Universal thermal response of the Prussian blue lattice
Abstract
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)xMII[FeIII(CN)6]yzH2O ( M=Ni , Cu, Zn, and Cd) and (Cs,Rb)xMIII[FeII(CN)6]yzH2O ( M=Fe and Co) by means of the synchrotron-radiation x-ray powder diffraction. We found a universal relation between the coefficient ( β≡dlna/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.
- Publication:
-
Physical Review B
- Pub Date:
- May 2009
- DOI:
- Bibcode:
- 2009PhRvB..79q2302M
- Keywords:
-
- 65.40.De;
- 61.05.C-;
- 61.05.F-;
- Thermal expansion;
- thermomechanical effects;
- X-ray diffraction and scattering;
- Neutron diffraction and scattering