A recent article on giant shape memory effect in antiferroelectric (AFE) single crystals11. F. Zhuo, D. Damjanovic, Q. Li, Y. Zhou, Y. Ji, Q. Yan, Y. Zhang, Y. Zhou, and X. Chu, Mater. Horiz. 6, 1699 (2019). https://doi.org/10.1039/C9MH00352E has once again rekindled the interest of researchers in the area of active materials like shape memory alloys/oxides with adaptive electromechanical responses. Designing new oxide materials with large remnant strain is of importance, as the use of these oxides in the thin-film form could result in simpler and lighter devices compared to conventional actuators and significantly reduce the weight and cost of the components.2,32. X. Wang and A. Ludwig, Shap. Mem. Superelasticity 6, 287 (2020). https://doi.org/10.1007/s40830-020-00299-73. A. Sellitto and A. Riccio, Materials 12, 708 (2019). https://doi.org/10.3390/ma12050708 It is known that on application of an electric field, usually the appearance of strain in ferroelectric (FE) materials is due to their electrostrictive or piezoelectric characteristic only and becomes almost zero on removal of the field; however, for compositions near the morphotropic phase boundary (MPB), changes in a primitive cell of the material also get involved in this process. Thus, reversible field induced phase transitions can be realized when the field is applied in a non-polar direction. On the other hand, the strain in AFE materials occurs as the applied electric field drives the sample to its corresponding FE state, which usually has a different structural unit and, thus, an additional strain from the requirement of atomic re-arrangement is also involved.4–84. D. Berlincourt, H. H. A. Krueger, and B. Jaffe, J. Phys. Chem. Solids 25, 659 (1964). https://doi.org/10.1016/0022-3697(64)90175-15. S. E. Park, M. J. Pan, K. Markowski, S. Yoshikawa, and L. E. Cross, J. Appl. Phys. 82, 1798 (1997). https://doi.org/10.1063/1.3659826. T. Lu, A. J. Studer, L. Noren, W. Hu, D. Yu, B. McBride, Y. Feng, R. L. Withers, H. Chen, Z. Xu, and Y. Liu, Sci. Rep. 6(1), 1–8 (2016). https://doi.org/10.1038/srep236597. K. Uchino, Actuators 5(2), 11 (2016). https://doi.org/10.3390/act50200118. K. Uchino, Ferroelectric Devices ( CRC Press, Florida, 2018). An added advantage in using an AFE sample is the remnant strain that has its origin in the electric field driven metastable FE-state, in which the strain remains even when the field is completely removed. This strain can be removed on application of the electric field in the opposite direction; as if, they are able to “memorize” their parent shape. The effect is known as shape memory effect (SME), and these oxides are referred to as shape memory (SM) ceramics/oxides.9,109. A. Pathak, C. Prakash, and R. Chatterjee, Phys. B: Condens. Matter 404, 3457 (2009). https://doi.org/10.1016/j.physb.2009.05.04410. J. Ly, W. Gao, J. Li, T. Li, C. Long, X. Lou, and J. Wu, J. Mater. Chem. C 5, 9528 (2017). https://doi.org/10.1039/C7TC03282JIn a lead zirconate stannate titanate Pb(Zr0.7Sn0.3)xTi1-xO3 (PZST) system, a phase diagram showing AFE-FE phase boundaries was first given by Jaffe in 1971.1111. B. Jaffe, W. R. Cook, Jr., and H. Jaffe, Piezoelectric Ceramics ( Academic Press, London, 1971). Two AFE-FE morphotropic phase boundaries (MPBs), (i) orthorhombic AFE-ferroelectric rhombohedral (AO-FR) and (ii) antiferroelectric tetragonal-ferroelectric rhombohedral (AT-FR) phases, are depicted in this phase diagram. It has been established88. K. Uchino, Ferroelectric Devices ( CRC Press, Florida, 2018). that at room temperature, while the composition with x = 0.93 on the AT-FR MPB shows a FE behavior, x = 0.94 is antiferroelectric. Later, Pathak et al. verified that the exact MPB of this AT-FR PZST system lies at x = 0.938, and the structure of this composition was identified as tetragonal.99. A. Pathak, C. Prakash, and R. Chatterjee, Phys. B: Condens. Matter 404, 3457 (2009). https://doi.org/10.1016/j.physb.2009.05.044 Since then, it has been shown in the literature that the ceramics at exact morphotropic phase boundary (MPB) have advantage over the AFE materials due to their optimal power requirements for phase-switching.12,1312. A. Pathak, C. Prakash, and R. Chatterjee, Ferroelectr. Lett. 37, 60 (2010). https://doi.org/10.1080/07315171.2010.51998713. X. Hao and J. Zhai, J. Phys. D: Appl. Phys. 40, 7447 (2007). https://doi.org/10.1088/0022-3727/40/23/028We start with the (AT-FR) MPB composition Pb[(Zr0.7Sn0.3)0.938Ti0.062]O3 and aim to improve the remnant strain (Srem) and field-induced maximum strain (Smax) by appropriately tailoring the composition. Many researchers have reported the effect of the A site5,125. S. E. Park, M. J. Pan, K. Markowski, S. Yoshikawa, and L. E. Cross, J. Appl. Phys. 82, 1798 (1997). https://doi.org/10.1063/1.36598212. A. Pathak, C. Prakash, and R. Chatterjee, Ferroelectr. Lett. 37, 60 (2010). https://doi.org/10.1080/07315171.2010.519987 as well as B site1414. A. Pathak, C. Prakash, and R. Chatterjee, Mater. Chem. Phys. 123, 132 (2010). https://doi.org/10.1016/j.matchemphys.2010.03.072 modifications on the above system. However, the results of A-site modification by Bi3+ in the place of Pb2+ have not been discussed yet in the literature. Since the ionic radius of Bi3+ ∼1.45 Å is close to the ionic radius of Pb2+ ∼1.49 Å,1515. B. Zhu, X. Zeng, P. Qie, L. Ling, D. Sun, S. Zhao, and X. He, Materials 12(9), 1437 (2019). https://doi.org/10.3390/ma12091437 Bi3+ goes mostly into A sites of PZST. As a result of the difference in valences of ions at the A-site, substantial concentrations of vacancies are expected in the composition. In the absence of any experimental estimation, both A-site and B-site vacancies are expected to be present.16,1716. K. H. Hardtl and D. Hennings, J. Am. Ceram. Soc. 55, 230 (1972). https://doi.org/10.1111/j.1151-2916.1972.tb11267.x17. L. Wu, C. C. Lee, T. S. Wu, and C. C. Wei, Ferroelectrics 41, 157 (1982). https://doi.org/10.1080/00150198208210618We particularly address here, two important results: (i)

