Ferroelectric Tetragonal Phase Research Articles

Lattice match between coexisting cubic and tetragonal phases in PMN-PT at the phase transition

(1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) perovskite-like solid solutions are recognized for their outstanding electromechanical properties, which are of technological importance. However, some significant aspects of the crystal structures and domain assemblages in this system and the role of these characteristics in defining the functional performance of PMN-PT remain uncertain. Here, we used synchrotron x-ray diffraction to investigate the phase transition linking the paraelectric (cubic) and ferroelectric (tetragonal) phases in a single crystal of 0.65PMN-0.35PT. We analyzed the evolution of reciprocal-space maps across this transition. These maps were collected using small temperature step (1 K) and a high reciprocal-space resolution to reveal changes in the splitting of Bragg peaks caused by the formation of ferroelastic domains in the low-symmetry phase. Our results uncovered a two-phase state, cubic plus tetragonal phases, which exists over a narrow temperature range of only ≈4 K and exhibits a thermal hysteresis of ≈1.8 K. Remarkably, within this state, the lattice parameter of the cubic phase, aC, matches the orientational average of the lattice parameters for the tetragonal polymorph, 23aT+13cT. We discuss the implications of this matching, highlighting the possibility of it being realized by the formation of an assemblage of tetragonal twin domains separated from the cubic phase by a strain-free {110} boundary, as in the “adaptive phase” but without domain miniaturization.

Structural and dielectric features of (Bi0.5Na0.5)1−xBaxTiO3 lead-free ferroelectric ceramics: An approach to the phase diagram

(Bi0.5Na0.5)1−xBaxTiO3 lead-free ferroelectric ceramics were synthesized via the conventional solid-state reaction method. Structural and dielectric properties were investigated as a function of the doping concentration, considering x = 0, 2, 5, 8, 10, 12, 16, and 18 at. % Ba. The structural analyses were carried out from the x-ray diffraction technique, including the Rietveld refinement method, and Raman spectroscopy. Results confirmed the formation of the perovskite structure, revealing different crystalline symmetries, depending on the Ba2+ concentration: the single rhombohedral ferroelectric phase (R3c) for x = 0 and 2 at. %; coexistence of both rhombohedral ferroelectric (R3c) and tetragonal antiferroelectric (P4bm) phases for x = 5 at. % Ba; the single tetragonal antiferroelectric phase (P4bm) for x = 8 at. % Ba; coexistence of two tetragonal phases (antiferroelectric P4bm and ferroelectric P4mm) for x = 10 at. % Ba; and the single tetragonal ferroelectric phase (P4mm) for x = 12, 16, and 18 at. % Ba. The characteristics of the phases’ transition, investigated from dielectric analysis, revealed the presence of two dielectric anomalies, which indeed have been associated to different phases’ transitions, one of them showing relaxor-like characteristics. The obtained results offer new insights for a better understanding on the features of the phase diagram for the studied ceramic system, according to the different observed crystalline symmetries (ferroelectric and antiferroelectric) in a very wide doping concentration. In the light of the obtained results, a new phase diagram has been proposed considering a wider compositional range than those reported in the literature.

Macroscopic Piezoelectricity of Halide Perovskite Single Crystals and Their Highly Sensitive Self-Powered X-ray Detectors.

The FAxMA1-xPbI3 single crystal has excellent semiconductor photoelectric performance and good stability; however, there have been conflicting opinions regarding its macroscopic piezoelectricity. Here, the FAxMA1-xPbI3 (x = 0-0.1) single crystals (FAx SCs) exhibit a high macroscopic piezoelectric d33 coefficient of over 10 pC/N. The single crystal transforms from a tetragonal ferroelectric phase to a cubic paraelectric phase at x = 0.1-0.125. Furthermore, the fully polarized MAPbI3 and FA0.05 SCs were applied to prepare self-powered X-ray detectors with vertical structures. The sensitivity of the detector reaches 5.1 × 104 μC·Gy-1·cm-2 under a 0 V bias voltage, and its detection limit is as low as 50 nGy/s. This work provides an approach to designing self-powered and high-quality detectors with piezoelectric semiconductors.

Understanding Crystal Spatial Symmetry of Sm/Mg Heterovalent‐Doped BST–BNT Ceramics: An Effect Mechanism for Electrical Properties

The effect mechanism of lattice distortion caused by heterovalent rare‐earth and alkaline‐earth ions co‐doping in the electrical properties of piezo‐ceramics is generally concerning. Herein, the Sm2O3/MgO co‐doped 0.65(Ba0.96Sr0.04TiO3)–0.35(Bi0.50Na0.50TiO3) (BST–BNT: x(Sm, Mg)) (0 ≤ x ≤ 0.25 wt%) ceramics are prepared by Pechini sol–gel method. The reversibility transition from the tetragonal P4/mmm relaxation paraelectric phase to the tetragonal P4mm relaxation ferroelectric phase confirms the doping‐modulated piezoelectric constants’ response to the spatial symmetry. Excessive Sm3+ and Mg2+ in the interstitial lattice inhibit the Jahn–Teller effect of distortion in the crystal spatial symmetry. The restored P4/mmm spatial symmetry of BST–BNT: x(Sm, Mg) (x = 0.15 wt%) ceramics contributes to the large electric‐induced strain, increased Curie temperature, and the stabilized frequency dependence of the Curie temperature (TC [1 MHz] = 167 °C, εr [1 MHz] = 2151.92, d33 = 43 pC N−1, Smax/Emax = 535.22 pm V−1). The samples with large electric‐induced strain and good temperature stability of electrical properties can be applied in the heat dissipation actuators.

Structure, dielectric, and ferroelectric properties of (1-x)Bi0.5Na0.5TiO3 – X K0.5Na0.5NbO3 (0 ≤ x ≤ 0.1) solid solution

The correlation of the phase structure, dielectric, and ferroelectric properties of lead-free (1-x)(Na0.5Bi0.5)TiO3–xK0.5Na0.5NbO3 (NBTKNx) (0 = x ≤ 0.1) polycrystalline ceramics, fabricated via a solid state reaction technique, were investigated. The Rietveld refinement allowed identifying the crystallographic transformation from a rhombohedral to a coexisting rhombohedral-tetragonal or tetragonal long range-ordered ferroelectric (FE) phase. The dielectric investigations showed an increase of the dielectric diffuseness (1.53 = γ ≤ 1.73) and a clear shift of the depolarization temperature (Td) to a lower temperature while increasing substitution. More importantly, the lattice disorder also generated a plateau-like dielectric anomaly, leading to a thermally stable ϵr ∼2859 ± 20% (120–500 °C) and ∼3112 ± 10% (120–420 °C) for x = 0.075 and 0.1 samples, respectively. At room temperature (RT), Raman spectroscopy investigations revealed a downshift of the frequencies as a function of the composition with an inhomogeneous broadening of the Raman lines. On heating, Raman spectra showed changes in the region where the dielectric transitions are observed. Moreover, the composition dependence of the current peaks in the I-E loops confirmed the occurrence of a phase transition from a non-ergodic polar phase to an ergodic weakly polar after the applying of an electric field of 60 kV/cm−1.

Investigation of relaxor and diffuse dielectric phase transitions of Ba1-XBixTi0.8Fe0·2O3 materials

Different doping elements have been used to enhance the dielectric properties of BaTiO3 ceramic. In this work, the effect of substitution of Ba by Bi in A site and Ti by Fe in B site on structural, dielectric and electrical properties of Ba1-xBixTi0.80Fe0·20O3 ceramics at (x = 0.00, 0.05, 0.10 and 0.15) was investigated by X-ray diffraction, Raman spectroscopy, Scanning Electron Microscopy (SEM), Mössbauer spectroscopy as well as dielectric measurements. The Rietveld refinement results revealed that the prepared compounds crystallize in both tetragonal (P4mm) and hexagonal (P63/mmc) phases for x = 0.00 and 0.05 while at x = 0.10 and 0.15, the hexagonal phase disappears and only the tetragonal phase is fitted. The Raman spectra confirmed the disappearance of hexagonal phase in benefit of tetragonal phase as the Bi3+ substitution increases. Based on Mössbauer analyses results, all the samples are in paramagnetic state at room temperature and the Fe is oxidized under Fe3+ without the presence of Fe2+ or Fe4+ ions. The dielectric measurements as function of temperature are studied and tree broad and relaxor phase transitions were detected: from rhombohedral to orthorhombic phase TR-O and to tetragonal ferroelectric phase TO-T then to cubic paraelectric phase Tm. These phase transitions were displaced to the lower temperature with increasing of Bi3+ substitution. The values of ε′r increase gradually with increasing of Bi3+contents which confirmed the enhancement of dielectric properties of BaTi0·80Fe0·20O3 by Bi substitution on Ba site. The diffuse phase transitions were described by fitting the modified Uchino relation. The Cole–Cole analyses showed that both the grain and grain boundaries resistivity values are higher for Bi3+ substituted samples which are responsible to the dielectric properties improvement.

