PbTiO3 Content Research Articles

ESR and optical investigation of tetragonal PbTiO3 nanoparticles embedded in lithium tetraborate glass matrix

Glass-nanocomposites (GNCs) samples of composition [(100−x) Li2B4O7–xPbTiO3] with x = 5, 10, 15 and 20 mol% were prepared by melt quenching method. The two phases of the GNCs samples, a glassy phase and PbTiO3 nanoparticles/clusters phase, can be seen in the energy dispersive X-ray spectra and scanning electron microscopic micrographs. Fourier transformation infrared spectra of the GNCs samples exhibited bands due to triangular with NBO’s and tetrahedral borate groups. Additionally, the Ti4+ ions exist in both TiO4 and TiO6 structural units while the Ti3+ ions exist in TiO6 structural units. The electron spin resonance (ESR) spectra of the GNCs samples exhibit two ESR signals, broad and narrow, corresponding to the Ti3+ (3d1) ions in both tetragonal deformed octahedral and in the other structural configuration, respectively. The optical transmission spectra of the GNCs samples exhibited three transmission bands, 3Γ5 → 2Γ3, 2B2g → 2B1g and 2B2g → 2A1g transitions, in the visible region. The variation in optical band gap (Eopt) with increasing PbTiO3 content were due to the conversion between BO3 with NBOs and BO4 units as well as the reduction of Ti4+ to Ti3+ ions in the GNCs matrix. These results demonstrate that the present GNCs may be used for practical applications such as optical devices.

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.

Efficient Charge Storage Capability of BiFeO3-Based Bi-Phase Nanocomposites

Here, we report a facile synthesis of bi-phase nanocomposites of the form (1−x)BiFeO3−xPbTiO3 for their efficient utilization in modern day energy storage gadgets. X-ray diffraction confirmed the distorted rhombohedral structure of pure BiFeO3 while PbTiO3 exhibited tetragonal structure and hence confirmed the formation of nanocomposites. Morphological analysis revealed the reduction in particle size, improvement in bulk density and decrease in porosity with the increase of PbTiO3 contents. A wide dispersion in dielectric response was explained on the basis of Maxwell-Wagner model. A significant improvement in dielectric behavior was observed when PbTiO3 was added in the composite. The contribution of grains and grain boundaries in the electrical response of these composites was witnessed through impedance analysis. The nature of charge transport mechanism was established using electric modulus spectroscopy. These kinds of nanocomposites are recommended for the improvement of data storage capacity of devices as compared with phase-pure compounds.

AC Conductivity and Dielectric Properties of BiScO3–PbTiO3 Piezoelectric Ceramics

Bi-based BiMeO3 (where Me is a transition metal) has been extensively studied owing to its outstanding ferroelectric properties. The dielectric and electrical properties of piezoelectric ceramics can be enhanced by the addition of Bi-based materials such as BiAlO3, BiScO3 , and Bi(Mg, Ti)O3. Among them, BiScO3–PbTiO3 ceramics have shown excellent piezoelectric properties and temperature stability near the morphotropic phase boundary (MPB) region. Meanwhile, it is important to study the electrical properties of piezoelectric materials such as dielectric permittivity, conductivity of ferroelectric compounds, since dielectric and conductivities are related to pyroelectricity and piezoelectricity. In this study, the AC conductivity and dielectric properties of BiScO3–PbTiO3 ceramics were investigated with a wide range of frequencies and temperatures. Especially,the effect of PbTiO3 content on dielectric behavior of the BiScO3–PbTiO3 system was intensively studied by impedance spectroscopy.

Solid solutions of the (1-x)Ba(Ti0.50Sn0.50)O3∙xPbTiO3 system: Preparation, structural and dielectric characterization

Ceramic samples of the (1-x)BaTi0.5Sn0.5O3∙xPbTiO3 system with 0 ≤ x ≤ 1 were synthesized by solid-state reaction method. The samples were characterized by X-ray diffraction, dielectric measurements, and thermally stimulated depolarization currents (TSDCs) technique. It was established that the solid solutions with the perovskite structure were formed in the entire range of the compositions. The structure symmetry of the solid solutions changes from cubic (x ≤ 0.30) to tetragonal (x > 0.47) with increasing PbTiO3 content. The samples with 0.30 < x ≤ 0.47 contained mixtures of the tetragonal and cubic phases. The solid solutions exhibit a pronounced aging effect. This effect manifests itself as non-reproducible maxima in the temperature-dependent spectra of the dielectric permittivity ε(T,f) and losses tangent tanδ(T,f) measured around room temperature. The increase of the amount of PbTiO3 in the ceramic samples causes sequential changes of their dielectric response from that typical for relaxor ferroelectric for x = 0 – 0.3 to ferroelectric-like with a diffuse phase transition for x = 0.4 - ~0.8 and, finally, to usual ferroelectric response for x = ~0.8 – 1. The compositions with 0.20 < x < 0.40 show coexistence of both ferroelectric and relaxor properties. The temperature dependences of the TSDCs show pronounced maxima at temperatures T ≈ TC, T ∼ 100 K and T ∼ 300 K; the phenomena that are at the origin of the effects are discussed.

