Local structural view on the polarization rotation in relaxor ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3

We performed comprehensive structural studies on local ionic displacements and medium-range ordering across a series of phase transitions in (1-x)Pb(Zn1/3Nb2/3)O-3-xPbTiO(3) (PZN-xPT) at 15 K by using neutron pair-distribution-function (PDF) and Rietveld analyses. PDF spectra clearly demonstrate that all phases of PZN-xPT have nearly identical ionic pair correlations on a length scale of xi similar to 15 A. At longer pair distances, however, PZN-xPT exhibits different pair correlations. This local- and medium-range structural information provides direct evidence that local polarizations do not rotate with long-range phase transitions, and an order-disorder type ordering of polar nanoregions determines the long-range polarization rotations in PZN-xPT. (c) 2008 American Institute of Physics.