The optimal A-site modification with Bi3+ in Pb(1 − 3/2y)Biy[(Zr0.7Sn0.3)xTi1-x]O3 leads to an increase in AFE characteristics of the oxide.

(ii)

For the optimized Bi-content, the work also reports the optimal ratio of (Zr, Sn): Ti for an increased Srem and Smax.

Initially, a series of Bi-doped PZST samples with the stoichiometric formula Pb(1 − 3/2y)Biy[(Zr0.7Sn0.3)xTi1-x]O3 (PBZST) with x = 0.938 and y = 0, 0.01, and 0.02 (abbreviated as B0, B1, and B2) were synthesized by a conventional ceramic method. The result of this variation points out the AFE phase stabilization characteristic of Bi addition in PZST. In order to optimize further, the (Zr,Sn)/Ti ratio was then varied for the above determined/optimized PBZST composition (with y = 0.01) that shows the largest field induced strain value. For a synthesis process, the stoichiometric amounts of PbO, ZrO2, Sn2O3, TiO2, and Bi2O3 (purity 99.9%) were mixed using ball milling for 24 h in the acetone solvent followed by drying in an oven. The mixture was then calcined at ∼950 °C for 4 h. Both heating and cooling rates were kept as ∼5 °C/min. The ∼10 mm diameter disks were prepared by mixing the powder with 2 wt. % polyvinyl alcohol (PVA) and pressing it at ∼100 MPa using a hydraulic press. The calcined disks were sintered at ∼1250 °C for 4 h; a heating and cooling rate of 2 °C/min was used for this treatment. To counter the problem of volatilization of some of these oxides at high calcination/sintering temperatures, 1% excess PbO and Bi2O3 were added into the pellet during synthesis to get the desired stoichiometric composition. The sintering was done in the presence of PbZrO3 as sacrificial powder. The details of EDX results and the SEM micrographs for B0, B1, and B2 can be seen in the supplementary material (Figs. S1 and S2). The relative density was measured using the Archimedes principle and found to be > 95%. The electrical contacts were made on both sides of the disk using silver paste, and then annealing at 450 °C for 30 min was done. The Rigaku x-ray diffractometer with Cu Kα radiation (wavelength, λ = 1.54 Å) was used to record the x-ray diffraction (XRD) patterns. A step size of 0.02° and a scan rate of 2°/min were used for the measurement. Dielectric measurements were performed in the frequency range 1 kHz≤ f ≤1 MHz and the temperature range 40 °C ≤ T ≤ 300 °C using an HP 4192 A impedance analyzer. The room temperature ferroelectric properties were measured at 1 Hz using Precision Premier II, Radiant Technologies, USA, a P–E Loop Tracer. Current vs electric field measurements were performed using a radiant technology system at 1 Hz. Strain vs electric field hysteresis plots were recorded at 1 Hz frequency using the MTI-2100 Fotonic Sensor (MTI Instruments, Inc., USA) at room temperature.The effect of Bi addition at the A-site of Pb1−(3/2) yBiy[(Zr0.7Sn0.3)0.938Ti0.062]O3 (0 ≤y ≤ 0.02) is on structural and dielectric properties: The XRD powder patterns at room temperature, for all samples are shown in Fig. 1(a). All compositions exhibit a perovskite structure without any secondary phase. The lattice parameters have been calculated for all compositions (B0, B1, B2) using Le-Bail refinement of the recorded XRD patterns and are listed/included in Table I. The c/a values of B0, B1, and B2 shown in Table I are calculated from the refinement of the XRD data of poled samples using the lattice parameters extracted for the majority phase, i.e., a P4 mm phase. From the given lattice parameters, one can find a systematic increase in the c/a values from y = 0 (B0) to y = 0.02 (B2) for poled samples. The detailed refined data using Le Bail fitting for both poled and unpoled samples are shown in in supplementary material (Fig. S3). A single peak of (111) without any splitting and a doublet of the (200) peak [see the inset of Fig. 1(a)] confirm the formation of the sample in a tetragonal phase. However, after poling of the samples using a high electric field ∼77 kV/cm, the doublet of the (200) peak is observed to vanish [see Fig. 1(b)], possibly indicating the beginning of a field induced AFE tetragonal to mixed polymorphic phase. Due to the presence of the local R3m distortions that strengthen with application of the external field, there is no splitting of the peak observed for poled samples; however, the structure remains in the majority phase, i.e., tetragonal-P4 mm.1818. W. Wang, Y. Song, C. Cao, K. Tseng, T. Keller, Y. Li, L. W. Harriger, W. Tian, S. Chi, R. Yu, A. H. Nevidomskyy, and P. Dai, Nat. Commun. 9(1), 3128 (2018). https://doi.org/10.1038/s41467-018-05529-2

TABLE I. Comparison of lattice parameters, tolerance factor, transition temperature, maximum dielectric constant, and diffusivity factor values for all Bi doped PZST poled compositions.

