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This work compares the dielectric properties of two new materials. One was 0.88 bismuth manganite–0.12 lead titanate (noted BM–PT hereafter) ceramics composite obtained by standard high-temperature sintering. The second composite was obtained from powdered ceramics dispersed in epoxy glue (noted BM–PT–epoxy). The occurrence of four phases in the ceramics, using X-ray powder diffraction (XRD), was recognized: orthorhombic Pbam, cubic Pn 3 ‾ m, cubic Pm 3 ‾ m, and monoclinic P2/m phase. Pseudo-Voigt function fitting confirmed significant structural disorder in the BiMn2O5 crystal lattice. Analysis of broadband dielectric spectroscopy data confirmed the applicability of the small polaron model to explain detected relaxation processes. Involvement of oxygen vacancies in relaxation and their correspondence to ordered, uniform potential wells in crystal lattices was deduced. Electric conductivity relaxation times behavior proved the sensitivity of the ceramics’ electrical features to hydrostatic pressure. BM–PT–epoxy composite exhibited dielectric permittivity and losses two orders of magnitude lower than those of BM–PT ceramics that opened new prospects to application. One relaxation process in BM–PT–epoxy composite related to the ceramics fill contribution. Other induced relaxation, observed only in this composite, was attributed to interactions at interfaces between the introduced powdered ceramics and the epoxy glue matrix. We showed that stresses generated either by hydrostatic pressure or through the interfacial interaction of epoxy matrix led to the same results: relaxation times shortening.

Glasses containing lead titanate (PbTiO3) have recently attracted much attention due to its unique electrical properties at high temperature. However, its large lattice anisotropy makes its sinterability difficult. 10PbTiO3–10Fe2O3–30V2O5–50B2O3 glass was prepared by conventional fast quenching technique. The estimated crystallite size after annealing at 773 K for 20 h was 62.6 nm. After annealing, triclinic iron vanadium oxide and monoclinic lead vanadium oxide phases were partially formed. The crystallization temperature (Tc) at different heating rates (β) has been investigated using Kissinger and Ozawa models under non-isothermal mode. The values of various kinetic parameters such as activation energy of crystallization (Ec), rate of crystallization (Kp), Avrami index (n), thermal stability (S), and Hruby number (Hr) have been calculated. The presence of Fe2O3 and PbTiO3 in the glass after annealing was found to enhance its thermal stability and electrical conductivity. The electrical conductivities of as-quenched and annealed glass were evaluated by dc conductivity. The dc conductivity was discussed in terms of small polaron hopping (SPH) mechanism.

Chemical solution deposition (CSD) is a well-established process for the fabrication of metal oxide functional layers such as piezoelectric lead zirconate titanate (PZT) thin films. The latter exhibit an enhanced electromechanical response in the presence of {100} crystalline orientation with respect to the substrate surface. Lead titanate (PbTiO3) seed layers are commonly used to promote the growth of this orientation on platinized silicon, which otherwise usually affords the {111} orientation. In this work, we present a comparative study of two solvents used for the preparation of PZT and PbTiO3 solutions for CSD, i.e. the popular but highly carcinogenic and teratogenic solvent 2-methoxyethanol and the benign solvent 1-methoxy-2-propanol. In addition to tremendous health and safety benefits, we show that 1-methoxy-2-propanol-derived PbTiO3 seed layers promote the {100} orientation more efficiently than their 2-methoxyethanol-derived counterparts, owing to their nanocrystalline microstructure and strong orientation. This resulted in a noticeable enhancement of the electrical and piezoelectric properties, with Pr = 38 μC cm−2, Ec = 55 kV cm−1, er = 1300, tan δ = 0.04 and e31,f ≈ 14 C m−2.

Phase transitions in the mixture of powders C6H16NBr (DIPAB) and PbTiO3 and composites x-bTiO3–(1 – x)C6H16NBr at x from 0.05 to 0.45 have been studied by the differential thermal analysis (DTA) method. The DTA signal is compared to the temperature dependence of dielectric permittivity e'(T) of the xPbTiO3–(1 – x)C6H16NBr composites. The addition of lead titanate to C6H16NBr is shown to lead to the appearance of new phase transition in both the composites and the powder mixture.

Due to requirements for miniaturization and integration of electronic devices, ferroelectric materials with high dielectric permittivity would have potential applications in dielectric capacitors. In this work, (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) powders with x from 0.10 to 0.30 were obtained on the basis of a transitional columbite precursor method, while sintering processes were carried out under three protocols, i.e., (I) 1230 °C for 2 h, (II) 1230 °C for 16 h and (III) 1250 °C for 2 h. The temperature-dependent dielectric properties measured from 25 °C to 225 °C show that, under protocols II and III, the maximum permittivity (em) is significantly improved compared to those obtained via protocol I. A maximum em of 47036 is obtained in x = 0.25 composition under protocol II, and the em is increased by more than 90% at the same composition. In the ceramics sintered through protocols II and III, the characteristics of both dielectric relaxations and dielectric dispersions are also enhanced. In addition, the ferroelectric and piezoelectric properties also show a marked increase in the composition of x = 0.3. Our results suggest that the dielectric and ferroelectric properties of PMN-xPT solid solutions could be effectively enhanced by controlling the sintering protocols.

