Compressibility, Phase Transitions, and Oxygen Migration in
Zirconium Tungstate, ZrW2O8
J. S. O. Evans,
Z. Hu,
J. D. Jorgensen,
D. N. Argyriou,
S. Short,
A. W. Sleight
*
In situ neutron diffraction experiments show that at pressures
above 2 kilobars, cubic zirconium tungstate
(ZrW2O8) undergoes a quenchable phase
transition to an orthorhombic phase, the structure of which has
been solved from powder diffraction data. This phase transition can be
reversed by heating at 393 kelvin and 1 atmosphere and involves the
migration of oxygen atoms in the lattice. The high-pressure phase shows
negative thermal expansion from 20 to 300 kelvin. The relative thermal
expansion and compressibilities of the cubic and orthorhombic forms can
be explained in terms of the "cross-bracing" between polyhedra that
occurs as a result of the phase transition.
J. S. O. Evans and A. W. Sleight, Department of Chemistry, Oregon
State University, Corvallis, OR 97331, USA.
Z. Hu, Intense Pulsed Neutron Source Division, Argonne National
Laboratory, Argonne, IL 60439, USA.
J. D. Jorgensen and S. Short, Materials Science Division, Argonne
National Laboratory, Argonne, IL 60439, USA.
D. N. Argyriou, Science and Technology Center for Superconductivity,
Argonne National Laboratory, Argonne, IL 60439, USA.
*
To whom correspondence should be addressed.
