**3. Results and discussion**

Plate-like particles play a crucial role in the texture engineering. For texture development of BNT–BZ ceramics, plate-like BNT templates were first produced by a topochemical reaction from bismuth layered-structure ferroelectric (BLSF) BNT4 precursor through molten salt process. **Figure 1** shows the crystalline phase and FE-SEM micrograph of BNT4 precursor particles synthesized by molten salt process. The X-ray diffraction pattern of the BNT4 precursor (**Figure 1a**) reveals the development of a single phase with no traces of secondary or parasite phases. All diffraction peaks inherit the characteristics features of the typical layered-perovskite structure. All diffraction peaks matches with the JCPDS card no. 74–1316 of the BLSF. Maximum number of peaks, for instance (006), (008), (0010), (0018), and (0020), were observed to possess higher intensities than the other peaks, signifying that the surface of BNT4 particles is parallel to the (00l) plane and suggesting that the BNT4 particles have high degree of preferred grain orientation. The FE-SEM micrograph of the BNT4 particles (**Figure 1b**) shows a plate-like morphology with size ranging from 15 to 20 *μ*m. Some small grains of size less than one micron can be also observed that might be the broken pieces of BNT4 crystals. BNT4 has the characteristics anisotropic BLSF materials, in which the growth along the *a* and *b* axis is much higher than that of the c-axis. Thus, it is reasonable for them to adopt a plate-like morphology. The as-synthesized BNT4 particles produce in this work were used as a precursor materials for the TMC process [38].

Grain-oriented ceramics with a composition of 0.994Bi0.5Na0.5TiO3–0.006BaZrO3 (BNT–BZ) were fabricated through RTGG process utilizing the as-synthesized BNT templates [38]. Commercially accessible carbonate powders such as: Na2CO3 and BaCO3 (99.95%, Sigma Aldrich) along with metal oxide powders such as: Bi2O3, TiO2, and ZrO2 (99.9% Junsei Co., Limited) were first weighed according to the stoichiometric formula of BNT–BZ and then mixed by ball milling for 24 h at 250 rpm. The slurry was dried and then calcined at 850°C for 2 h to form a perovskite phase. The as-prepared calcined powders of BNT–BZ were mixed thoroughly with a solvent (60 vol.% ethanol and 40 vol.% methyl-ethyl-ketone, MEK) and triethyl phosphate (dispersant) in a ball mill for 24 h. Subsequently, polyvinyl butyral (binder) and polyethylene glycol/diethyl-ophthalate (plasticizer) were added to the mixtures and the milling was continued again for another 24 h. BNT templates of 15 wt% were then added to the mixture and ball milled with a slow rotation for another 12 h to form a slurry for tape casting. The viscous slurry was tape cast to form a green sheet with a thickness of ~100 *μ*m on a SiO2-coated polyethylene film by a doctor blade apparatus. Afterward drying, a single layer sheet was cut, laminated, and hot-pressed at a temperature of 45°C and a pressure of 50 MPa for 2 min to form a 2-mm-thick green compact. The compacts were further cut into small samples of about 1 × 1 cm2 and then heated at 600°C for 12 h with intermediated steps of 250 and 350°C for 6 and 8 h and to remove organic substances prior to sintering. The samples were sintered at 1150°C for 15 h in air atmosphere and were then brought to room temperature at cooling rate of 5°C/min. For comparison, non-textured BNT–BZ ceramics were also prepared

Crystalline phase and purity information of the as-synthesized BNT particles and BNT–BZ ceramics were checked by X-ray diffraction machine (XRD, RAD III, Rigaku, Japan) using CuK*α* radiation (*λ* = 1.541 Å) at room temperature. The XRD patterns were collected in the Braggs–Brentano configuration operated at 10 mA and 20 kV with a step size of 0.02°. The particle size and shape was observed through field emission scanning electron microscope (FE-SEM, JP/JSM 5200, Japan). At room temperature, Raman scattering investigation was performed using a dispersive Raman spectrometer (ALMEGA, Nicelot, USA). Selected area electron diffraction (SAED) pattern and high-resolution transmission electron microscopy (HRTEM) images were obtained by transmission electron microscope (TEM) using a FE-TEM (JEOL/JEM-2100F version) operated at 200 kV. Both surfaces of the samples were polished and coated with a silver–palladium paste to form electrodes for electrical properties measurements. The dielectric constant and loss response were measured through an impedance analyzer (HP4194A, Agilent Technologies, Palo Alto, CA). The ferroelectric hysteresis loops were measured using a Precision Premier II device (Radiant Technology, Inc.) at 50 Hz. Fieldinduced strain response was measured using a contact-type displacement sensor (Model 1240;

Plate-like particles play a crucial role in the texture engineering. For texture development of BNT–BZ ceramics, plate-like BNT templates were first produced by a topochemical reaction from bismuth layered-structure ferroelectric (BLSF) BNT4 precursor through molten salt

through conventional solid-state reaction [38].