Proceedings of the National Academy of Sciences, 117 (46), ISSN:0027-8424, ISSN:1091-6490

Results of calorimetric and dielectric studies of ferroelectric composite (C6H16NBr)1-x/(PbTiO3)x (x = 0.1, 0.2, 0.3) are presented. It was shown that addition of lead titanate leads to a change of...

Piezo- and pyroelectricity is an intrinsically combined material property for all ferroelectric materials. While the pyroelectric coefficients of most ferroelectric ceramics and polymers have the same sign, their piezoelectric coefficients have opposite ones. On this basis, we can create a polymer-ceramic nanocomposite material where either the piezo- or the pyroelectric effect is suppressed by a selective poling of the single constituents, a concept that was shown for composite pellets in the late 1990s. Motivated by the current demand for lightweight and low-cost piezoelectric sensors with reduced cross-sensitivity to temperature variations, we have taken up this idea and formulated screen-printable nanocomposite pastes from poly(vinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) and lead titanate (PbTiO3, PT) or sodium bismuth titanate (NaBiTi2O6 or BNT) nanoparticles, respectively. We demonstrate that printed sensors on flexible substrates based on these materials can be conditioned by selective poling of the nanoparticles and the polymer matrix to show either only piezoelectric or only pyroelectric sensor response. We examined the degree of cross-talk between the thermal and pressure sensing channels and show a reduction of over 90% cross-sensitivity for the ferroelectric composites compared to pure P(VDF-TrFE) sensors.

Lead titanate (PbTiO3) glass and glass ceramics (GCs) are technologically very useful materials that played significant role in various applications due to attractive optical and electrical properties. Based on its structural comparability with the perovskite barium titanate (BaTiO3) lattice, PbTiO3 was the first reported ferroelectric material in 1950. High Curie temperature (490 °C) exhibited by PbTiO3 has led to its utilization for high-temperature applications. The high molecular mass of lead also raises the density of the material, considering its mass of 207.2 g/mol, versus 40.08 g/mol for calcium. Thus, lead-based GCs also have an advantageous use to protect from the highly penetrating X-rays, γ-rays radiations, and high energy storage in barrier layer capacitors. Dielectric behavior of the GCs mainly depends on its doping with numerous oxides such as La2O3, Bi2O3, CrO3, Nb2O5, the heat treatment processes, and their respective soaking times. Herein, we report the different methods of the synthesis of PbTiO3 glass and GCs which showed distinct optical, structural, dielectric, and mechanical properties. Moreover, this review emphases on the past and recent dielectric characteristics of the various PbTiO3 glass ceramics.

Detailed studies of structural, dielectric, and electrical characteristics of a precursor solution method synthesized, bismuth and lead titanate modified manganese titanate (MnTiO3) are reported in this communication. Analysis of X-ray diffraction data shows that MnTiO3 goes through a structural change on the addition of Bi and PbTiO3 (PT). At room temperature, MnTiO3 has a rhombohedral crystal system, which changes to an orthorhombic crystal system with the addition of bismuth in it (i.e., BiMn1/2Ti1/2O3 = BMT). On further addition of PT in BMT (i.e., 0.5 BiMn1/2Ti1/2O3–0.5PbTiO3), a stable perovskite structure with tetragonal symmetry was obtained. It is found that the addition of bismuth and lead titanate effectively reduces the grain size, and hence enhances the relative permittivity of the compound. It is further found that ferroelectricity can be induced in a non-ferroelectric MnTiO3 on the addition of Bi and PbTiO3 in it. However, the addition of bismuth and lead titanate increases the leakage current density of the compound.

The influence of La3+-doping on the electrocaloric effect (ECE) of the 0.75(Pb1-3x/2Lax)(Mg1/3Nb2/3)O3-0.25(Pb1-3x/2Lax)TiO3 (L-PMN-PT: x/75/25 x = 0.0–4.0 mol.%) ceramics was studied. With the increase of La3+-doping in these ceramics, the relaxor ferroelectric properties increase, while the average grain size, coercive field E c and Curie temperature T C decrease. As a result, a maximum adiabatic temperature change Δ T as high as 0.68 K, measured by direct measurement method, was achieved under a lower electric field ( E ) intensity of 5 kV/mm at 383 K for samples with x = 2.0 mol.%. Besides the high Δ T value, the La3+-doping also leads to a temperature insensitivity of ΔT. The variation of Δ T is less than 0.15 K, or 28.3%, over a wide temperature range of 303–423 K. The La3+-doped PMN-PT ceramics, with large and temperature insensitive Δ T over a broad temperature range, is very helpful for practical application. The reduction of E c and T C can be attributed to the suppression of long-range coupling between oxygen octahedrons due to the partial replacement of Pb2+ by La3+. The temperature insensitivity of ECE is attributed to the enhancement of relaxor ferroelectric properties.

This novel research work addresses the physical properties of Lead titanate (PT), PbTiO3 sample with additives. The modification of this sample was carried out by adding calcium in proportion of 5 to 15mol%. The samples in bulk form were synthesized by utilizing traditional method of solid state synthesis. The properties like structural analysis, and grain size determination were studied for the PbTiO3 sample & for the calcium modified lead titanate (PCT). The phase identification, structural characterizations and microstructural analysis hasanalyzed in this manuscript.

