Lead Lanthanum Zirconate Titanate Research Articles

Spectroscopic analysis of lead lanthanum zirconate titanate films using UV-VIS and ellipsometry

Spectroscopic ellipsometry and ultraviolet-visible (UV-VIS) spectrometry were utilized to study the optical properties of ferroelectric lead lanthanum zirconate titanate (PLZT) films. These films were deposited on platinized silicon [Si(100)/ SiO2/TiO2/Pt(111)] substrates using the chemical solution deposition method. Films were annealed at two different temperatures (650 and 750 °C) using rapid thermal annealing. Shimadzu UV-1800 UV-VIS spectrophotometer with a resolution of 1 nm was used to measure the reflectance data in the spectral range of 300–1000 nm with a step size of 1 nm. The bandgap values were determined from the reflectance spectra using appropriate equations. A J.A. Woollam RC2 small spot spectroscopic ellipsometer was used to obtain the change in amplitude (Ψ) and phase (Δ) of polarized light upon reflection from the film surface. The spectra were recorded in the wavelength range of 210–1500 nm at an incident angle of 65°. Refractive index (n) and extinction coefficient (k) were obtained by fitting the spectra (Ψ, Δ) with the appropriate models. No significant changes were observed in the optical constants of PLZT films annealed at 650 and 750 °C. The optical transparency and the strong absorption in the ultraviolet (UV) region of PLZT films make them an attractive material for optoelectronic and UV sensing applications.

Enhanced piezoelectric properties in europium-doped lead lanthanum zirconate titanate thin films

This paper investigates the effect of europium (Eu3+) doping on the crystal structure, dielectric and piezoelectric properties of lead lanthanum zirconate titanate (PLZT) thin film. For the present study, Pb0·92(La1-yEuy)0·08(Zr0·52Ti0·48)O3 (PLEZT) compositions with various Eu concentrations (y = 0.0, 0.3, 0.5 and 0.7) were prepared on Si/SiO2/Ti/Pt substrates by chemical solution deposition technique. The X-ray diffraction and Raman spectroscopy studies revealed the structural distortions in PLZT films with Eu doping. The piezoelectric charge coefficient showed significant enhancement with Eu doping for y = 0.5 composition, with good room temperature frequency stability. This improvement in the piezoelectric characteristics of PLEZT films is the result of stronger intrinsic contributions brought in by bigger c/a ratios and higher extrinsic contributions from non-180° domain wall motions.

Photo-induced electrostatic actuators towards micro gap regulator and micro gripper based on lead lanthanum zirconate titanate ceramics

Photo-induced actuators enable potential applications involving soft robots, biomedical engineering, and microelectromechanical system due to the contactless energy supply and high spatial and temporal controllability of light. However, obtaining a fast and reliable photo-induced actuation remains a great challenge. Herein, we report a strategy to realize rapid photo-induced actuation by utilizing a composite actuation mechanism, which combines photoelectric effect and electrostatic actuation mechanism. Novel photo-induced PLZT-based electrostatic actuators (PPEAs) are then proposed towards micro gap regulator (MGR) and micro gripper. Within the electrostatic pull-in point, we demonstrate that the gap of the PPEA regarded as an MGR can be tunable upon light irradiation through simulations. Besides, the pull-in instability enables the PPEA with rapid clamping action to be a micro gripper. Micro grippers with sandwich-like multilayer arms are fabricated using a simplified photolithography process and the fundamental operation and performance of our gripper are demonstrated through a series of experiments. More importantly, the two developed components are driven rapidly and reliably by light, providing great potential to facilitate the current research in photo-induced actuation.

Improved sensitivity of temperature sensor based on three-photons pumped upconversion in highly transparent Er3+ doped lead lanthanum zirconate titanate ceramics

Efficient two-photons and three-photons pumped upconversion emission were investigated in highly transparent Er3+ ions doped lead lanthanum zirconate titanate ceramics excited by using near infrared lasers centered at 980 nm, 1064 nm, and 1550 nm. Temperature dependent spectral changes of the multi-photons upconversion emission were explored, and highly sensitive temperature sensors were obtained based on the energy difference between 2H11/2 and 4S3/2. Using this temperature sensor, the temperature changes of the Er3+ ions doped lead lanthanum zirconate titanate ceramics was tested by irradiating the sample with a high-energy femtosecond laser at 1550 nm. This work is useful for developing a highly sensitive non-contact temperature measurement sensors, which provides the necessary theoretical basis for its practical application.

