Regensburg 2007 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DF: Fachverband Dielektrische Festkörper

DF 3: Relaxor Ferroelectrics

DF 3.2: Vortrag

Montag, 26. März 2007, 15:10–15:30, H11

Electric-field induced phase transition in near-electrode region of PbMg0.33Nb0.67O3 - 28% PbTiO3 relaxor -ferroelectric (001) single-crystal wafer — •Alexander A. Levin, Anja I. Pommrich, Torsten Weißbach, and Dirk C. Meyer — Institut für Strukturphysik, Technische Universität Dresden, 01062 Dresden, Germany

A (001) single-crystal PbMg0.33Nb0.67O3 - 28% PbTiO3 (PMN - 28% PT) wafer was investigated by means of Wide-Angle X-ray Scattering (WAXS) techniques in situ under the influence of an external static unipolar electric field (field strength E up to 13 kV/cm). Changes of profiles of X-ray 001 reflections of 1st and 3d orders and their rocking curves were recorded under applying the electric field along the [001] direction of the single-crystal plate. Evidences of a reversible phase transition between ferroelectric modifications of PMN-PT in a near-electrode region of about 1 micrometer depth are found. Under the influence of the static electric field, a part of the near-electrode layer (of about 5 vol. % and 15 vol. % at E = 4.5 kV/cm and 13 kV/cm, respectively) transforms from initially rhombohedral type of the structure (R, space group R3m) to another one (most probably, monoclinic Mb (space group Cm)).The transition is manifestated by change of the phase lattice constant (a = 4.0227(1) Å and c = 4.016(1) Å according to interpolation to E = 0 kV/cm for R and Mb phases, resp.), piezoelectric coefficient (d33 = 1092(14) pC/N (R) and 1735(248) pC/N (Mb), resp.) and the profile shape of the rocking curves. Financial support by the DFG research unit FOR 520 is gratefully acknowledged.