Temperature Of Permittivity Maximum Research Articles

Composition design of BNBT-ST relaxor ferroelectric ceramics in superparaelectric state with ultrahigh energy density

BNT-6BT-based lead-free ceramics have gained significant attention due to their relatively large piezoelectric coefficients and tunable morphotropic phase boundary conditions. In this investigation, SrTiO3 (ST) was added to BNT-6BT ceramics to fabricate the BNT-6BT-xST (BNBT-xST) composition. The impact of ST content on the phase structure and dielectric permittivity of the BNBT-xST ceramics was studied. The XRD refinement data show that with increasing ST content, the crystal structure of BNBT-xST ceramics was transformed from the morphotropic phase structure (coexisting tetragonal (P4/mmm) and pseudo-cubic (Pmm) phase) to the pseudo-cubic phase. The dielectric permittivity data of the BNBT-80ST showed that the Tm (the maximum permittivity temperature) moved to −61.9 °C, which caused the room temperature to fall within the range of Tm < T < TB (the Burns temperature). This makes the BNBT-80ST a superparaelectric state in relaxor ferroelectrics (RFE). Furthermore, the maximum energy density and the charge-discharge efficiency of the BNBT-80ST achieved 5.48 J/cm3 and 87% at 495 kV/cm, respectively. The energy density of the BNBT-80ST was improved by 2.97-fold and 49% compared with that of the BNBT-30ST and BNBT-70ST. This is mostly attributed to weakened ferroelectricity and improved paraelectricity in the BNBT-80ST. This investigation demonstrates that BNBT-xST ceramics can be adjusted to a superparaelectric state with an ST content of 80%. This makes the material to possess both a large polarization and a high breakdown field. This material holds great promise for high energy density capacitor applications.

Structural evolution and coexistence of ferroelectricity and antiferromagnetism in Fe, Nb co-doped BaTiO3 ceramics

Multiferroics are materials that exhibit two or more primary ferroic properties within the same phase and have potential applications in sensors, spintronics and memory devices. Here, the dielectric, ferroelectric and magnetic properties of novel multiferroics derived from BaTi1−x(Fe0.5Nb0.5)xO3 (BTFN, 0.01 ≤ x ≤ 0.10) ceramics are investigated. Multiferroism in these ceramics is manifested by the coexistence of ferroelectric long-range ordering and antiferromagnetism. With increasing x-value, there is a structural evolution from a tetragonal perovskite to a mixture of tetragonal and cubic phases, accompanied by a decrease in the temperature of maximum permittivity. At room temperature, ferroelectric behaviour is evidenced by the presence of current peaks corresponding to domain switching in the current-electric field loops, while the observation of non-linear narrow magnetic hysteresis loops suggests dilute magnetism. The results indicate that in the x = 0.07 composition the antiferromagnetic order is established through an indirect super-exchange interaction between adjacent Fe ions.

Research on optimized piezoelectric properties of PNN-PMN-PT ceramics and corresponding underlying factors based on component regulation

To meet the increasing demands for developing miniaturized high-precision modern piezoelectric devices, researchers are focusing their attention on PbTiO3 (PT) relaxor ferroelectrics having excellent comprehensive performance. Although the partial substitution of Pb(Mg1/3Nb2/3)O3 (PMN)-PT with Pb(Ni1/3Nb2/3)O3 (PNN)-PT has been reported to improve dielectric and piezoelectric properties, the factors underlying the performance improvement of the PNN-PMN-PT ternary system remain unclear. Therefore, based on PT content regulation, the 0.128PNN-(0.872-x)PMN-xPT (x = 0.316, 0.326, 0.336, 0.346, and 0.356) ternary ceramics were fabricated, and the crystal structure and electrical properties were systematically investigated during the rhombohedral-tetragonal phase transition. The 0.128PNN-0.536PMN-0.336PT composition exhibited optimum performance with the piezoelectric charge coefficient, effective piezoelectric strain coefficient, dielectric constant were 691 pC/N, 1060 pm/V and 4545 respectively at a maximum permittivity temperature of 136 ℃, signifying its potential for use in transducers and actuators. The outstanding properties of this system were mainly derived from the lattice distortion and reversible domain wall motion. The results indicated that the multiphase coexistence and enhanced B-site disorder in the perovskite structure contribute to the improvement in the piezoelectric properties, which would facilitate the design and development of novel piezoelectric materials.

