Shock-synthesis of a metastable tetragonal phase of EuBa2Cu3Oy

Shock-synthesized EuBa2Cu3Oy was found to be a metastable tetragonal phase with c/a=3.00, which is only obtainable at relatively low temperatures by conventional solid state reactions. The annealing of the shock-synthesized phase above 900 °C and subsequent oxidation lead to superconduction together with the increase in the c/a ratio to 3.05, presumably due to formation of perfect ordering of Eu and Ba atoms. These results suggest that no complete ordering between Eu and Ba, hence incomplete formation of CuO2 plane necessary for superconduction, would be established during a short time interval of shock synthesis process.