Substitution of alkali earth metal ion of Sr2+, in the Pb2+ site of Pb(Mg1/3Nb2/3)O3–PbTiO3 is expected to induce functional modulations in the system. Doping of 4 at.% of Sr2+ in 0.68PMN-0.32PT was carried out to lower the transition temperature, and to investigate the intended ferroelectric and dielectric variations. Excellent relaxor property was observed in the doped sample without appreciable reduction in remnant polarization. Doping with Sr2+ led to a reduction in transition temperature from 165 °C to 117 °C. Doped sample exhibited remnant polarization Pr = 16.2 μC/cm2, Squareness factor (Rsq) = 1.05 and Relaxor exponent (γ) around 2. Modulation in the functional response was exhibited by the doped composition, having low transition temperature, and its prospect in electrocaloric applications was analyzed.

Lead zinc niobate-lead titanate (PZN-PT) system is of particular interest for scientific researches and commercial applications due to the unique relaxation feature and superior electromechanical responses. However, it is difficult to prepare polycrystalline ceramics near the morphotropic phase boundary due to the stability of a competing lead niobate pyrochlore phase. BaTiO3 (BT) was reported to be an effective perovskite phase stabilizer at a cost of reduction in Curie temperature and piezoelectric properties. Herein, the amount of BT in PZN-PT-BT system and the sintering conditions were optimized to simultaneously stabilize the perovskite phase and maintain high dielectric and piezoelectric response. An optimum piezoelectric coefficient d33 ∼ 870 pC/N along with a Tm ∼ 133 °C and an electromechanical coupling coefficient k33 ∼ 0.61 was obtained in the PZN-8PT-6BT ceramics sintered at 1100 °C. The low sintering temperature, wide processing window, and improved dielectric and piezoelectric properties make PZN-PT-BT ceramics potential candidates for piezoelectric devices.

The solid solution of relaxor and lead titanate single crystals have been an excellent choice for electromechanical applications such as energy harvesters, SONARs, transducers, and biomedical equipment. The mechanical quality factor (Qm) plays a crucial role in such applications using high power resonance condition. In this work, 32 mode (011) oriented along thickness direction, Generation-III piezoelectric single crystals based on PMN-PZT [71Pb(Mg1/3Nb2/3)O3–29PbZrTiO3] have been grown by solid state single crystal growth method. The Mn doping concentration in the crystals were systematically controlled within the range of 0 to 1.0 mol.%. The piezoelectric properties noticeably varied with the Mn doping concentration when the content is over 0.1 mol.%. In order to obtain significant enhancement in Qm in PMN-PZT single crystals, especially, the Mn doping concentration should be higher than 0.7 mol.% (which offers highest figure of merit) for high power resonance applications.

Glasses were prepared using the conventional melt quench technique and converted to glass-ceramics by two stage heat treatment. The density of glass and glass–ceramic samples was measured by Archimedes principle. Formation of ferroelectric phase in the glass–ceramic samples was confirmed using XRD. The resulting glass-ceramics contained most stable tetragonal lead titanate (PbTiO3) phase along with lead zirconate titanate phase. Volume fraction of tetragonal lead titanate phase was calculated from XRD. Microstructure of the glass-ceramics revealed the formation of lead titanate crystals. Dielectric properties were studied at different frequencies and temperature. Ferroelectric hysteresis measurement was carried out using PE-loop tracer. The presence of dielectric and ferroelectric properties in these samples may further explored for piezoelectric applications.

Lead based relaxor ferroelectric like Lead Magnesium Niobate and their binary solid solutions with Lead Titanate have great interest of research because of their significant and excellent dielectric, piezoelectric and electrostrictive properties. In the present work, the Lead Magnesium Niobate (PMN) and Lead Magnesium Niobate-Lead Titanate (0.75PMN-0.25PT) were prepared through solid state reaction method with double sintering process at 1200 °C for 6 hr. XRD data shows the pervoskite structure of the prepared sample. SEM report of PMN and 0.75PMN-0.25PT shows the different microstructure with dense grains. Dielectric study of PMN and 0.75PMN-0.25PT shows the effect of addition of PT content on electrical properties at room temperature.

The frequency and temperature depending structural, morphological and dielectric features of the Neodymium (Nd+3) doped bismuth ferrite (BFO; BiFeO3) and lead titanate (PT; PbTiO3) electronic system have been processed by using solid state chemical route. The capacitive properties of the prepared solid ceramic [(Pb0.9Bi.05Nd0.05)(Fe0.1Ti0.9)O3] have been investigated experimentally. The apprehension of the preferred sample material shows tetragonal crystal structure which is affirm through XRD (X-ray diffraction) investigation. The uniform grain scattering is perceived from the SEM study. The rare earth Nd modified BFO-PT compound unveils high dielectric constant and low tangent loss with respect to temperature and frequency, which substantiate the material as a promising candidate for invention of electronic devices.

