Zirconate Titanate Research Articles

Understanding the impact of gadolinium substitution on the impedance and conduction mechanism of barium zirconium titanate ceramics

Understanding the impact of gadolinium substitution on the impedance and conduction mechanism of barium zirconium titanate ceramics

Molded, Solid-State Biomolecular Assemblies with Programmable Electromechanical Properties.

Piezoelectric and ferroelectric technologies are currently dominated by perovskite-based ceramics, not only due to their impressive figures of merit, but due to their versatility in size and shape. This allows the dimensions of, for example, lead zirconium titanate and potassium sodium niobate, to be tailored to the needs of thousands of applications across the automotive, medical device, and consumer electronics industries. In this Letter, we significantly advance the performance and customization of biomolecular crystal (nontoxic, biocompatible amino acids, viz., trans-4-hydroxy-L-proline, L-alanine, hydrates of L-arginine and L-asparagine, and γ-glycine) assemblies by growing them as molded, substrate-free piezoelectric elements. This methodology allows for electromechanical properties to be embedded in these assemblies by fine-tuning the chemistry of the biomolecules and thus the functional properties of the single crystal space group. Here, we report the piezoelectric, mechanical, thermal, and structural properties of these amino acid-based polycrystalline actuators. This versatile, low-cost, low-temperature growth method opens up the path to phase in biomolecular piezoelectrics as high-performance, eco-friendly alternatives to ceramics.

Design of bi-axial piezoelectric MEMS micro mirror with gimbal actuator for dynamic decoupling

Abstract This study presents a novel structural design of a bi-axial piezoelectric micro-electro-mechanical-systems scanning mirror aimed at preventing the dynamic coupling between the two scanning axes and avoiding distortion of the scanning pattern. In the proposed design, the gimbal actuator, constrained by torsional springs at both ends, not only serves as the torque generation component for the actuation of one axis but also acts as a pivot to prevent structural interference between the two axes during scanning. This approach achieves the advantages of decoupling and compactness simultaneously. Simulations indicate that the gimbal actuator experiences very small displacement during y-axis actuation, thus realizing the dynamic decoupling from the x-axis scanning unit. To evaluate the proposed designs, fabrication processes were adopted on a silicon-on-insulator wafer with a lead zirconium titanate film. The miniaturized scanners, featuring a mirror with a 1.2 mm diameter, were realized on a compact 5 × 5 mm2 chip. Measurements indicate that the resonant frequencies of x-axis and y-axis scanning are 2.69 kHz and 4.29 kHz, respectively, and the optical scanning angles reach 33° and 21° under an 8 Vpp driving voltage. Additionally, measurements show that the displacement ratio between the central mirror and the gimbal actuator can reach up to 17 during y-axis actuation, verifying the concept of dynamic decoupling. The bi-axial Lissajous scanning pattern with straight edges also demonstrates the effective decoupling by the proposed gimbal actuator design.

Preparation, structural, electrical, and ferroelectric properties of solid and lead zirconium titanate ink

The novelty of the work lies in the design and development of a significantly low-cost lead zirconate titanate (PZT) ink similar in its electrical properties to its original solid materials, which can be used for 3-D printing to print electronic circuits, shape memory, and devices quickly. The Zr/Ti=52/48 ratio was achieved during the solid-state reaction to create the PZT powder. XRD, FT-IR, and SEM characterized the synthesized material. The PZT powder was found to form in a tetragonal phase. The PZT powder was used to prepare PZT ink with a 13 % Wt/Wt solid content composition. The ink's rheological characteristics and physical properties, such as particle size distribution, surface tension, viscosity, and electrical properties, were studied. Dielectric properties like dielectric constant (ε/) and dielectric loss (ε") indicate the poly-dispersive nature of the material. The temperature-dependent dielectric constant (ε/) curve indicates relaxor behavior with a maximum at high temperatures. The poly-dispersive nature of the material was analyzed using Cole-Cole plots. The frequency dependence of AC conductivity follows the universal power law. The temperature dependence of dc-conductivity follows the Arrhenius law, with an activation energy of 0.14 eV at lower temperatures and 0.85 eV at higher temperatures. The electrical conductance study showed that PZT ceramic can be used in electronic circuits because of its high resistivity value and small temperature coefficient of resistance. The piezoelectric measurement displays d33 as 129 pC/N at room temperature.

