Three-dimensional mapping of diffuse scattering in Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3}

High energy (67 keV) x-ray diffuse scattering measurements were performed on single crystals of Pb(Zn{sub 1}/{sub 3}Nb{sub 2}/{sub 3})O{sub 3}-xPbTiO{sub 3} (PZN-xPT), to map out the diffuse scattering distribution in all three dimensions around a large number of Bragg peaks simultaneously. For x=0,4.5%, and 8%, the results are very similar, indicating same type of correlations of polarizations in these compounds. Our results show that the diffuse scattering intensity consists of six rod-type intensities around reciprocal lattice points. A simple model is suggested where {l_brace}110{r_brace} type planar correlations of the in-plane type polarizations in real space contribute to the rod-type diffuse intensities in the reciprocal space. The planar correlations of polarizations are likely a result from condensations of soft polarized optic phonon modes.