Perovskite Lead Zirconate Titanate Research Articles

Perovskite lead zirconate titanate (PbZr0.52Ti0.48O3) nanofibers for inhibiting polysulfide shuttle effect in lithium-sulfur batteries

Rapid capacity fade and untimely failure caused by the infamous “shuttle effect” prevents the commercialization of Lithium-sulfur batteries (LSB). In this work, lead zirconate titanate (PZT) nanofibers have been employed as polysulfide immobilizer in LSB. Ferroelectric materials possess a unique domain structure where each individual domain carries a dipole moment. The dipole-dipole interaction between the domains of the ferroelectric PZT nanofibers and polysulfides inhibits the diffusion of polysulfides from the cathode. In addition to electrostatic interactions, the 1-dimensional nanofibers with large specific surface area are accompanied by lithiophilic and sulfiphilic heteroatoms which act as anchoring points for chemically binding the polysulfides. Moreover, the enhanced wettability of the electrode arising from the favorable affinity of PZT nanofibers towards the electrolyte along with lithiophilic heteroatoms aids the diffusion of Lithium-ions. Briefly, the synergy of physical and chemical interaction of PZT nanofibers towards the polysulfide species is found to mitigate the shuttle effect and improve electrochemical performance of LSB. Further, a promising long-term cycling over 200 cycles for LSB cell with PZT interlayer is observed with 98% Coulombic efficiency and slow fade rate of 0.08% per cycle.

High electro-optic coefficient lead zirconate titanate films toward low-power and compact modulators

Developing strong electro-optic (EO) effect materials and devices is vital for high-speed optical communications and integrated photonics. In this work, we explored a chemical solution deposition technique to grow pure perovskite lead zirconate titanate (PZT) films on sapphire substrates. The grown PZT films demonstrated a preferential orientation and a broadband optical transmission window ranging from 600 to 2500 nm. Based on the high-quality film, we subsequently designed and fabricated a PZT Mach-Zehnder interference waveguide EO modulator. The measured half-wave voltage Vπ is 3.6 V at the wavelength of 1550 nm, corresponding to an in-device EO coefficient as high as ∼133 pm/V. The response of the PZT modulator from 6 to 12 GHz has been measured. We foresee that our work may pave the way towards power-efficient, ultra-compact integrated devices, including modulators, switches and sensors.

The low-power law emergent response of random RCC’ networks

In this paper, we analyse the emergent response of random resistor-capacitor (RC) networks, which are widely used in modeling binary composite materials. By simply introducing two kinds of capacitors C and C ′ , we simulate the size effect of micro-capacitors formed by dielectric regions separating conductive regions in real materials. A low-power law emergent response (low PLER) is obtained in the framework of these random networks which we will be naming (RCC’) therein. This simple model also explains the observed low frequency dispersion in porous sample of the perovskite lead zirconate titanate (PZT) as well as lead halide perovskite solar cells. The calculations has been achieved by using the well known Frank and Lobb algorithm. In addition, we investigate the effect of capacitor proportions and value ratios (C ′ /C ) on the PLER. A good agreement with EMA predictions is obtained at intermediate frequencies.

Studying the Composition and Phase State of Thin PZT Films Obtained by High-Frequency Magnetron Sputtering under Variation of Working Gas Pressure

Variation of the working gas pressure (from 8 to 2 Pa) during RF magnetron sputtering deposition of thin perovskite lead zirconate titanate (PZT) films revealed strong changes in their lead content, which decreased below the stoichiometric level and led to the formation of a two-phase (perovskite–pyrochlore) structure upon subsequent high-temperature annealing. Measurements of the composition of perovskite islands in the two-phase films showed that the lead content in these islands was equal to or greater than stoichiometric. These results lead to the conclusion that the obtained PZT films are free of lead vacancies.

Исследование состава и фазового состояния тонких пленок цирконата-титаната свинца, полученных высокочастотным магнетронным осаждением, при изменении давления рабочего газа

AbstractVariation of the working gas pressure (from 8 to 2 Pa) during RF magnetron sputtering deposition of thin perovskite lead zirconate titanate (PZT) films revealed strong changes in their lead content, which decreased below the stoichiometric level and led to the formation of a two-phase (perovskite–pyrochlore) structure upon subsequent high-temperature annealing. Measurements of the composition of perovskite islands in the two-phase films showed that the lead content in these islands was equal to or greater than stoichiometric. These results lead to the conclusion that the obtained PZT films are free of lead vacancies.

