Polar Anisotropy and Inter-Ferroelectric Transitions in Barium Titanate and its Solid Solutions

Heitmann, A. A.; Rossetti, George A.

doi:10.1080/10584587.2011.575018

Cited by 13 publications

(10 citation statements)

References 22 publications

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“…Moreover, as shown in Fig. 1b, this M C phase is thermodynamically stabilized in significant volume fractions (20-60%) over a wide temperature range of over 100 K. This intriguing reduction of the polar anisotropy 40 is illustrated by the domain structure in Fig. 1c, which reveals a persistent network of bulk M C regions at room temperature (298 K).…”

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confidence: 76%

Thermotropic phase boundaries in classic ferroelectrics

et al. 2014

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High-performance piezoelectrics are lead-based solid solutions that exhibit a so-called morphotropic phase boundary, which separates two competing phases as a function of chemical composition; as a consequence, an intermediate low-symmetry phase with a strong piezoelectric effect arises. In search for environmentally sustainable lead-free alternatives that exhibit analogous characteristics, we use a network of competing domains to create similar conditions across thermal inter-ferroelectric transitions in simple, lead-free ferroelectrics such as BaTiO 3 and KNbO 3 . Here we report the experimental observation of thermotropic phase boundaries in these classic ferroelectrics, through direct imaging of low-symmetry intermediate phases that exhibit large enhancements in the existing nonlinear optical and piezoelectric property coefficients. Furthermore, the symmetry lowering in these phases allows for new property coefficients that exceed all the existing coefficients in both parent phases. Discovering the thermotropic nature of thermal phase transitions in simple ferroelectrics thus presents unique opportunities for the design of 'green' high-performance materials.

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confidence: 76%

Thermotropic phase boundaries in classic ferroelectrics

et al. 2014

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“…, it should be noted that, unlike lead titanate, the temperature dependencies of the sextic terms are expected to be important in barium titanate . To maintain consistency with the approximation used for the lead‐based systems, this was not taken account here . Nonetheless, as seen in Fig.…”

Section: Application To Binary and Ternary Morphotropic Systemsmentioning

confidence: 99%

Thermodynamics of Ferroelectric Solid Solutions with Morphotropic Phase Boundaries

2014

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A thermodynamic analysis is presented for the diffusionless phase diagrams of ferroelectric solid solutions that display a morphotropic phase boundary (MPB) separating adjacent tetragonal and rhombohedral phases. Equations are developed for the shape of the MPB, the locations of triple and tricritical points, and for the line along which the anisotropy of polarization vanishes. The appearance of lower symmetry orthorhombic and monoclinic phases is considered and the topologies of energy surfaces in the region of the phase diagram where these phases may stabilize are illustrated. The theory is applied to the solid solution of lead zirconate with lead titanate (PZT) and relationships between polar anisotropy and the transformation strain, dielectric susceptibility and piezoelectric properties, are discussed. The analysis is used to reproduce phase boundary lines for solid solutions of lead titanate with lead magnesium niobate (PMN‐PT) and lead zinc niobate (PZN‐PT) and composition–temperature diagrams along isopleths in the ternary system PMN‐PZT are estimated. The anisotropies of polarization in solid solutions based on lead titanate and barium titanate are contrasted. The results provide a thermodynamic framework useful for guiding experimental investigations of ferroelectric solid solutions and for generating energy functions used in constitutive modeling and phase field simulations of microstructure and properties.

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“…[1,2]. Thus, ferroelectric solid solutions come into picture since the change in composition in these systems influences properties such as Curie temperature and Curie constant thereby affecting ferroelectric transitions [4]. The evolution of domains in these systems is intricately governed by the complex interplay of ferroelastic and ferroelectric interactions which arise due to the presence of the primary ferroic orders in the systems.…”

Section: Introductionmentioning

confidence: 99%

A phase-field study of domain dynamics in ferroelectric BCT-BZT system

et al. 2016

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We present a thermodynamically consistent phase-field model describing the free energy of perovskite-based BCT-BZT solid solution containing an intermediate morphotropic phase boundaries. The Landau coefficients are derived as functions of composition of zirconium. The electrostrictive and elastic constants are appropriately chosen from experimental findings. The resulting Landau free energy is constructed to describe the stable polarization states as a function of composition. The evolution of the polarization order parameters at a particular composition is described by a set of time-dependent Ginzburg-Landau (TDGL) equations. Additionally, we solve Poisson's equation and mechanical equilibrium equation to account for the ferroelectric/ferroelastic interactions. We have performed two dimensional and three-dimensional simulations with appropriate electrical boundary conditions to study the effect of external electric field on domain dynamics in BCT-BZT system at the equimolar composition.

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Polar Anisotropy and Inter-Ferroelectric Transitions in Barium Titanate and its Solid Solutions

Cited by 13 publications

References 22 publications

Thermotropic phase boundaries in classic ferroelectrics

Thermotropic phase boundaries in classic ferroelectrics

Thermodynamics of Ferroelectric Solid Solutions with Morphotropic Phase Boundaries

A phase-field study of domain dynamics in ferroelectric BCT-BZT system

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