Mihailova, B.; Waeselmann, N.; Maier, Bernd J.; Welsch, A.-M.; Angel, R. J.; Bismayer, U.
Pressure-induced structural transformations in advanced ferroelectrics with relaxor behaviour.
In: High Pressure Research, Vol. 33, No. 3: pp. 595-606
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A series of model perovskite-type relaxor ferroelectrics (pure and A-/B-site doped PbSc1/2Ta1/2O3 and PbSc 1/2Nb1/2O3 as well as of 0.9PbZn 1/3Nb2/3O3-0.1PbTiO3) were studied by high pressure diffraction and inelastic light scattering in order to elucidate the mesoscopic-scale ferroic atomic arrangements responsible for the superb macroscopic properties of these materials. The combined analysis of the pressure-enhanced phonon anomalies observed by Raman spectroscopy and the pressure-induced long-range order detected by synchrotron X-ray and neutron diffraction revealed that at ambient conditions antiferrodistortive order coexists with the ferroelectric order on the mesoscopic scale. This suggests that the locally polarized spatial nanoregions known as polar nanoregions are ferrielectric in nature and their abundance and mean size depend on both the antiferrodistortive and ferroelectric coupling, which in turn can be tuned by appropriate chemical variations.