Thermal responses of Prussian blue lattice, that is, a rocksalt-type network of metal ions bridged by cyano group, are systematically investigated for (Cs,Rb) x MII [FeIII (CN) 6] y z H2 O (M=Ni, Cu, Zn, and Cd) and (Cs,Rb) x MIII [FeII (CN) 6] y z H2 O (M=Fe and Co) by means of the synchrotron-radiation x-ray powder diffraction. We found a universal relation between the coefficient (βdlna/dT; a is lattice constant) of the thermal expansion and magnitude of a: β changes the sign from positive to negative with increase in a. We ascribed the negative thermal expansion observed in the large- a region to intrinsic rotational instability of the [Fe (CN) 6] unit.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2009 May 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics