High and temperature-insensitive piezoelectric performance in the lead-free Sm-doped BiFeO3–BaTiO3 ceramics with high Curie temperature

Large sensor piezoelectric constant (d₃₃ = 334 pC/N) and superior actuator piezoelectric constant (d₃₃* = 552 pm/V) as well as a high Curie temperature (T_C = 454 °C) were obtained simultaneously in the lead-free 0.67Bi_1.03FeO₃-0.33Ba_1-xSm_xTiO₃ ceramics. Such an excellent and temperature-insensitive piezoelectric performance with only 10% temperature variation of piezoelectric strain at the range of 25–125 °C is highly desirable for real applications. The structural origin of the enhanced piezoelectric performance is mainly attributed to the morphotropic phase boundary and the highest known tetragonality (c_T/a_T = 1.02) in such materials. Transmission electron microscopy and electro-mechanical phenomenological theory demonstrate that the superior d₃₃ and d₃₃* are associated with the hybrids nanodomains (60–90 nm) and flattened thermodynamic energy profile owing to the local structure heterogeneity. These results are superior as the piezoelectric properties are temperature-independent and the material has large d₃₃*, and high T_C compared to other lead-free piezoelectric ceramics.     

Nanodomains in KNN‐Based Lead‐Free Piezoelectric ceramics: Origin of Strong Piezoelectric Properties

Excellent piezoelectric properties of d₃₃* = 768 pm/V and strain = 0.07% at 1 kV/mm, were obtained by lead‐free in (Na_0.52K_0.4425Li_0.0375)(Nb_0.86Ta_0.06Sb_0.08)O₃ ceramics. They displayed good temperature stability up to 200°C. Significantly enhanced piezoelectricity originated from nanodomains of width 20–30 nm, and the result was confirmed by transmission electron microscopy. The above‐mentioned nanodomains emerged because of low domain wall energy near polymorphic phase transition regions and insignificant differences in cell parameters between orthorhombic and tetragonal phases. The nanodomain configuration easily responded to an external electric field, leading to high electric field‐induced strain.     

Electrocaloric behavior and piezoelectric effect in relaxor NaNbO3-based ceramics

We firstly reported the electrocaloric properties in relaxor (1−x−y)NaNbO₃–yBaTiO₃–xCaZrO₃ ceramics, and high electrocaloric effect (∆T ~0.451 K and∣∆T/∆E∣~0.282 Km/MV) can be realized in the ceramics (x = 0.04 and y = 0.10) under low temperature and low electric field. Relaxor behavior of NaNbO₃ ceramics can be found by doping both BaTiO₃ and CaZrO₃. In addition, optimized piezoelectric effects (d₃₃ ~235 pC/N and d₃₃* ~230 pm/V) can be observed in the ceramics (x = 0.04 and y = 0.10) due to the involved morphotropic phase boundary (MPB). Excellent piezoelectric effect (ie, d₃₃~330 pm/V at 41°C, and d₃₃*~332 pm/V at 60°C) can be found because of the characteristics of MPB. Good temperature reliability of piezoelectric effect can be shown because of both MPB and relaxor behavior. We believe that the ceramics with high electrocaloric effect and good piezoelectric effect can be considered as one of the most promising lead-free materials for piezoelectric devices.     

Tuning the ferroelectric-relaxor transition temperature in NBT-based lead-free ceramics by Bi nonstoichiometry

In this study, the Bi-nonstoichiometric 0.99Bi_x(Na_0.8K_0.2)_0.5TiO₃-0.01SrTiO₃ (BNKST) ceramics with x = 0.5–0.535 mol (Bi50-Bi53.5) were prepared by a conventional solid-state reaction method. The effects of Bi excess on structural transition and ferroelectric stability of BNKST ceramics were systematically investigated by the Raman spectra, dielectric analyses and electromechanical measurements. The introduction of excess Bi³⁺ could significantly break the long-range ferroelectric order and favor the presence of relaxor phase, then the ferroelectric-relaxor transition temperature (T_FR) can be effectively tuned to around room temperature by Bi nonstoichiometry, giving rise to an enhanced room-temperature strain property. The positive strain S_pos and dynamic piezoelectric constant d₃₃^* of Bi52.5 critical composition reach 0.33% and 440 pm/V, respectively at 6 kV/mm. The high recoverable strain of Bi52.5 sample can be attributed to the electric-field-induced reversible relaxor-ferroelectric phase transition. The present work may be helpful for further understanding and designing high-performance NBT-based lead-free ceramics for piezoelectric actuator applications.     

