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Phase diagram of the relaxor ferroelectric (1-x)PbZn(1/3)Nb(2/3)O3-xPbTiO3

D. La-Orauttapong·B. Noheda·Z. -G. Ye·P. M. Gehring·J. Toulouse·D. E. Cox·G. Shirane
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Abstract

Recently, a new orthorhombic phase has been discovered in the ferroelectric system Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-xPT) for x= 9%, and for x= 8% after the application of an electric field. In the present work, synchrotron x-ray measurements have been extended to higher concentrations, 10% <= x <=15%. The orthorhombic phase was observed for x= 10%, but, surprisingly, for x>= 11% only a tetragonal phase was found down to 20 K. The orthorhombic phase thus exists only in a narrow concentration range with near vertical phase boundaries on both sides. This orthorhombic symmetry (MC-type) is in contrast to the monoclinic MA-type symmetry recently identified at low temperatures in the PbZr(1-x)TixO3 (PZT) system over a triangle-shaped region of the phase diagram in the range x= 0.46-0.52. To further characterize this relaxor-type system neutron inelastic scattering measurements have also been performed on a crystal of PZN-xPT with x= 15%. The anomalous soft-phonon behaviour (''waterfall'' effect) previously observed for x= 0% and 8% is clearly observed for the 15% crystal, which indicates that the presence of polar nanoregions extends to large values of x.

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D. La-Orauttapong, B. Noheda, Z. -G. Ye, P. M. Gehring, J. Toulouse, D. E. Cox, G. Shirane. 2001-11-01. Phase diagram of the relaxor ferroelectric (1-x)PbZn(1/3)Nb(2/3)O3-xPbTiO3. https://doi.org/10.1103/physrevb.65.144101

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