A novel lead zinc titanate tungsten oxide (PbZn[Formula: see text]Ti[Formula: see text]W[Formula: see text]O[Formula: see text] single perovskite was synthesized employing a cost-effective solid-state reaction technique. A phase transition occurs from tetragonal (P4mm) to monoclinic (C2/m) after substituting zinc (Zn) and tungsten (W) into the B-site of the pure lead titanate. The average crystallite size and micro-lattice strain are 66.2[Formula: see text]nm and 0.159%, respectively, calculated by the Williamson–Hall method. The grains are uniformly distributed through well-defined grain boundaries and the average grain size is about 17.8[Formula: see text][Formula: see text]m analyzed from the SEM micrograph. Raman spectrum suggests the presence of all constituent elements in the sample. The UV–Visible study suggests that the sample is suitable for photovoltaic applications because of high bandgap energy [Formula: see text][Formula: see text]eV. The dielectric study confirms the negative temperature coefficient resistance (NTCR) behavior of the sample. The activation energy increases from 13.9[Formula: see text]meV to 142[Formula: see text]meV with a rise of temperature suggesting that ac conductivity is thermally activated. The thermally activated relaxation process was managed by immobile charge carriers at low temperatures while defects and oxygen vacancies at higher temperatures. The presence of the asymmetrical curves in modulus plots confirms the non-Debye-type behavior. Both Nyquist and Cole–Cole semi-circular arcs confirm the semiconductor nature of the sample.

In this paper a new stabilization method applied to ethylene-propylene-diene monomer (EPDM) against oxidation is presented. The doped lead titanate (PbTiO3) with several atoms (Ce, Pr, In, Gd and Nb) is a typical example of protection effect of inorganic filler. The isothermal and nonisothermal (CL) procedures were used for monitoring the progresses and the protection degrees of oxidation. The most evident effect was promoted when the filler was doped with gadolinium and dysprosium. The contribution of doped filler as the delay activities in material oxidation is described by the activation energies required for thermal ageing of modified polymer. They were calculated based on temporal kinetic parameters (oxidation induction time, half period of oxidation and maximum oxidation time). The highest stabilization efficiencies were found for the sample containing 5 and 10 phr of inorganic phase. The replacement of organic synthesis antioxidants by doped compounds demonstrates that the choice of inorganic structures may become a usual praxis for the extension of product life time operating in several hazardous circumstances: nuclear engineering, space applications, electrical equipments, where the degradation occurs in a large extent.

We perform parameter subset selection and uncertainty analysis for phase-field models that are applied to the ferroelectric material lead titanate. A motivating objective is to determine which parameters are influential in the sense that their uncertainties directly affect the uncertainty in the model response, and fix noninfluential parameters at nominal values for subsequent uncertainty propagation. We employ Bayesian inference to quantify the uncertainties of gradient exchange parameters governing 180° and 90° tetragonal phase domain wall energies. The uncertainties of influential parameters determined by parameter subset selection are then propagated through the models to obtain credible intervals when estimating energy densities quantifying polarization and strain across domain walls. The results illustrate various properties of Landau and electromechanical coupling parameters and their influence on domain wall interactions. We employ energy statistics, which quantify distances between statistical observations, to compare credible intervals constructed using a complete set of parameters against an influential subset of parameters. These intervals are obtained from the uncertainty propagation of the model input parameters on the domain wall energy densities. The investigation provides critical insight into the development of parameter subset selection, uncertainty quantification, and propagation methodologies for material modeling domain wall structure evolution, informed by density functional theory simulations.

Ilmenites, which find enormous applications, because of their high relative permittivity and modest dielectric losses can have their efficiency and practical applicability enhanced by incorporation of ferroelectricity and multiferroicity in them. In our present work, ferroelectricity and magneto-electric (ME) effect is induced in the non-ferroelectric ilmenite FeTiO3 by modifying it with bismuth and lead titanate. The structural, micro-structural, electrical, ferroelectric and magneto-electric effect of the studied compounds were investigated using x-ray diffraction, field emission scanning electron microscope, phase sensitive impedance analyser, polarization–electric field hysteresis loop measurements and ME set up respectively. The analysis of I ∼ V characteristics curve shows that the modification results in the decrease of leakage current of the parent compound by three order of magnitude. Thus, in the present work, it is shown that the modifications not only induce ferroelectricity and multiferroicity in the parent compound, but also reduces the leakage current drastically.

By X-ray microprobe analysis, X-ray phase analysis, IR spectroscopy, high resolution scanning electron microscopy, and atomic force microscopy thermally stimulated surface heterosegregation is studied in non-oxygen and oxygen-containing single crystals with the participation of oxygen. It is concluded that sodium chlorite NaClO2 and sodium hydrocarbonate NaHCO3 are formed on the surface of sodium chloride NaCl, gallium oxide Ga2O3 on the surface of gallium arsenide GaAs, titanium dioxide TiO2 and lead oxide PbO on the surface of lead titanate PbTiO3, the complex oxide Bi2Ti4O11 and bismuth oxide Bi2O3 on the surface of bismuth titanate Bi4Ti3O12, the complex oxides Bi2Fe4O9, Bi26– xFexO39 and bismuth oxide Bi2O3 on the surface of bismuth ferrite BiFeO3, the complex oxide Pb3GeO5 and lead oxide PbO on the surface of lead germanate Pb5Ge3O11. The mechanisms of the formation of surface oxygen-containing phases including the self-diffusion of matrix crystal atoms to the surface, the migration of segregated atoms on the surface, the evaporation and absorption of molecules of water, carbon oxides, hydrocarbons, oxygen, as well as the surface reactions of segregated atoms with the participation of both lattice oxygen and oxygen of the external environment are reported.