Controlling ferroelectric properties in Y-doped HfO2 thin films by precise introduction of oxygen vacancies

Thin-film ferroelectric doped hafnia has emerged as a promising candidate for non-volatile computer memory devices due to its CMOS compatibility. The ferroelectricity in thin-film HfO2 is defined by the polar orthorhombic phase, whose stabilization depends on various parameters, such as doping species, stress, thickness, crystallization annealing temperature, etc. The concentration of oxygen vacancies is yet another parameter affecting the stabilization of the ferroelectric phase in HfO2 thin films. Here, we report on the effect of oxygen vacancies introduced in Y-doped HfO2 (HYO) films during reactive pulsed laser deposition on their ferroelectric properties, which we systematically study by correlating structural and electrical properties. Among different techniques, near-edge x-ray absorption fine structure analysis is successfully employed to distinguish between structurally similar ferroelectric orthorhombic and paraelectric tetragonal phases. It is shown that oxygen vacancies introduced at a certain concentration in HYO films can be used as a tool to control the phase composition as well as to decrease the formation energy (crystallization temperature) of the ferroelectric phase. Based on these results, we demonstrate a back-end-of-line compatible ferroelectric HYO capacitor device with competitive functional properties.

Фазовые состояния твердого раствора (1-x)PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=--xPbTiO-=SUB=-3-=/SUB=-. Описание на основе многоминимумных моделей

Based on the composition of two multiminimum models, a statistical model has been developed on the basis of which the formation of tetragonal and monoclinic ferroelectric phases in a solid solution (1-x)PbFe0.5Nb0.5O3-xPbTiO3 has been investigated and described. By selecting the parameters of the model, it was possible to reproduce the diagram T(x) of this solid solution. The peculiarity of the diagram is that when approaching the concentration of x~0.1, the temperatures of the phase transitions between the tetragonal and monoclinic phases decrease sharply, turning to zero. It is shown that the disappearance of the monoclinic phase is due to the specifics of the statistical properties of the eight-minimum model describing the subsystem of octahedra with eight minima. The features of the thermodynamic properties of a solid solution in the vicinity of the morphotropic boundary between the tetragonal and monoclinic phases are also investigated

Structure, performance regulation and typical device applications of HfO<sub>2</sub>-based ferroelectric films

The rapid developments of big data, the internet of things, and artificial intelligence have put forward more and more requirements for memory chips, logic chips and other electronic components. This study introduces the ferroelectric origin of HfO<sub>2</sub>-based ferroelectric film and explains how element doping, defects, stresses, surfaces and interfaces, regulate and enhance the ferroelectric polarization of the film. It is widely accepted that the ferroelectricity of HfO<sub>2</sub>-based ferroelectric film originates from the metastable tetragonal phase. The ferroelectricity of the HfO<sub>2</sub>-based film can be enhanced by doping some elements such as Zr, Si, Al, Gd, La, and Ta, thereby affecting the crystal structure symmetry. The introduction of an appropriate number of oxygen vacancy defects can reduce the potential barrier of phase transition between the tetragonal phase and the monoclinic phase, making the monoclinic phase easy to transition to tetragonal ferroelectric phase. The stability of the ferroelectric phase can be improved by some methods, including forming the stress between the substrate and electrode, reducing the film thickness, constructing a nanolayered structure, and reducing the annealing temperature. Compared with perovskite oxide ferroelectric thin films, HfO<sub>2</sub>-based films have the advantages of good complementary-metal-oxide-semiconductor compatibility and strong ferroelectricity at nanometer thickness, so they are expected to be used in ferroelectric memory. The HfO<sub>2</sub>-based 1T1C memory has the advantages of fast reading and writing speed, more than reading and writing 10<sup>12</sup> times, and high storage density, and it is the fast reading and writing speed that the only commercial ferroelectric memory possesses at present. The 1T ferroelectric field effect transistor memory has the advantages of non-destructive reading and high storage density. Theoretically, these memories can achieve the same storage density as flash memory, more than reading 10<sup>10</sup> times, the fast reading/writing speed, low operating voltage, and low power consumption, simultaneously. Besides, ferroelectric negative capacitance transistor can obtain a subthreshold swing lower than 60 mV/dec, which greatly reduces the power consumption of integrated circuits and provides an excellent solution for further reducing the size of transistors. Ferroelectric tunnel junction has the advantages of small size and easy integration since the tunneling current can be largely adjusted through ferroelectric polarization switching. In addition, the HfO<sub>2</sub>-based field effect transistors can be used to simulate biological synapses for applications in neural morphology calculations. Moreover, the HfO<sub>2</sub>-based films also have broad application prospects in antiferroelectric energy storage, capacitor dielectric energy storage, memristor, piezoelectric, and pyroelectric devices, etc. Finally, the current challenges and future opportunities of the HfO<sub>2</sub>-based thin films and devices are analyzed.

