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 electrochemis try to re-insert oxygen. With thin films this led to homogeneous produ cts, as judged by X ray diffraction and temperature dependence of elec trical resistivity. Because reduction leads to loss of superconductivi ty and re-oxidation restores it, this method allows room temperature c ontrol over superconducting properties of (parts of) films and, thus, can be used for patterning of (1237) thin films. We showed this by pre paring SNS-like structures by this method. The method affords control not only over bulk properties, but also over the quality of the interg ranular contact, possibly via control of oxygen concentration and orde ring in the outermost layers of grains (in films and pellets). The res ults imply rapid, field-assisted, oxygen motion and this was confirmed by independent measurements.