Giant energy storage efficiency and low strain hysteresis in lead-free relaxor ferroelectrics by designing the dynamic behavior of PNRs

Lead-free ferroelectric ceramics have aroused widespread concerns, due to their properties of rapid charge/discharge and electric-induced strain without harming the environment. However, compared with thin-film capacitors, ceramics have a larger energy loss. In addition, the large time lag between electric field and strain also reduces its accuracy as an actuator. Therefore, the relaxor ternary solid solution (BaTiO3–Bi0.48Na0.48La0.03TiO3–NaNbO3) was constructed in this work, aiming to obtain large energy storage efficiency and low time delay. The strategy and optimization aim to improve the relaxation degree and reduce the maximum permittivity temperature to room temperature, building a special crossover region where high and low dynamic polar nano regions co-existence. Thus a recoverable energy density of 1.24 J/cm3 under a low electric field (135 kV/cm) and a high energy storage efficiency (96%) are obtained and low hysteresis electrostriction with a large electrostriction coefficient (Q33 = 0.0367 m4/C2) is also achieved in this system. This work suggests that this system can be considered promising materials as high-efficiency capacitors and high-precision actuators. It also attracts interest in the basic research on the dynamic changes of polar nano regions.

High Electrocaloric Effect in Lead Scandium Tantalate Thin Films with Interdigitated Electrodes.

Lead scandium tantalate, Pb(Sc,Ta)O3, is an excellent electrocaloric material showing large temperature variations, good efficiency, and a broad operating temperature window. In form of multilayer ceramic capacitors integrated into a cooling device, the device can generate a temperature difference larger than 13 K. Here, we investigate Pb(Sc,Ta)O3 in form of thin films prepared using the sol–gel chemical solution deposition method. We report the detailed fabrication process of high-quality films on various substrates such as c-sapphire and fused silica. The main originality of this research is the use of interdigitated top electrodes, enabling the application of very large electric fields in PST. We provide structural and electrical characterisation, as well as electrocaloric temperature variation, using the Maxwell relation approach. Films do not show a B-site ordering. The temperature variation from 7.2 to 15.7 K was measured on the Pb(Sc,Ta)O3 film on a c-sapphire substrate under the electric field of 1330 kV/cm between 14.5 °C and 50 °C. This temperature variation is the highest reported so far in Pb(Sc,Ta)O3 thin films. Moreover, stress seems to have an effect on the maximum permittivity temperature and thus electrocaloric temperature variation with temperature in Pb(Sc,Ta)O3 films. Tensile stress induced by fused silica shifts the “transition” of Pb(Sc,Ta)O3 to lower temperatures. This study shows the possibility for electrocaloric temperature variation tuning with stress conditions.

Grain-size-insensitive dielectric properties of Sr0.6Ba0.4Nb2O6 relaxor ferroelectric ceramics with tetragonal tungsten bronze structure

The influence of grain size on the dielectric properties of Sr0.6Ba0.4Nb2O6 (SBN60) ceramics with a tetragonal tungsten bronze structure was examined. The conventional and two-step sintering procedures were used to fabricate dense and phase-pure SBN60 ceramics with grain sizes ranging from 2.2 μm to 17.3 μm. In the temperature dependence of the dielectric permittivity, all samples showed a relaxor-like broad dielectric peak with a maximum at around 60 °C. The maximum dielectric permittivity and dielectric maximum temperature of the SBN ceramics were found to be less dependent on the grain size. The reason for the grain-size-insensitive dielectric properties of the SBN60 ceramics is discussed based on the analysis of the dielectric properties and Raman spectra.

Influence of processing parameters on the ferroelectric-relaxor crossover in BNT-based piezoelectric ceramics

