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Textured process is considered an effective way to enhance the performance of piezoelectric ceramics. To obtain lead-free piezoelectric KNN-based ceramics with high performance, ⟨001⟩c-textured lead-free piezoelectric 0.915(K0.45Na0.5Li0.05)–0.075BaZrO3–0.01Bi0.5Na0.5TiO3 (KNLN–BZ–BNT) ceramics with the addition of 5 mol. % NaNbO3 templates were prepared, and the improved piezoelectric properties and thermal stability were expectedly achieved. For textured ceramics, the textured degree is one of the very important parameters and strongly depends on the amount of templates. Therefore, in this work, the effect of the amount of templates on the textured degree and electrical properties of ⟨001⟩c-textured KNLN–BZ–BNT ceramics were investigated in detail. It was found that the templates take a positive effect when the template amount is low, in which the textured degree and electrical properties increased with the amount of templates. In contrast, excess templates could induce a severe shift of stoichiometry within the textured ceramics, accompanied by degraded performances. As a result, for the ceramics with template amount less than 4 mol. %, enhanced textured degree and electrical properties were obtained. When the template amount exceeds 5 mol. %, the textured degree and electrical properties become degraded. The textured ceramic with the 4 mol. % template shows the highest textured degree of 93% and the highest piezoelectric constants of d33 = 360 pC/N and d 33 ∗ = 615 pm/V. Combining a vertical morphotropic phase boundary with an appropriate template amount of 4 mol. %, the ceramics exhibit superior thermal stability within the temperature range of 30–200 °C. [ABSTRACT FROM AUTHOR]

We investigated the effects of alternating current poling (ACP) on the piezoelectric and dielectric properties of 3-MHz sliver mode (L13 mm $\times $ W0.10–0.25 mm $\times $ T0.48 mm) vibrators fashioned from Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (PMN-0.30PT) single crystal (SC) plate manufactured using the continuous-feeding Bridgman (CF-BM) method for cardiac probes. The ACP SC plate (L13 mm $\times $ W24 mm $\times $ T0.48 mm) exhibited ultrahigh dielectric permittivity ($\varepsilon ^{T}_{33}/\varepsilon _{0}$) and piezoelectric coefficient (${d}_{33}$) of 9690 and 2920 pC/N, respectively. After array dicing, the SC slivers with widths of 0.10, 0.15, 0.20, and 0.25 mm were obtained, and their average $\varepsilon ^{T}_{33}/\varepsilon _{0}$ values decreased from the SC plate $\varepsilon ^{T}_{33}/\varepsilon _{0}$ by 45% (5330), 29% (6880), 19% (7840), and 15% (8240), respectively, possibly because of heat and mechanical damage during the dicing. A combination of the ACP and a postdicing direct current poling (ACP-DCP) recovered their $\varepsilon ^{T}_{33}/\varepsilon _{0}$ values to 6050, 7080, 8140, and 8540, respectively. The sliver mode electromechanical coupling factors (${k}'_{33}$) were confirmed to exceed 93% after the ACP-DCP process, which were more than 4% higher than those of DCP-DCP SC slivers. The measured impedance spectra indicated that the SC slivers with 0.10–0.20 mm in width showed no spurious mode vibration near the fundamental ${k}'_{33}$ mode. We conclude that the ACP-DCP SC slivers maintained more enhanced piezoelectric and dielectric properties than the DCP-DCP samples. These results will have important implications for the commercial application of ACP technology to medical imaging ultrasound probes. [ABSTRACT FROM AUTHOR]

With the great success on verifying its effectiveness on relaxor-PbTiO3 (PT) single crystals (SCs), alternating current poling (ACP) has been taking a center as a new domain engineering method in the last few years. Compared with the conventional direct current poling (DCP), ACP enables enhanced piezoelectric and dielectric properties. In this article, research progress in ACP and perspectives are introduced. Initially, optimized conditions of ACP for relaxor-PT SCs and unsolved issues on polycrystalline ceramics and spurious modes are reviewed. Second, the ferroelectric domain size dependence of piezoelectricity associated with ACP is discussed. We hypothesize that a tradeoff between domain and domain wall contributions exists for high piezoelectricity, suggesting an optimum 109° domain wall size, which is presumably dependent on compositions, crystallographic symmetries, and domain configurations. Finally, crystals synthesized by a solid-state crystal growth (SSCG) method are briefly introduced due to their unprecedented piezoelectricity obtained by ACP (${d}_{33} \sim 5500$ pC/N). We hope that this work helps to grasp the current status of ACP and to guide future tasks to be studied. [ABSTRACT FROM AUTHOR]

