Electrochemical, Room Temperature Reduction, Oxidation and Microscopic Patterning of Multinary Cuprate Superconductors

YBa2Cu3O7 (1237) was reduced and reoxidized at room temperature (RT), by using wet electrochemistry to extract, or solid state electrochemistry to re-insert oxygen. With thin films this led to homogeneous products, as judged by X ray diffraction and temperature dependence of electrical resistivity. Because reduction leads to loss of superconductivity and re-oxidation restores it, this method allows room temperature control over superconducting properties of (parts of) films and, thus, can be used for patterning of (1237) thin films. We showed this by preparing SNS-like structures by this method. The method affords control not only over bulk properties, but also over the quality of the intergranular contact, possibly via control of oxygen concentration and ordering in the outermost layers of grains (in films and pellets). The results imply rapid, field-assisted, oxygen motion and this was confirmed by independent measurements.