ORCID Profile
0000-0001-9409-1334
Current Organisation
Nanchang University
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Publisher: Elsevier BV
Date: 03-2022
Publisher: AIP Publishing
Date: 16-12-2019
DOI: 10.1063/1.5126987
Abstract: Coupling between polarization and the strain gradient, namely, flexoelectricity, is a universal phenomenon that widely exists in all solid dielectrics and polymers. At a low level of the applied strain gradient, this electromechanical coupling is strictly a linear effect. In this Letter, a strong nonlinearity between the polarization and the strain gradient was experimentally found in polyvinylidene fluoride when the strain gradient was higher than a material-dependent threshold value. Such nonlinear behavior was in good accordance with an ion chain theory and could be fitted by a nonlinear equation. The observed flexoelectric nonlinearity in this work will help in the understanding of the discrepancy between the previous findings about the bulk materials and their nanoscale counterparts.
Publisher: AIP Publishing
Date: 04-05-2021
DOI: 10.1063/5.0048925
Abstract: The recently discovered large flexoelectricity in relaxor ferroelectrics has rekindled considerable research interest. In this paper, several Sm-doped Pb(Mg2/3Nb1/3)O3–xPbTiO3 (PMN–xPT) ferroelectric ceramics were prepared and the relationship between flexoelectricity and PT content was systematically investigated. The largest flexoelectric response (∼550 μC/m) was observed in the Sm-doped PMN–32PT ceramic, which should be accounted for in the reorientation of the polar nanoregions. At room temperature, the flexoelectric response of Sm-doped PMN–32PT ceramic is an order of magnitude higher than that of the parent PMN–PT ceramics and even 50% higher than that of Bi–PMN–32PT ceramic (∼300 μC/m). Such a big increment is directly related to the greater local structural heterogeneity caused by Sm3+ ions into PMN–PT. Therefore, the result presented in this paper verifies that introducing local structural heterogeneity is a feasible approach to achieve ultrahigh flexoelectricity.
Publisher: American Physical Society (APS)
Date: 20-07-2022
Publisher: Springer Science and Business Media LLC
Date: 20-04-2020
Publisher: AIP Publishing
Date: 07-11-2022
DOI: 10.1063/5.0097238
Abstract: Flexoelectricity of semiconductors usually exhibits large flexoelectric coefficients due to their significantly enhanced surface piezoelectricity caused by surface symmetry breaking. In this Letter, we reported a general paradigm to tune the semiconductor flexoelectricity through interface engineering. We selected Nb-SrTiO3 (Nb-STO) single crystals as the targets and tuned their surface piezoelectricity through depositing TiO2-terminated and SrO-terminated ultra-thin BaTiO3 (BTO) films. The results suggested that the deposition of TiO2-terminated and SrO-terminated ultra-thin BaTiO3 films to Nb-STO can induce a downward and upward out-of-plane surface polarization, respectively, thereby significantly increasing/decreasing the apparent flexoelectric coefficients of Nb-STO single crystals. Our work proves the feasibility of interface engineering in the application of flexoelectricity and also provides a possible route to achieve the large apparent flexoelectricity of semiconductor materials.
Publisher: American Physical Society (APS)
Date: 07-12-2022
Publisher: AIP Publishing
Date: 30-09-2019
DOI: 10.1063/1.5115561
Abstract: Flexoelectricity yields electric polarization through graded strains and exists in various kinds of solid dielectrics but usually with a weak coupling response. In this letter, several Bi-doped Pb(Mg2/3Nb1/3)O3-xPbTiO3 (PMN-xPT) ferroelectric ceramics were prepared and the interplay of their piezoelectricity and flexoelectricity was systematically investigated. The largest flexoelectric response (∼300 μC/m) was 30 times larger than that of pure PMN-PT and was observed in the Bi-doped PMN-32PT, where the after poling piezoelectric coefficients were also the largest (990 pC/N) among all the compositions. This suggests that the apparent flexoelectricity in ferroelectrics is highly related to the bulk piezoelectricity. Therefore, introducing a local structural heterogeneity is considered as a feasible approach to achieve an ultrahigh piezoelectric response while also providing an ultrahigh flexoelectricity.
Publisher: AIP Publishing
Date: 08-07-2022
DOI: 10.1063/5.0087676
Abstract: Significant flexoelectricity is expected to exist in materials with colossal permittivity. Here, we systematically studied the interplay of flexoelectricity and permittivity in CaCu3Ti4O12 (CCTO) ceramic by examining the thickness and electrode dependence of the flexoelectric coefficients over a wide range of temperatures. We found that an abnormal flexoelectric transition occurs at 95 °C. Below this critical temperature, the barrier layer mechanism dominates the significant flexoelectricity in CCTO ceramic, whereas above this critical temperature, the flexoelectric response mainly originates from the contributions of semiconducting grains and insulating grain boundaries. The observed flexoelectric transition is beneficial not only for developing new materials with high flexoelectric coefficients but also for understanding the colossal permittivity mechanism in CCTO ceramics.
No related grants have been discovered for Zhiguo Wang.