Heterogeneous grain-scale response in ferroic polycrystals under electric field

Daniels, John E.; Majkut, Marta; Cao, Qingua; Schmidt, Søren; Wright, Jonathan P.; Jo, Wook; Oddershede, Jette

doi:10.1038/srep22820

Cited by 30 publications

(22 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(b) was calculated for an average over a group of grains of similar orientation at a variety of group sizes. It was found that the RMS distance was halved for groups of 10 similarly oriented grains as compared to individual grains, which agrees well with our previous measurements of grain‐scale heterogeneity . The present work builds on this by combining the domain volume‐fraction information with the 3D microstructure grain map, reconstructed from the near‐field data and shown in Fig.…”

Section: Resultssupporting

confidence: 90%

“…It was found that the RMS distance was halved for groups of 10 similarly oriented grains as compared to individual grains, which agrees well with our previous measurements of grain-scale heterogeneity. 47 The present work builds on this by combining the domain volume-fraction information with the 3D microstructure grain map, reconstructed from the near-field data and shown in Figure 4 where individual grains are colored by the non-180°d omain switching strains at (a) e p,F0 and (b) e p,F2 , extracted from far-field data. The combination of these two results enables a correlative study of ferroelastic strain response with microstructural features of the grains themselves as well as their local neighborhoods.…”

Section: Strain Response Heterogeneitymentioning

confidence: 99%

See 1 more Smart Citation

Electromechanical Response of Polycrystalline Barium Titanate Resolved at the Grain Scale

et al. 2016

Self Cite

View full text Add to dashboard Cite

Ferroic materials are critical components in many modern devices. Polycrystalline states of these materials dominate the market due to their cost effectiveness and ease of production. Studying the coupling of ferroic properties across grain boundaries and within clusters of grains is therefore critical for understanding bulk polycrystalline ferroic behavior. Here, three-dimensional X-ray diffraction is used to reconstruct a 3D grain map (grain orientations and neighborhoods) of a polycrystalline barium titanate sample and track the grain-scale non-180°ferro-electric domain switching strains of 139 individual grains in situ under an applied electric field. The map shows that each grain is located in a very unique local environment in terms of intergranular misorientations, leading to local strain heterogeneity in the as-processed state of the sample. While primarily dependent on the crystallographic orientation relative to the field directions, the response of individual grains is also heterogeneous. These unique experimental results are of critical importance both when building the starting conditions and considering the validity of grain-scale modeling efforts, and provide additional considerations in the design of novel ferroic materials. K E Y W O R D Sdomains, microstructure, polycrystalline materials, X-ray methods

show abstract

Section: Resultssupporting

confidence: 90%

Section: Strain Response Heterogeneitymentioning

confidence: 99%

Electromechanical Response of Polycrystalline Barium Titanate Resolved at the Grain Scale

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…For example, powder diffraction measurements of BaTiO3 typically identify the average crystal symmetry at room temperature as tetragonal, not triclinic [31]. However, grain-scale mechanical interactions may locally break the crystal symmetry inferred from the powder-averaged aggregate [32]. Figures 2 and 3 show the topological origin of this anomaly; strain gradients in many directions that, when averaged over many grains within the aggregate, result in isotropic peak broadening and diffuse scattering that obscures the true local symmetry.…”

Section: Correlating Strain Symmetry and Functional Responsementioning

confidence: 99%

Long-range symmetry breaking in embedded ferroelectrics

et al. 2018

Self Cite

View full text Add to dashboard Cite

The characteristic functionality of ferroelectric materials is due to the symmetry of their crystalline structure. As such, ferroelectrics lend themselves to design approaches that manipulate this structural symmetry by introducing extrinsic strain. Using in situ dark-field X-ray microscopy to map lattice distortions around deeply embedded domain walls and grain boundaries in BaTiO, we reveal that symmetry-breaking strain fields extend up to several micrometres from domain walls. As this exceeds the average domain width, no part of the material is elastically relaxed, and symmetry is universally broken. Such extrinsic strains are pivotal in defining the local properties and self-organization of embedded domain walls, and must be accounted for by emerging computational approaches to material design.

show abstract

“…11,14 The magnitude of this compliance or intergranular coupling effect, as well as its influence on the macroscopic strain properties, is not thoroughly understood. It has also been demonstrated that the magnitude of the electric-field-induced strain response in phase change piezoelectric ceramics is highly heterogeneous at the grain scale, 15 adding further evidence to the importance of understanding the coupling of properties between grains. These local compliance effects are expected to vary the response of the polycrystalline microstructure under different constraint conditions.…”

mentioning

confidence: 99%

The effect of inter-granular constraints on the response of polycrystalline piezoelectric ceramics at the surface and in the bulk

Hossain

Wang

Khansur

et al. 2016

Applied Physics Letters

Self Cite

View full text Add to dashboard Cite

The electro-mechanical coupling mechanisms in polycrystalline ferroelectric materials, including a soft PbZrxTi1−xO3 (PZT) and lead-free 0.9375(Bi1/2Na1/2)TiO3-0.0625BaTiO3 (BNT-6.25BT), have been studied using a surface sensitive low-energy (12.4 keV) and bulk sensitive high-energy (73 keV) synchrotron X-ray diffraction with in situ electric fields. The results show that for tetragonal PZT at a maximum electric field of 2.8 kV/mm, the electric-field-induced lattice strain (ε111) is 20% higher at the surface than in the bulk, and non-180° ferroelectric domain texture (as indicated by the intensity ratio I002/I200) is 16% higher at the surface. In the case of BNT-6.25BT, which is pseudo-cubic up to fields of 2 kV/mm, lattice strains, ε111 and ε200, are 15% and 20% higher at the surface, while in the mixed tetragonal and rhombohedral phases at 5 kV/mm, the domain texture indicated by the intensity ratio, I111/I111¯ and I002/I200, are 12% and 10% higher at the surface than in the bulk, respectively. The observed difference in the strain contributions between the surface and bulk is suggested to result from the fact that surface grains are not constrained in three dimensions, and consequently, domain reorientation and lattice expansion in surface grains are promoted. It is suggested that the magnitude of property difference between the surface and bulk is higher for the PZT than for BNT-6.25BT due to the level of anisotropy in the strain mechanism. The comparison of the results from different methods demonstrates that the intergranular constraints have a significant influence on the electric-field-induced electro-mechanical responses in polycrystalline ferroelectrics. These results have implications for the design of higher performance polycrystalline piezoelectrics.

show abstract

Heterogeneous grain-scale response in ferroic polycrystals under electric field

Cited by 30 publications

References 36 publications

Electromechanical Response of Polycrystalline Barium Titanate Resolved at the Grain Scale

Electromechanical Response of Polycrystalline Barium Titanate Resolved at the Grain Scale

Long-range symmetry breaking in embedded ferroelectrics

The effect of inter-granular constraints on the response of polycrystalline piezoelectric ceramics at the surface and in the bulk

Contact Info

Product

Resources

About