High-pressure and variable temperature single crystal synchrotron X-ray measurements combined with first-principles based molecular dynamics simulations study diffuse scattering in the relaxor ferroelectric system PSN (PbSc1/2Nb1/2O3). Constant temperature experiments show pressure induced transition to the relaxor phase at different temperatures characterized by butterfly and rod shaped diffuse scattering around the {h00} and {hh0} Bragg spots, respectively. The simulations reproduce the observed diffuse scattering features as well as their pressure-temperature behavior, and show that they arise from polarization correlations between chemically-ordered regions, which in previous simulations were shown to behave as polar nanoregions. Simulations also exhibit radial diffuse scattering (elongated towards and away from {\bf Q}=(000)), that persists even in the paraelectric phase, consistent with previous neutron experiments on (PbMg1/3Nb2/3O3) (PMN)
@article{arxiv.0908.2373,
title = {Origin of Diffuse Scattering in Relaxor Ferroelectrics},
author = {P. Ganesh and E. Cockayne and M. Ahart and R. E. Cohen and B. Burton and R. J. Hemley and Yang Ren and Wenge Yang and Z-G Ye},
journal= {arXiv preprint arXiv:0908.2373},
year = {2015}
}