We have synthesized high-quality samples of the s=3 member of the (Cu,Mo)-12s2 homologous series of layered copper oxides. The (Cu,Mo)-1232 phase forms as a single phase for the cation composition (Cu0.75Mo 0.25)Sr2(Ce0.67 Y0.33) 3Cu2O11+δ through solid-state synthesis in air, but the samples as synthesized are not superconductive. Superconductivity is induced in the air-synthesized samples by means of high-pressure oxygenation carried out at 5 GPa and 500°C in the presence of Ag2O2 as an excess oxygen source. With increasing ratio of Ag2O2 to the (Cu,Mo)-1232 phase the c-axis lattice parameter gradually decreases and Tc increases. The highest T c value of 53 K reached for samples oxygenated in the presence of 100 mol% Ag2O2 exceeds the values reported for Cu-based two-fluorite-layer compounds.
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1 Nov 2004|
|MoE publication type||A1 Journal article-refereed|