A systematic investigation of the seeding effects on the mechanochemical synthesis of lead magnesium niobate – lead titanate 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 (PMN–10PT), one of the most studied relaxor-ferroelectric material for electrocaloric applications, is reported. The perovskite crystallisation process was followed by X-ray diffraction using the Rietveld refinement method and transmission electron microscopy. Compared to the mixed-oxides case which requires 143 h of high-energy milling, the milling time needed to obtain a phase-pure PMN–10PT perovskite using PT seeds is reduced almost twice. The presence of PT seeds leads to faster transitions from the amorphous to pyrochlore and to perovskite phases compared to the mixed-oxides case. A sintering study demonstrates, for the first time, that a second, metastable, pyrochlore phase is taking part in the processes of perovskite formation. The PMN–10PT ceramic prepared from the PT-seeded powder exhibits electrocaloric properties comparable to reported values for PMN–10 PT prepared from oxides.

Complex topological configurations are fertile ground for exploring emergent phenomena and exotic phases in condensed-matter physics. For example, the recent discovery of polarization vortices and their associated complex-phase coexistence and response under applied electric fields in superlattices of (PbTiO3)n/(SrTiO3)n suggests the presence of a complex, multi-dimensional system capable of interesting physical responses, such as chirality, negative capacitance and large piezo-electric responses1-3. Here, by varying epitaxial constraints, we discover room-temperature polar-skyrmion bubbles in a lead titanate layer confined by strontium titanate layers, which are imaged by atomic-resolution scanning transmission electron microscopy. Phase-field modelling and second-principles calculations reveal that the polar-skyrmion bubbles have a skyrmion number of +1, and resonant soft-X-ray diffraction experiments show circular dichroism, confirming chirality. Such nanometre-scale polar-skyrmion bubbles are the electric analogues of magnetic skyrmions, and could contribute to the advancement of ferroelectrics towards functionalities incorporating emergent chirality and electrically controllable negative capacitance.

In this research, the nanosized Pb0.8-yLayCo0.2TiO3 (y = 0.2–0.8) (PLCT) samples were synthesized by microwave heated sol-gel method. The diffraction pattern revealed the existence of tetragonal phases related to lead titanate (PT) and lanthanum cobalt titanate (LCT) structures. Moreover, the PLCT structure was found to be on par with PT structure up to y = 0.4 while for y = 0.6 & 0.8 contents, the PLCT adopted the standard LCT structure. The field emission (FESEM) and transmission (TEM) electron microscopes accomplished complete formation of nanofibers at y = 0.8. The impedance spectroscopy analysis was performed over frequency ranging from 100 Hz to 5 MHz to address the microstructure variation. Furthermore, in order to account for total electrical conductivity, the grain and grain boundary contribution was described. In addition, the Nyquist plots illustrated two-layer model using two series RC circuits as a function of temperature. For the fitted Cole-Cole plots, the corresponding resistances (Rg & Rgb) and capacitances (Cg & Cgb) of grain and grain boundary were evaluated. Moreover, electrical conductivity was improved upon increasing the La-content. Later on, the Arrhenius plots (lnτ versus 1/T) were drawn to determine the activation energies.

High-energy X-ray diffraction study was performed on lead titanate (PbTiO3). Short-range order structure was revealed using atomic pair-distribution function (PDF) method. In the high-temperature c...

In the present study, lead titanate nano-sized powders were synthesized using citric acid gel method. The nanopowders were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Then, a nanocomposite system based on lead titanate nanopowders and carbon paste electrode (CPE) was designed and applied for determination of pentoxifylline (PTX). The prepared nanostructured electrode exhibited voltammetric responses with high sensitivity and selectivity for PTX and a detection limit of 2.1 nM was achieved. Finally, the proposed method was used for analysis of PTX in environmental and biological samples with satisfactory results. Graphical abstract

Pure and modified lead titanate PbTiO3 (PT) by 3% of the lanthanum iron oxide LaFeO3 (LF) samples were prepared by a sol-gel process. The calcined powders (at 700 °C for 2h) were structurally characterized by X-ray diffraction and Raman spectroscopy, it has been proven that these materials have a single phase as a perovskite-type. Furthermore, DRX and Raman spectrum revealed local lattice distortions from tetragonal structure (P4/mmm) for non-doped sample (PT-LF0%) to pseudo-cubic structure (Pm-3m) for doped sample (PT-LF3%). Optical properties were investigated by UV visible (UV-vis) absorption spectroscopy at room temperature. The UV-vis spectrum indicated that the studied powder has an optical band gap of 2.032 eV making of this material a good candidate for photovoltaic applications. In order to investigate their electrical properties, we have pressed the calcined powder into the pellets and heat treated at 1100 °C for 4h. The compound exhibited a high dielectric constant and a low dielectric loss. Empirical laws of the Curie-Weiss and of the Uchino were performed to extract electrical parameters in wide frequency range.

