Transport mechanism in La1.85Sr0.15Cu1-xNixO4+δ (0<=x<=1)
Abstract
The transport properties of the La1.85Sr0.15Cu1-xNixO4+δ (0<=x<=1) solid solution series have been investigated by means of electric resistivity and thermoelectric power (TEP). The TEP measurements reveal that the Ni doping at the Cu site brings about an anomalous change in the TEP. The TEP value S(T) increases with increasing Ni content for the samples with low dopant levels (x<0.3) and reaches a maximum at x=0.3, but decreases rapidly with the further increase of Ni content for x>0.3 and becomes negative at x=1.0. The resistivity measurements show that the character of the conductivity for the samples with x>=0.1 changes from thermally activated at high temperature to hoppinglike at low temperature. By the comparison of the thermal activation energy derived from the resistivity with that from the TEP, we find that the transport mechanism in La1.85Sr0.15Cu1-xNixO4+δ can be understood in terms of the polaron model.
- Publication:
-
Physical Review B
- Pub Date:
- December 1998
- DOI:
- 10.1103/PhysRevB.58.15116
- Bibcode:
- 1998PhRvB..5815116Z
- Keywords:
-
- 74.72.Dn;
- 74.25.Fy;
- La-based cuprates;
- Transport properties