Structural evolution and ferroelectric properties of relaxor ferroelectric single crystal Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 under high pressure

Relaxor ferroelectric crystals of lead magnesium niobate–lead titanate (PMN-xPT) have attracted great attention due to their extraordinary dielectric, piezoelectric, and electromechanical properties. PMN-xPT shows different relaxor behavior and structural phase transitions in a wide temperature and chemical component range. Here, we studied spectroscopy and ferroelectricity of PMN-0.28PT under high pressure. The appearance of a new Raman band and the sudden redshift of UV-vis absorption edge imply a structural phase transition at about 8 GPa. More importantly, the ferroelectricity of the sample is suppressed above a pressure of 5 GPa, and there is no ferroelectricity under further compression. We suggest that the disappearance of ferroelectricity may be related to the polar nanoregions being suppressed by pressure. Our observations of ferroelectricity disappearance above 5 GPa indicate the B-site cation rearrangement in the several nanometers region.