28 Piezoelectric Materials

Mahr GmbH, Göttingen, Germany) at 50 mHz.

**3. Results and discussion**

**Figure 1.** Crystal structure and FE-SEM micrograph of Bi4.5Na0.5Ti4O15 precursor particles synthesized by molten salt synthesis at 1150°C for 4 h (a) X-ray diffraction, (b) FE-SEM micrograph.

A schematic diagram showing the conversion of the layered perovskite into a simple perov‐ skite structure by a topochemical conversion is illustrated in **Figure 2**. Bismuth layeredstructure materials have a chemical formulation Bi2O2(*Am*−1*B*mO3*m*+1) (where *A*-sites is occupied by Bi3+ and Na+ , while *B*-sites by Ti4+, m is an integer with a certain value). For *m* = 4, the formula takes the form of Bi2O2(Na0.5Bi2.5)Ti4O13 and this formula unit has the intergrowths of pseudoperovskite blocks that are sandwiched between bismuth oxide layers. The BO6 octahedron have a covalent linkage of [Bi2O2] 2+ among two-dimensional pseudo-perovskite layers. BNT4 belongs to the bismuth layered-structure compounds family, where Na+ ions partially occupy the *A*-site. Na+ could replace the [Bi2O2] 2+ slabs and the *A*-site (Bi3+ ions) during the topochemical reaction, where Bi2O3 forms and the weak covalent linkage of [Bi2O2] 2+ layer disappears. Furthermore, Na+ ions substitute the Bi3+ ions in the *A*-site of the perovskite structure. More‐ over, the tetragonal BNT4 transforms into a cubic BNT that preserves the morphological topographies of the precursor BNT4 [38].

**Figure 2.** Schematic diagram of the conversion of layered-structure perovskite Bi4.5Na0.5Ti4O15 into a simple perovskite Bi0.5Na0.5TiO3 by a topochemical microcrystal conversion. Reprinted with permission from Hussain et al. [38] with a copyright from Elsevier 2015.

**Figure 3** presents the X-ray diffractogram of the BNT particles produced through TMC (**Figure 3a**) and CMO (**Figure 3b**) methods, respectively. BNT particles produced through both methods exhibit a single-phase perovskite structure and both match well with the JCPDS card No. 36–0340 of the Bi0.5Na0.5TiO3. Because of the small rhombohedral distortion, all diffraction peaks were indexed on the basis of the pseudocubic perovskite unit cell. A significant differ‐ ence in the peak intensities can be observed in BNT particles synthesized by two different routes. BNT particles synthesized by TMC shown in **Figure 3a** exhibit strong (100) and (200) diffraction peaks while that synthesized by CMO have (110) as major peak (shown in **Figure 3b**). This diffraction profile clearly indicate that the layered structure of BNT4 particles completely transformed into perovskite BNT templates after the TMC process (**Figure 3a**). Furthermore, the perovskite BNT preserves the plate-like morphology BNT4. Analogous to BNT4 templates, most of the large and plate-like BNT particles laid down with the c-axis aligned along the vertical direction during the sample preparation for the XRD analysis. Accordingly, they show strong diffraction peaks of (100) and (200). BNT4 belongs to the BLSFs family that possess (Bi2.5Na0.5Ti4O13) 2− (pseudo-perovskite layers) enclosed in (Bi2O2) 2+ fluorite layers where the *A*-site is co-occupied by Na+ as well as Bi3+ in a Na/Bi ratio of 0.2. This conversion from the layered structure into a simple perovskite is composed of two stages: firstly, the transmission of Na+ and Bi3+ through the perovskite layers; secondly, the transfigu‐ ration of (Bi2O2) 2+ fluorite layers into the perovskite phase. It has been also reported that this transformation implies a change from a lamellar phase to a perovskite phase [36]; nevertheless, the process involving the change of the (Bi2O2) 2+ layers to perovskite structure still needs further detailed investigations [38].

over, the tetragonal BNT4 transforms into a cubic BNT that preserves the morphological

