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

Artikel i vetenskaplig tidskrift, 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.