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  1. A dual energy harvester based upon the magnetoelectric mechanism is reported. The harvester can generate ∼52.1 mW under simultaneously applied magnetic field and ultrasound in porcine tissue operating under safety limits.

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    Free, publicly-accessible full text available March 19, 2025
  2. Free, publicly-accessible full text available August 1, 2024
  3. Abstract

    Electromechanical coupling factor,k, of piezoelectric materials determines the conversion efficiency of mechanical to electrical energy or electrical to mechanical energy. Here, we provide an fundamental approach to design piezoelectric materials that provide near-ideal magnitude ofk, via exploiting the electrocrystalline anisotropy through fabrication of grain-oriented or textured ceramics. Coupled phase field simulation and experimental investigation on <001> textured Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3ceramics illustrate thatkcan reach same magnitude as that for a single crystal, far beyond the average value of traditional ceramics. To provide atomistic-scale understanding of our approach, we employ a theoretical model to determine the physical origin ofkin perovskite ferroelectrics and find that strong covalent bonding between B-site cation and oxygen viad-phybridization contributes most towards the magnitude ofk. This demonstration of near-idealkvalue in textured ceramics will have tremendous impact on design of ultra-wide bandwidth, high efficiency, high power density, and high stability piezoelectric devices.

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  4. null (Ed.)
  5. Abstract

    Piezoelectric materials should simultaneously possess the soft properties (high piezoelectric coefficient,d33; high voltage coefficient,g33; high electromechanical coupling factor,k) and hard properties (high mechanical quality factor,Qm; low dielectric loss, tan δ) along with wide operation temperature (e.g., high rhombohedral–tetragonal phase transition temperatureTr–t) for covering off‐resonance (figure of merit (FOM),d33 ×g33) and on‐resonance (FOM,Qm ×k2) applications. However, achieving hard and soft piezoelectric properties simultaneously along with high transition temperature is quite challenging since these properties are inversely related to each other. Here, through a synergistic design strategy of combining composition/phase selection, crystallographic texturing, defect engineering, and water quenching technique, <001> textured 2 mol% MnO2doped 0.19PIN‐0.445PSN‐0.365PT ceramics exhibiting giant FOM values ofQm × (227–261) along with highd33 ×g33(28–35 × 10−12m2N−1), low tan δ (0.3–0.39%) and highTr–tof 140–190 °C, which is far beyond the performance of the state‐of‐the‐art piezoelectric materials, are fabricated. Further, a novel water quenching (WQ) room temperature poling technique, which results in enhanced piezoelectricity of textured MnO2doped PIN‐PSN‐PT ceramics, is reported. Based upon the experiments and phase‐field modeling, the enhanced piezoelectricity is explained in terms of the quenching‐induced rhombohedral phase formation. These findings will have tremendous impact on development of high performance off‐resonance and on‐resonance piezoelectric devices with high stability.

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  6. Abstract

    Piezoelectric materials enable the conversion of mechanical energy into electrical energy and vice‐versa. Ultrahigh piezoelectricity has been only observed in single crystals. Realization of piezoelectric ceramics with longitudinal piezoelectric constant (d33) close to 2000 pC N–1, which combines single crystal‐like high properties and ceramic‐like cost effectiveness, large‐scale manufacturing, and machinability will be a milestone in advancement of piezoelectric ceramic materials. Here, guided by phenomenological models and phase‐field simulations that provide conditions for flattening the energy landscape of polarization, a synergistic design strategy is demonstrated that exploits compositionally driven local structural heterogeneity and microstructural grain orientation/texturing to provide record piezoelectricity in ceramics. This strategy is demonstrated on [001]PC‐textured and Eu3+‐doped Pb(Mg1/3Nb2/3)O3‐PbTiO3(PMN‐PT) ceramics that exhibit the highest piezoelectric coefficient (small‐signald33of up to 1950 pC N–1and large‐signald33* of ≈2100 pm V–1) among all the reported piezoelectric ceramics. Extensive characterization conducted using high‐resolution microscopy and diffraction techniques in conjunction with the computational models reveals the underlying mechanisms governing the piezoelectric performance. Further, the impact of losses on the electromechanical coupling is identified, which plays major role in suppressing the percentage of piezoelectricity enhancement, and the fundamental understanding of loss in this study sheds light on further enhancement of piezoelectricity. These results on cost‐effective and record performance piezoelectric ceramics will launch a new generation of piezoelectric applications.

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