**Figure 2.** Schematic diagram of the conversion of layered-structure perovskite Bi4.5Na0.5Ti4O15 into a simple perovskite Bi0.5Na0.5TiO3 by a topochemical microcrystal conversion. Reprinted with permission from Hussain et al. [38] with a

**Figure 3** presents the X-ray diffractogram of the BNT particles produced through TMC (**Figure 3a**) and CMO (**Figure 3b**) methods, respectively. BNT particles produced through both methods exhibit a single-phase perovskite structure and both match well with the JCPDS card No. 36–0340 of the Bi0.5Na0.5TiO3. Because of the small rhombohedral distortion, all diffraction peaks were indexed on the basis of the pseudocubic perovskite unit cell. A significant differ‐ ence in the peak intensities can be observed in BNT particles synthesized by two different routes. BNT particles synthesized by TMC shown in **Figure 3a** exhibit strong (100) and (200) diffraction peaks while that synthesized by CMO have (110) as major peak (shown in **Figure 3b**). This diffraction profile clearly indicate that the layered structure of BNT4 particles completely transformed into perovskite BNT templates after the TMC process (**Figure 3a**). Furthermore, the perovskite BNT preserves the plate-like morphology BNT4. Analogous to BNT4 templates, most of the large and plate-like BNT particles laid down with the c-axis aligned along the vertical direction during the sample preparation for the XRD analysis. Accordingly, they show strong diffraction peaks of (100) and (200). BNT4 belongs to the BLSFs

conversion from the layered structure into a simple perovskite is composed of two stages:

transformation implies a change from a lamellar phase to a perovskite phase [36]; nevertheless,

2− (pseudo-perovskite layers) enclosed in (Bi2O2)

2+ fluorite layers into the perovskite phase. It has been also reported that this

and Bi3+ through the perovskite layers; secondly, the transfigu‐

as well as Bi3+ in a Na/Bi ratio of 0.2. This

2+ layers to perovskite structure still needs further

2+ fluorite

topographies of the precursor BNT4 [38].

30 Piezoelectric Materials

copyright from Elsevier 2015.

family that possess (Bi2.5Na0.5Ti4O13)

firstly, the transmission of Na+

detailed investigations [38].

ration of (Bi2O2)

layers where the *A*-site is co-occupied by Na+

the process involving the change of the (Bi2O2)

**Figure 3.** XRD diffraction of Bi0.5Na0.5TiO3 particles synthesized by different methods (a) topochemical microcrystal conversion, (b) conventional mixed oxide route.

**Figure 4** provides the FE-SEM micrographs of the BNT templates produced from the BNT4 precursor by TMC process along with the BNT particles prepared via a CMO route. Similar to BNT4 particles, most of the BNT templates have large grains of plate-like morphology. Such kind of large and plate-like particles are reasonably more suitable for the preparation textured ceramics by tape-casting process. Beside this, the BNT particles prepared by CMO possess small- and spherical-type grains. This kind of spherical grains is not appropriate to use as templates in development textured ceramics by RTGG technique. The EDS spectra of the BNT particles produced by TMC and CMO processes are displayed in **Figure 5**. This spectra clearly show the presence of Bi3+, Na+ , Ti4+, and O2− ions in the particles, recommending successful synthesis of BNT particles through both processes. Additionally, the ratio of mBi3+:mNa:mTi4+:mO2− is close to the stoichiometric amount of the receptive BNT composition [38] in both cases.

**Figure 4.** FE-SEM micrograph of Bi0.5Na0.5TiO3 particles synthesized by different methods (a) topochemical microcrys‐ tal conversion, (b) conventional mixed oxide route. Reprinted with permission from Hussain et al. [38] with a copy‐ right from Elsevier 2015.

**Figure 5.** EDS spectrum of Bi0.5Na0.5TiO3 particles synthesized by different methods (a) topochemical microcrystal con‐ version, (b) conventional mixed oxide route [38].

