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Divacancy superstructures and enhanced thermopower in NaxCayCoO2
Replacing Na ions in NaxCoO2 with divalent Ca ions results in the formation of ordered arrays of divacancy clusters, rather than the trivacancy clusters found for the pure... -
High temperature superstructures in thermoelectric oxides
Sodium cobalate has emerged as one of the best thermoelectric materials. Our previous neutron Laue diffraction studies on SXD have found ordered arrays of multivacancy clusters,... -
Influence of superstructures on rich transport properties of lithium cobaltate
In the vicinity of x ~ 0.75, LixCoO2 has potential as a thermoelectric, since it has a high Seebeck coefficient and metallic conductivity. We have performed the first successful... -
Understanding enhanced thermoelectric properties of sodium cobaltate doped by...
The thermoelectric power factor for (Na1-y¿My¿)0.8CoO2 is dramatically increased when M = Sr, but it is essentally unchanged from the pure compound when M = Ca. Our previous SXD... -
Superstructures in lithium cobaltate
The battery material LixCoO2 has recently been shown to have high thermopower comparable to NaxCoO2 at high x. In the case of NaxCoO2 we showed using neutron Laue diffraction on... -
Superstructures in insulating and metallic lanthanum-doped sodium cobaltate
The thermoelectric properties of NaxCoO2 can be substantially improved by replacing Na ions by cations of higher valence. Our neutron diffraction studies on SXD for doping with...
