Sodium ion ordering and vacancy cluster formation in NaxCoO2 (x=0.71 and 0.84) single crystals by synchrotron X-Ray diffraction.
In the rich phase diagram of NaxCoO2, x=0.71 enjoys special stability and is called the Curie-Weiss metal due to its anomalous properties. Similarly, x=0.84 prepared from high temperature melt is a special end point beyond which the system phase separates. Using synchrotron x-ray diffraction on single crystals, we discovered sqrt[12]a and sqrt[13]a superlattice structures which we interpret as the ordering of Na (vacancy) clusters. These results lead to a picture of coexisting local moments and itinerant carriers and form the first step towards understanding the many anomalous properties of cobaltates.
Chou
F C
FC
Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan. fcchou@ntu.edu.tw
Chu
M -W
M-
Shu
G J
GJ
Huang
F-T
FT
Pai
Woei Wu
WW
Sheu
H S
HS
Lee
Patrick A
PA