**Figure 6** provides the Raman scattering spectra (in range 100–1000 cm−1) of the polished surface of NBT particles measured at room temperature. The different vibration modes observed in Raman spectra of both sample is consistent with previously reported NBT-based ceramics [40– 44]. The Raman-active mode (A1) positioned around 150 cm−1 is associated with the *A*-site cations vibrations of the perovskite structure, which could be due to cations distortion or clusters of octahedral [BiO6] and [NaO6]. The peak around 270 cm−1 is attributed to the Ti–O vibrations, and the wavenumber in the range of 450–700 cm−1 often known as host modes is related to the TiO6 octahedra vibrations, while high-frequency range over 700 cm−1 is due to

**Figure 6.** Raman scattering spectra of Bi0.5Na0.5TiO3 particles synthesized by different methods (a) topochemical micro‐ crystal conversion, (b) conventional mixed oxide route.

overlapping of A1 (longitudinal optical) and E (longitudinal optical) bands. The NBT particles produced by TMC method show broadened and diffuse peaks around 270 cm−1 (Ti–O) and 450–700 cm−1 (TiO6) vibration modes. It can be noted that the two individual TiO6 octahedra vibration modes tend to diffuse, where the later mode centered around 550 cm−1 of the TMCsynthesized BNT sample exhibits weakening in intensity, which indicates the softening behavior in modes. Such phonon behavior suggests higher asymmetry in structure.

**Figure 7** presents the TEM pictures of the BNT particles synthesized by TMC and CMO methods, respectively. The SEAD pattern of the BNT particles synthesized by TMC method shows dot pattern (**Figure 7a**), suggesting its single-crystal-type behavior, while that synthe‐ sized by CMO exhibits a ring-type configuration (**Figure 7b**) indicating a polycrystalline nature. The lattice spacing calculated from the HRTEM image (**Figure 7c**) of the TMCsynthesized BNT particles is 0.389 nm, which is consistent with the lattice spacing of the cubic (100) plane. This calculation suggests that TMC-synthesized BNT particles have a singlecrystal nature and preferentially grow along the [100] direction which is further confirmed by the SAED pattern provided in (**Figure 7a**). Beside this, the lattice spacing of the CMOsynthesized BNT particles calculated from the HRTEM image (**Figure 7b**) is 0.275 nm; this value is consistent with the (110) plane lattice spacing of the BNT composition signifying a grain orientation of particles along [110] direction. These findings verify the XRD analysis of BNT particles synthesized by different routes. Therefore, the variation in microstructure along with the difference in lattice spacing of the CMO- and TMC-synthesized BNT particles indicates their successful fabrication [38].

**Figure 5.** EDS spectrum of Bi0.5Na0.5TiO3 particles synthesized by different methods (a) topochemical microcrystal con‐

**Figure 6** provides the Raman scattering spectra (in range 100–1000 cm−1) of the polished surface of NBT particles measured at room temperature. The different vibration modes observed in Raman spectra of both sample is consistent with previously reported NBT-based ceramics [40– 44]. The Raman-active mode (A1) positioned around 150 cm−1 is associated with the *A*-site cations vibrations of the perovskite structure, which could be due to cations distortion or clusters of octahedral [BiO6] and [NaO6]. The peak around 270 cm−1 is attributed to the Ti–O vibrations, and the wavenumber in the range of 450–700 cm−1 often known as host modes is related to the TiO6 octahedra vibrations, while high-frequency range over 700 cm−1 is due to

**Figure 6.** Raman scattering spectra of Bi0.5Na0.5TiO3 particles synthesized by different methods (a) topochemical micro‐

version, (b) conventional mixed oxide route [38].

32 Piezoelectric Materials

crystal conversion, (b) conventional mixed oxide route.

**Figure 7.** TEM images of Bi0.5Na0.5TiO3 particles synthesized by different techniques (a) SAED pattern of Bi0.5Na0.5TiO3 particles synthesized by topochemical microcrystal conversion method, (b) SAED pattern of Bi0.5Na0.5TiO3 particles synthesized by conventional mixed oxide route, (c) HRTEM image of Bi0.5Na0.5TiO3 particles synthesized by topochem‐ ical microcrystal conversion method, (d) HRTEM image of Bi0.5Na0.5TiO3 particles synthesized by conventional mixed oxide route Reproduced from reference [38] with a copyright from Elsevier 2015.

The BNT particles synthesized by TMC method were further utilized as templates for texture development of BNT–BZ ceramics. **Figure 8** shows a schematic diagram for the development of textured BNT–BZ ceramics by tape-casting method. A green sheet of a thickness about 100 μm was formed on SiO2-coated polyethylene film through a doctor blade technique, and 25 different green sheets were laminated and hot-pressed to develop a thick green compact of about 2 mm. The green compacts were then sintered to measure their structural and electro‐ mechanical properties.