The effects of sintering time on the ferroelectric to relaxor crossover were systematically investigated for Sr(Hf0.5Zr0.5)O3-modified Bi0.5(Na0.8K0.2)TiO3 ceramics, prepared using the conventional solid-state mixed-oxide route. Scanning electron microscopy indicated a modest increase in grain size from 1.0 ± 0.2 to 2.0 ± 0.5 μm when the sintering time increased from 2 to 24 h. Furthermore, it was observed that the sintering time does not affect the long-range average crystal structure, as x-ray diffraction data suggest the presence of a single pseudocubic phase for all the samples, irrespective of the sintering time. Interestingly, ferroelectric and piezoelectric characterization showed evidence of a ferroelectric to relaxor transition when the sintering time increased from 2 to 6 h. This transition was marked by a sudden decrease in remanent polarization, a loss in negative strain along with a drastic increase in the maximum electromechanical strain. This was further exemplified in the unipolar strain data, which showed a transition from linear to non-linear dependence with electric field when the sintering time increased from 2 to 6 h. The piezoelectric properties were enhanced with further increase in sintering time up to 12 h, with the corresponding normalized strain value (Smax/Emax) d33∗=647pm/V. However, the d33∗ decreased with further increase in sintering time to 24 h. As the sintering time increased, temperature-dependent dielectric data show a decrease in the maximum permittivity along with the slight shift of the Tmax (temperature of maximum permittivity) to a higher temperature. In addition, results from impedance spectroscopy indicate that the DC resistivity increased by approximately two orders of magnitude when the sintering time increased from 2 to 12 h. These results suggest that while sintering time has a minimal impact on either the microstructure or the long-range average structure, it has a strong influence on the ferroelectric to relaxor crossover, which is often associated with enhanced electromechanical properties. This work presents further evidence that the crossover phenomenon is closely tied to the local structure, where disruption of the long-range dipole order results in stabilization of the relaxor state.

Electrocaloric temperature changes in epitaxial Ba1−xSrxTiO3 films

The basic aim of our study is to investigate the correlation between structural parameters and the electrocaloric effect in lead-free epitaxial Ba1−xSrxTiO3 (BSTO) based thin film architectures. Therefore, BSTO thin films with Sr contents of x = 0 to x = 0.3 were grown on SrRuO3 buffered SrTiO3 single crystalline substrates by pulsed laser deposition. Structural characterization verified an epitaxial growth for all Sr contents with an additional tetragonal distortion compared to bulk material. Temperature and frequency-dependent measurements of dielectric properties revealed increased permittivity values for thicker films with broad maxima indicating a diffuse phase transition. The temperature of maximum permittivity decreases with increasing Sr content, whereas polarization measurements indicate a relaxor-like behaviour in particular above room temperature. Adiabatic temperature changes were determined with the indirect method resulting in |ΔT| values of up to 2.9 K for a 680 nm thick BSTO layer with x = 0.3 at an applied electric field of 750 kV cm−1.

Influence of the stoichiometry, microstructure, and metallization method on the dielectric properties of 0.94 Na0.5Bi0.5TiO3‐0.06 BaTiO3

AbstractThe morphotropic composition of the lead‐free solid solution between Na0.5Bi0.5TiO3 and BaTiO3 (0.94 Na0.5Bi0.5TiO3‐0.06 BaTiO3 or NBT‐6BT) is of particular interest for the next generation of high‐temperature capacitors but remains plagued by the diversity of dielectric properties reported in the literature. In order to explain the apparent inconsistencies among the reported dielectric properties of NBT‐6BT, we examine the influence of stoichiometry, phase separation, and metallization method. We show that the nominal stoichiometry has a crucial effect, since increasing the nominal Na/Bi ratio increases conductivity and dielectric losses (tan δ). It also increases the real part of the permittivity (ε’) and the frequency dispersion of both ε’ and tan δ, thereby altering the shape of the evolution with temperature of the dielectric properties. Moreover it increases the depolarization temperature (Td) and decreases the temperature of maximum permittivity (Tm). Phase separation also occurs during the synthesis of NBT‐6BT as Na evaporation leads to the formation of secondary Ba‐containing phases. We report that these phases can have a positive impact on the dielectric properties: a moderate volume fraction (2.5 to 3.0%) and average grain surface (0.9 to 3.0 µm2) of these secondary Ba‐containing phases increase the relative permittivity, decrease the dielectric losses, and increase the insulation resistance. We also show that the metallization method impacts the dielectric properties and therefore may contribute to the differences between various reports. The dielectric properties of NBT‐6BT samples are measured during successive heating/cooling cycles and reveal that the permittivity value is lower during the first heating when silver paste, even cured, is used. These three components contribute to explaining the diversity of the reported dielectric properties of NBT‐6BT.