High strain (0.4%) Bi(Mg2/3Nb1/3)O3‐BaTiO3‐BiFeO3 lead‐free piezoelectric ceramics and multilayers

The relationship between the piezoelectric properties and the structure/microstructure for 0.05Bi(Mg_2/3Nb_1/3)O₃‐(0.95‐x)BaTiO₃‐xBiFeO₃ (BBFT, x = 0.55, 0.60, 0.63, 0.65, 0.70, and 0.75) ceramics has been investigated. Scanning electron microscopy revealed a homogeneous microstructure for x < 0.75 but there was evidence of a core‐shell cation distribution for x = 0.75 which could be suppressed in part through quenching from the sintering temperature. X‐ray diffraction (XRD) suggested a gradual structural transition from pseudocubic to rhombohedral for 0.63 < x < 0.70, characterized by the coexistence of phases. The temperature dependence of relative permittivity, polarization‐electric field hysteresis loops, bipolar strain‐electric field curves revealed that BBFT transformed from relaxor‐like to ferroelectric behavior with an increase in x, consistent with changes in the phase assemblage and domain structure. The largest strain was 0.41% for x = 0.63 at 10 kV/mm. The largest effective piezoelectric coefficient (d₃₃^*) was 544 pm/V for x = 0.63 at 5 kV/mm but the largest Berlincourt d₃₃ (148 pC/N) was obtained for x = 0.70. We propose that d₃₃^* is optimized at the point of crossover from relaxor to ferroelectric which facilitates a macroscopic field induced transition to a ferroelectric state but that d₃₃ is optimized in the ferroelectric, rhombohedral phase. Unipolar strain was measured as a function of temperature for x = 0.63 with strains of 0.30% achieved at 175°C, accompanied by a significant decrease in hysteresis with respect to room temperature measurements. The potential for BBFT compositions to be used as high strain actuators is demonstrated by the fabrication of a prototype multilayer which achieved 3 μm displacement at 150°C.     

Giant electric field-induced strain at room temperature in LiNbO3-doped 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3

We report experimental investigation on the ferroelectricity and electric field-induced strain response in LiNbO₃-doped 0.94(Bi_0.5Na_0.5)TiO₃-0.06BaTiO₃ (BNT-BT) piezoelectric ceramics. At room temperature, a large strain of 0.6% (at 70 kV/cm) is achieved in the 2.5%-LiNbO₃-doped BNT-BT, higher than that of commercially-utilized Pb(Zr,Ti)O₃. The corresponding piezoelectric coefficient d^*₃₃ reaches 857 pm/V, which is high among these of BNT-based ceramics at room temperature. Further study indicates that the superior piezoelectric properties are realized at the ferroelectric-relaxor transition temperature T_F-R, which is pushed to room temperature with 2.5% LiNbO₃ doping. This indicates that large electromechanical response can be induced via delicate mixing of the ferroelectric rhombohedral phase and the polar nanoregions (PNRs) relaxor-ferroelectric tetragonal phase.     

Enhanced piezoresponse and electric field induced relaxor-ferroelectric phase transition in NBT-0.06BT ceramic prepared from hydrothermally synthesized nanoparticles

0.94Na_0.5Bi_0.5TiO₃-0.06BaTiO₃ (NBT-0.06BT) nanoparticles were synthesized by hydrothermal method and subsequently used to prepare NBT-0.06BT ceramics. After poling at the electric field of 3.5 kV/mm, the piezoelectric coefficient (d₃₃) and electromechanical coupling factor (κ_p) reached 171 pC/N and 0.31, respectively. The NBT-0.06BT ceramics also exhibited a large remanent polarization of 46.10 μC/cm² and electric field induced strain of 0.243% at 8 kV/mm corresponding to normalized strain d₃₃^*=303 pm/V (S_max/E_max). The effects of polarization on crystalline phase, microstructures, dielectric properties and domain structures were investigated to reveal the origin of enhanced piezoresponse and electric field induced strain in as-prepared NBT-0.06BT ceramics. It can be observed that the tetragonal phase in NBT-0.06BT ceramics was enhanced and polar nanoregions were transformed into tweed-like structures and some lamellar domains after E-field poling. The dielectric response of NBT-0.06BT ceramics also exhibited an electric-field-induced relaxor-to-ferroelectric phase transition.     