High‐temperature BiFeO3–PbTiO3‐Ba(Zr,Ti)O3 ternary ceramics with excellent piezoelectricity

AbstractTernary ceramics of (0.87−x)BiFeO3–xPbTiO3–0.13Ba(Zr0.5Ti0.5)O3 (BF–xPT–0.13BZT, 0.27 ≤ x ≤ 0.37) were prepared by the traditional solid state reaction methods. X‐ray diffraction results display that BF‐xPT‐0.13BZT ternary ceramics of x ≥ 0.29 exhibit the perovskite structure with dominant tetragonal (T) phases mixed with a small amount of rhombohedral (R) phases. Scanning electron microscopy (SEM) images reveal that the average grain size of BF‐xPT‐0.13BZT ternary ceramics is in a range of 10–11 μm, increasing first and then decreasing with the increase of PbTiO3 (PT) content. The low tanδ of about 0.015 and high Curie temperature Tc of above 450°C were obtained for BF‐xPT‐0.13BZT ternary ceramics. Moreover, the fluctuation of piezoelectric coefficient d33 is less than ±10% over a broad temperature range of 30°C–400°C. BF‐xPT‐0.13BZT ternary ceramics for x = 0.33 possess the maximum Tc and d33 of 470°C and 320 pC/N respectively, with the room temperature resistivity of about 1011 Ω·cm. These results indicate that BF‐xPT‐0.13BZT ternary ceramics for x = 0.33 with both excellent piezoelectric properties and high Curie temperature have promising applications in high‐temperature piezoelectric devices.

Phase stability and Landau phenomenological model of relaxor ferroelectric single crystals 0.78Pb(Mg1/3Nb2/3)O3-0.22PbTiO3

Relaxor-based ferroelectric single crystal with lower PbTiO3 content has complex phase transitions and mixed ferroelectric and relaxor characteristics, making it very challenging for the construction of Landau free energy expansion crucially used for theoretical investigation of this system. In this work, relaxor behavior in 0.78Pb(Mg1/3Nb2/3)O3-0.22PbTiO3 (PMN-0.22PT) single crystals was well suppressed through careful experimental design, leaving preserved single domain state for the Landau parameter extraction in this rhombohedral-phase composition. Using these extracted Landau free energy expansion parameters, energy profile and phase coexistence were theoretically studied and compared with those of PMN-0.30PT and PMN-0.36PT single crystals. Results show that rhombohedral phase dominates in PMN-0.22PT, and tetragonal phase dominates in PMN-0.36PT around room temperature. While, rhombohedral phase and tetragonal phase coexist in MPB composition PMN-0.30PT with small discrepancy of both free energies and polarization vectors.

Composition and electrical properties characterization of a 5” diameter PIN-PMN-PT single crystal by the modified Bridgman method

A Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 relaxor ferroelectric single crystal with a 5” diameter and 145 mm length was grown by the modified Bridgman method. The composition distribution of the crystal boule was investigated. The result showed that the PbTiO3 contents increased along the growth direction, which means that compositional segregation existed, and the effective segregation coefficient was simulated to be 0.84, which is close to that of 3” single crystal. The horizontal composition distribution in the crystal demonstrated that the solid-melt interface of the 5” single crystal was serious convex during crystal growth and was caused by the nonuniform radial thermal field of the large melt. The dielectric, piezoelectric, ferroelectric properties and domain structures were measured to investigate the effect of the composition change along the crystal growth direction. Based on the domain structure and electrical performance, the crystal boule was divided into rhombohedral, morphotropic phase boundary and tetragonal regions. It was found that the optimal piezoelectric coefficient d33 of the 5” single crystal was more than 2000 pC/N. This work provided positive information for large sized single crystal growth of a relaxor ferroelectric single crystal.

