Pressure effect on structural and vibrational properties of Y-substituted BiFeO₃

The structural and vibrational properties of 5% Y-substituted BiFeO ₃ under pressure have been investigated using synchrotron x-ray diffraction (SXRD) and Raman scattering measurements. At a pressure below 30.3 GPa, distinct changes in the Raman spectra and SRXD pattern show evidence for one pressure-induced structural transition from the polar rhombohedral R3c phase to the nonpolar orthorhombic Pnma phase commencing at 3.6 and completed at 7.2 GPa, where there is a region of phase coexistence between the R3c and Pnma phases. At a higher pressure of 40.8 GPa, another phase transition from orthorhombic to cubic is observed accompanied by the insulator-metal transition. Our data do not suggest the pressure-induced re-entrance of ferroelectricity in the model multiferroic Bi_0.95Fe_0.05O₃ in the pressure range studied.