Determination of the ordered structures of Pb„Mg1/3Nb2/3...O3 and Ba„Mg1/3Nb2/3...O3 by atomic-resolution Z-contrast imaging
نویسندگان
چکیده
The atomic structure of ordered domains in Ba~Mg1/3Nb2/3)O3 and La-doped and undoped Pb~Mg1/3Nb2/3)O3 is studied by high-resolution Z-contrast imaging. The ordered domain structure in both doped and undoped Pb~Mg1/3Nb2/3)O3 is determined to be in agreement with the charge balanced random-layer model and inconsistent with the space-charge model. It is shown that La doping in Pb~Mg1/3Nb2/3)O3 enhances not only the domain size but also the degree of ordering. © 1998 American Institute of Physics. @S0003-6951~98!00424-0#
منابع مشابه
Evolution of nanodomains during the electric-field-induced relaxor to normal ferroelectric phase transition in a Sc-doped Pb(Mg1/3Nb2/3)O3 ceramic
Sc doping in Pb(Mg1/3Nb2/3)O3 enhances the B-site 1:1 cation order significantly but promotes the ferroelectric polar order moderately. At low doping levels, the electrical polar domains remain at the nanometer scale and the relaxor ferroelectric behavior is preserved. A normal ferroelectric state can be triggered with electric fields from the relaxor state at lower temperatures. This electric-...
متن کاملZr-Modified Pb(Mg1/3Nb2/3)O3 with a Long-Range Cation Order
The 1:1 structural order and B-site cation order in Pb(Mg1/3Nb2/3)O3 ceramics was significantly enhanced by Zr4+ substituting Nb5+ according to the chemical formula Pb(Mg1/ 3Zr2x/3Nb2(1−x)/3)O3−x/3. The enhanced structural and cation order was revealed by both X-ray diffraction and transmission electron microscopy. The increased charge difference and the introduced oxygen vacancies were suggest...
متن کاملInnovative Approach to Synthesis of Pb(Mg1/3Nb2/3)O3 Based Materials using Colloidal Interactions
A new approach to the synthesis of Pb(Mg1/3Nb2/3)O3 (PMN) based materials is presented. By manipulating the colloidal interactions, the designed self-assembled aggregates are formed, which enable the synthesis of PMN based materials in a single-annealing step. Furthermore the as prepared ceramics are sintered at 200 K lower temperatures compared to conventionally used methods and exhibit excell...
متن کاملThermally Induced Coarsening of the Chemically Ordered Domains in Pb(Mg1/3Nb2/3)O3 (PMN)-Based Relaxor Ferroelectrics
The effect of different tetravalent octahedral-site substitutions (M 5 Zr, Tb, and Ce) on the stability of the 1;1 chemically ordered phase in Pb(Mg1/3Nb2/3)O3 (PMN) relaxor ferroelectrics were investigated using X-ray diffractometry and transmission electron microscopy. In their as-sintered form, all the samples adopted a phase-separated microstructure that consisted of nanosized 1;1 ordered d...
متن کاملStructure and Dielectric Properties of the Ba(Mg1/3Nb2/3)O3â•fiLa(Mg2/3Nb1/3)O3 System
A complete range of perovskite solid solutions can be formed in the (1 x)Ba(Mg1/3Nb2/3)O3–xLa(Mg2/ 3Nb1/3)O3 (BMN–LMN) pseudobinary system. While pure BMN adopts a 1:2 cation ordered structure, 1:1 ordered phases are stabilized for 0.05 ≤ x ≤ 1.0. Dark-field TEM images indicate that the La-doped solid solutions are comprised of large 1:1 ordered domains and no evidence was found for a phase-sep...
متن کامل