Synthesis of a YBa2Cu3O7-x-Ag composite using a sol-gel method

The preparation of YBa2Cu3O7-x-Ag powders by a sol-gel method and the characterization of these powders and also pellets made from these powders is presented. Transmission electron microscopy (TEM) observations show that the silver is highly dispersed in the sample. However, the size of the silver particles in the YBa2Cu3O7-x matrix depends largely on the silver concentration in the sample. For low concentrations, the silver particles have sizes of area 10 nm and for higher concentrations the silver particle is larger. The TEM investigations of the powders shows fibre structures for the YBa2Cu3O7-x-Ag composite. This structure is different from the structures usually observed in the YBa2Cu3O7-x system. The microanalysis of these fibres shows that they possess a composition of YBa2Cu3O7-x. The oxygenation of the samples seems easier in YBa2Cu3O7-x-Ag composites. The room temperature electrical resistivity of the pellets is decreased by the addition of silver but no enhancement of the superconducting critical temperature is observed.