A novel mechanism to reduce coercive field of ferroelectric materials via {1 1 1} twin engineering

Cao, Shigu; Wu, Hong; Ren, Hang; Chen, Lei; Wang, Jie; Li, Jiangyu; Zhang, Tong Yi

doi:10.1016/j.actamat.2015.07.009

Cited by 17 publications

(12 citation statements)

References 36 publications

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“…The previous work has proved that twins can be induced by stress at temperature 550 °C and the present experiment with TMT at 575 °C indicates that the h-phase plates are commonly found at the twinning sites. This might imply that the stress in TMT is able to produce twins and h-phase.…”

supporting

confidence: 62%

“…The BTO thin films were deposited and then treated by thermomechanical method (TMT) at 575 ± 1 °C (Figure ) by using the same experimental procedure as that reported before . There is a residual tensile biaxial stress of 112.5 MPa in the nanofilms before the TMT treatment.…”

Section: Methodsmentioning

confidence: 99%

“…The BTO thin films were deposited and then treated by thermomechanical method (TMT) at 575 ± 1 °C (Figure 2) by using the same experimental procedure as that reported before. 25 There is a residual tensile biaxial stress of 112.5 MPa in the nanofilms before the TMT treatment. The bending moments of −0.073, 0, and 0.073 N•M were applied to the T, R, and C samples, respectively, and maintained during the TMT treatment, as shown in Figure 2.…”

Section: Nano Lettersmentioning

confidence: 98%

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Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films

Cao

et al. 2017

Nano Lett.

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The strong coupling between crystal structure and mechanical deformation can stabilize low-symmetry phases from high-symmetry phases or induce novel phase transformation in oxide thin films. Stress-induced structural phase transformation in oxide thin films has drawn more and more attention due to its significant influence on the functionalities of the materials. Here, we discovered experimentally a novel stress-induced cubic-to-hexagonal phase transformation in the perovskite nanothin films of barium titanate (BaTiO) with a special thermomechanical treatment (TMT), where BaTiO nanothin films under various stresses are annealed at temperature of 575 °C. Both high-resolution transmission electron microscopy and Raman spectroscopy show a higher density of hexagonal phase in the perovskite thin film under higher tensile stress. Both X-ray photoelectron spectroscopy and electron energy loss spectroscopy does not detect any change in the valence state of Ti atoms, thereby excluding the mechanism of oxygen vacancy induced cubic-to-hexagonal (c-to-h) phase transformation. First-principles calculations show that the c-to-h phase transformation can be completed by lattice shear at elevated temperature, which is consistent with the experimental observation. The applied bending plus the residual tensile stress produces shear stress in the nanothin film. The thermal energy at the elevated temperature assists the shear stress to overcome the energy barriers during the c-to-h phase transformation. The stress-induced phase transformation in perovskite nanothin films with TMT provides materials scientists and engineers a novel approach to tailor nano/microstructures and properties of ferroelectric materials.

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supporting

confidence: 62%

Section: Methodsmentioning

confidence: 99%

Section: Nano Lettersmentioning

confidence: 98%

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Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films

Cao

et al. 2017

Nano Lett.

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“…Pt atoms can isolate Co nuclei and facilitate the formation of Co nanoclusters with a single magnetic domain, thereby resulting in the single-crystalline structure. 39 The TEM observations showed that the single-crystalline NW structure was very dominant but that some of the NWs contained GBs. To elucidate the effect of precursor concentration on the growth of Pt−Co NWs, different amounts of the Co precursor from 0 to 1.0 equiv were added to the Pt precursor according to the standard protocol for each NW structure.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…During the growth of the Pt–Co SC-NWs (Figure S11c,d), Pt played a particular role in determining the anisotropic deposition of Co nuclei in the ⟨110⟩ direction. Pt atoms can isolate Co nuclei and facilitate the formation of Co nanoclusters with a single magnetic domain, thereby resulting in the single-crystalline structure . The TEM observations showed that the single-crystalline NW structure was very dominant but that some of the NWs contained GBs.…”

Section: Resultsmentioning

confidence: 99%

Understanding the Grain Boundary Behavior of Bimetallic Platinum–Cobalt Alloy Nanowires toward Oxygen Electro-Reduction

et al. 2022

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Grain boundaries (GBs) are defects in crystal structures, which are in general known to be highly active toward various electrocatalytic reactions. Herein, we identify the adverse behaviors of the GBs for bimetallic platinum–cobalt (Pt–Co) nanocatalysts in the oxygen reduction reaction (ORR). As model catalysts, GB-rich Pt–Co nanowires (Pt–Co GB-NWs) and single-crystalline Pt–Co nanowires (Pt–Co SC-NWs) are synthesized. They have very similar diameters, Pt-to-Co ratios, and Pt-rich surface structures, except for the GB populations, which can be precisely controlled by applying an external magnetic field during their synthesis. The presence of GBs in Pt–Co NWs promotes Co leaching at an applied electrochemical potential, inducing significant changes in the surface Pt-to-Co ratio. The resulting Pt–Co GB-NWs perform only half the ORR activity compared with the Pt–Co SC-NWs. As a result, it is revealed that the surface GB sites are deactivated by causing elemental leaching and may not act as an ORR promoter for the Pt–Co nanowire catalyst.

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Complex morphotropic phase transformations and high piezoelectric properties in new ternary perovskite single crystals

Liu

Ren

et al. 2018

Acta Materialia

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A novel mechanism to reduce coercive field of ferroelectric materials via {1 1 1} twin engineering

Cited by 17 publications

References 36 publications

Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films

Stress-Induced Cubic-to-Hexagonal Phase Transformation in Perovskite Nanothin Films

Understanding the Grain Boundary Behavior of Bimetallic Platinum–Cobalt Alloy Nanowires toward Oxygen Electro-Reduction

Complex morphotropic phase transformations and high piezoelectric properties in new ternary perovskite single crystals

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