Pb1−(3/2) yBiy[(Zr0.7Sn0.3)0.938Ti0.062]O3Sample nameacc/aTolerance factor (t)Transition temp. Tc (°C)Max. dielectric constant (at 1 kHz)Diffusivity factor (γ)Pb(Zr0.7Sn0.3)0.938Ti0.062O3B04.09734.11961.00540.97921022301.44Pb0.985Bi0.01(Zr0.7Sn0.3)0.938Ti0.062O3B14.09504.11951.00600.97621811321.69Pb0.970Bi0.02(Zr0.7Sn0.3)0.938Ti0.062O3B24.09314.11931.00640.9732429591.47Pb0.985Bi0.01[(Zr0.7Sn0.3)xTi1-x]O3Pb0.985Bi0.01[(Zr0.7Sn0.3)0.934Ti0.066]O3B34.09794.11921.00520.97620428461.71Pb0.985Bi0.01[(Zr0.7Sn0.3)0.933Ti0.067]O3B44.09894.11911.00490.97619431071.78Pb0.985Bi0.01[(Zr0.7Sn0.3)0.932Ti0.068]O3B54.09954.11891.00470.97620619211.50Pb0.985Bi0.01[(Zr0.7Sn0.3)0.931Ti0.069]O3B64.09994.11881.00460.97619823541.43Pb0.985Bi0.01[(Zr0.7Sn0.3)0.930Ti0.070]O3B74.10044.11871.00450.97618628811.36In Fig. 2, a comparison of temperature-dependent dielectric constant at 1 kHz for B0, B1, and B2 is shown. In general, the dielectric constant decreases with an increase in the substitution of smaller trivalent Bi3+ ions at the Pb2+ site. This result agrees with previous reports on the A-site substituted (with La3+, Nd3+, and Sm3+) PZST based oxides system.1919. Q. Zhang, T. Yang, and Y. Zhang, Appl. Phys. Lett. 102, 222904 (2013). https://doi.org/10.1063/1.4809934 Moreover, the ferroelectric-paraelectric transition temperature (TC) is noted to systematically increase 210 °C ≤ TC ≤ 242 °C for compositions 0 ≤ y ≤ 0.02. The temperature dependence (40 °C ≤ T≤ 300 °C) of the real part of dielectric permittivity (ε′) of bismuth modified (y = 0.01) PBZST ceramics in a broad frequency range 1 kHz ≤ f ≤ 1 MHz is given in the inset of Fig. 2(a). A slight frequency dispersion in dielectric constant can be seen, and the addition of Bi is observed to reduce the dielectric constant while broadening the dielectric peak. The degree of diffusivity, γ ∼1.69 for B1 (y = 0.01) is noted (see Table I). As expected, the introduction of bismuth brings diffuse phase transition and sets a disordered state in the samples that aids the shape memory characteristics2020. H. Qi, L. Chen, H. Luo, H. Liu, S. Deng, X. Xing, and J. Chen, J. Mater. Chem. C 9, 9859 (2021). https://doi.org/10.1039/D1TC02490F of this composition.Effect of Bi addition at the A-site on polarization and strain measurements: The polarization vs electric field (P–E) data at room temperature for B0, B1, and B2 at 1 Hz frequency are shown in Fig. 2(b). The remnant polarization Prem is seen to decrease with the Bi content on going from y = 0 to y = 0.02. Also, the electric field E required to drive the AFE-FE transition (EAFE-FE) is observed to increase with increasing Bi content. The pinched hysteresis loop observed for B0 usually indicates the presence of both ferroelectric and antiferroelectric phases in the sample. Our starting composition (B0) is evidently at exact MPB of the AT-FR of PZST and shows a pinched loop with a sudden increase in polarization on application of electric field ∼20 kV/cm, as shown earlier by Pathak et al.99. A. Pathak, C. Prakash, and R. Chatterjee, Phys. B: Condens. Matter 404, 3457 (2009). https://doi.org/10.1016/j.physb.2009.05.044 Addition of Bi in the PBZST samples, however, is seen to require ∼40 kV/cm (in B1) and ∼60 kV/cm (in B2) for such rise in polarization. Substitution of Bi results in larger EAFE-FE for field driven transitions. Thus, it is clearly demonstrated that addition of even 1% Bi (B1) seems to favor the stabilization of the AFE phase in the PZST system. Figure 2(c) demonstrates that the maximum strain value (∼0.3%) is noted for this B1, as expected for a sample in which the strain is increased due to a change in atomic arrangements related to the AT-FR phase transition. However, in contrast to the B0 composition at MPB, sample B1 does not show any remnant strain. As evident from the above results, Bi addition in PZST is established as an AFE phase stabilizer. Sample B1 showing the maximum strain is then chosen as the optimized composition; wherein, the AFE phase close to the MPB helps inducing an atomic rearrangement aided maximum strain in the composition.In the next paragraph, we summarize the results of tailoring the B-site of Pb0.985Bi0.01[(Zr0.7Sn0.3) xTi1-x]O3, keeping Zr: Sn as 70:30 and varying the x (Ti4+ content) for obtaining the best Srem and Smax. From here onwards, the samples with a variation of x, 0.934 ≥ x ≥ 0.930 will be referred to as B3, B4, B5, B6, and B7 (see Table I).The effects of Ti variation at the B-site of modified Pb0.985Bi0.01[(Zr0.7Sn0.3)xTi1-x]O3 (0.934 ≥ x ≥ 0.930) are: (i) Le Bail refined XRD data indicate that the Ti variation at the B site introduces a polymorphic mixed phase of tetragonal P4 mm and rhombohedral R3m structures (see supplementary material Fig. S4). Refining the experimental data, we have estimated the fractional % of both tetragonal and rhombohedral phases present in B3, B4, B5, B6, and B7 samples. (ii) The polarization vs electric field hysteresis (P–E) loops, leakage current (I–E), and bipolar strain (S–E) curves for all samples Pb0.985Bi0.01[(Zr0.7Sn0.3)xTi1-x]O3 are plotted in Fig. 3 along with the curves obtained for sample B1 (Pb0.985Bi0.01[(Zr0.7Sn0.3)0.938Ti0.062]O3). The AFE state of B1 is evident from the zero current state in zero electric field, i.e., the polarization at zero voltage is zero as expected for a typical AFE. Compared to typical antiferroelectric B1, sample B4 with x = 0.933 is observed to bring back the MPB state (pinched loop), now with an optimal Bi inclusion. For samples B3, B4 with x = 0.934 and 0.933, respectively, the P–E loops are again pinched loops with increased Pmax of ∼47.1 and 55.7 μC/cm2, respectively. The Prem of ∼11.21 and 24.88 μC/cm2 were noted for B3 and B4, respectively, as shown in Fig. 3 and recorded in Table II. In the I–E loops, the current corresponding to the ferroelectric domain switching depicts itself as peak 1. Current peak 2 in the I–E loop that appears in the first quadrant very close to zero electric field is observed to shift a little on the electric field axis for different samples. This peak 2 in the I–E loop of the B4 sample is observed to shift to larger fields for B5 and B6, until it vanishes for purely ferroelectric sample B7. This additional signature (peak 2) possibly can be attributed to the electric field-induced phase transition from a disordered state to a typical ferroelectric phase.21,2221. Y. Ehara, N. Novak, S. Yasui, M. Itoh, and K. G. Webber, Appl. Phys. Lett. 107, 262903 (2015). https://doi.org/10.1063/1.493875922. J. Yin, C. Zhao, Y. Zhang, and J. Wu, J. Am. Ceram. Soc. 100, 5601 (2017). https://doi.org/10.1111/jace.15083 In fact, the structural mixed phase origin of the pinched P–E loop at x = 0.933 is this electric field driven phase transition that causes a peak in I–E curves, namely, peak 2.

