Pressure-Induced Structural Phase Transition in Gd2Ce2O7 Oxide

The high-pressure structural evolution of Gd2Ce2O7 has been studied by synchrotron X-ray diffraction (up to 31.8 GPa) and Raman spectroscopy (up to 38.9 GPa). A pressure-induced phase transition from cubic (space group Ia-3) to monoclinic (C2/m) crystal structure was observed to initiate at 11.3 GPa. This transition was primarily driven by the compression-induced cation rearrangement, which significantly altered the local coordination environment. The structural transformation proceeded via a gradual, continuous pathway and persisted up to the maximum experimental pressure of 31.8 GPa. Notably, the high-pressure phase remains stable upon complete decompression, confirming an irreversible structural transformation of Gd2Ce2O7.