<i>In situ</i>
 TEM observation of nanodomain mechanics in barium titanate under external loads

Sumigawa, Takashi; Hikasa, K.; Kusunose, Akihisa; Unno, Hiroki; Masuda, Kairi; Shimada, Takahiro; Kitamura, Takayuki

doi:10.1103/physrevmaterials.4.054415

Cited by 4 publications

(2 citation statements)

References 43 publications

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“…Otherwise, the nucleation and mobility of dislocations near the tip of a crack have a strong impact on the fracture mechanics of the material [ 7 ]. Furthermore, an in-depth understanding of dislocation dynamics and dislocation-induced elastic fields near traction-free boundaries [ 8 , 9 , 10 ] and grain boundaries [ 9 , 11 , 12 , 13 , 14 ], as well as the assessment of the boundary conditions used in the existing formulations [ 15 ] are critical to predicting the performance of advanced materials: they include gold nanowires [ 16 , 17 ], barium titanium nanomaterials [ 18 ], functionally graded materials [ 19 ], and other metallic and semiconductor materials [ 20 , 21 , 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Nonsingular Stress Distribution of Edge Dislocations near Zero-Traction Boundary

2022

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Among many types of defects present in crystalline materials, dislocations are the most influential in determining the deformation process and various physical properties of the materials. However, the mathematical description of the elastic field generated around dislocations is challenging because of various theoretical difficulties, such as physically irrelevant singularities near the dislocation-core and nontrivial modulation in the spatial distribution near the material interface. As a theoretical solution to this problem, in the present study, we develop an explicit formulation for the nonsingular stress field generated by an edge dislocation near the zero-traction surface of an elastic medium. The obtained stress field is free from nonphysical divergence near the dislocation-core, as compared to classical solutions. Because of the nonsingular property, our results allow the accurate estimation of the effect of the zero-traction surface on the near-surface stress distribution, as well as its dependence on the orientation of the Burgers vector. Finally, the degree of surface-induced modulation in the stress field is evaluated using the concept of the L2-norm for function spaces and the comparison with the stress field in an infinitely large system without any surface.

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Section: Introductionmentioning

confidence: 99%

Nonsingular Stress Distribution of Edge Dislocations near Zero-Traction Boundary

2022

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“…Various ferroelectric systems have been studied over the last decades, ranging from the common perovskite ferroelectrics, such as BaTiO 3 [ 16 , 17 , 18 , 19 ], multiferroic materials [ 20 , 21 ], such as BiFeO 3 [ 22 , 23 , 24 ] and hexagonal manganites [ 25 , 26 ], multilayered structures of different ferroelectrics [ 14 , 27 , 28 ] to ferroelectric polymers [ 29 , 30 , 31 , 32 ]. In the prototypical perovskite ferroelectrics, the spontaneous polarization originates from the off-center displacement of the transition metal cation at the center of the oxygen octahedron.…”

Section: Introductionmentioning

confidence: 99%

Monitoring Electrical Biasing of Pb(Zr0.2Ti0.8)O3 Ferroelectric Thin Films In Situ by DPC-STEM Imaging

et al. 2021

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Increased data storage densities are required for the next generation of nonvolatile random access memories and data storage devices based on ferroelectric materials. Yet, with intensified miniaturization, these devices face a loss of their ferroelectric properties. Therefore, a full microscopic understanding of the impact of the nanoscale defects on the ferroelectric switching dynamics is crucial. However, collecting real-time data at the atomic and nanoscale remains very challenging. In this work, we explore the ferroelectric response of a Pb(Zr0.2Ti0.8)O3 thin film ferroelectric capacitor to electrical biasing in situ in the transmission electron microscope. Using a combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and differential phase contrast (DPC)-STEM imaging we unveil the structural and polarization state of the ferroelectric thin film, integrated into a capacitor architecture, before and during biasing. Thus, we can correlate real-time changes in the DPC signal with the presence of misfit dislocations and ferroelastic domains. A reduction in the domain wall velocity of 24% is measured in defective regions of the film when compared to predominantly defect-free regions.

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Phase field study on the performance of artificial synapse device based on the motion of domain wall in ferroelectric thin films

Xiong

Liu

Chen

et al. 2021

Applied Physics Letters

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Artificial neural networks have gained intensive attention in recent years because of their potential in effectively reducing energy consumption and improving computation performance. Ferroelectric materials are considered to be promising candidates for artificial synapses because of their multiple and nonvolatile polarization states under external stimuli. Despite artificial ferroelectric synapses with multilevel states, long retention and fast switching speed have been reported, and some key fundamental issues, e.g., the influence of domain wall configuration and evolution on the performance of synapse behaviors, also remain unclear. In this work, we study the performance of artificial synapses based on the motion of 180° ferroelectric domain walls of stripe domain and cylinder domain in ferroelectric thin films via a dynamical phase field model. The results demonstrate that artificial synapses based on the stripe domain exhibit high linearity and symmetry in weight update under a weak electric field, compared with the cylinder domain. Based on such artificial synapses, the accuracy of an artificial neural network for the Modified National Institute of Standards and Technology handwritten digit recognition is over 92%. This work provides a domain-wall-based strategy to improve the weight updating linearity and symmetry of artificial synapse devices and the recognition accuracy of artificial neural networks.

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In situ TEM observation of nanodomain mechanics in barium titanate under external loads

Cited by 4 publications

References 43 publications

Nonsingular Stress Distribution of Edge Dislocations near Zero-Traction Boundary

Nonsingular Stress Distribution of Edge Dislocations near Zero-Traction Boundary

Monitoring Electrical Biasing of Pb(Zr0.2Ti0.8)O3 Ferroelectric Thin Films In Situ by DPC-STEM Imaging

Phase field study on the performance of artificial synapse device based on the motion of domain wall in ferroelectric thin films

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