Diffused morphotropic phase boundary in relaxor-PbTiO3 crystals: High piezoelectricity with improved thermal stability

Solid solution ferroelectrics are the most widely used piezoelectric material for numerous electromechanical applications, including sensors, actuators, and transducers. A milestone in ferroelectric research is the discovery of the morphotropic phase boundary that was first reported in Pb(ZrxTi1−x)O3, which has been extensively solicited to improve the performance of various solid solution ferroelectrics, including those having the highest piezoelectricity known today. However, due to the inherent correlation between phase transition and thermodynamic imbalance, the efforts of building the phase boundary encounter the challenge that high performance materials are generally accompanied by property instability. Here, we report a comprehensive study on the crystalline symmetry and polar nano-regions in relaxor-PbTiO3 crystals by synchrotron measurements and property characterizations. In contrast to the common belief that the morphotropic phase boundary is a narrow composition region, the morphotropic phase boundary in ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 is demonstrated as an extensive region covering at least 9% of the PbTiO3 content. Such a diffused morphotropic phase boundary is associated with the intensive interaction of polar nano-regions, leading to high piezoelectricity (>1500 pC/N) with greatly improved thermal stability, where the piezoelectric variation is ∼90% over the temperature range of 273–373 K, which is about a factor of 3 lower compared to its binary counterpart Pb(Mg1/3Nb2/3)O3-PbTiO3. This work sheds light on the fundamental understanding of nanoscale inhomogeneity and macroscopic symmetry in relaxor-PbTiO3, and successfully interlinks the structure and properties in complex solid solutions. The existence of a diffused morphotropic phase boundary is also expected to benefit other ferroic systems beyond ferroelectrics, such as ferromagnetic and multiferroic materials.

Improved ferroelectric response of pulsed laser deposited BiFeO3-PbTiO3 thin films around morphotropic phase boundary with interfacial PbTiO3 buffer layer

(1 − x)BiFeO3-xPbTiO3 (BF-xPT) is an interesting material for sensing and actuating devices with large polarization near the morphotropic phase boundary (MPB) (x = 0.30) in the bulk form. However, pulsed laser deposition (PLD) grown (BF-xPT) thin films usually show high electrical leakage and, hence, saturated ferroelectric hysteresis loops are only obtained at subzero temperatures. In this article, we report on high room temperature ferroelectric polarization with saturated hysteresis loops in pulsed laser deposited (BF-xPT) polycrystalline thin films of compositions near the MPB with the use of a thin buffer layer of PbTiO3 (PT). The thin films possessed a perovskite structure with excellent crystallinity and exhibit the presence of a monoclinic (Cm) phase (MA-type) for x = 0.20–0.25 and a mixture of a monoclinic (Cm) phase and a tetragonal (P4mm) phase for x = 0.30–0.35 compositions. The thin films with composition x = 0.25 exhibit a monoclinic phase and yield very large room temperature ferroelectric polarization (2Pr &amp;gt; 80μC/cm2), perhaps the highest room temperature ferroelectric polarization and excellent piezoelectric properties in PLD deposited (BF-xPT) thin films of near-MPB composition. Furthermore, the evolution of ferroelectricity with PT content, studied using room temperature Raman spectroscopy, reveals a correlation with lattice dynamics and stereochemical activity of Bi. Piezoforce domain analysis of the thin films reveals that ferroelectric polarization and electrical leakage in the thin films are intricately related to the type of domains present in the samples, viz., 180°, 109°, 90°, and 71° due to differences in the nature of the domain walls.

Sm-doped Pb(Mg1/3Nb2/3)O3-xPbTiO3 piezocatalyst: Exploring the relationship between piezoelectric property and piezocatalytic activity

The piezocatalytic performance of Sm-doped Pb(Mg1/3Nb2/3)O3-xPbTiO3 solid solutions, which exhibit ultrahigh piezoelectric coefficient with a dependence on PbTiO3 content, was thoroughly investigated. We focused mainly on the influence of piezoelectric property modulation on the piezocatalytic performance of the materials by composition arrangement. The maximal piezocatalytic activity was achieved as the composition approached the morphotropic phase boundary (MPB) at x = 0.29, in which the piezoelectric coefficient also reached the maximum. The linear relationship between the two properties proves that the piezoelectric effect plays a key role in the piezocatalytic performance. As a direct evidence of catalytic reactions, free radicals were detected by electron spin resonance (ESR) technique. Revolution of intermediate products observed by liquid chromatography-mass spectrometry (LC–MS) further confirms the catalytic reactions in the piezoelectricity induced dye degradation process. This work is of great significance for understanding the mechanism of piezocatalytic effect.