TABLE II. Comparison of the maximum polarization, remnant polarization, current at zero electric field, maximum strain, remnant Strain, and current values for all Bi doped PZST compositions.

Sample nameMaximum polarization (μC/cm2)Remnant polarization PR (μC/cm2)Current at zero electric fieldMaximum strain (%)Remnant strain (%)Current (mA)B125.211.0400.30—0.44B347.111.210.080.40.020.60B455.724.880.360.440.271.17B540.2223.580.20.190.1040.25B634.0921.10.180.150.0970.23B732.3024.010.060.1050.050.21It can be noted that with 1% Bi and the optimized (Zr (0.653)/Sn (0.280): Ti (0.067) ratio, the B4 sample shows a maximum strain of ∼0.44% and a remnant strain value of ∼0.27%. Samples B5, B6, and B7 show typical ferroelectric butterfly loops as expected. As shown in Table II, the maximum strain and remnant strain values first increase, maximize at MPB composition, and decrease after that.Figure 4 shows the comparative P–E, I–E, and S–E curves for sample B0, i.e., the MPB composition of PZST, (Pb[(Zr0.7Sn0.3)0.938Ti0.062]O3) and the MPB composition of Bi-doped PBZST, Pb0.985Bi0.01[(Zr0.7Sn0.3)0.933Ti0.067]O3. Evidently, the Srem in PBZST has shown a drastic improvement to 0.27% (in the place of 0.08% for PZST) and the Smax values also improved from 0.20% to 0.44%.Although the reported SME of PZST-based and also some lead-free ceramics at room temperature so far are relatively small (∼0.03%–0.25%),11. F. Zhuo, D. Damjanovic, Q. Li, Y. Zhou, Y. Ji, Q. Yan, Y. Zhang, Y. Zhou, and X. Chu, Mater. Horiz. 6, 1699 (2019). https://doi.org/10.1039/C9MH00352E we achieve Srem ∼ 0.27% (approximately three times higher than the value reported for pure PZST) and Smax ∼ 0.44% for the optimized composition (x = 0.933, y = 0.01) in Pb1−(3/2)yBiy[(Zr0.7Sn0.3)xTi1-x]O3. This value is larger than the values found for other Pb-based, BNT-based, BT- based, KNN-based, BiFeO3, NaNbO3, and AgNbO3 based ceramics, ⟨001⟩ textured BNT-BKT-BT ceramics, and BNKT doped BNT-STO.1,20,23,241. F. Zhuo, D. Damjanovic, Q. Li, Y. Zhou, Y. Ji, Q. Yan, Y. Zhang, Y. Zhou, and X. Chu, Mater. Horiz. 6, 1699 (2019). https://doi.org/10.1039/C9MH00352E20. H. Qi, L. Chen, H. Luo, H. Liu, S. Deng, X. Xing, and J. Chen, J. Mater. Chem. C 9, 9859 (2021). https://doi.org/10.1039/D1TC02490F23. Z. Zhao, M. Ye, H. Ji, X. Li, X. Zhang, and Y. Dai, Mater. Des. 137, 184 (2018). https://doi.org/10.1016/j.matdes.2017.10.00324. M. Sheeraj, A. Khaliq, A. Ulaah, H. Han, A. Khan, A. Ulaah, I. W. Kim, T. H. Kim, and C. W. Ahn, J. Eur. Ceram. Soc. 39, 4688 (2019). https://doi.org/10.1016/j.jeurceramsoc.2019.07.049Evidently, the substitution of 1% Bi at the A-site increases the diffusivity, and along with the AFE phase stabilization, a disordered state in the composition is introduced. PZST is an ABO3 perovskite consisting of a network of BO6 octahedra, where oxygen octahedron contains the B-site cations, and the A-site cations couple these octahedra.2525. N. W. Thomas, Ferroelectrics 100, 77 (1989). https://doi.org/10.1080/00150198908007902 When Bi3+ ions replace Pb2+ ions, to preserve charge neutrality, lattice vacancies are created.2626. R. B. Atkin, R. L. Holman, and R. M. Fulrath, J. Am. Ceram. Soc. 54, 113 (1971). https://doi.org/10.1111/j.1151-2916.1971.tb12231.x This interrupts the long-range coupling of the ferroelectrically active BO6 in PBZST and stabilizes the antiferroelectric state with the tetragonal structure as evidenced by the XRD of sample B1 and P–E curves in Fig. 2(b). Another measure of the stability of the antiferroelectric phase is the tolerance factor, t.2727. V. M. Goldschmidt, Naturwisenchaften 14, 477 (1926). https://doi.org/10.1007/BF01507527 The tolerance factors of all compositions studied here are close to, but less than 1 (see Table I).

