ELECTRON-PHONON ENHANCEMENT OF THERMOPOWER IN SILVER-DOPED SUPERCONDUCTING BI COMPOUNDS

Resistivity, thermoelectric power (S) and critical current measurement s on bulk samples of superconducting (Bi0.8Pb0.2)(2)Sr2Ca3(CU1-xAgx)(4 )O12-x for different x values at small concentrations (0 less than or equal to x less than or equal to 0.02) have been carried out in the te mperature range 77K - 300K. The Seebeck coefficient exhibits an enhanc ement above the critical temperature that increases with x. The resist ivity correlates very well with the highest value of S for each sample . Although the results for S follow the universal trends found in prev ious works, there are some peculiarities in our data for this compound . We try to explain the S results in terms of rather conventional mode ls. It is argued that in the copper oxides the e-p effects, usually ne gligible in normal metals at temperatures small compared to the Debye temperature, are significant near and above the critical temperature. A small contribution due to the phonon-drag effect is also discussed.