**Figure 8.** Schematic diagram of the textured BNT–BZ ceramics produced by RTGG method.

**Figure 9a, b** provides a comparison of the XRD pattern of the textured and non-textured BNT– BZ ceramics. For texture development of BNT–BZ ceramics, 15 wt% BNT templates were used as seed particles. The diffraction pattern of both samples display a single-phase perovskite structure**.** Textured sample (**Figure 9a**) produced by RTGG process shows (100) and (200) peaks much higher than that of the corresponding non-texture sample, suggesting a preferred grain orientation. The non-textured ceramic (**Figure 9b**) produced by conventional method shows a strong (110) diffraction peak indicating a random orientation. The overall comparison shows that the textured ceramics exhibit [100] diffraction peak dominant, indicating that a large fraction of grains are aligned with their *a*-axis normal to the sample surface. The degree of grain orientation was estimated by the Lotgering factor (F), which is given by

$$F = \frac{P - P\_o}{1 - P\_o}$$

Where

#### Grain-Oriented Bi0.5Na0.5TiO3–BaZrO3 Piezoelectric Ceramics http://dx.doi.org/10.5772/62688 35

**Figure 9.** XRD pattern of the BNT–BZ ceramics (a) textured sample, (b) non-textured sample.

The BNT particles synthesized by TMC method were further utilized as templates for texture development of BNT–BZ ceramics. **Figure 8** shows a schematic diagram for the development of textured BNT–BZ ceramics by tape-casting method. A green sheet of a thickness about 100 μm was formed on SiO2-coated polyethylene film through a doctor blade technique, and 25 different green sheets were laminated and hot-pressed to develop a thick green compact of about 2 mm. The green compacts were then sintered to measure their structural and electro‐

**Figure 8.** Schematic diagram of the textured BNT–BZ ceramics produced by RTGG method.

grain orientation was estimated by the Lotgering factor (F), which is given by

**Figure 9a, b** provides a comparison of the XRD pattern of the textured and non-textured BNT– BZ ceramics. For texture development of BNT–BZ ceramics, 15 wt% BNT templates were used as seed particles. The diffraction pattern of both samples display a single-phase perovskite structure**.** Textured sample (**Figure 9a**) produced by RTGG process shows (100) and (200) peaks much higher than that of the corresponding non-texture sample, suggesting a preferred grain orientation. The non-textured ceramic (**Figure 9b**) produced by conventional method shows a strong (110) diffraction peak indicating a random orientation. The overall comparison shows that the textured ceramics exhibit [100] diffraction peak dominant, indicating that a large fraction of grains are aligned with their *a*-axis normal to the sample surface. The degree of

1

*P P <sup>F</sup> P* - = -

*o o*

mechanical properties.

34 Piezoelectric Materials

Where

where *I* and *I*o are the relative intensity of the diffraction peaks of the textured and non-textured ceramics, respectively, and (h00) and (hkl) are their miller indices. The degree of grain orientation obtained by the method is not very accurate due to the intensity of the diffraction peaks from which the slightly misaligned grains are not counted in the measurement of *I*(h00) and *I*(hkl). However, the *F* values are used in this work because of their convenience in the measurements. The *F* values vary from zero for a randomly oriented sample, to one, for a completely oriented sample. The *F* values were calculated from the diffraction peaks lies in the 2*θ* range from 20° to 70°. A high Lotgering factor *F* about 0.83 was obtained for the textured BNT–BZ sample, signifying a high degree of preferred grain orientation. This result also indicates that the plate-like BNT templates are proficient in prompting grain orientation in the BNT–BZ ceramics. Previously, Tam et al. [45] utilized (20 wt%) BNT templates for Bi0.5Na0.35K0.1Li0.05TiO3 (BNKLT) ceramics and reported a Lotgering factor of 0.6. The results obtained in this work indicate that the present high-quality BNT template by TMC process has the potential to develop oriented ceramics with enhanced grain orientation factor in regular perovskite-type ceramics. Moreover, high grain orientation factor of the textured BNT–BZ ceramics usually improves the piezoelectric properties in comparison with the non-textured sample of the same material [38].