A comparative study of direct and indirect evaluation of piezoelectric properties of electrophoreticaly deposited (Ba,Ca) (Zr,Ti)O3 lead-free piezoceramics

The development and optimisation of piezoceramics are targeted usually to enhance their piezoelectric properties evaluated by both the direct or indirect measurement methods. The presented work aims to elaborate on the correlation of one direct (Berlincourt) and two indirect (convert and field-dependent) piezoelectric measurement methods on various material states. The role of the ceramic powder treatment by ball milling and electrophoretic deposition (EPD) technique on the determined electric properties as well as basic physical and mechanical properties of (Ba_0.85Ca_0.15) (Zr_0.1Ti_0.9)O₃ ceramics (BCZT) was investigated. It was found that the EPD technologically supported by milling allows obtaining thick and dense deposits (>2 mm). After sintering, the BCZT ceramics with a relative density of >95%, hardness in the range of 2.3–2.9 GPa and piezoelectric coefficients of d₃₃* = 940 pm/V, d_33(E=0) = 427 pm/V and d₃₃ = 364 pC/N can be achieved. Reported results also suggest that indirect (field-dependent) and direct (Berlincourt) measurements of the piezoelectric coefficients can be comparable at optimal poling conditions.     

Determining the effects of BaTiO3 template alignment on template grain growth of Pb(Mg1/3Nb2/3)O3 –PbTiO3 and effects on piezoelectric properties

Crystallographic texturing of ferroelectric ceramics is an established method of inducing single crystal-like properties in a ceramic material via epitaxial grain growth according to the template used, otherwise known as Templated Grain Growth (TGG). The piezoelectric enhancement is dependent on the degree of TGG throughout the ceramic, which is closely linked to the tape casting parameters and sintering conditions. Pb(Mg1/3Nb2/3)O₃-PbTiO₃ (PMN-PT) perovskite ferroelectrics with morphotropic phase boundary compositions using 3 vol% BaTiO₃ templates were used for analysis. The blade gap and template size have the greatest impact on the overall grain alignment. The varying degrees of template alignment is related to the different enhancements of TGG and the correlating piezoelectric d₃₃ and d*₃₃. The highest piezoelectric property was demonstrated in PMN-31PT with Lotgering factor of 93% where d₃₃ = 1020 pC/N and d*₃₃ = 1420 pm/V were achieved.     

Ultrahigh-performance [001]-oriented porous PZT-5H single crystal grown by the solid state crystal growth method

Porous PZT-5H single crystals are grown by the solid state crystal growth (SSCG) method. The microstructure, phase structure and dielectric/piezoelectric properties are investigated for [001]-oriented porous PZT-5H single crystal. Evolution of phase structure with temperature is researched using in-situ temperature-dependent X-ray diffraction. The effect of pores on performance parameters is simulated using COMSOL Multiphysics® software. Ultrahigh piezoelectric coefficient d₃₃ of up to about 1700 pC/N and effective piezoelectric coefficient d₃₃* of up to about 3700 pm/V at 5 kV/cm are obtained. Moreover, the effective piezoelectric coefficient d₃₃* is stable around 1900 pm/V under 3 kV/cm and 5 kV/cm in the temperature range of 70–160 °C. Importantly, the sample possess an extremely large figure of merit g₃₃*d₃₃ (111 × 10⁻¹² m²/N), which is related to the presence of pores in the single crystal. This work expands the scope of PZT based single crystal and highlights their significant application possibilities in piezoelectric energy harvester, and actuator at high temperature.     

Piezoelectric Property and Strain Behavior of Pb(Yb0.5Nb0.5)O3–PbHfO3–PbTiO3 Polycrystalline Ceramics

(1?x)Pb(Hf_1?yTi_y)O₃–xPb(Yb_0.5Nb_0.5)O₃ (x = 0.10–0.44, y = 0.55–0.80) ceramics were fabricated. The morphotropic phase boundary (MPB) of the ternary system was determined by X‐ray powder diffraction. The optimum dielectric and piezoelectric properties were achieved in 0.8Pb(Hf_0.4Ti_0.6)O₃–0.2Pb(Yb_0.5Nb_0.5)O₃ ceramics with MPB composition, where the dielectric permittivity ε_r, piezoelectric coefficient d₃₃, planar electromechanical coupling k_p, and Curie temperature T_c were found to be on the order of 1930,480 pC/N, 62%, and 360°C, respectively. The unipolar strain behavior was evaluated as a function of applied electric field up to 50 kV/cm to investigate the strain nonlinearity and domain wall motion under large drive field, where the high field piezoelectric d₃₃* was found to be 620 pm/V for 0.82Pb(Hf_0.4Ti_0.6)O₃–0.18Pb(Yb_0.5Nb_0.5)O₃. In addition, Rayleigh analysis was carried out to study the extrinsic contribution, where the value was found to be in the range 2%–18%.     