Strain Characteristics of PLZT-Based Ceramics for Actuator Applications

Lead lanthanum zirconate titanate (PLZT) ceramics exhibit excellent dielectric, ferroelectric and piezoelectric properties, and they can be used in many applications, including actuators. In this review, the processing and properties of PLZT-based ceramics will be the main focus of the first part. An introduction to PLZT ceramics is given and the methods to improve processing of PLZT-based ceramics are explained in terms of the addition of sintering aids, fabrication in the form of composites, and the application of dopants. The second part will be related to strain measurement to investigate converse piezoelectric properties (actuating effect). Strain measurement techniques by Michelson interferometry and case studies in PLZT-based ceramics (aging effect, temperature dependence and magnetic field effect) are included.

Dielectric Parametric Study in Electrospun PLZT/PVDF Nanocomposite Membranes

Electrospun lead lanthanum zirconate titanate (PLZT)/polyvinylidene fluoride(PVDF) nanocomposite-based membranes were fabricated using a traditional electrospinning process. Scanning electron microscopy (SEM) was utilized to observe the surface morphology of the electrospun nanofiber membrane. The dielectric parameters of the nanocomposite membranes, such as permittivity, electric modulus, ac conductivity, and Impedance in the frequency range of 103 -106 Hz, were measured via an LCR measurement system. All-important electrical parameters were calculated from experimental measurements of capacitance and dissipation factor at ambient temperature. Frequency-dependent of, the above-cited parameters are presented.

Photo-induced DC drift in Mach-Zehnder modulators using lead lanthanum zirconate titanate thin films

We experimentally investigated the photo-induced direct current (DC) drift of a lead lanthanum zirconate titanate (PLZT) Mach-Zehnder modulator with large optical input power. We clarify the mechanism by which short-term and long-term DC drifts arise and discuss each case of DC drift. We reveal that short-term DC drift can be reduced by adjusting the buffer-layer resistivity of the PLZT modulator. We also found that the impurity level of the buffer layer affects long-term DC drift.

Neodymium and samarium codoped PLZT ferroelectric ceramics for potential betavoltaic nuclear batteries

In this work, neodymium (Nd) and samarium (Sm) codoped lead lanthanum zirconate titanate (PLZT) ceramics were prepared by a high-temperature solid-state method. The samples were characterized by X-ray diffraction, scanning electron microscopy and ferroelectric analysis. Rare earth-doped PLZT ceramics show good phase formation. An appropriate rare earth element doping amount increases the densities of PLZT ceramics and reduces their resistivities, which is due to the role of rare earth elements in grain refinement. However, the increase in the amount of grain boundaries caused by grain refinement also affects domain inversion. Therefore, with increasing doping concentration, the remnant polarization of PLZT gradually decreases, and the doping of rare earth elements also slightly reduces the band gap of PLZT. Under irradiation with an X-ray simulated beta source with a particle energy of 10 keV (between the average energies of the beta particles of 3H and 63Ni), the ceramic sheets in this work produce current densities of up to 1.38 nA/cm2. This indicates that Nd and Sm codoped PLZT ceramics have a certain potential for application in betavoltaic batteries.

Tunable equivalent dielectric constant and superior energy storage stability in relaxor-like antiferroelectric PLZT ceramic

Pulse ceramic capacitors that request particularly high reliability and long lifetime forbid over-applied electric field, hence demanding high energy density (Wre) and energy storage efficiency (η) at low electric field. In this work, we investigated a lead lanthanum zirconate titanate (PLZT) ceramic featuring both of tetragonal antiferroelectric phase (AFET) and relaxor characteristic, which emerge in converged area of PLZT phase diagram (mole ratio of La reaches ~10%). Temperature dependent permittivity and XRD analysis proves the crossover trait in this structure. In this special relaxor-like AFET structure, decent Wre (1.2–1.3 J cm−3) and η (86–90%) are achieved at 12 V μm−1. Equivalent dielectric constant (εeq) is also introduced to illustrate nonlinear energy storage performance at different electric field. Compared to common dielectric materials, tunable εeq in relaxor-like AFET structure shows advantages of excellent low-field energy density and wide working span, leading to the convenience in size design of capacitors. Finally, good energy storage stability under various external field was verified: ~1.00 J cm−3 in Wre and ~92% in η were stabilized under varied frequency (<±8.9%, 0.01–2000 Hz), temperature (<±9.8%, −60 to 120 ℃) and fatigue loading (<±9.8%, >108 times) at ~10 V μm−1.

