Pressure-induced phase transitions in Zr-rich PbZr1-xTixO3 ceramics

A Raman study of structural changes in the Zr-rich PbZr1-xTixO3 (PZT) syste m under hydrostatic pressures up to 5.0 GPa is presented. We observe that e xternally applied pressure induces several phase transitions in PZT ceramic s among phases with orthorhombic (A(O)), rhombohedral low-temperature (R-LT ), and rhombohedral high-temperature (R-HT) symmetries (all found in PZT at ambient pressure and room temperature). Each of the compositions investiga ted (0.02 less than or equal to x less than or equal to 0.14) exhibits a hi gh-pressure phase with orthorhombic (O-I ') symmetry. We further report a d etailed study of the pressure dependence of Raman frequencies to elucidate the phase transitions and to provide a set of pressure coefficients for the high-pressure phases.