Phase‐Composition‐Dependent Piezoelectric and Electromechanical Strain Properties in (Bi1/2Na1/2)TiO3–Ba(Ni1/2Nb1/2)O3 Lead‐Free Ceramics

New lead‐free perovskite solid solution ceramics of (1 ? x)(Bi_1/2Na_1/2)TiO₃–xBa(Ni_1/2Nb_1/2)O₃[(1?x)BNT–xBNN,x = 0.02–0.06) were prepared and their dielectric, ferroelectric, piezoelectric, and electromechanical properties were investigated as a function of the BNN content. The X‐ray diffraction results indicated that the addition of BNN has induced a morphotropic phase transformation from rhombohedral to pseudocubic symmetry approximately at x = 0.045, accompanying an evolution of dielectric relaxor behavior as characterized by enhanced dielectric diffuseness and frequency dispersion. In the proximity of the ferroelectric rhombohedral and pseudocubic phase coexistence zone, the x = 0.045 ceramics exhibited optimal piezoelectric and electromechanical coupling properties of d₃₃~121 pC/N and k_p~0.27 owing to decreased energy barriers for polarization switching. However, further addition of BNN could cause a decrease in freezing temperatures of polar nanoregions till the coexistence of nonergodic and ergodic relaxor phases occurred near room temperature, especially for the x = 0.05 sample which has negligible negative strains and thus show the maximum electrostrain of 0.3% under an external electric field of 7 kV/mm, but almost vanished piezoelectric properties. This was attributed to the fact that the induced long‐range ferroelectric order could reversibly switch back to its original ergodic state upon removal of external electric fields.     

Lead-reduced Bi(Ni2/3Ta1/3)O3-PbTiO3 perovskite ceramics with high Curie temperature and performance

With increasing demand of high-temperature piezoelectric devices and growing concern over environment protection, a feasible reduction in lead from lead-based high Curie temperature piezoelectric materials are desperately needed. Herein, a new system of lead-reduced Bi(Ni_2/3Ta_1/3)O₃-PbTiO₃ (BNT-PT) ferroelectric ceramics is fabricated by a conventional solid-state sintering process. The phase transition behaviors as a function of composition and temperature, electrical properties, as well as the domain configurations from a microscopic level have been investigated in detail. The results indicate that crystal structures, phase transition behaviors, and electric properties of BNT-PT ceramics can be affected significantly by the content of BNT counterpart. Dielectric measurements show that xBNT-(1−x)PT ceramics transfer from the normal ferroelectrics to the relaxor ferroelectrics at compositions of x = 0.3-0.35. The BNT-PT ceramics exhibit high Curie temperature T_C ranging from 474 to 185°C with the variation in BNT content. The relative dielectric tunability n_r also rises from only 0.65% for 0.10BNT-0.90PT to 50.23% for 0.40BNT-0.60PT with increasing BNT content. The tetragonal-rich composition 0.30BNT-0.70PT ceramic possesses the maximum remnant polarization of P_r ~ 34.9 μC/cm². Meanwhile, a highest piezoelectric coefficient of d₃₃ ~ 271 pC/N and a high field piezoelectric strain coefficient of  ~ 560 pm/V are achieved at morphotropic phase boundary (MPB) composition of 0.38BNT-0.62PT. The maximum value of strain ~0.31% is obtained in the 0.36BNT-0.64PT ceramic. The largest electromechanical coupling coefficient k_p is 44.5% for 0.37BNT-0.63PT ceramic. These findings demonstrate that BNT-PT ceramics are a system of high-performance Pb-reduced ferro/piezoelectrics, which will be very promising materials for piezoelectric devices. This study offers an approach to developing and exploring new lead-reduced ferroelectric ceramics with high performances.     