Simultaneous effect of microwave sintering and TiO2 addition on sinterability, mechanical properties, and scratch resistance of zirconia toughened alumina ceramics

This paper delves into the transformative impact of varying titanium dioxide (TiO2) content on the sinterability, physical, and mechanical properties, as well as scratch behavior, of zirconia-toughened alumina (ZTA) ceramic composites. By adjusting TiO2 content from 0 wt% to 5 wt% and employing advanced microwave sintering at 1150 °C, the study aims to lower the sintering temperature of ZTA. Microwave sintering, known for its efficiency and rapid processing, enables significant enhancements in material properties at reduced temperatures. Notably, incorporating TiO2 into ZTA yields remarkable improvements in physical and mechanical attributes, with the optimal TiO2 content determined to be 3 wt%. At this concentration, the composite achieves exceptional properties: a relative density of ∼99 %, microhardness of ∼2002 HV, and an indentation fracture toughness of ∼6.13 MPa m0.5. These enhancements represent increases of over 120 % in hardness and 61 % in toughness compared to TiO2-free ZTA. Additionally, the highest scratch resistance is observed at 3 wt% TiO2, evidenced by a minimal scratch depth of ∼7.53 μm. However, exceeding the 3 wt% solubility limit results in the formation of secondary phases, such as tialite (Al2TiO5) and zirconium titanate (ZrTiO4), which degrade the composite's properties. This research underscores the potential of TiO2 doping and microwave sintering to elevate the performance of ZTA ceramics, offering a pathway to superior materials for advanced applications.

Reaction-sintered zircon-based nanostructured coatings obtained by suspension plasma spraying

Zircon (ZrSiO4) is an inexpensive and widely available material with excellent thermal properties that makes it an ideal candidate for thermal barrier coatings. Previous works have demonstrated the feasibility of obtaining coatings with a high retention of zircon by plasma spraying of ZrSiO4 and ZrSiO4/ZrO2 suspensions.Suspensions of ZrSiO4/Al2O3 and ZrSiO4/TiO2 were produced by dispersing a micrometric zircon powder into alumina and titania colloidal sols, optimising their colloidal stability and rheological behaviour. Optimised slurries were plasma sprayed onto metallic substrates, obtaining coatings with the typical morphologies obtained by suspension plasma spraying (SPS). Nanostructured coatings with nanoparticles embedded in the molten matrix were obtained at higher proportions of sprayed colloidal sol. The high retention of ZrSiO4 in the final coatings and the formation of new crystallographic phases of mullite and zirconium titanate by reaction of the by-products of zircon decomposition (SiO2 and ZrO2) and the Al2O3 and TiO2 colloids was demonstrated.

THD improvement of piezoelectric MEMS speakers by dual cantilever units with well-designed resonant frequencies

In this study, a piezoelectric MEMS (Micro-Electro-Mechanical-System) speaker with thoughtfully selected resonant frequencies of dual cantilever units is designed and implemented. Based on the lead zirconium titanate (PZT) thin film with superior piezoelectric coefficient, the cantilever diaphragm is designed through the modal analysis. In the 1.5 mm by 1.5 mm cantilever array, a high-frequency actuation unit with resonance of 13.1 kHz and a low-frequency actuation unit with resonance of 6.35 kHz constitute the proposed piezoelectric MEMS speaker. The boost of sound pressure level (SPL) due to the resonant mode of low-frequency actuation unit reduces the total harmonic distortion (THD) around the subharmonic frequency of high-frequency actuation unit. Meanwhile, the asymmetric triangle diaphragm reduces the maximum stress in the structure when operating at the resonant frequency, thereby mitigating the THD spikes resulting from the nonlinear structural behavior. In pressure-field measurements, the proposed design can reach SPL ≥ 70.0 dB from 2.7 kHz to 15.0 kHz with only 0.179 Vrms input. At the same time, THD remains below 3.0 % from 3.2 kHz to 20 kHz. The outstanding performance under larger input signal and bias voltage is also verified. Actuated by 0.354 Vrms and 2 VDC bias, the maximum SPL achieves 111.9 dB and the SPL is higher than 80.0 dB from 3.3 kHz to 14.1 kHz. Furthermore, THD is lower than 3.0 % from 1.0 kHz to 8.9 kHz. A promising solution of piezoelectric MEMS speaker for in-ear applications is demonstrated in this study.

Coupling of Triboelectric and Piezoelectric Effects in Nafion-Containing Polyvinylidene Fluoride: Lead Zirconium Titanate Nanofiber-Based Nanogenerators for Self-Powered Systems

Coupling of Triboelectric and Piezoelectric Effects in Nafion-Containing Polyvinylidene Fluoride: Lead Zirconium Titanate Nanofiber-Based Nanogenerators for Self-Powered Systems

Influence of Lithium on Structural Properties of Lead Zirconium Titanate (PZT)

Lead Zirconium Titanate (PZT) is a potential piezoelectric material for sensor and transducer applications due to its outstanding piezoelectric coupling near the morphotropic phase boundary (MPB). This is because PZT can switch between tetragonal and rhombohedral phases. PZT is still considered to be one of the piezoelectric materials that has received the greatest amount of attention from researchers and is used the most frequently. Modification with Lithium will improve the piezoelectric properties. In this study, the structural properties and morphological studies of Lead zirconium titanate and Lead zirconium titanate with Lithium modification have been evaluated. Various Scherrer’s models and other models, such as the Williamson-Hall model and Size-strain plots model, were used to display the observed fluctuations in crystallite size. Morphological analysis was used to determine the particle size. Graphs showing the distribution of particle sizes were drawn.

