Stability of the monoclinic phase in the ferroelectric perovskitePbZr1−xTix

Abstract

Stability of the monoclinic phase in the ferroelectric perovskite PbZr1-xTixO3 Noheda, B.; Cox, D.E.; Shirane, G.; Guo, R.; Jones, B.; Cross, L.E. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Recent structural studies of ferroelectric PbZr 1Ϫx Ti x O 3 ͑PZT͒ with xϭ0.48, have revealed a monoclinic phase in the vicinity of the morphotropic phase boundary ͑MPB͒, previously regarded as the boundary separating the rhombohedral and tetragonal regions of the PZT phase diagram. In the present paper, the stability region of all three phases has been established from high-resolution synchrotron x-ray powder-diffraction measurements on a series of highly homogeneous samples with 0.42рxр0.52. At 20 K, the monoclinic phase is stable in the range 0.46рxр0.51, and this range narrows as the temperature is increased. A first-order phase transition from tetragonal to rhombohedral symmetry is observed only for xϭ0.45. The MPB, therefore, corresponds not to the tetragonal-rhombohedral phase boundary, but instead to the boundary between the tetragonal and monoclinic phases for 0.46рxр0.51. This result provides important insight into the close relationship between the monoclinic phase and the striking piezoelectric properties of PZT; in particular, investigations of poled samples have shown that the monoclinic distortion is the origin of the unusually high piezoelectric response of PZT.

Low-temperature superlattice in monoclinicPbZr0.52Ti0.48O3Noheda1, Wu2, Zhu3 2002Phys. Rev. BSelf Cite9120810View full textAdd to dashboardCite

“…However, recently, Ragini et al 10 have observed superlattice ͑sl͒ reflections at low temperatures by transmission-electron microscopy ͑TEM͒ that are not consistent with the M A phase. These sl reflections are also observed by neutron diffraction, 4,11,12 but are not seen in the x-ray-diffraction patterns. 3,10 The appearance of a superlattice is a common phenomenon in perovskites, related in most cases to the softening of one or more ⌫ 25 zone-corner ͑R-point͒ phonons, 13 which involves rotations of the oxygen octahedra.…”

“…Recently, a monoclinic ͑M͒ phase with space group ͑sg͒ Cm, has been discovered by x-ray powder diffraction at the MPB of PZT, [2][3][4] in between the rhombohedral ͑R͒ and tetragonal ͑T͒ phases, as shown in Fig. 1.…”

“…5 All the above is a clear indication of the very high anharmonicity of the energy potentials in PZT, which is also present in other related systems. 9 With decreasing temperatures PbZr 0.52 Ti 0.48 O 3 ͑PZT48͒ transforms from a cubic to a tetragonal phase at about 660 K, and from a tetragonal to a monoclinic phase at about 300 K. 3,4 X-ray diffraction reveals no further phase transformation down to 20 K. 3 The reported M A cell is rotated 45°a bout the c axis with respect to the tetragonal one and is double in volume, with a m Ӎb m Ӎa p ͱ2 and c m Ӎa p , with a p Ӎ4 Å being the length of the cubic cell. However, recently, Ragini et al 10 have observed superlattice ͑sl͒ reflections at low temperatures by transmission-electron microscopy ͑TEM͒ that are not consistent with the M A phase.…”

Dynamic origin of the morphotropic phase boundary: Soft modes and phase instability in0.68Pb(Mg1/3Nb2/3Cao1, Stock2, Xu3 et al. 2008Phys. Rev. B262150View full textAdd to dashboardCite

“…1 Historically, the excellent electromechanical properties of the closely related Pb͑Zr 1−x Ti x ͒O 3 ͑PZT͒ ceramics were attributed to the steep morphotropic phase boundary ͑MPB͒ that separates Ti-poor rhombohedral ͑R͒ and Ti-rich tetragonal ͑T͒ ferroelectric phases as a function of the Ti content x. 2 In 1997 Park and Shrout 3 conjectured that the ultrahigh strains they achieved in ͗001͘-oriented crystals of PMN-xPT and PZN-xPT, which exhibit similar MPBs, resulted from an R → T transition induced by an applied electric field E. However various intermediate monoclinic phases ͑M C , M A , and M B ͒, which provide a natural bridge connecting the R and T phases, have subsequently been reported near the MPB in both PZT ceramics [4][5][6] and in single crystals of PZN-xPT ͑Refs. 7-11͒ and PMN-xPT.…”

Elastic and anelastic relaxation behaviour of perovskite multiferroics I: PbZr0.53Ti0.47O3 (PZT)–PbFe0.5Nb0.5O3 (PFN)

“…This treats the average structures without consideration of the possibility that the tetragonal and monoclinic or tetragonal and rhombohedral phases coexist over some temperature interval near the MPB of PZT (e.g. [105,156,157]). MPB transitions are also known to be complicated by the possible presence of nanotwinning, as has considered in the context of adaptive structures (e.g.…”