Electric field-induced irreversible relaxor to ferroelectric phase transformations in Na0.5Bi0.5TiO3-NaNbO3 ceramics

(1-x)Na_0.5Bi_0.5TiO₃-xNaNbO₃ (x = 0.02, 0.04, 0.06, and 0.08) ceramics were fabricated by solid-state reaction. High-resolution synchrotron x-ray powder diffraction (SXPD) data, coupled with macroscopic electromechanical measurements, reveal the occurrence of an electric field-induced irreversible crystallographic transformation for x = 0.02 and 0.04, from a pseudo-cubic non-ergodic relaxor to a rhombohedral or coexisting rhombohedral-tetragonal long range-ordered ferroelectric phase, respectively. The highest unipolar electrostrain, corresponding to an effective longitudinal piezoelectric strain coefficient of approximately 340 pm V⁻¹, was obtained for x = 0.04; this effect is attributed to enhanced domain switching as a result of the co-existing rhombohedral and tetragonal phases for this composition, which is critical for piezoelectric actuator applications.     

Phase evolution and origin of the high piezoelectric properties in lead-free BiFeO3–BaTiO3 ceramics

La-substitution effects for Bi³⁺-site in 0.7Bi_1.03(1-x)La_xFeO₃-0.3BaTiO₃ (abbreviated as BF30BT-100xLF with x = 0.00, 0.01, 0.035, 0.06, 0.07 and 0.10) ceramics were investigated systematically. All ceramics were synthesized by a conventional solid-state reaction method and quenched in water from its sintering temperature. The crystal structure Rietveld refinement shows that undoped BF30BT ceramic exhibited dominant rhombohedral (R) symmetry and gradually changed to the tetragonal (T) phase with La-doping. However, for x ≥ 0.07 compositions the lattice distortions (c_T/a_T and 90°−α_R) significantly decrease as a result crystal structures become close to the cubic-like (CL) phase. Hence, two different morphotropic phase boundaries (MPBs) were reported for BF30BT-100xLa ceramic system; one MPB-I between the R and T phases and the other MPB-II between T and CL phases. The largest direct piezoelectric coefficient (d₃₃ = 274 pC/N) with a high Curie temperature (T_C = 532 °C) for BF30BT-1LF composition was obtained due to the typical MPB-I between R and T phases. However, a maximum electric field-induced strain (S_max = 0.27%) with a high converse piezoelectric coefficient (d₃₃* = 500 pm/V) for BF30BT-7LF ceramic was mainly attributed to the MPB-II of T + CL phases and soft ferroelectric switching properties.     

Large electric‐field‐induced strain and enhanced piezoelectric constant in CuO‐modified BiFeO3‐BaTiO3 ceramics

In this work, we fabricated the (1‐x)BiFeO₃‐xBaTiO₃+y‰ mol CuO ceramics by the modified thermal quenching technique. The pure perovskite phase was formed and a morphotropic phase boundary (MPB) was observed in the ceramics with x = 0.30‐0.33. The addition of CuO can significantly enhance the density of the BiFeO₃‐BaTiO₃ material. Importantly, an enhanced piezoelectric constant (d₃₃=165 pC/N), a large electric‐field‐induced strain (?S = 0.54%: peak to peak strain) and a large piezoelectric actuator constant (d₃₃*=449 pm/V) together with a high Curie temperature (T_C) of 503°C were observed in the ceramics with x = 0.30 and y = 5. As a result, the enhanced piezoelectricity and large electric‐field‐induced strain could significantly stimulate further researches in BFO‐based ceramics.     

Comparison of multi-valent manganese oxides (Mn4+, Mn3+, and Mn2+) doping in BiFeO3-BaTiO3 piezoelectric ceramics

Different manganese oxides-doping effects were compared in piezoceramic BiFeO₃-BaTiO₃ system. 0.67Bi_1.05(Fe_0.99Mn^x_0.01)O₃-0.33BaTiO₃ (valence state x = 4+, 3+, and 2+) ceramics were prepared via a solid-state reaction process followed by furnace-cooling (FC) or water-quenching (WQ) process. For the FC ceramics, the direct piezoelectric sensor coefficient (d₃₃) was almost independent of valence state of doped Mn, while d₃₃ depended on the fraction of Fe³⁺/Fe²⁺ in WQ ceramics. The d₃₃ value was highest for the donor Mn⁴⁺-doped ceramic, among the FC ceramics, with 175 pC/N. However, acceptor-doping with Mn²⁺ prevented the transition of Fe ion valence state from 3+ to 2+ in the WQ ceramics, the Mn²⁺-doped WQ ceramic showed the largest d₃₃ of 313 pC/N and converse piezoelectric actuator coefficient, d₃₃^* of 352 pm/V, with high Curie phase transition temperature (482 °C).     