The temperature dependence of the dielectric constant (ε) and loss (tanδ) of the textured and non-textured BNT–BZ ceramics measured at different frequencies (1, 10, and 100 kHz) is shown in **Figure 10**. Both samples show increase in dielectric constant with increase in temperature up to certain value and then decrease with further increase in temperature. At all measured frequencies, textured sample exhibits two visible diffuse dielectric anomalies, termed as a depolarization temperature (*T*d) appeared at 140°C along with a permittivity maximum temperature (*T*m) around 280°C. Nevertheless, the *T*<sup>d</sup> anomaly is not visible in the dielectric curves of the non-textured specimen and its *T*m values are lower than that of the textured sample. The fading of *T*<sup>d</sup> anomaly in the non-textured specimen signifies the weak‐ ening of the ferroelectric phase and formation of the relaxor phase as reported previously for BNT–BZ system [44]. The dielectric constant measured at room temperature increased from 1200 for the non-texture sample to 1500 for the textured sample. Furthermore, the dielectric loss of the textured sample is slightly higher than that of non-textured sample, probably due to its lower density and defects/impurities introduced into the green laminates during the tapecasting process.

**Figure 10.** Dielectric constant and loss of BNT–BZ ceramics (a) textured sample, (b) non-textured sample.

**Figure 11a, b** shows the room temperature P–E hysteresis loops of the textured and nontextured BNT–BZ ceramics measured at 50 Hz. The textured sample (**Figure 11a**) exhibits a pinch-type P–E loop, while the non-textured sample (**Figure 11b**) exhibits a slim at an applied field of 70 kV/cm. Moreover, texture development improved the ferroelectric response of the BNT–BZ ceramics. The remnant and maximum polarization at an electric field of 70 kV/cm, respectively, increased from 5 and 26 μm/cm2 for non-textured sample to 11 and 35 μm/cm2

**Figure 11.** Ferroelectric response of BNT–BZ ceramics (a) textured sample, (b) non-textured sample.

for it textured counterpart. The coercive field (*E*c) increased from 13 kV/cm for the non-textured sample to 18 kV/cm for the textured sample. This enhancement in the polarization can be associated with the crystallographic grain orientation of the textured sample.

BNT–BZ system [44]. The dielectric constant measured at room temperature increased from 1200 for the non-texture sample to 1500 for the textured sample. Furthermore, the dielectric loss of the textured sample is slightly higher than that of non-textured sample, probably due to its lower density and defects/impurities introduced into the green laminates during the tape-

**Figure 10.** Dielectric constant and loss of BNT–BZ ceramics (a) textured sample, (b) non-textured sample.

**Figure 11.** Ferroelectric response of BNT–BZ ceramics (a) textured sample, (b) non-textured sample.

respectively, increased from 5 and 26 μm/cm2

**Figure 11a, b** shows the room temperature P–E hysteresis loops of the textured and nontextured BNT–BZ ceramics measured at 50 Hz. The textured sample (**Figure 11a**) exhibits a pinch-type P–E loop, while the non-textured sample (**Figure 11b**) exhibits a slim at an applied field of 70 kV/cm. Moreover, texture development improved the ferroelectric response of the BNT–BZ ceramics. The remnant and maximum polarization at an electric field of 70 kV/cm,

for non-textured sample to 11 and 35 μm/cm2

casting process.

36 Piezoelectric Materials

**Figure 12.** Unipolar field-induced strain response of BNT–BZ ceramics (a) textured sample, (b) non-textured sample. Reproduced from reference [38] with a copyright from Elsevier 2015.


**Table 1.** Dielectric and piezoelectric properties of textured and non-textured BNT–BZ ceramics.

The field-induced unipolar strain of the textured and non-textured BNT–BZ ceramics was examined at an applied electric field of 70 kV/cm and is shown in **Figure 12**. The overall fieldinduced strain response of textured specimen (**Figure 12a**) is higher than that of the nontextured sample (**Figure 12b**). The unipolar field-induced strain level raised from 0.15% for the non-textured sample to 0.30% for the textured sample. The corresponding normalized strain (*d*\* 33 = *S*max/*E*max) obtained for these specimens are 214 and 428 pm/V, respectively. **Table 1** provides the density, dielectric, and piezoelectric response of the textured and non-textured BNT–BZ samples at room temperature. The comparison of both specimens clearly shows that textured ceramics have a better electromechanical properties than non-textured counterparts. The dielectric constant measured at room temperature increased from 1200 to 1500, while the unipolar field-induced strain level enhanced from 0.15 to 0.30% for the non-textured and textured samples, respectively. This is almost 25 and 100% enhancement after texturing process. This increase in dielectric and field-induced strain response can be attributed to the (100) preferred orientation developed by plate-like BNT templates. The results obtained from the BNT–BZ ceramics evidently show that texture development significantly improve the electromechanical properties of the BNT–BZ ceramics and enable them as promising lead-free candidates in piezoelectric industry.
