Composition dependence of the diffuse scattering in the relaxor ferroelectric compound (1-x)Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3} (0{<=}x{<=}0.40)
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581 (Japan)
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8562 (United States)
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (Canada)
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)
We have used neutron diffraction to characterize the diffuse scattering in five single crystals of the relaxor ferroelectric (1-x)Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3} (PMN-xPT) with x=0, 10, 20, 30, and 40%. The addition of ferroelectric PbTiO{sub 3} modifies the well-known 'butterfly' and 'ellipsoidal' diffuse scattering patterns observed in pure PMN (x=0), which are believed to be associated with the presence of randomly oriented polar nanoregions. In particular, the anisotropy of the diffuse scattering diminishes as the PT content increases. The spatial correlation length {xi} along the [110] direction derived from the width of the diffuse scattering at room temperature increases from 12.6 A for PMN to 350 A for PMN-20%PT. In addition, the diffuse scattering intensity at q=0 grows and reaches a maximum value around the morphotropic phase boundary (MPB), which suggests that it is proportional to the dielectric susceptibility. Beyond x=30%, a concentration very close to the MPB, no diffuse scattering is observed below T{sub C}, and well-defined critical behavior appears near T{sub C}. By contrast, the diffuse scattering for x{<=}20% persists down to low temperatures, where the system retains an average cubic structure (T{sub C}=0). Finally, the anisotropic soft transverse optic (TO) modes observed in PMN are found to be isotropic for PMN-30%PT, which strongly suggests a connection between the anisotropic diffuse scattering and the TO modes.
- OSTI ID:
- 20853750
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 74, Issue 14; Other Information: DOI: 10.1103/PhysRevB.74.144107; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nanoscopic Study of the Polarization-Strain Coupling in Relaxor Ferroelectric and the Search for New Relaxor Materials for Transducer and Optical Applications
Symmetry of piezoelectric (1–x)Pb(Mg1/3Nb2/3)O₃-xPbTiO₃ (x=0.31) single crystal at different length scales in the morphotropic phase boundary region