Attaining excellent piezoelectric properties and thermal stability in PIN-PHT ceramics by integrating tetragonal phase and relaxor ferroelectrics

Herein, Nd₂O₃-doped 0.11PIN-0.89PHT (PIN-PHT) single-phase tetragonal piezoelectric ceramics are prepared by traditional solid-phase method. In addition, impacts of Nd-doping on crystal structure and electrical performance for 0.11PIN-0.89PHT ceramics are systematically investigated. Based on Landau theory, we propose a novel strategy for obtaining high-performance ceramics by combining tetragonal phase and relaxor ferroelectrics. Results reveal that the introduction of polar nano-regions in tetragonal phase ceramics by doping with rare-earth ions to convert normal ferroelectrics into relaxed ferroelectrics is responsible for excellent properties of 0.11PIN-0.89PHT-xNd ceramics. The optimized comprehensive performance is obtained at x = 0.9 mol%, where d₃₃ = 670 pC/N, S_max = 0.29% (45 kV/cm), strain hysteresis = 8.68% (45 kV/cm), d₃₃* = 736 p.m./V (30 kV/cm), T_C = 312.6 °C, ε_r = 3234, k_p = 0.62, tanδ = 0.014, and excellent high-temperature stability in temperature range of 20–240 °C. After 10⁶ cycles, electrical properties and strain remain unchanged, showing excellent anti-fatigue behavior. This work provides a novel approach for the development of ceramics with outstanding piezoelectric response, high strain, low strain hysteresis, excellent anti-fatigue resistance and thermal stability, and is expected to realize practical applications of piezoelectric ceramics.     

Low sintering temperature for lead-free BiFeO3-BaTiO3 ceramics with high piezoelectric performance

Through modification of the heat-treatment process using a higher heating rate and a lower binder burnout temperature, the piezoelectric performance of water-quenched 0.67Bi_1.05FeO₃-0.33BaTiO₃ (BF33BT) lead-free piezoelectric ceramics was improved. The observed physical properties of BF33BT ceramics were very sensitive to the process temperatures. The sintering temperature (T_S) was changed within a narrow temperature range, and its effects were investigated. The largest rhombohedral distortion (90°-α_R = 0.14°) and tetragonality (c_T/a_T = 1.022) were observed for the ceramic sintered at 980°C, and its Curie temperature was 476°C. This ceramic showed good piezoelectric properties and large grains; the piezoelectric sensor charge coefficient (d₃₃) was 352 pC/N, and the piezoelectric actuator charge coefficient () was 270 pm/V. The high piezoelectric performance and low T_S of BF33BT ceramics indicate their potential as new low-cost eco-friendly lead-free piezoceramics.     

Enhanced piezoelectric performance of donor La3+-doped BiFeO3–BaTiO3 lead-free piezoceramics

Lead-free 0.70Bi_1.03FeO₃-0.30Ba_(1-x)La_xTiO₃ piezoelectric ceramics (with x = 0.000, 0.005, 0.010, 0.015 and 0.035 abbreviated as 0.0BaLa, 0.5BaLa, 1.0BaLa, 1.5BaLa and 3.5BaLa) were prepared through the conventional solid-state reaction route followed by water quenching process. The X-ray diffraction profile shows that the substitution of Ba²⁺ = 1.61 Å with a donor ion, La³⁺ = 1.36 Å, has a profound impact on the crystal symmetry as results the crystal structure transform from dominant rhombohedral (R) to tetragonal (T) phase. A large remnant polarization (P_r = 30.3 μC/cm²) and an enhanced direct piezoelectric coefficient, (d₃₃ = 297 pC/N) together with a high Curie temperature (T_C = 530 °C) was obtained near to the morphotropic phase boundary (MPB) of the R and T phases. A maximum strain of (S_max = 0.188%) with corresponding converse piezoelectric coefficient (d₃₃* = 340 pm/V) and low strain hysteresis (≈20%) was found for 1.5BaLa ceramic. Additionally, the water quenching effect was more prominent for 1.0BaLa ceramic as observed from the high thermal hysteresis in heating/cooling results of the dielectric constant (ε_r), leading to the enhancement of ferroelectric switching behavior. Hence, a small amount of La³⁺-substitution for Ba²⁺-site is more effective for the enhancement of ferroelectric and piezoelectric properties, similarly to the donor La³⁺-doped Pb(Zr,Ti)O₃ ceramic.