permits patterning of (1237) thin films. SNS-like structures were already prepared by this method. The method affords control not only over n(E_F) via [oxygen]_bulk, but also over the quality of the intergranular contact, possibly via control of [oxygen] in the outermost layers of grains (in films and pellets).