Influence of Low-temperature Fluorination On the Transport-properties of Yba2cu3o7-delta

The influence of fluorination on the thermal conductivity, the electrical resistivity and the thermoelectric power of YBa2Cu3O7-delta has been investigated. It was found that the presence of fluorine does not drastically modify the thermal conductivity of the YBa2Cu3O7-delta compounds. The sip of the thermoelectric power was found to be negative between 92 and approximately 200 K for the sample without fluorine and positive above 92 K for the YBa2Cu3O7-delta compound treated in fluorine atmosphere. Also, a small increase of the electrical resistivity was found after treatment with fluorine. These results are consistent with the fact that the fluorine treatment generates passivation layers around the ceramic grains without affecting the inner structure of the grains.