Order-disorder-order phase transitions in the pyrochlore superconductor Cd2Re2O7

Journal article, 2005

The structural phase transitions of the pyrochlore superconductor Cd2Re2O7 are investigated by Raman light scattering. The cubic to tetragonal transition at 200 K is characterized by the appearance of a broad mode originating from oxygen ion motion in agreement with recent theoretical predictions [I. A. Sergienko , Phys. Rev. Lett. 92, 065501 (2004)]. The appearance of well-defined low-frequency modes at the 120-K transition indicates that it is driven by ordering of the Cd ions within the channel voids of the distorted pyrochlore.