Structural and dielectric properties of sol–gel processed Ce-doped BaTi0.97Y0.03O3 ceramics

Structural and dielectric properties of Ce-doped [Formula: see text][Formula: see text]O3 powders, with the chemical formulation (Ba[Formula: see text][Formula: see text](Ti([Formula: see text]- [Formula: see text]O3 such as [Formula: see text] = 0%, 1%, 3%, 5%, 7% and 9%, produced by the sol–gel method, have been investigated. X-ray diffraction analysis showed that Ce[Formula: see text] ions incorporated Ba sites until [Formula: see text]= 7% indicating that this concentration represents a solubility limit of Ce[Formula: see text] ions in [Formula: see text][Formula: see text]O3 matrix. Scanning electron microscopy (SEM) analysis showed a decrease in grain size down to the same concentration of 7%. Raman spectroscopy analysis showed the appearance of [Formula: see text] mode, which we attributed to the effect of incorporation of Ce[Formula: see text] and Y[Formula: see text] in BaTiO3 matrix. Dielectric measurements revealed that doping with cerium lowers the temperature of permittivity maximum at the ferroelectric-to-paraelectric transition (FPT) of the [Formula: see text][Formula: see text]O3 sample, and reaches a value that should be below [Formula: see text]C for [Formula: see text]= 9%. Moreover, the phenomenon of dielectric resonance was observed on all Ce-doped samples, which was not the case with other dopants as reported in the literature.

Effect of sintering temperature on dielectric properties of barium titanate ceramics and composite

The structure and dielectric properties of barium titanate ceramics samples sintered at 1100, 1150, 1200, 1250 and 1350 °C have been compared with the dielectric properties of 80 vol.% barium titanate + 20 vol.% barium ferrite composite samples sintered at 1150, 1200 and 1250 °C. It has been shown that polarization sufficient for existence of the piezoelectric effect is only achieved in barium titanate samples sintered at 1250 and 1350 °C. Furthermore the pyroelectric coefficient and reversal polarization of these samples are far higher than those of samples sintered at lower temperatures. Analysis of the sample structures has confirmed that the dielectric properties of barium titanate ceramics depend on grain size and therefore on sintering temperature. Based on the experimental results we have selected the optimum sintering temperature for 80 vol.% barium titanate + 20 vol.% barium ferrite composite to be 1250 °С. Further increase in sintering temperature to 1300 °C showed that this composite has a eutectic. The temperature dependence of the permittivity of the barium titanate / barium ferrite composite sintered at 1250 °С is similar to that of BaTiO3 ceramics samples sintered at 1350 °С. The room temperature permittivity of the composite samples also proves to be far higher than that of barium titanate ceramics samples sintered at the same temperatures. Barium ferrite addition to barium titanate increases the permittivity of the composite and also diffuses the ferroelectric phase transition and shifts the permittivity maximum temperature by 10 °C towards higher temperatures.

Dielectric and ferroelectric properties evolution of (1−x)(Bi0.5Na0.5TiO3)–xK0.5Na0.5NbO3 piezoceramics

In this work, piezoceramics of (1−x)(Bi0.5Na0.5)TiO3–x(K0.5Na0.5)NbO3, (1−x)BNT–xKNN, in the compositional range 0.00 ≤ x ≤ 0.07, were prepared by a mechanochemically activated solid-state method. The structural phase formation and microstructural, dielectric, and ferroelectric properties were studied. Although changes, in symmetry of the perovskite structure, were not detected with the composition (i.e., from a perspective of its intrinsic properties), the microstructural evolution was strongly dependent on the content of the KNN phase (i.e., based on its extrinsic properties). Specifically, KNN favoured the formation of a microstructure with cubic grains, typical morphology of the alkaline niobate ceramics. After KNN addition, both the maximum permittivity temperature and the long-range to short-range ordered transition temperature were reduced. Additionally, ferroelectric loops and strain deformation curves also reflect the long-range to short-range order evolution with KNN addition and temperature.

Investigation of microstructure and dielectric properties of LaMnO3 doped BaTiO3 ceramics

The microstructure and dielectric properties of LaMnO3 (LM) doped BaTiO3 (BT) ceramics have been investigated. By adding LM, (1–x)BT-xLM (x = 0–0.5) ceramics keep in a single-phase solid-solution state, but gradually transform from tetragonal structure to pseudocubic one, and much denser microstructure is obtained. As for dielectric properties, when x ≤ 0.1, the Curie temperature of BT-LM shifts to a lower temperature and the permittivity maximum is lowered with the increase of LM content, which are attributed to the introduction of La2O3 and the degradation of tetragonality, respectively. When x > 0.1, BT–LM presents a typical relaxation behavior. Colossal permittivity appears as x reaches 0.4, which is related to large number of giant electron-pinned defect-dipoles ( $${\text{Mn}}^{4 + } \cdot 2e - V_{\text{O}}^{ \cdot \cdot }$$ ) and existence of grain-boundary segregation. Detailed analyses show that 0.5BT–0.5LM possesses the highest permittivity maximum (41,683) and widest temperature range (– 42 to 300 °C) with permittivity larger than pure BT at 100 kHz. Therefore, 0.5BT–0.5LM can be a very promising candidate as colossal permittivity material.

