| Abstract |
We measure the internal friction Q-1 in YBa2Cu3O7-x and Bi2Sr2CaCu2O8+x samples. At temperatures near 35 K for KHz frequencies we observe an attenuation peak. In the case of YBa2Cu3O7-x, assuming a thermally activated relaxation behaviour, we are able to show that it corresponds to the same process as other peaks observed at higher frequencies. For Bi2Sr2CaCu2O8+x this is not the case, and the origin of the peak, found in all the measured samples, remains unknown. |