Potassium–Sodium Ceramics Modified with Metal Oxide Additives: Synthesis, Microstructure, and Properties

Single phase ceramic samples of new compounds (1 − x)(K0.5Na0.5)NbO3−xLa(Ag0.5Sb0.5)O3 (x = 0–0.15), modified by metal oxide additives ZnO, CuO, and MnO2, are prepared via a solid state reaction. The crystal structure, microstructure, and dielectric and ferroelectric properties of the samples are studied. It is established that a phase with a perovskite structure and an orthorhombic unit cell formed in each sample. Ferroelectric phase transitions are confirmed via dielectric spectroscopy. Generation of the second harmonic is observed, along with a drop in the temperature of transitions from the ferroelectric orthorhombic phase to the ferroelectric tetragonal phase, and then to the cubic paraelectric phase.

Investigation into the crystal structure-dielectric property correlation in barium titanate nanocrystals of different sizes.

For high capacitance multilayer ceramic capacitors, high dielectric constant and lead-free ceramic nanoparticles are highly desired. However, as the particle size decreases to a few tens of nanometers, their dielectric constant significantly decreases, and the underlying mechanism has yet to be fully elucidated. Herein, we report a systematic investigation into the crystal structure-dielectric property relationship of combustion-made BaTiO3 (BTO) nanocrystals. When the nanocrystal size was 100 nm and below, a metastable paraelectric cubic phase was found in the as-received BTO (denoted as arBTO) nanocrystals based on an X-ray diffraction (XRD) study. A stable ferroelectric tetragonal phase was present when the nanocrystal size was above 200 nm. Notably, the cubic arBTO (particle size ≤100 nm) exhibited tetragonal fluctuations as revealed by Raman spectroscopy, whereas the tetragonal arBTO (particle size ≥200 nm) contained ∼10% cubic fraction according to the Rietveld fitting of the XRD profiles. Thermal annealing of the multi-grain tetragonal arBTO at 950 °C yielded single crystals of annealed BTO (denoted as anBTO), whose dielectric constants were higher than those of arBTO. However, the single crystalline anBTO prevented the formation of 90° domains; therefore, they exhibited a low dielectric constant of ∼300. Although X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy could not identify the exact structural defects, our study revealed that surface and bulk defects formed during synthesis affect the final crystal structures and thus the dielectric properties of BTO nanocrystals with different sizes. The understanding obtained from this study will help us design high dielectric constant perovskite nanocrystals for next-generation multilayer ceramic capacitor applications.

Implementing a sol-gel route to adjust the structural and dielectric characteristics of Bi and Fe co-doped BaTiO3 ceramics

The present work explores the impact of Fe insertion on the physical properties of Ba0.95Bi0.05Ti1-xFexO3 (x = 0.025, 0.050, and 0.075) prepared via sol gel method. The resulting samples crystallize in the tetragonal structure with space group P4mm and their morphological features point out the variation of the microstructure with Fe content. In turn, the dielectric constant versus temperature plot reveals the existence of two transition phases: the first one is ferroelectric-paraelectric transition phase (TF-P) and the second one is ferroelectric orthorhombic - ferroelectric tetragonal phase (TO-T). Analysis of conductivity curves using Jonscher’s augmented equation (for x = 0.025) and Jonscher’s power law (for x = 0.075) suggests the Non-Overlapping Small Polaron Tunneling (NSPT) model as a conduction mechanism.

