THERMOELECTRIC-POWER OF SINGLE-PHASE YBA2CU3O7-XSUPERCONDUCTORS

Thermoelectric power, s, of single phase YBa//2Cu//3O//7// minus //x superconductors was measured in the temperature range 4. 2-300 K. Thermopower reaches zero within experimental uncertainty in the superconducting state. The values for the high-T//c samples are small, which are typical of metals. The results prefer hole conduction. According to Nordheim-Gorter rule, the S(T) behavior of the oxygen deficient samples can be understood by assumption of the simultaneous existence of two kinds of carriers - metallic and semiconductive. To get the density of carriers in the order of magnite of 10**2**1 cm** minus **3, the effective mass of the carriers is about 6-10 times of the free electron mass.