Phase formation behavior of perovskite ferroelectric lead zirconate titanate - lead zinc niobate powders by X-ray absorption spectroscopy

ABSTRACTLead zirconate titanate - lead zinc niobate (PZT-PZN) powders were prepared by a modified mixed-oxide synthetic route via a combination of Zn2Nb34O87 precursor and vibro-milling techniques. The effects of calcination temperature and chemical composition on phase formation were investigated by x-ray absorption spectroscopy. The Zn K-edge x-ray absorption near edge structure (XANES) was simulated with PZT-PZN in pyrochlore phase and perovskite phase. The comparison between simulated and measured XANES shows the increasing perovskite phase formation of PZT-PZN with increasing calcination temperature and the optimization of calcination temperature lead to 100% yield of PZT-PZN in perovskite phase. In addition, the Zn K-edge x-ray absorption near edge structure (XANES) was simulated with various compositions of PZT in PZT-PZN. The comparison between simulated and measured XANES shows the increasing perovskite phase formation of PZT-PZN with increasing composition of PZT. The results show the optimization of calcination conditions lead to formation of PZT-PZN in perovskite phase.

Low-voltage micromechanical RF switch based on a piezoelectric micro-cantilever integrated with a transmission line

This paper reports a class of compact low-voltage-actuated micromechanical radio-frequency (RF) switches with a piezoelectric micro-cantilever and a signal transmission line in an integrated form. Perovskite lead zirconate titanate (PZT) thin film was prepared by using a facile sol-gel process in a programmable manner. The proposed RF switch was demonstrated without significant structural deformation by optimization of both the structural design and batch fabrication with various micromachining techniques. The proposed compact RF switch was experimentally found to be actuated with an applied voltage as low as 2 V. The switch also showed high isolation and moderate insertion loss for frequencies up to 5 GHz.

Ultra high strain properties of lanthanum substituted PZT electro-ceramics prepared via mechanical activation

Substitution of lanthanum at the A sites of perovskite lead zirconate titanate ceramics shows an improvement in the structural and electrical properties. (Pb0.92La0.08)(Zr0.60Ti0.40)O3 (PLZT 8/60/40) was prepared using high energy mechano-chemical milling. The effect of milling on the microstructure and electrical properties of PLZT 8/60/40 has been studied. X-ray diffraction shows the phase formation after milling itself. TEM was used to measure the particle size. The SEM image of the sintered pellet shows a dense microstructure and the average grain size was found to be <1.5μm. Electrical properties of the ceramics were characterized. Piezoelectric charge coefficient (d33) was found to be 561pC/N. Resonance studies were performed on poled ceramics and the electromechanical coupling factor was calculated by the resonance method. The PLZT 8/60/40 composition showed a well saturated and uniform P–E hysteresis loop with remanent polarization (Pr) of 33.29μC/cm2 and a coercive field (Ec) of 10.57kV/cm. Electric field induced strain (S–E loop) shows a value of ∼0.27% with minimum loss.

Pulsed Laser Deposition and Ferroelectric Characterization of Nanostructured Perovskite Lead Zirconate Titanate (52/48) Thin Films

Perovskite lead zirconate titanate nanostructured (PZT) thin films with Zr/Ti ratio of 52/48 were deposited on Pt/TiO2/SiO2/Si(100) substrate using pulsed laser deposition method. A metal/ ferroelectric/metal (MFM) structure was used for ferroelectric property measurements, formed by depositing gold electrode on top of the film. A Nd:YAG UV laser having a wavelength of 355 nm and an energy fluence of -2.7 J/cm2 was used to deposit the film. The film was deposited on platinum (Pt) coated silicon substrate at the substrate temperature of 600 degrees C and the base vacuum of 10(-6) mbar. The scanning electron microscopy (SEM) images revealed well-crystallized films with a fine microstructure and an average grain size of - 50 nm. The ferroelectric properties of the film were studied and the results were discussed. The voltage dependent Polarization versus Electric field hysteresis measurements of PZT (52/48) pellet showed a well-defined hysteresis loop with a fairly high remnant polarization (P(r)) and low coercive field (E(c)).

Crystallization of lead zirconate titanate without passing through pyrochlore by new solution process

We report a novel low-temperature crystallization path for perovskite lead zirconate titanate (PZT) from solution. The modification of a PZT solution by monoethanolamine (MEA) resulted in a change in the crystallization behavior. MEA was strongly coordinated to the metal ions, resulting in destroy of multinuclear metal organic complexes. This led to a remarkably increased pyrolysis temperature, and Pb 2+ was reduced into Pb 0 because of a reducing environment at 200–300 °C. Nanoscopic separations of Pb 0 was later transformed into uniformly distributed α-PbO nanocrystals and clusters in the amorphous Zr/Ti–O matrix, and finally the sample crystallized into perovskite at 400–500 °C. On the other hand, pyrochlore phase was observed in the conventional crystallization process. The avoidance of pyrochlore formation is the key for the low-temperature crystallization of perovskite. X-ray absorption fine structure (XAFS) analysis was performed to reveal the structures in solutions and amorphous phases.