Solid solution between bismuth ferrite and lead titanate exhibits high potential to deliver excellent multiferroic performance. However, the mechanism is still not clear, especially that the attentions paid to the formation and influence of extra phases are lacking. Here, we revealed a new extra phase in La/Ga-doped BiFeO3-PbTiO3 solid solution, which was demonstrated to be Pb(Fe,Ga)12O19 by energy dispersive spectroscopy and multi-axis electron diffraction techniques. Such Pb(Fe,Ga)12O19 phase could be controllably manipulated by exceeding the content of Pb and Fe in the BiFeO3-PbTiO3-based ceramics, and has been demonstrated to play an important role in improving the ferromagnetism.

Various composition of lead bismuth titanate borosilicate glasses doped with one mol percent of cerium oxide in the system 55[(PbxBi1−x)TiO3]-44[2SiO2.B2O3]-1CeO2 (0.0 ≤ x ≤ 1.0) were prepared using rapid melt quenching technique. X-ray diffraction study confirmed the amorphous nature of the samples. Structural and optical properties of the glass samples were carried out using infrared spectroscopy, Raman spectroscopy, and UV–vis spectroscopy respectively. Absorption peaks in IR spectra mainly occurred due to asymmetric vibrational stretching modes of the B O bond of trigonal BO3 units. Raman study revealed that the structural network of B-O-B stretching in metaborate rings of the glass sample. The optical band gap values were determined from Davis and Mott plots. On the basis of the differential thermal analysis, all glass samples were crystallized by given a controlled heat treatment schedule within the temperature range 607–693 °C. For the determination of phase, crystal structure and crystallite size, XRD was also performed on the glass ceramic samples. To understand the surface morphology of the glass ceramic samples, scanning electron microscopy was employed. The dielectric properties were studied with varying temperature at few selected frequencies. The maximum value of relative dielectric constant, er was found to be 973 at 100 Hz with dissipation factor, D, 3.99 for bismuth free lead titanate glass ceramic sample (x = 1.0).

In this paper, we present the synthesis and studies of physical properties of the ferroelectromagnetic composites (1–x)PbMn1/3Ta2/3O3–xPbTiO3 [(1–x)PMnT–xPT], which exhibit a relaxor behavior. Using a synergistic application of scanning electron microscopy (SEM), X-ray structure analysis, and energy-dispersive X-ray analysis (EDX), we revealed that two phases always coexist in the synthesis of the composition PbMn1/3Ta2/3O3 (PMnT), one phase of which has a pyrochlore structure, and the other has a pseudo-cubic cell of the perovskite structure. We further demonstrated that doping with lead titanate PbTiO3 (PT) suppresses the dielectric polarization’s relaxor behavior. Using X-ray diffraction techniques at room temperature, we studied the dependencies of the structural parameters of each phase on the mole fractions of PT. The dielectric characteristics were studied at various frequencies by the dielectric spectroscopy method, and the dependency of the bandgap Eg on the dopant’s mole fractions was determined by the optical absorption method. The dopant’s influence on the IR Fourier spectra and magnetic hysteresis loops was analyzed. The magnetodielectric and magnetoresistive effects in these composites were studied.

In this study, a novel and simple synthetic sol-gel procedure was established to directly prepare spherical lead titanate powders without prior synthesis/usage of spherical templates such as TiO2 particles. Isotropic submicron particles with a mean diameter of 1–4 μm were prepared in this way. This synthetic process takes advantage of acetone as a stabilizing ligand and autogenous pressure generated in the autoclave during the reaction. The influence of various experimental factors (nature of the ligand, thermal treatment mode, and post-calcining temperature) as well as the formation mechanism were studied. Scanning electron microscopy and transmission electron microscopy were used to explore the particle morphology. The crystalline phases were explored and identified by X-ray diffraction analysis.

PbTiO3 (PTO) suffers from difficulty in preparing high-density robust bulk ceramics, which in turn has been a bottleneck in thin films growth with physical vapor deposition (PVD) methods. In the present work, we prepared non-doped PTO thin films by a pulsed laser deposition (PLD) method with either a single PTO target or a mosaic target consisting of PbO and TiO2 pie-shaped pieces. On the PTO single target, laser irradiation caused selective ablation of Pb, resulting in Tirich cone-shaped pillar structure on the surface, whereas the irradiated surface of PbO and TiO2 pieces was smoother. Epitaxial PTO films deposited on SrTiO3 (001) substrates from the pie-chart targets with PbO:TiO2 areal ratio from 3:5 to 5:3 resulted in composition, crystallinity, flatness, and ferroelectric properties almost independent of the areal ratio. The averaged composition of each film was close to stoichiometric, suggesting a compositional self-control mechanism. For growing epitaxial and high-quality non-doped PTO films, a PbO-TiO2 pie-chart target is advantageous in easiness of handling and stable surface structure., This research was supported by Spanish Ministry of Competitiveness (projects MAT2016-77100-C2-1-P and PID2019-108573GB-C21) and the AGAUR agency (project 2017SGR). ICN2 is funded by the CERCA programme/Generalitat de Catalunya and by the Severo Ochoa programme of the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, Grant No. SEV-2017-0706).

