Observation of cation reordering during the olivine-spinel transition in fayalite by in situ synchrotron X-ray diffraction at high pressure and temperature.
The olivine-spinel phase transition in fayalite at high pressure and temperature has been studied using time-resolved x-ray diffraction. Structure refinements show a delay of cation reordering relative to anions during the phase transformation and an increase in the cell volume while the cations reorder into their sites. A significant stress drop in the sample is observed. This experiment, for the first time, quantitatively demonstrates a pseudomartensitic transformation: a diffusionless anion sublattice transition coupled with short-range diffusional cation reordering.
Chen
J
J
Center for High Pressure Research, Department of Geosciences, State University of New York at Stony Brook, Stony Brook, New York 11794-2100, USA.
Weidner
D J
DJ
Parise
J B
JB
Vaughan
M T
MT
Raterron
P
P