On the mechanisms of DC conduction in electrospun PLZT/PVDF nanocomposite membranes

Designing dielectric nanocomposite films with excellent dielectric properties is of strategic importance for a variety of applications requiring pressure sensing, energy harvesting and storing, and biomedical technology. Hence, the present investigation aims at studying the dielectric properties of lead lanthanum zirconate titanate (PLZT)/poly(vinylidene fluoride) (PVDF) nanocomposite based membranes fabricated using traditional electrospinning techniques. The composites were investigated for structural and electrical conductivity properties at varying temperatures. While the Scanning Electron microscope revealed beaded and unannealed micro/nanofibers, the observations of temperature-dependent electrical conductivity imply that the charge carrier transport phenomena involve more than one conduction mechanism. This is an interesting observation and can be explained in terms of the contents and porosity of the composites. As compared to PVDF, PLZT/PVDF nanocomposite films have somewhat better conductivity. The space charge limited current was the dominant mechanism at high voltages, while the Schottky–Richardson conduction mechanism was dominating at high temperature, according to observed J–V characteristics. The DC activation energy was found to be different, as expected, due to the dynamically heterogeneous nature of PLZT aggregates within the polymer matrix; however, the films exhibit the well-known Arrhenius relationship. This indicates that the dominant conduction mechanism is observed to be electronic and thermally activated.Graphical abstract

Simulation of neutron irradiation damage in lead lanthanum zirconate titanate by Monte Carlo method

Lead lanthanum zirconate titanate (PLZT) has a broad application prospect for energy storage devices with high energy density, since it possesses excellent dielectric and energy storage properties. To investigate the irradiation damage to the PLZT induced by neutrons with different energy, the primary energetic recoil spectra of each kind of element are first extracted from the transportation simulations of neutrons with energy ranging from 1 to 14 MeV, respectively. Then, the displacement damages (including vacancies and interstitial atoms) induced by each type of recoil with different energy are simulated based on the binary collision approximation method. Finally the number of defects in PLZT produced by neutrons with an energy range from 1 to 14 MeV is calculated based on the recoil energy spectra and the defect number produced by the recoils. The results show that the number of defects produced in the PLZT material with a thickness of 3 cm is approximately independent of the neutron energy for the fast neutrons with energy in a range from 1 to 14 MeV, even though the primary recoil energy spectra from neutrons with different energy are completely different. The average number of defects produced in 3-cm-thick PLZT is about 460 ± 120 vacancies/neutrons. For neutrons with energy ranging from 1 to 14 MeV, the produced defect concentration in PLZT decreases slightly with the depth increasing within a thickness of 3 cm. The difference in defect concentration in this 3 cm is in a range of 50%. This decrease is caused mainly by the fact that some of neutrons are back-scattered during transport. The average defect concentration produced by neutron irradiation in the PLZT with a thickness of 3 cm is slightly(～20%) higher than that in the PLZT with a thickness of 1 mm. The reason for the higher defect concentration in a thicker (3 cm) PLZT can be attributed to the following facts: (i) the (n, 2n) reactions between neutron and material can make the number of neutrons increase during transport; (ii) the scattering can make the path of neutron longer; (iii) the inelastic scattering can lead to a smallnumber of moderated neutrons, which have a slightly larger interaction cross section with materials. This indicates the damage produced in thick PLZT is quite complicated and closely related to the process of neutron transport. This work presents a method of calculating the displacement damage of neutrons in materials, and the simulation results can provide guidance for studying the neutron irradiation effects of PLZT-based electronic devices.