Enhanced temperature stability of ferroelectric properties in lead-free (1−x)(Bi0.5Na0.4K0.1)TiO3-x(Ba0.5Sr0.5)TiO3 solid solutions

With its complicated composition architecture, (Bi 0.5 Na 0.5 )TiO 3 (BNT)-based relaxor ferroelectrics exhibit distinctive dielectric relaxation phenomena and attractive characteristics. The structural, dielectric, and ferroelectric characteristics of (1– x )(Bi 0.5 Na 0.4 K 0.1 )TiO 3 - x (Ba 0.5 Sr 0.5 )TiO 3 (BNKT- x BST) solid solutions with x = 0–0.4 were thoroughly examined in this study. The x = 0.1 and 0.2 versions exhibited unexpected ferroelectricity enhancement, and the depolarization temperatures and ferroelectric-relaxor transition temperature were both increased compared to that of the BNKT undoped sample. This enhancement is due to the creation of a tetragonal ferroelectric phase after the introduction of a moderate BST member, according to room temperature and temperature-dependent x-ray diffraction data. The characterization of ferroelectric properties indicated that ferroelectricity was enhanced by increasing the rapidly declining temperatures for the remnant polarization and coercive field, compared to those of the BNKT undoped sample. This discovery contributes to a better understanding of the relationship between the structure and properties of complex relaxor ferroelectrics. A phase diagram of the BNKT- x BST solid solution is also provided, which can be used to guide the search for specific lead-free functional materials for the capacitors, actuators, and transducers based on this eco-friendly system.

Structural Evolution and Enhanced Piezoelectric Activity in Novel Lead-Free BaTiO3-Ca(Sn1/2Zr1/2)O3 Solid Solutions

In this study, a series of solid solutions of (1−x)BaTiO3-xCa(Sn1/2Zr1/2)O3 (abbreviated as (1−x)BT-xCSZ, x = 0.00–0.15) ceramics have been prepared by the conventional solid-state reaction method to search for high performance lead-free piezoelectric materials. The structural evolution, microstructure, and piezoelectric properties are investigated. X-ray diffraction (XRD) results indicate that the phase symmetry strongly depends on the CSZ content. A tetragonal phase is well-maintained in the compositions of 0 ≤ x ≤ 0.03, and coexistence of tetragonal and cubic phases is obtained in the range of x = 0.06–0.09, beyond which a pure cubic phase becomes stable. More importantly, a significantly enhanced piezoelectric coefficient of d33 = 388 ± 9 pC/N is attained in the composition of x = 0.06 in the MPB region, where a tetragonal ferroelectric phase and an ergodic relaxor phase with average cubic symmetry coexist. Based on the analysis of crystal structure and dielectric properties, a temperature-composition phase diagram consisting of four phase regions is established. This study indicates that the lead-free BT-CSZ binary system has great potential for use in electromechanical transducer applications.

The origin of piezoelectric enhancement in compositionally graded ferroelectrics with sinusoidal variation

The direct piezoelectric effect of BaTiO3↔ Ba1−xSrxTiO3 graded ferroelectrics, whose compositions change in a sinusoidal form, is investigated via an extended phase-field method. The obtained results demonstrate that the piezoelectric coefficient can be significantly enhanced by controlling the amplitude of sinusoidal variation. The origin of piezoelectric enhancement is investigated by considering the formation of polarization domain structures and their behaviors under strain. Although a ferroelectric tetragonal phase or a paraelectric cubic phase primarily form in homogeneous Ba1−xSrxTiO3 ferroelectrics with a different content x, interestingly, an unusual ferroelectric monoclinic phase can be formed in compositionally graded ferroelectrics, giving rise to the coexistence of multiple phases. The monoclinic phase emerges as a result of the process that reduces built-in electric potential induced by a large gradient of polarization. In turn, the formation of the monoclinic phase gives rise to transient zones that make the polarization field more susceptible to external strains, thereby enhancing the piezoelectric response. We further demonstrate that the piezoelectric enhancement strongly depends on the volume fraction of the monoclinic phase in compositionally graded ferroelectrics, suggesting a route for the rational design of polarization domains and piezoelectric effects.