Electrorheological properties of novel piezoelectric lead zirconate titanate Pb(Zr 0.5,Ti 0.5)O 3-acrylic rubber composites

Perovskite lead zirconate titanate, comprised of PbTi 1 − x O 3 and PbZr x O 3, was synthesized at a temperature below the Curie temperature, T C. The tetragonal form obtained is a noncentrosymmetric structure capable of spontaneous polarization. FTIR spectra and XRD patterns confirm the successful synthesis of the lead zirconate titanate (PZT). PZT particles were mixed with an arcrylic rubber solution and cast as a thin sheet. SEM micrographs indicate that PZT particles are moderately dispersed in the acrylic rubber (AR71) matrix. Without electric field, the particles merely act as a reinforcing filler which can absorb and store additional stress. Under electric field, particle-induced dipole moments are generated, leading to interparticle interactions, and a substantial increase in the storage modulus. At a lead zirconate titanate volume fraction of 0.038600, the storage modulus response attains its maximum value with the corresponding storage modulus sensitivity value of 0.58 as the electric field strength is varied from 0 to 2 kV/mm.

Template-based electrophoretic deposition of perovskite PZT nanotubes

Template-based electrophoretic deposition of perovskite lead zirconate titanate (PZT) nanotubes was achieved using anodic alumina (AA) membranes and sols, containing lead, zirconium and titanium precursors. The effect of various anodizing voltages on the size of the channels in the anodic alumina template was investigated. The prepared sol was driven into the channels under the influence of various electric fields and subsequently sintered at about 700 °C. The effects of the initial heating rates and the burn-out temperature on the phase evolution of the samples were studied and a modified firing process was employed. The effects of the electrophoretic voltage and the deposition time on the average wall thickness of the tubes were investigated. Scanning and transmission electron microscopy (SEM and TEM) revealed the efficiency of electrophoresis in the growth of lead zirconate titanate nanotubes in a close-packed array. The X-ray diffraction analyses indicated the presence of perovskite as the principal phase after a modified firing schedule.

A novel route to perovskite lead zirconate titanate from glycolate precursors via the sol–gel process

AbstractA perovskite lead zirconate titanate was synthesized by the sol‐gel process, using lead glycolate, sodium tris(glycozirconate) and titanium glycolate as the starting precursors. For the mole ratio Pb:Zr:Ti of 1:0.5:0.5 [Pb(Zr0.5Ti0.5)O3], TGA‐DSC thermal analysis indicated that the percentage of ceramic yield was 55.8, close to the calculated chemical composition value of 49.5. The exothermic peak occurred at 268 °C below the theoretical Curie temperature of 400 °C. The pyrolysis of Pb(Zr0.5Ti0.5)O3 of the perovskite phase was investigated in terms of calcination temperature and time. The structure obtained was of the tetragonal form when calcined at temperatures below 400 °C; it transformed to the tetragonal and the cubic forms of the perovskite phase on calcination above the Curie temperature, as verified by X‐ray data. The lead zirconate titanate synthesized and calcined at 400 °C for 1 h had the highest dielectric constant, the highest electrical conductivity and the dielectric loss tangent of 10 190, 0.803 × 10−3 (Ω.m)−1 and 1.513 at 1000 Hz, respectively. The lead zirconate titanate powder synthesized has potential applications as an electronic material. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Effect of pH on the Crystallization of Homogeneously Precipitated Nanosized PZT Powder

Nanosized lead zirconate titanate (PZT) powder with Zr:Ti ratio in the morphotropic phase boundary region was synthesized by homogeneous precipitation of metal ions. The powder precipitated at 90°C and at pH 6.7 resulted single-phase perovskite lead zirconate titanate powder when calcined at 550°C and above for 4 hours in air. The solution pH and the precipitation temperature strongly affect the composition of the calcined powder. The results obtained by structural characterization of homogeneously precipitated powder were compared with that obtained from the conventional precipitation method using ammonia in terms of crystallization, homogeneity, and microstructure. The homogeneously precipitated powder showed smaller particle size, minimum agglomeration and uniform shape on calcination and annealing. Powdered samples that precipitated by homogeneous precipitation crystallized directly to perovskite PZT, without any intermediate pyrochlore phase formation. In contrast, the NH3 precipitated powder converted to perovskite PZT via metastable pyrochlore and it showed phase segregation upon annealing at higher temperatures. The reaction kinetics has been studied by X-ray diffraction, differential thermal analysis, and differential scanning calorimetry.

