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The development of ferroelectric ceramics with both large piezoelectric responses and broad service temperature range is still a key challenge for practical applications due to the so-called d 33 - T C trade-off. Here we report the strategy to utilize the synergistic contribution of morphotropic phase boundary and enhanced local structural heterogeneity, in which an excellent piezoelectric coefficient d 33 of 680 pC/N and a high Curie temperature of 330 ℃ are simultaneously achieved in Sm modified 0.25PIN-0.325PZ-0.425PT ceramics. The underlying mechanism responsible for the high dielectric and piezoelectric properties is studied based on cryogenic dielectric measurement and Rayleigh analysis. Of particular interest is that, a high field-induced strain of 0.19% is achieved in 0.25PIN-0.32PZ-0.43PT at electric field of 20 kV/cm, corresponding to a piezoelectric d 33 * of 945 pm/V, showing an excellent temperature stability with minimal variation of 7% up to 310 °C. This work demonstrates the introduction of high temperature end members and rare earth doping are conducive to ferroelectric solid solutions with desired broad usage temperature range and superior piezoelectric properties, which will greatly benefit high temperature actuator applications. [ABSTRACT FROM AUTHOR]

There is a great demand to develop ferroelectric ceramics with both high piezoelectric coefficient and broad temperature usage range for emerging electromechanical applications. Herein, a series of Sm3+‐doped 0.25Pb(Mg1/3Nb2/3)O3‐(0.75−x)PbZrO3‐xPbTiO3 ceramics were fabricated by solid‐state reaction method. The phase structure, dielectric and piezoelectric properties were investigated, where the optimum piezoelectric coefficient d33 = 745 pC/N and electromechanical coupling factor k33 = 0.79 were obtained at the morphotropic phase boundary composition x = 0.39, with good Curie temperature TC of 242°C. Of particular importance is that high‐temperature stability of the piezoelectric and field‐induced strain was obtained over the temperature range up to 230°C for the tetragonal compositions of x = 0.40. The underlying mechanism responsible for the high piezoelectricity and temperature stability is the synergistic contribution of the MPB and local structural heterogeneity, providing a good paradigm for the design of high‐performance piezoelectric materials to meet the challenge of piezoelectric applications at elevated temperature. [ABSTRACT FROM AUTHOR]

In this study, Sm 3+ doped Na 0.5 La 0.5 Bi 8- x Sm x Ti 7 O 27 (NBT-BITL- x Sm, x = 0, 0.01, 0.015, 0.02, and 0.03) ceramics were synthesized via a conventional solid-state reaction process. The structural, electrical, and photoluminescence properties of NBT-BITL- x Sm ceramics were systematically investigated. The crystal structure of NBT-BITL- x Sm was refined using XRD Rietveld refinement and found to possess a single orthorhombic structure at room temperature. Raman spectroscopy revealed that Sm 3+ ions preferred to substitute for Bi 3+ located in the A-sites of pseudo-perovskite layers, inducing a slight decrease in orthorhombic distortion. Strong characteristic emission peaks of Sm 3+ ions were observed in orange-red regions under a 407 nm laser source, and the sample with x = 0.015 achieved the optimal photoluminescent property. Dielectric measurements showed double anomaly permittivity peaks at the temperature of 589 and 600 ∘ C ( T m and T c , respectively). The complex impedance spectrum indicated that the electrical conductivities mainly originated from crystal grains at high temperature. The activation energy was calculated to be 1.37–1.44 e V from Arrhenius fitting results. After Sm 3+ substitution, the activation energy for conductivity was increased as a result of reduced oxygen vacancies. [ABSTRACT FROM AUTHOR]

Rare earth (Eu3+)‐modified Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) polycrystalline ferroelectric ceramics were fabricated by high‐temperature solid‐state sintering, the phase structure, dielectric and piezoelectric properties were investigated. Eu3+ addition was found to significantly improve dielectric and piezoelectric properties of PMN‐PT, where the optimized properties were achieved for the composition of 2.5 mol%Eu: 0.72PMN‐0.28PT, with the piezoelectric d33 = 1420 pC/N, dielectric εr = 12 200 and electromechanical k33 = 0.78, respectively. All these results indicate that the Eu3+‐doped PMN‐PT ceramics are promising candidates for high‐performance room‐temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]