Lead-based antiferroelectrics revisited for high energy density capacitors and large strain actuators

Lead zirconate stannate titanate (PZST) ceramics with the generic composition of Pb1-0.5xNbx[(ZrySn1-y)1-zTiz]1-xO3 with x representing Nb content (x = 0 or 0.02), y representing Zr:Sn ratio (y = 0.57 or 0.60), and z representing Ti content (z = 0.06 or 0.08), and lead lanthanum zirconate titanate (PLZT) ceramics with the general composition of Pb1-xLax(ZryTi1−y)1−x/4O3 with x = 0.050 − 0.120 were synthesized using solid state reaction method and sintering. The energy density and field induced strain behavior of these compositions were investigated for capacitor and actuator applications, respectively. The focus of the study was to evaluate and discuss the change in the polar state of these ceramics from normal ferroelectric to antiferroelectric to relaxor antiferroelectric to linear dielectric with compositional modification. The highest releasable energy density (1.053 J/cm3) was obtained from the antiferroelectric Pb[(Zr0.60Sn0.40)0.94Ti0.06]O3 composition among the PZST compositions that were investigated, but the efficiencies were generally low (max. 60%) due to the large hysteresis that was observed in these compositions. The highest field induced strain level of 0.26% was also measured in the same composition. In the case of PLZT compositions, the highest releasable energy density values (0.313 J/cm3) with much higher efficiencies (76%) and highest field induced strain levels (0.23%) were obtained from the PLZT compositions with relaxor antiferroelectric character.

Lead lanthanum zirconate titanate (PLZT)-based fiber composites for enhanced photostrictive actuation: a numerical study

Lead lanthanum zirconate titanate (PLZT)-based fiber composites for enhanced photostrictive actuation: a numerical study

The delay time of phase transition to the polar phase in relaxor ferroelectrics

We measured the time dependence behavior of the dielectric permittivity of lead lanthanum zirconate titanate (PLZT) transparent ceramic sample and a single-crystal lead magnoniobate (PMN) from the moment of the field application at certain temperatures after the zero-field cooled regime. The delay time of the phase transition from the glasslike state to the field-induced ferroelectric state was determined from the sharp change in the dielectric permittivity in PMN single crystal. The same transition in PLZT has more smooth behavior. We found the temperature dependence of the delay time of the phase transition under ultraviolet illumination for PMN single crystal.

Significant photostrictive response in lead‐free Bi0.5Na0.5TiO3 ceramics under visible light illumination

AbstractPhotostrictive effect that has been discovered for over half a century is getting renewed interest in recent years in view of the great potential for the wireless remote‐control technology. Compared with lead lanthanum zirconate titanate (PLZT) ferroelectrics that have been intensively studied, Bi0.5Na0.5TiO3 (BNT) ceramics have a more environment‐friendly prospect. In this study, we present a significant photostrictive response for Bi0.5Na0.5TiO3 ceramics under visible light illumination. The ultraviolet–visible diffuse reflectance spectrum indicates that the BNT ceramic is a direct bandgap semiconductor (Eg = 2.93 eV) with a long tail absorbance till wavelength ~560 nm. Transmission electron microscopy analysis reveals nanoscale domains and fluctuated local structure in BNT ceramics. A significant photostriction ΔL/L about 0.08% was observed for BNT when irradiated by 405‐nm laser at the power of 20 kW/m2. The nonuniform shifts of the X‐ray diffraction peaks under external laser illumination indicates that the photostriction is mainly attributed to the light‐induced distortion of crystalline lattice. Such a big deformation approaching that of piezoelectrics/ferroelectrics induced by electric field shows great promise for photo‐driven multifunctional applications.

Size and temperature effects on dielectric breakdown of ferroelectric films

The paper introduces a model of dielectric breakdown strength. The model integrated thermal breakdown and defect models, representing the relationship between the electric field of ferroelectric films and dimensional parameters and operating temperature. This model is verified with experimental results of the lead lanthanum zirconate titanate (PLZT) films of various film thickness (d = 0.8–3 μm), electrode area (A = 0.0020–25 mm2) tested under a range of operating temperature (T = 300–400 K) with satisfying fitting results. Also learned is a relationship that the recoverable electric energy density is directly proportional to the square of breakdown electric field. This relationship is found viable in predicting the electric energy density in terms of variables of d, A, and T for the PLZT films.

