Pressure induced structural stability studies on pyrochlore

High-pressure Raman spectroscopic investigations of Nd2Zr2O7 upto 20 GPa together with low temperature Raman and IR studies in the temperature range 300–10 K are being reported. The effect of oxygen vacancy on the structural transition of the highly ordered pyrochlore structure was established by these studies. Few subtle changes in the spectra including substantial broadening of Raman modes at 4 GPa were observed. These changes are suggestive of structural phase transition to disordered pyrochlore phase. The origin of this transition is due to the structural disorder induced by the random statistical nature of the oxygen vacancies at high pressure. The low temperature measurement on Nd2Zr2O7 indicates that the broadening of the Raman modes is not due to anharmonic vibration but due to an inherent disorder present in the system.