In situ x-ray diffraction study of an electric field induced phase transition in the single crystal relaxor ferroelectric, 92% Pb(Zn1/3Nb2/3)O-3-8% PbTiO3

We have used in situ x-ray diffraction to measure strain curves of single c rystals of 92% Pb(Zn1/3Nb2/3)O-3-8% PbTiO3 poled in the [001] direction. We observed shifts in the (002) and (330) peaks as functions of applied volta ge (in the [001] direction), thereby measuring the crystallographic strain. Our measurements confirm that the high strains observed using macroscopic methods reflect microscopic strains in the crystal lattice. By watching the disappearance of a rhombohedral splitting in the (330) peak, we also find direct evidence that the field-induced phase transition reported by S.-E. P ark and T.R. Shrout [J. Appl. Phys. 82, 1804 (1997)] occurs between a pseud orhombohedral and tetragonal crystal structure. (C) 1999 American Institute of Physics. [S0003-6951(99)04219-9].