| 摘要 |
<p>Superconducting metal-oxide crystalline compounds having the general formula (Me<1>)p(Me<2>)qCu3OxFy, wherein Me<1> is selected from Y, Sc and the lanthanides, Me<2> is Ba and/or Sr, p is 0.8-2.5, q is 0.8-3, x is 5-8.5 and y is 0-6, are prepared by reacting Me<2> peroxide in the molten state with oxides and optionally fluorides of Me<1> and Cu, possibly accompanied by Me<2> oxide. Since the reaction takes place in the melt of Me<2> peroxide, there is obtained a better contact between the reactants than it is possible in known solid state reactions, and the chance of obtaining large, very pure monocrystals. Especially the Me<2> peroxide renders it possible to obtain a compound in which Cu to a high degree is present in a higher state of oxidation than 2. Particularly well defined end products are obtained when the reaction is carried out in a closed vessel with an oxygen-free atmosphere, whereby the peroxide alone is the source for the oxygen that can increase the oxidation state of the copper.</p> |