Charged domain walls (DWs) in ferroelectric materials are an area of intense research. Microscale strain has been identified as a method of inducing arrays of twin walls to meet at right angles, forming needlepoint domains which exhibit novel material properties. Atomic scale characterisation of the features exhibiting these exciting behaviours was inaccessible with the piezoresponse force microscopy resolution of previous work. Here we use aberration corrected scanning transmission electron microscopy to observe short, stepped, highly charged DWs at the tip of the needle points in ferroelectric PbTiO3. Reverse Ti4+ shift polarisation mapping confirms the head-to-head polarisation in adjacent domains. Strain mapping reveals large deviations from the bulk and a wider DW with a high Pb2+ vacancy concentration. The extra screening charge is found to stabilise the DW perpendicular to the opposing polarisation vectors and thus constitutes the most highly charged DW possible in PbTiO3. This feature at the needle point junction is a 5 nm × 2 nm channel running through the sample and is likely to have useful conducting properties. We envisage that similar junctions can be formed in other ferroelastic materials and yield exciting phenomena for future research. Domain walls are the basic building blocks of a ferroic system and determine the overall ferroic properties. Here, the authors use aberration corrected scanning transmission electron microscopy to observe the formation of charged needle point domain walls in ferroelectric PbTiO3 and how their characteristics depend on the lead vacancy concentration.

We report the deposition and characterization of calcium lead titanate (PCT) thin films for pyroelectric detectors. PCT films of thicknesses ranging from ~250 to 400 nm were deposited on both silicon and Si/SiN/Ti/Au substrates at 13 mTorr pressure by 200W radio frequency sputtering in an Ar + O2 environment. Substrates were kept at variable temperatures during the deposition. The PCT films were annealed at various temperatures in an O2 environment for 15 min. X-ray diffraction results confirm the polycrystalline nature of these films. Energy dispersive spectroscopy function of scanning electron microscope showed that the films are stoichiometric (Ca0.43Pb0.57) TiO3 (Ca/Ti = 0.5, Pb/Ti = 0.66). Temperature dependence of capacitance, pyroelectric current, and pyroelectric coefficient was investigated for different PCT films. Our results show that films deposited at 550 &deg, C and 600 &deg, C demonstrate better quality and larger values of the pyroelectric coefficient. On the other hand, the capacitance fabricated on the PCT films at 550 &deg, C showed the highest value of pyroelectric current and pyroelectric coefficient which were 14 pA and at 30 &deg, C was ~2 &micro, C/m2K respectively at a higher temperature. In addition, we used density functional theory to determine the atomic and band structure, real and imaginary parts of dielectric constant and refractive index, and absorption and reflection constants with energy.

P.P. and C.W. acknowledge partial support by Swiss National Science Foundation Division II grant 200021_178782. L.R.D. acknowledges support from the US National Science Foundation under grant DMR‐1708615. L.W.M. acknowledges support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE‐AC02‐05‐CH11231 (Materials Project program KC23MP) for the growth and study of defect structures in ferroic materials. A.B.N. gratefully acknowledges support from the Engineering and Physics Sciences Research Council (EPSRC) through grants EP/R023751/1 and EP/L017008/1. Deterministic control of the intrinsic polarization state of ferroelectric thin films is essential for device applications. Independently of the well-established role of electrostatic boundary conditions and epitaxial strain, the importance of growth temperature as a tool to stabilize a target polarization state during thin film growth is shown here. Full control of the intrinsic polarization orientation of PbTiO3 thin films is demonstrated-from monodomain up, through polydomain, to monodomain down as imaged by piezoresponse force microscopy-using changes in the film growth temperature. X-ray diffraction and scanning transmission electron microscopy reveal a variation of c-axis related to out-of-plane strain gradients. These measurements, supported by Ginzburg-Landau-Devonshire free energy calculations and Rutherford backscattering spectroscopy, point to a defect mediated polarization gradient initiated by a temperature dependent effective built-in field during growth, allowing polarization control not only under specific growth conditions, but ex-situ, for subsequent processing and device applications. Publisher PDF

This research work illustrates the improvement in performance study of dye-sensitized solar cell (DSSC) in the presence of dielectric nanoparticles coupled with TiO2 mesoporous film. Lanthanum-doped lead titanate (PLT15) was the chosen dielectric material used for this due to its strong field–effect passivation, screened columbic attraction, back reflector, and recombination inhibitor for solar cell. Natural dye extracted by a three-step drying and grinding process followed by solvent extraction from carrot is, namely, carotene. Postfiltration, the solution underwent through various absorption media for better purification. The synthesized dielectric nanoparticles were introduced into the TiO2 matrix and coated on the FTO glass substrate by doctor blading technique followed annealing, and then dye depositional process was performed by dipping TiO2–PLT15-coated FTO glass in extracted organic dye solution for overnight. UV–Vis, FTIR spectroscopy, and SEM tools were used for the characterization of dyes. Finally the electrical performance of the fabricated cell was analyzed under simulated AM 1.5G solar illumination using 100 mW/cm2 power.