Element Segregation and Electrical Properties of PMN-32PT Grown Using the Bridgman Method

A single crystal with nominal composition Pb(Mg1/3Nb2/3)O3-32PbTiO3 (PMN-32PT) was grown by the Bridgman technique. Crystal orientation was determined using the rotating orientation X-ray diffraction (RO-XRD). Element distribution was measured along different directions using inductively coupled plasma-mass spectrometry (ICP-MS). The effect of the element segregation along axial and radial directions on the electrical properties of the PMN-32PT crystal was investigated. It is indicated that the electrical properties of the samples along the axial direction were strongly dependent on the PT (PbTiO3) content. With the increase of the PT content, the piezoelectric coefficient and remnant polarization were improved. Differently, the electrical properties of the samples along the radial direction were mainly determined by the ratio of the Nb and Mg. The reasons for the element segregation and electrical properties varied with the composition were discussed.

Magnetically driven robust polarization in (1 − x)BiFeO3–xPbTiO3 multiferroic composites

In this letter, we demonstrate an apparent magnetically activated electric polarization reorientation at room temperature through magneto-electric coupling in (1 − x)BiFeO3–xPbTiO3 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) composites. A change in magnetic field causes variation in electric polarization, attributed to the destruction of space modulated spin antiferromagnetic structure with the PbTiO3 addition. This behavior also results in the increase in magnetic parameters as the coercive field of the composites increases with the increase in PbTiO3 contents. The analysis demonstrates that the magneto-electric coupling in the prepared ferromagnetic/ferroelectric composites is dominant at room temperature, quite feasible for modern day devices.

Enhanced piezoelectric performance of BiScO3-PbTiO3 ceramics modified by 0.03Pb(Sb1/2Nb1/2)O3

A series of (0.97-x)BiScO3-xPbTiO3-0.03Pb(Sb1/2Nb1/2)O3 (BS-xPT-PSN) piezoelectric ceramics near the morphotropic phase boundary (MPB) for high-temperature actuation application have been devised and synthesized by traditional solid-state reaction method. The phase structure, morphology, dielectric, piezoelectric, and ferroelectric properties have been systematically investigated as a function of PbTiO3 content. X-ray diffraction (XRD) results revealed that with the content of PbTiO3 increasing, the phase structure of BS-xPT-PSN ceramics gradually varied from rhombohedral phase toward tetragonal phase. Combined with the dielectric, piezoelectric, and ferroelectric performances, it was clear that MPB of BS-xPT-PSN ceramics located at the region of x = 0.62. The piezoelectric constant d33, electromechanical coupling factor kp, Curie temperature Tc, remnant polarization Pr of BS-xPT-PSN ceramics with MPB composition were 553 pC/N, 56.7%, 384 °C, and 39.1 μC/cm2, respectively, which shows that BS-xPT-PSN ceramics exhibit enhanced piezoelectric performance, and also high Tc. Moreover, the devised BS-xPT-PSN ceramics reduced the consumption of expensive Sc2O3 component in pure BS-PT systems. Based on the enhanced piezoelectric performance and decreased cost, it can be deduced that the BS-xPT-PSN ceramics are promising for practical actuator or sensor applications in a relative high temperature environment.

Magnetic controlled voltage in the pseudo-ternary multiferroic BiFeO3–PbTiO3–BaTiO3

We have investigated the magnetoelectric coupling in multiferroic system (0.9 − x)BiFeO3–xPbTiO3–0.1BaTiO3 with x = 0.21, 0.23 and 0.25, synthesized by conventional solid state reaction. X-ray diffraction study revealed the coexistence of monoclinic (Cc) and tetragonal (P4mm) symmetries, suggesting these compositions to be at the morphotropic phase boundary (MPB) of this alloy system. We found a systematic increase in polarization with increasing PbTiO3 content. These compositions also exhibit weak ferromagnetism at room temperature. These MPB compositions are shown to exhibit high values of the dynamic magnetoelectric coupling coefficient (αE), viz. 3.6, 11.4 and 15.45 mV/cmOe, respectively, for x = 0.21, 0.23 and 0.25.

