Diffuse neutron scattering study of a disordered complex perovskite (formula presented) crystal

Diffuse scattering around the (110) reciprocal lattice point has been investigated by elastic neutron scattering in the paraelectric and relaxor phases of the disordered complex perovskite crystal (formula presented) (PZN). The appearance of a diffuse intensity peak indicates the formation of polar nanoregions at temperature (formula presented) approximately 40 K above (formula presented) The analysis of this diffuse scattering indicates that these regions are in the shape of ellipsoids, more extended in the (formula presented) direction than in the (formula presented) direction. The quantitative analysis provides an estimate of the correlation length ξ, or size of the regions, and shows that (formula presented) consistent with the primary or dominant displacement of Pb leading to the low-temperature rhombohedral phase. Both the appearance of the polar regions at (formula presented) and the structural transition at (formula presented) are marked by kinks in the (formula presented) curve but not in the (formula presented) one, also indicating that the primary changes take place in a (formula presented) direction at both temperatures.