Evidence against the polarization rotation model of piezoelectric perovskites at the morphotropic phase boundary

Abstract

The origin of the very large piezoelectric response observed in the vicinity of the morphotropic phase boundary (MPB) in perovskite lead zirconate titanate and related systems has been under intensive studies. Polarization rotation ideas are frequently invoked to explain the piezoelectric properties. It was recently reported that lead titanate undergoes a phase transformation sequence $P4mm\to Pm\to Cm\to R\bar{3}c$ at 10 K as a function of hydrostatic pressure [M. Ahart et al. Nature Letters. \textbf{451}, 545 (2008)]. We demonstrate that this interpretation is not correct by (i) simulating the reported diffraction patterns, and (ii) by density-functional theory computations which show that neither the $Pm$, $Cm$ nor $Pmm2$ phase is stable in the studied pressure range, and further show that octahedral tilting is the key stabilization mechanism under high pressure. Notes on a more general ground are given to demonstrate that a continuous phase transition between rhombohedral and tetragonal phases via intermediate monoclinic phase is not possible. Thus, two-phase co-existence in the vicinity of the phase transition region is probable and has an important role for electromechanical properties.

arXiv comment4 pages, 2 figures

References in corpus (4)

• Origin of the high piezoelectric response in PbZr(1-x)TixO3
• Pressure-Induced Anomalous Phase Transitions and Colossal Enhancement of Piezoelectricity in PbTiO${}_3$
• Phenomenological theory of phase transitions in highly piezoelectric perovskites
• Low-temperature phases in Pb(Zr0.52Ti0.48)O3: A neutron powder diffraction study

Cited by in corpus (5)

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• Phase transitions and ferroelectrics: revival and the future in the field
• High-pressure neutron study of the morphotropic PZT: phase transitions in a two-phase system
• X-ray and neutron scattering on disordered nanosize clusters: a case study of lead-zirconate-titanate solid solutions
• Phase transitions and thermal-stress-induced structural changes in a ferroelectric Pb(Zr0.80Ti0.20)O3 single crystal