This work describes the process of synthesizing and printing a novel (0–3) piezocomposite material using solution mixing technique and digital light processing technique. This piezoelectric composite material was developed using a photopolymer, grey resin and lead magnesium niobate and lead titanate (PMN-PT) with particles size 5 µm. The 3D-printing of this thick film was achieved using the piezocomposite material with high filler content upto 60% w/w of PMN-PT. Results showed a satisfactory print resolution, a thick film with high flexibility and exceptionally high d33 coefficient of 49 pm/V during single point scan and an average of 67 pm/V during full surface scan measured using the laser vibrometer technique.

The desire for highly sensitive, miniature sensors and actuators has grown in recent years. This desire has led to the recent development of 3D-printed sensors and actuators using piezocomposites. The use of 3D-printing leads to the rapid development of devices at lower costs and device personalization. This work describes the process of developing a novel 0-3 piezocomposite material, 3D – printing using a digital light processing technique, and characterization. The composite material was made using a photopolymer, grey resin and lead magnesium niobate and lead titanate (PMN-PT) with particles sizes $5 \mu \mathrm{m}$. 3D-printing of a membrane using the piezoelectric composite with high concentrations of PMN-PT was achieved with good print resolution and remarkably high $d _{33}$ coefficient of 74 pm/V, measured using the laser vibrometer technique. Thin film samples of the composites were also made using spin coating technique to produce composites with 0-3 connectivity pattern and layer thickness of $90 \mu \mathrm{m}$. The bottom-up digital light processing method used provides a narrow design space in which the composite may be selectively cured and the parameters which allow successful generation of highly piezoelectric printed parts was investigated. The microstructure of the piezocomposites was analyzed using a scanning electron micrograph.

The first goal of this study is to identify the ideal piezoelectric material for the manufacturing of rheological reflectance ultrasonic sensors. The second goal is to integrate the ultrasonic rheometer within a gas absorption reactor and to measure viscosity changes in an ionic liquid (IL) caused by gas absorption. To achieve the objectives, bismuth titanate, lead titanate, lead metaniobate and lead zirconate titanate materials in layer, tungsten bronze and perovskite structures were assembled on aluminum delay lines and tested under thermal cycling between room temperature and 150 &deg, C. The results showed that lead metaniobate in tungsten bronze structure is the most suitable material for long time duration thermal cycling. Therefore, the ultrasonic rheometer was assembled using this material and installed in a pressurized reactor to test a reference IL at the operating conditions of 50 &deg, C and at a pressure of 80 bar. The reference IL was saturated with nitrogen as well as hydrogen gas. Viscosity signals remained constant under the hydrogen atmosphere, while in nitrogen atmosphere the absorption of the gas lead to a rise in the value of viscosity.

Summary Ferroelectric domain wall (DW) conduction, confirmed in recent experiments, has attracted intense attention due to its promising applications in optoelectronic devices. Herein, we provide theoretical evidence of electric conduction in Pb0.8Ca0.2TiO3 (PCT) DWs. The separation of charge accumulation in DWs, corresponding to the electronic conduction-band minimum (CBM) and valence-band maximum (VBM), weakens the tendency for the electron-hole recombination, thereby providing more efficient channels for charge transfer. We fabricate PCT-based functional photovoltaic devices with polarization tunable charge transfer to exploit the combined conduction and ferroelectric properties of the DW. The photovoltaic performance of the devices can be regulated by the alternation of ferroelectric domains in PCT, caused by variation of the external poling. Our work broadens the applicability of DW conduction and may inspire the future design of high-performance materials in photovoltaic devices.

The sol-gel method was used to prepare perovskite type (Pb1-1.5x Lax□0.5x)TiO3 (PLT) ceramics with x = 0.21, 0.22, 0.23, 0.24, 0.25 in order to investigate their structural, optical, and dielectric properties. The crystallite compounds were obtained by calcinating the mixture of PbCO3, TiO2, and La2O3 at 1000 °C for different time periods. After 4 h annealing, PLT23 sample, approximately a very little secondary phases have been observed in the XRD spectrum of the PLT sample with 23% La content (PLT23). The presence of La dopants might have affected the tetragonality of the Lead titanate crystal structure. The PLT samples tolerance factor decreases from 0.991 as in x = 0.21 to 0.986 for x = 0.25. Hence, these structures tend, generally, to be in the perovskite phase as t ~ 1. In the doped ceramics, characteristic phase transitions were shifted to lower temperatures. The dielectric permittivity value showed the tendency of a slight increase with lanthanum addition and achieved its maximum εm (3649) at x = 0.23, then it decreases for higher concentrations of La. The samples' estimated average crystallite size ranged from 40 nm to 50 nm, the maximum crystallite size about (49.6 nm) at x = 0.23 La. The calculated bandgaps were 3.1, 3.26, 3.28, 3.08, and 3.12 for the PLT with 0.21, 0.22, 0.23,0.24 and 0.25% La, respectively. The Curie constant C was obtained as the slope of the curve of the inverse values of εr vs. temperature. The highest C value (5.2 × 105 K) was measured for the 23% La sample. The sample with 23% La content appears to be notably distinguished in its structural, optical, and dielectric characteristics compared with other samples., Materials science; Nanotechnology; Ceramics; Ferroelectrics; PLT; Sol-gel; Optical; Dielectric