The electrical resistivity and the thermoelectric power of Nb3Te4 inserted with mercury have been measured in the temperature range from 1.4 to 300 K. The magnitude of the resistivity and the residual-resistivity ratio are not greatly affected by addition of Hg. The magnitude of the resistive anomaly at 90 K increases when adding a small amount of Hg but begins to decrease at about x = 0.03 and is no longer visible at about x = 0.15. Similarly, the magnitude of the resistive anomaly at 30 K decreases with increasing Hg concentration and disappears at about x = 0.26. The thermoelectric power S also shows two anomalies at about 90 and 30 K. The anomaly of S at 90 K becomes smeared by addition of Hg and disappears at about x = 0.3. The anomaly of S at 30 K becomes clear by addition of Hg and is still present at an amount of x = 0.8. The sign of S is negative at all measured temperatures for x<0.3 and is positive at temperatures below 7 K for x>0.3. The superconducting transition temperature is enhanced from 1.9 to 5.4 K by addition of Hg. The upper critical fields parallel (Hc2∥) and perpendicular (Hc2⊥) to the c axis have been measured near TC. The critical fields show large anisotropy for x≥0.3: the ratio Hc2∥/Hc2⊥ is about 5 for x<0.3 and 40 for x≥0.3. These results are discussed on the basis of the multiband model with electron-like and hole-like carriers and with phonon drag.
|Number of pages||12|
|Journal||Journal of Physics Condensed Matter|
|State||Published - Aug 23 1999|
ASJC Scopus subject areas
- Materials Science (all)
- Condensed Matter Physics