Dielectric relaxation properties of [001]c‐, [011]c‐, and [111]c‐oriented 0.24PIN‐0.47PMN‐0.29PT single crystals

AbstractThe dielectric relaxation properties and freezing behavior of polar nanoregions (PNRs) of 0.24Pb(In1/2Nb1/2)O3‐0.47Pb(Mg1/3Nb2/3)O3‐0.29PbTiO3 single crystals have been studied. The Burns temperature TB, permittivity maximum temperature Tm, and freezing temperature Tf were determined, respectively. It was found that the temperature‐dependent dielectric constant can be well described by the Lorenz‐type relationship in the ergodic phase due to the existence of PNRs. The diffuseness factor δ is &gt;30 and is basically not dependent on crystal orientation. The frequency dependence of Tm obeys the Vogel‐Fulcher relationship. The residual effect of the poling electric field disappears and the remnant polarization has a sharp decrease near the freezing temperature Tf.

Optimisation of SrBi2(Nb,Ta)2O9 Aurivillius phase for lead-free electrocaloric cooling

The influence of different substitutional mechanisms on the electrocaloric effect of a lead-free SrBi2(Nb0.2Ta0.8)2O9 Aurivillius phase was studied for application in electrocaloric cooling systems. The A-site substitution with barium efficiently reduced the temperature of maximum permittivity from about 300 °C to 100 °C. The A-site substitution induced phenomena that are typical of strong relaxor ferroelectrics such as significant broadening of the permittivity peak and an increase in its frequency dispersion and with a depolarization temperature below room temperature. These features directly influenced the electrocaloric effect. A direct measurement system, based on a modified-differential scanning calorimeter, was used to analyze the EC effect of the dense (Sr0.5Ba0.5)Bi2(Nb0.2Ta0.8)2O9 ceramics. In accordance with the relaxor characteristics, the EC effect was found to increase continuously over a broad temperature range above the room temperature. This was attributed to the alignment of field induced polar nanodomains. Directions for optimization towards a high-performing EC ceramic were identified.

High electromechanical strain and enhanced temperature characteristics in lead-free (Na,Bi)TiO3\u2013BaTiO3 thin films on Si substrates

Here, we demonstrate the high electromechanical strain and enhanced temperature characteristics in the c-axis-oriented lead-free (Na,Bi)TiO3–BaTiO3 (NBT–BT) polycrystalline thin film prepared on Si substrates by rf magnetron sputtering. The effective transverse piezoelectric coefficient, e31*, estimated from the electromechanical strain measured under high electric field, reaches a high level of −12.5 C/m2, and is comparable to those of conventional Pb(Zr,Ti)O3 films. In-situ X-ray diffraction measurement and electron diffraction analysis revealed the electromechanical strain of the NBT–BT film to originate predominantly in elongation of the tetragonal (P4bm) crystal lattice in the c-axis direction. In addition to the large e31*, the NBT–BT film exhibits enhanced permittivity maximum temperature, Tm, of ~400 °C and no depolarization below Tm, as compared to bulk NBT–BT having Tm ≈ 300 °C and a depolarization temperature of ~100 °C. We conclude that the enhancement of temperature characteristics is associated with the distorted P4bm crystal lattice formed by deposition-induced stress and defects. We believe that the present study paves the way for practical applications of lead-free piezoelectric thin films in electromechanical devices.

Dielectric anomalies in stoichiometric Bi.49Er.01Na.5TiO3-K.5Na.5NbO3 ceramics

(1-x)Bi.49Er.01Na.5TiO3-xK.5Na.5NbO3 (abbreviated as BENT-xKNN) ceramics have been prepared via solid state reaction technique and their electric properties have been investigated by impedance spectroscopy. X-ray diffraction results show that the incorporation of KNN into BENT forms (Bi.49Er.01)1-xK.5xNa.5Ti1-xNbxO3 solid solution with perovskite structure. Dielectric measurements reveal that there exists a diffuse anomaly above permittivity-maximum temperature whether heating or cooling, which exhibits thermal hysteresis at low frequency. It is proposed that the anomaly is probably ascribed to weakly bound electrons trapped in NbTi• and VO•• defects based on a piecewise fitting for their conductivity vs. temperature.