Analysis of non-180° domain structures in lead-free ferroelectric solid solutions based on NaNbO3 and KNbO3, perovskites and CdNb2O6 coulombite

A ferroelectric solid solution of a three-component system of 0.90NaNbO3 − 0.05KNbO3 − 0.05CdNb2O6 was prepared by means of a two-stage solid-phase synthesis with subsequent sintering based on conventional ceramic technology. An X-ray diffraction study was carried out, and unit-cell parameters of the solid solutions with the aforementioned composition were determined. The two-phase states and related non-180° domain (or twin) structures are analyzed for the same lead-free composition. A tendency of the ferroelectric tetragonal phase to a monodemonization in the heterophase structures is discussed.

Comprehensive properties and thermal stability of Ta2O5-doped PIN-PHT ceramics

Herein, high-performance 0.11 Pb(In1/2Nb1/2)O3-0.89 Pb(Hf0.47Ti0.53)O3-0.8Ta2O5 (PIN-PHT-0.8Ta) ceramics are successfully synthesized. In addition, performance improvement is comprehensively analyzed from viewpoints of microstructure, phase structure and electrical properties. Experimental results reveal that the addition of Ta2O5 changes phase structure of PIN-PHT ceramics from ferroelectric tetragonal phase to rhombohedral phase. This leads to the appearance of morphotropic phase boundaries (MPBs). At the same time, the addition of Ta2O5 reduces grain size and enhances grain uniformity. Also, Ta2O5 doping improves internal and external contribution of piezoelectric response, which greatly improves dielectric, piezoelectric and ferroelectric properties of PIN-PHT. Key performance parameters include d33, kp, TC, εr and tanδ, which are found to be 630 pC/N, 0.73, 322.6 °C, 1917 and 1.55%, respectively. In particular, thermal stability of PIN-PHT-0.8Ta ceramics is found to be higher than PZT-based ceramics, as well as d33 value and performance retention rate of PIN-PHT-0.8Ta are found to be 560 pC/N and 89% at 300 °C, respectively, which are far superior to commercial PZT-5 and PZT-8 ceramics. These properties indicate potential of PIN-PHT-0.8Ta ceramics in high-temperature applications.

Influence of pH on crystal phase formation in BaTiO3 nanoparticles during their peroxide synthesis

Influence of pH of the medium on the crystal phases formation in BaTiO3 nanoparticles during their peroxide synthesis has been investigated. Nanoparticles in the ferroelectric tetragonal phase are formed at pH 9 when annealed at temperatures above 900 °C. Decreasing pH value to 8 leads to formation of nanoparticles in paraelectric cubic phase, while increasing the annealing temperature to 1100 °C does not lead to formation of other crystalline phases. Increasing pH value to 10 results in the formation of Ba2TiO4 and BaTi4O9 in addition to BaTiO3.

Effect of electric field on elastic properties of BaTiO3 single crystals: a micro-Brillouin scattering study

The analysis of local polar clusters formed by random fields in ferroelectrics is of technical and fundamental importance in understanding piezoelectricity. The temperature and electric field dependences of elastic properties and the ferroelectric phase transition have been investigated in (100)-oriented BaTiO3 single crystals by micro-Brillouin scattering. In the field cooling process, LA phonons are scattered by polar clusters. As a result, the LA phonon frequency increases as compared with that of the zero-field cooling process. Under the application of an external electric field along the [100] direction in the tetragonal ferroelectric phase, a complete 90° domain switching is accomplished. Under the electric field, abrupt changes in the frequency shift and FWHM of the LA phonons in the paraelectric cubic phase indicate the occurrence of a phase transition from the cubic to the tetragonal phase. An E–T phase diagram has been proposed from the field-induced phase transition.

Synthesis and Investigation of Ferroelectric Curie Transition in BaTiO3

Ferroelectric phase comprising BaTiO3 nanoparticles and nanorods have been prepared by high temperature sintering. The XRD spectra of sintered powder was used to confirm the ferroelectric phase crystallisation. The non-ferroelectric cubic phase to ferroelectric tetragonal phase transition of BaTiO3 was studied by temperature dependent dielectric study. The Curie temperature of 105 °C in sintered nanoparticles was observed from dielectric study of tetragonal phase BaTiO3.