The intermetallic perovskite MgCNi3 is a superconductor with a Tc =7 K. Substitution of Fe and Ru for Ni decreases Tc monotonically as the doping concentration is increased. Here we report thermopower measurements S(T) on MgCNi3, MgCNi3-x Fex, and MgCNi3-x Rux. For MgCNi3 the thermopower is negative, -12.5 μV/K, at 300 K. The absolute value of S decreases as x increases in MgCNi3-x Fex and MgCNi3-x Rux. The sign of S changes from negative to positive at low temperatures for values of x>0.01. These data show that the carriers in MgCNi3 are electrons, and by increasing x and decreasing temperature, the participation of hole carriers clearly increases. The influence of the magnetic moments of the Fe atoms on the thermopower is not visible.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Aug 1 2007|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics