Ve. Gasumyants et al., SCALING OF THE THERMOELECTRIC-POWER IN A WIDE TEMPERATURE-RANGE IN BI2SR2CA1-XNDXCU2OY (X=0-0.5) - EXPERIMENT AND INTERPRETATION, Physical review. B, Condensed matter, 53(2), 1996, pp. 905-910
We report measurements of the thermopower (S) in the temperature range
from T-c up to 1000 K, as well as of the resistivity and the Hall coe
fficient for temperatures up to T=300 K of single-phase Bi2Sr2Ca1-xNdx
Cu2Oy compounds with 0 less than or equal to x less than or equal to 0
.5. It was found that the S(T) dependences in the normal state have th
ree regions of different thermopower behavior. In the first region, at
low temperature (T<100-220 K), the S(T) curves have a smooth maximum,
which shifts to higher temperature as x increases. Then, as the tempe
rature increases, there is an extended second region where S decreases
nearly linearly with T. Finally, in the third region, at high tempera
ture (T>620 K), the thermopower demonstrates a temperature-independent
behavior for all the investigated samples. The temperature of the cro
ssover from the second S(T) region to the third one is unchanged with
x. The results are discussed in the framework of a phenomenological ba
nd spectrum model.