All compositions chosen for this work are near the AT-FR phase boundary. While the as-prepared samples show the tetragonal structure, on poling the tetragonality of the structure is driven to a mixed perovskite polymorph of tetragonal and rhombohedral phases as established in this work. This modified, randomly mixed phase re-arrangement seems to strongly influence the dielectric permittivity and enhance the electromechanical properties. The disorder and randomness introduced through 1% Bi substitution in composition B1 (that lies just toward the AFE side of MPB) impact the electromechanical property like strain quite drastically (Smax ∼ 0.3%). It is known that the atomic arrangements in the antiferroelectric tetragonal (AT) phase is smaller than its rhombohedral ferroelectric (FR) counterpart, and thus, large strain can be realized in a field-induced AT–FR phase transition process. Although our samples are polycrystalline, this effect is clearly seen.

When composition B1 is tweaked by tailoring the B-site of Pb0.985Bi0.01[(Zr0.7Sn0.3)xTi1-x]O3, keeping Zr: Sn as 70:30, the system is brought back to MPB again, and the strain values for B4 is improved further to Smax ∼ 0.44%. Sample B4 shows a pinched P–E loop, and along with this, a remnant strain Srem ∼ 0.27% is obtained.

In summary, we have clearly demonstrated that Bi acts as the antiferroelectric phase-stabilizer in the PZST system. Furthermore, the mismatched cations of higher charge along with the accompanied vacancies behave like randomly distributed defects within a three-dimensional lattice, giving rise to a disordered state and aid the SME. Choice of a composition just outside the morphotropic phase boundary toward the AFE side allows an electric field driven dipolar rearrangement for the disordered state structure toward ferroelectric states and leads to large strain. It should be noted that while the MPB composition without Bi (B0) shows Srem ∼ 0.08%, in the modified MPB composition with Bi inclusion and with modified Ti content, Pb0.985Bi0.01[(Zr0.7Sn0.3)0.933Ti0.067]O3 (B4), we could obtain large remnant strain Srem ∼0.27% and Smax ∼0.44%.

We gratefully acknowledge the financial support from the Aeronautics Research and Development Board (ARDB, Proposal No. 3842) and the Priority-2030 Program of NUST “MISiS” (Grant No. K2-2022-022). H.K. thanks the Nanoscale Research Facility (NRF) IIT Delhi for providing XRD facility and the Council of Scientific and Industrial Research (CSIR), Government of India, for providing fellowship. R.C. would like to thank Professor B. K. Mani for careful reading of the manuscript and giving his suggestions.

Conflict of Interest

The authors have no conflicts to disclose.

Author Contributions

Hitesh Kumar: Conceptualization (equal); Data curation (lead); Formal analysis (equal); Investigation (lead); Methodology (equal); Writing – original draft (lead). Divya Prakash Dubey: Formal analysis (supporting); Investigation (supporting); Writing – review & editing (supporting). Ratnamala Chatterjee: Funding acquisition (lead); Project administration (lead); Resources (lead); Supervision (lead); Writing – original draft (equal); Writing – review & editing (lead).

The data that support the findings of this study are available within the article.

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