Oxygen Plasma Effects on Zero Resistance Behavior of Yb,Er-doped YBCO (123) Based Superconductors.

Schäfer, Helmut; Banko, Franziska; Nordmann, Jörg; Voss, Benjamin; Steinhart, Martin; Walder, Lorenz; Rathmann, Dirk

Rare-earth doped YBa2Cu3O7- δ samples were synthesized starting from the corresponding oxides Y2O3, Yb2O3, Er2O3, CuO as well as Ba(OH)2 by heating to 950 °C under air. The doping concentrations were adjusted to 15 % Yb, 7 % Er and 20 % Yb, 15 % Er, respectively, with respect to the yttrium content. The orthogonal phased (123) YBCO ceramics were exposed to an oxygen plasma for 140 and 380 min. Zero resistance temperature ( Tc,0) was determined by measuring the resistivity-temperature dependence using a classical four point measurement approach. Under optimal conditions with respect to the material composition and the oxygen treatment an unusual high zero resistance temperature of 97.5 K ( Tc,onset ≈ 101 K) was achieved. This represents an increase of Tc,0 by 7.5 K. The oxygen treatment could not be monitored by IR spectroscopy, X-ray fluorescence spectroscopy, and X-ray powder diffraction. The results showed good reproducibility.

OXYGEN plasmas; PLASMA gases; SUPERCONDUCTORS; ELECTRICAL conductors; SPECTRUM analysis

Zeitschrift für Anorganische und Allgemeine Chemie, 2014, Vol 640, Issue 10, p1900

0044-2313

Academic Journal

10.1002/zaac.201400131