Effects of PbTiO 3 seeding layer on electrical properties of PbZr 0.4Ti 0.6O 3 thin films

Improvements in the ferroelectric properties were obtained by controlling process parameters of the lead titanate (PTO) seed layer. Highly oriented (1 1 1) perovskite lead zirconate titanate (PZT) films yielded the largest polarization switching charges, with an improved retention behavior, compared to those of PZT films without a PbTiO 3 seed layer. The degree of (1 1 1) orientation in a PZT perovskite film increased, when an additional heat treatment process was not applied during formation of the PTO seed layer. In addition, PTO seed layers showed the best results when 8% excess Pb was supplied.

Novel Synthesis Route to Make Nanocrystalline Lead Zirconate Titanate Powder

The present research describes synthesis of perovskite lead zirconate titanate (PZT) nanocrystalline mesoporous powders from the aqueous solutions of Pb2+, Zr4+, and Ti4+ metal ions using sucrose as a template material. Sucrose retains the metal ions in solution through complex formation. Dehydration and thermal decomposition of the metal ion–sucrose mass produces a large amount of gas, which helps to create porosity and high surface area in the final products. The particle size of the synthesized powder is between 50 and 60 nm, with a average specific surface area between 20 and 25 m2/g. The surface area increases as the amount of sucrose increases. Nanocrystalline PZT powder with high surface area can be useful for low-temperature sintering.

Sonochemical preparation of net-lead zirconate titanate (PZT)

Perovskite lead zirconate titanate (PZT) microstalline phase with a net (porous) morphology was obtained by the sonochemical method. The gel was prepared by using ultrasonic irradiation on lead acetate (Pb(OOCCH3)2·3H2O), zirconium nitrate (Zr(NO3)4) and tetrabutyl titanate (Ti(Obu-n)4) as the precursors. Phase evolution of the sonochemical gel was monitored by X-ray diffraction, TG–DTA, FTIR spectra and TEM. The results confirmed that the PZT fluorite phase transformed to the perovskite phase when calcined at high temperature. Sonochemical irradiation has an important effect on further phase evolution and the crystallization morphology of the gel as compared to the reflux method.

The Seeding Effects on the Phase Transformation of Sol-Gel Derived PZT Powder

†The formation temperature for the perovskite lead zirconate titanate [Pb(Zr,Ti)O 3, PZT] derived from sol-gel route was lowered by more than 100 o C with the addition of crystallographically suitable seed particles, such as barium titanate (BT) or PZT. We investigated the effect of seeding on the crystallization of perovskite phase and on the microstructure of the sol-gel derived PZT powder by varying the concentration, size and chemical species of seed particles. The phase transition as a function of temperature was monitored by DTA, XRD, and Raman spectroscopy, and the interface between the seed particle and grown PZT layer was analyzed by SEM and high resolution TEM techniques. It was found that both the heterogeneous and homogeneous nucleation contributes competitively in the formation of perovskite PZT grains.

Transition to a cubic phase with symmetry-breaking disorder inPbZr0.52Ti0.48O3at high pressure

The tetragonal perovskite lead zirconate titanate ${\mathrm{PbZr}}_{0.52}{\mathrm{Ti}}_{0.48}{\mathrm{O}}_{3}$ (PZT), which is an important piezoelectric ceramic material, was found to undergo a phase transition to a cubic phase at close to 5 GPa by x-ray diffraction and Raman spectroscopy. Whereas the x-ray diffraction data indicated no deviation from cubic symmetry above this pressure, a strong Raman signal was present in this phase. The Raman spectrum obtained indicates the presence of symmetry-breaking disorder and is similar to those observed for ferroelectric relaxors. This result is in sharp contrast with the forbidden first-order Raman spectrum, which would be expected for a cubic paraelectric phase such as that observed at high temperature in this material.

Inducing Crystallization in an Amorphous Lead Zirconate Titanate Precursor by Mechanical Activation

For the first time, crystallization of perovskite lead zirconate titanate (PZT) phase in an amorphous hydroxide precursor is realized by mechanical activation, instead of calcination at an intermediate temperature. The resulting PZT powder exhibits well‐established crystalline perovskite structure with a crystallite size of ∼20 nm, as indicated from the peak broadening of X‐ray diffraction. An average particle size of 30 to 50 nm is observed using transmission electron microscopy for the mechanical‐activation‐derived PZT powder.