Pressure induced structural transformation of pyrochlore Gd 2Zr 2O 7

Abstract

High pressure x-ray diffraction studies on Gd 2Zr 2O 7 pyrochlore were carried out up to 45 GPa using a diamond anvil cell. A structural transition leading to monoclinic phase is initiated at a very low pressure of ∼3 GPa. Coexistence of both the parent and the daughter phase was seen up to the maximum pressure of 45 GPa. Bulk modulus of the parent phase is found to be 161.5 GPa and the lattice parameters of the high pressure monoclinic phase at 9 GPa are found to be: a=7.4839 Å, b=5.7089 Å, c=12.6498 Å and β = 97.61 . The structural phase transition is found to be reversible when quenched from 10 GPa, but it is irreversible when quenched from 45 GPa. Also, onset of amorphisation is seen above 35 GPa.