Nonlinear Optical Properties and Ferroelectric Phase Transition of LaBGeO5
Ferroelectrics Taylor & Francis 389:1 (2009) 125-131
Publisher's Note: Crystal structure of the rhombohedral phase of PbZr1−xTixO3 ceramics at room temperature [Phys. Rev. B 80, 104109 (2009)]
Physical Review B American Physical Society (APS) 80:13 (2009) 139902
Crystal structure of the rhombohedral phase of PbZr1-x Tix O3 ceramics at room temperature
Physical Review B - Condensed Matter and Materials Physics 80:10 (2009)
Abstract:
PbZr1-x Tix O3 (PZT) ceramics made by mixed-oxide and sol-gel routes within the rhombohedral region of the phase diagram have been prepared, and their structures determined by Rietveld refinement using high-resolution time-of-flight neutron diffraction. Different structural models have been used but the best fits have been found using a mixture of rhombohedral R3c (C 3v 6) and monoclinic Cm (Cs3) across the whole rhombohedral range with the proportion of monoclinic phase increasing continuously with composition x toward the morphotropic phase boundary. Some differences are found between the ceramics prepared by the two routes, especially with respect to the diffraction peak widths, suggesting that the precise structural arrangements in these materials depend on the method of preparation. The results show that PZT ceramics made in this region always consist of mixed phases and this accounts for the fact that no phase boundary has been discovered in the PZT phase diagram between the monoclinic and rhombohedral phases. © 2009 The American Physical Society.A comprehensive study of the phase diagram of Kx Na 1-x NbO3
Applied Physics Letters 95:9 (2009)
Abstract:
The phase diagram of lead-free piezoelectric Kx Na1-x NbO3 has been studied, with particular focus on the proposed morphotropic phase boundaries, by powder and single crystal x-ray diffraction. The tilt system and cation displacement has been mapped out as a function of temperature and composition, highlighting changes in the oxygen octahedra at x=0.2 and x=0.4 at room temperature. The orthorhombic to monoclinic boundary at x=0.5 has been investigated, with a subtle change in the structure observed. The conclusion is that Kx Na1-x NbO3 does not display a morphotropic phase boundary comparable with that in lead zirconate titanate, and that the most significant structural change as a function of composition occurs at x=0.2 because of the change of the tilt system. © 2009 American Institute of Physics.Structures of K(0.05)Na(0.95)NbO3 (50-300 K) and K(0.30)Na(0.70)NbO3 (100-200 K).
Acta Crystallogr B 65:Pt 3 (2009) 291-299