Electrical properties of ceramic samples of (1–x)Ba(Ti1–y Zr y )O3 ∙ xPbTiO3 solid solutions

We have prepared ceramic samples of (1–x)Ba(Ti1–y Zr y )O3 ∙ xPbTiO3, (у = 0–0.10, x = 0–0.67) ferroelectric perovskite solid solutions and characterized them by X-ray diffraction and dielectric and pyroelectric measurements. The composition dependences of the unit-cell parameters for the solid solutions have been obtained; their Curie temperature T C, relative dielectric permittivity e, and loss tangent tan δ have been measured at temperatures from 100 to 700 K and frequencies from 25 Hz to 1 MHz; and characteristics of their dielectric hysteresis loops and pyroelectric effect have been assessed. With increasing PbTiO3 content, the T C of the samples increases from 400 (x = 0) to 670 K (x = 0.67), the temperatures of their low-temperature phase transitions decrease (to the point that they disappear for x > 0.15), and e(T = 296 K) decreases at x > 0.1.

X-ray diffraction and Raman spectroscopy studies in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 solid solutions

ABSTRACTThe long and short range orders in 0.4Na1/2Bi1/2TiO3-(0.6-x)SrTiO3-xPbTiO3 solid solutions were studied by x-ray diffraction and Raman spectroscopy. X-ray diffraction patterns for these compositions in the relaxor state are different for bulk and powdered samples. It was found that, in spite of different tetragonality depending on PbTiO3 content, the Raman spectra suggest similarity of local structure for all studied compositions. Both methods indicate a disappearance of tetragonal phase upon increasing temperature.

Growth and characterization of Pb(Lu1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary piezo-/ferroelectric crystals

Piezo-/ferroelectric crystals of Pb(Lu1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary solid solution system with high Curie temperature, in the vicinity of morphotropic phase boundary (MPB) region, are grown by the top-seeded solution growth (TSSG) method for the first time. The compositions and structures of the crystals are analyzed, all the structures are found to have pure perovskite structure using X-ray diffraction analysis. Di-/piezo-/ferroelectric properties of the crystals are also characterized systematically. The Curie temperature Tc and coercive field Ec, increase gradually with increasing PbTiO3 content. In particular, the crystal with composition 0.34PLN-0.31PMN-0.35PT possesses excellent electric properties including the Curie temperature, the rhombohedral–tetragonal phase transition temperature, the piezoelectric coefficient, the remnant polarization and the coercive field, which are Tc = 228 °C, TRT = 156 °C, d33 = 2092 pC N−1, Pr = 35.5 μC cm−2 and Ec = 8.1 kV cm−1, respectively, making it a promising material for transducers or detectors in a wide temperature range.

Phase Diagram of Ternary Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 Ferroelectric Ceramics Prepared Via a B-site Oxide Mixing Route

xPb(Mg1/3Nb2/3)O3-yPbZrO3-(1-x-y)PbTiO3 (PMN-PZ-PT) ferroelectric ceramics were prepared by the conventional ceramic processing via a B-site oxide mixing route. Complete solid solutions can be formed for PMN-PZ-PT in the whole composition range studied, which exhibits pure tetragonal, morphotropic phase boundary (MPB) or rhombohedral perovskite structure depending on compositions. Enhanced structure and electrical performance detected by XRD measurement, and dielectric, ferroelectric and piezoelectric properties characterization confirm the MPB effect. Such phenomena correspond well with the composition-induced successively structural change from rhombohedral, across MPB, and to tetragonal perovskite structure with the increase of the PbTiO3 content. The preliminary composition phase diagram of the PMN-PZ-PT system is determined by XRD measurement combining with electrical properties characterization. The mechanisms of the structure and electrical properties enhancement are related to easy paths with flattened free energy induced by polarization rotation and polarization extension.

Optical transmission and dispersion of 0.25Pb(In1/2Nb1/2)O3– (0.75 − x) Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals

Optical transmission spectra and refractive index dispersions of ternary relaxor-based ferroelectric 0.25Pb(In1/2Nb1/2)O3–(0.75 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 [PIMNT0.25/(0.75 − x)/x] single crystals were studied after poled along [001] direction. Sellmeier dispersion equations of the refractive index were obtained by least square fitting, which can be used to calculate the refractive indices in visible and near infrared spectra. The optical transmission of tetragonal PIMNT0.25/0.37/0.38 single crystal is about 70% from 0.5 to 5.8 μm, which is much higher than that of rhombohedral PIMNT0.25/0.45/0.30 and morphotropic phase boundary PIMNT0.25/0.41/0.34 single crystals. Optical interband direct and indirect transitions were investigated by absorption spectra. Our results show that as the PbTiO3 content increases the refractive indices of PIMNT single crystals increase, while the optical band gap decreases.