Summary: With the rapid development of electronic industry, the miniaturization and integration of components have become an irreversible development trend, which puts forward high requirements for lead‐free ceramic materials with excellent recoverable energy storage density and efficiency. In addition, it is also a great challenge to sustain excellent energy storage performance under different environmental conditions. In this work, a combined design strategy was proposed to induce polar nano regions and reduce grain size by introducing SrTi0.5Zr0.5O3 (STZ). The addition of STZ reduced the grain size to submicron level, accompanied by relaxation enhancement. The high energy storage properties (Wrec = 1.85 J/cm3, η = 65.92%) were achieved in 0.80Bi0.5Na0.5TiO3‐0.20SrTi0.5Zr0.5O3 (BNT‐STZ) ceramics at 150 kV/cm. Excellent temperature stability (40°C‐160°C) and frequency stability (1‐500 Hz) of energy storage performance have been obtained under 100 kV/cm, with the fluctuations below 8%. Importantly, A high power density of 3.64 MW/cm3 and a transitory discharge time (t0.9 ~ 0.632 μs) were achieved for 0.80BNT‐0.20STZ ceramic under 160 kV/cm. These characteristics indicate that 0.80BNT‐0.20STZ ceramic is expected to be applied in high‐power equipment. Highlights: A combined design strategy was proposed to induce polar nano regions and reduce grain size by introducing STZ.0.80BNT‐0.20STZ ceramic possesses a recoverable energy density of 1.85 J/cm3 and efficiency of 65.92%.0.80BNT‐0.20STZ ceramic exhibits good electrical stability in wide frequency (1‐500 Hz) and temperature range (40‐160°C).A high power density (PD) of 3.64 MW/cm3 and a transitory discharge time (t0.9 ~ 0.632 μs) can be achieved. [ABSTRACT FROM AUTHOR]

Various 2 inch SmxY1−xCa4O(BO3)3 (SmxY1−xCOB) crystals with good quality were grown successfully along the <010> axis by the Czochralski method. As the amount added increased, the unit cell dimensions for the obtained crystals were found to increase. At room temperature, the relative dielectric constants ε E11 /ε0, ε E22 /ε0 and ε E33 /ε0 were found to be 9.57, 11.87 and 9.58 for Sm0.05Y0.95COB, 9.66, 12.33 and 9.64 for Sm0.3Y0.7COB, 9.70, 12.78 and 9.75 for Sm0.5Y0.5COB, and 9.73, 14.10 and 10.14 for Sm0.75Y0.25COB, respectively. The electromechanical coupling factors and piezoelectric coefficients as a function of Sm content were studied, with maximum values found in the Sm0.75Y0.25COB crystal. All the as-grown crystals were observed to possess ultrahigh resistivities, and the values of the electrical resistivities of SmxY1−xCOB were approximately 1.1–3.1 × 108 Ω cm at 850 °C. In the range of the test temperature, the dielectric losses for the SmxY1−xCOB crystals were determined to be less than 45% at 840 °C, which together with the high thermal stability of the electromechanical and piezoelectric properties, with a variation of less than 5.5% at 850 °C, make the SmxY1−xCOB crystals important candidate materials for high-temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

This paper describes experimental trials that were performed to increase the electrorheological (ER) effect in ER fluids (ERFs) by introducing piezoelectric particles (PEPs). Five sample solutions were made using different PEPs, ER powders, and liquids that included ERFs provided with different solutions and silicone oil. The shear stress of each sample was measured by shearing the sample between parallel plate electrodes. Samples containing the PEP showed the same shear stress under steady voltage inputs but showed somewhat higher shear stress under sinusoidal voltage inputs. This suggests that mixtures of the piezoelectric powders (at approximately 5 wt.%) and the ERF may shorten the response time of the ERF to DC inputs or increase the response frequency to AC inputs. [ABSTRACT FROM AUTHOR]