Influence of the PbO-excess on the structural, microstructural and ferroelectric properties of PLZT ceramics

The physical properties of lead lanthanum zirconate titanate (PLZT) ceramics have been investigated as a function of a PbO excess from 0 to 20 mol% in samples of Pb0.94La0.06(Zr0.6895Ti0.2955)O3 (composition that reveals the best performance for piezoelectric applications for materials with rhombohedral symmetry). Results are presented in a compressive way in the frame of an overview on PLZT. Structural, microstructural and ferroelectric properties were investigated as a function of the PbO content. The X-ray diffraction results confirmed the formation of the perovskite structure for all the cases. However, the presence of the Pb2O3 secondary phase has been observed for the sample containing 15 mol% PbO excess. Raman spectroscopy studies revealed a strong influence of the PbO content on the active modes shifts. The ferroelectric properties have shown a decrease of both remnant (PR) and saturation (PS) polarizations for compositions up to 10 mol% PbO, whereas an increase of PR and PS was observed for the higher PbO content samples. Results reveal the effect of the PbO excess on the long-range order interactions for the studied system.

Visible or Near-Infrared Light Self-Powered Photodetectors Based on Transparent Ferroelectric Ceramics.

Transparent ferroelectrics, with promising prospects in transparent optoelectronic devices, have unique advantages in self-powered photodetection. The self-powered photodetectors based on the photovoltaic effect have quicker responses and higher stability compared with those based on the pyroelectric effect. However, the ferroelectric ceramics previously applied are always opaque and have no infrared light-stimulated photovoltaic effect. Thus, it would be very meaningful to design photodetectors based on infrared light-stimulated photovoltaic effect and/or transparent ferroelectric ceramics. In this work, highly optical transparent pristine lead lanthanum zirconate titanate (PLZT) and band gap-engineered Ni-doped PLZT ceramics with excellent piezoelectric/ferroelectric properties were prepared by hot-pressing sintering. Stable and excellent photovoltaic performance was obtained for pristine PLZT and band gap-engineered PLZT. The value of short-circuit current density is at least 2 orders of magnitude larger than those in PLZT reported in previous works. The transparent PLZT and Ni-doped PLZT ferroelectric ceramics are applied as self-powered photodetectors for the first time for 405 nm and near-infrared light, respectively. The devices based on PLZT under 405 nm light exhibit high detectivity (7.15 × 107 Jones) and quick response (9.5 ms for rise and 11.5 ms for decay), and those devices based on Ni-doped PLZT, under near-infrared light filtered from AM 1.5 G simulated sunlight, also exhibit high detectivity (6.86 × 107 Jones) and short response time (8.5 ms), both presenting great potential for future transparent photodetectors.

The delay of phase transition to the polar phase in relaxors: influence of ultraviolet illumination

The time dependence behavior of the dielectric permittivity of lead lanthanum zirconate titanate transparent ceramic sample from the moment of the field application at certain temperatures after the zero-field cooled regime is compared to that exhibited by a single-crystal lead magnoniobate. The delay time of the phase transition from the glasslike to the field-induced ferroelectric state was determined from the sharp change in the dielectric permittivity in a lead magnoniobate single crystal. The same transition in lead lanthanum zirconate titanate has more smooth behavior. In the case of ultraviolet illumination, the delay becomes a few times shorter for both cases.

Temperature dependent fluorescence properties and mid-infrared random lasing emission in Ho3+ and Tm3+ co-doped lead lanthanum zirconate titanate ceramics

In this study, obvious up-conversion emission peaks centred at 553 nm and 696 nm were investigated in transparent Ho3+ and Tm3+ co-doped lead lanthanum zirconate titanate (PLZT) ceramics. Temperature dependent visible up-conversion emission and mid-infrared photoluminescence at approximately 2.0 μm were studied, and obvious luminous color modulation from yellow-green to red was observed. Energy transfer between Ho3+ and Tm3+ ions was studied by analyzing the suppression and enhancement of the emission peaks. Moreover, random lasing emission peaks at 1.95 μm were achieved with a full width at half maximum of 5 nm, which was desirable for developing mid-infrared lasers in ceramics materials.