Structure and dielectric properties of (Ba0.7Sr0.3)1−x Na x (Ti0.9Sn0.1)1−x Nb x O3 ceramics

(Ba0.7Sr0.3)1−x Na x (Ti0.9Sn0.1)1−x Nb x O3 ceramics with compositions x = 0.6, 0.7, 0.8 and 0.9 were synthesized using the solid-state reaction method. These ceramics were examined by X-ray diffraction and dielectric measurements over a broad temperature and frequency ranges. X-ray diffraction patterns revealed a single-perovskite phase crystallized in a cubic structure, for x < 0.8, and in tetragonal, for x ≥ 0.8, with Pm3m and P4mm spaces groups, respectively. Two types of behaviors, classical ferroelectric or relaxor, were observed depending on the x composition. It is noted that temperatures T C (the Curie temperature) or T m (the temperature of maximum permittivity) rise when x increases and the relaxor character grows more significantly when x composition decreases. To analyze the dielectric relaxation degree of relaxor, various models were considered. It was proven that an exponential function could well describe the temperature dependence of the static dielectric constant and relaxation time.

Electrocaloric effect in lead-free Aurivillius relaxor ferroelectric ceramics

A lead-free Aurivillius phase based on SrBi2(Nb0.2Ta0.8)2O9 was studied for potential application in electrocaloric (EC) cooling systems. Doping with praseodymium proved to be effective in reducing the temperature of maximum permittivity from about 300 °C to 80 °C. The praseodymium doping also led to a broadening of the permittivity peak and an increase in its frequency dispersion, which are typical features of strong relaxor ferroelectrics. A direct measurement system, based on a modified-differential scanning calorimeter, was used to analyze the EC effect of dense SrBi1.85Pr0.15(Nb0.2Ta0.8)2O9 ceramics. Unlike the trend observed in classic ferroelectrics, the EC effect in this relaxor ferroelectric was found to increase significantly over a broad temperature range well above the temperature of depolarization. This was attributed to the contribution of the polar nanodomain alignment that is induced by the external electric field. Directions for further optimization of this lead-free relaxor towards a high-performing EC material were identified. A comparison between the direct and indirect EC measurements showed significant discrepancies, not only in a magnitude but also in the trend. These discrepancies were attributed to the non-ergodic relaxor state of the Aurivillius phase, which cannot be described with Maxwell equations. For materials displaying such characteristics indirect methods to predict EC effect may be unreliable requiring that the EC effect be measured by a direct EC characterization technique.

The Influence of Firing Temperatures on the Crystal Structure, Microstructure and Dielectric Properties of 0.68Bi0.5Na0.5TiO3-0.22Bi0.5K0.5TiO3-0.10Bi0.5Li0.5TiO3 Ceramics Prepared Via the Combustion Technique

The 0.68Bi0.5Na0.5TiO3–0.22Bi0.5K0.5TiO3–0.10Bi0.5Li0.5TiO3 (BNKLT) lead-free ferroelectric ceramics were prepared by the combustion technique. The BNKLT was calcined from 600°C to 850°C for 2 h and sintered from 900°C to 1050°C for 2 h. The XRD diffraction pattern was indexed on the basis of rhombohedral perovskite structure. The secondary phases K4Ti3O8 and K2Ti6O3 were detected in the powders calcined below 750° C. The highest perovskite percentage was observed in the powders calcined above 750°C. The sintered pellets showed single-phase perovskite structure for all samples, which indicated that K+, Bi+ and Li+ ions substituted onto the A-site in the BNKLT lattice to form a solid solution. The increase in sintering temperature up to 1025°C significantly promoted grain growth and microstructure densification. The depolarization temperature (Td) of the sample shifted to higher temperatures whereas the temperature of maximum permittivity (Tmaxε) shifted to lower temperatures with an increase in sintering temperature. The optimum dielectric properties were obtained from the sample sintered at 1025°C with ϵr = 4,340 (at Tmaxε), density (ρ = 5.79 g/cm−3) and shrinkage (∼18.4%).