Assessing mechanical and stray magnetic field energy harvesting capabilities in lead-free PVDF/BCT-BZT composites integrated with metglas

The exploration of energy harvesting encompasses a wide array of sources, with a specific focus on recovering mechanical and magnetic energy from overlooked outlets, driving current research endeavours. In this study, we developed highly flexible Magneto-Mechano-Electric (MME) harvesters by combining poly(vinylidene fluoride) (PVDF)/barium calcium zirconium titanate (BCT-BZT) composite films with metglas. The flexible piezoelectric polymer-ceramic composite films were fabricated using a solvent casting technique. The high piezoelectric BCT-BZT fillers were synthesized through a sol-gel reaction route. A thorough analysis was carried out on these composites to evaluate their structural, functional, microstructural, and dielectric properties. The composite film loaded with 20 wt% BCT-BZT filler achieved a 78 % β-phase with a significant enhancement in the dielectric properties, resulting in a high permittivity∼40 and low dielectric loss. Employing these films, we engineered nanogenerators capable of converting mechanical energy into electrical energy, yielding an output voltage of 11 V. Thereafter, to harvest mechanical and stray magnetic fields, we developed a MME generator comprising a magnetic Metglas layer and PVDF-BCT-BZT composite and achieved an output voltage of 3.3 V with a power density of 85 μW/m2 when subjected to an AC magnetic field of 5 Oe. Furthermore, the MME generator has demonstrated the ability to charge various capacitors showcasing its potential for usage in self-powered, non-contact, and implantable devices.

Synthesis, characterization, and application of PVDF-PZT composite thin film separator for self-charging supercapacitors

This work utilizes a simple ball milling and heating process to synthesize lead zirconium titanate (PZT). The thin film PVDF-PZT separator is fabricated with the use of dimethyl sulfoxide (DMSO) solvent. The separator's characterization is accomplished by using conventional characterization tools to examine its crystallinity, morphology, chemical composition, and other parameters. According to X-ray diffraction (XRD), Energy dispersive spectroscopy (EDS), and Elemental mapping, the separator is extremely pure and free of any impurities. The separator's surface is found to be uniform with minimal porosity. An analysis of the application of the fabricated thin film separator in a supercapacitor is conducted by placing it in between the previously prepared carbon and NiO thin film electrodes. Upon bending, twisting, and applying force, the device displayed output voltage. Twisting results in a maximum output potential of 140 mV, which is higher than some previously reported works. The results show that the PVDF-PZT thin film separator could potentially be utilized in self-charging supercapacitor applications.

Reduced graphene oxide decorated orthorhombic zirconium titanate nanoparticles for display technology and supercapacitor applications

In the present research work, reduced graphene oxide (rGO) decorated zirconium titanate nanocomposites at 1:1 (ZTOr11), 2:1 (ZTOr21) and 1:2 (ZTOr12) ratios are synthesized by green mediated approach. The Bragg reflections of all the three samples consists the Bragg reflections corresponding to orthorhombic zirconium titanate nanoparticles along with the reflections of rGO. The surface morphology consists irregular shaped nanoparticles decorated on the surface of rGO. The transmission electron microscopy shows the presence of both rGO and lattice fringes corresponding to ZrTiO4 matrix. The energy band gap was tuned from 2.7 to 2.61 eV. The photoluminescence emission spectra (λex = 223 nm) and CIE coordinates confirms the blue emission with color correlated temperature less than 5000 K. This clearly indicates that the present synthesized NCs finds an application in the field of display technology. Additionally, electrochemical investigations were conducted to determine the supercapacitance value of the material. The capacitance value vary in the range of 311 F/g to 404 F/g for ZTOr11 NPs, 157 F/g to 194 F/g for ZTOr21, and 36.8 F/g to 163 F/g for ZTOr12 NPS for scan rates 10 to 100 mV/s. The synthesized rGO NCs with ZTO might find an application in display and supercapacitor applications.

PZT based dual energy harvester using chemical solution deposition technique

The present finding reports the state-of-art thin film based dual energy harvester which can harvest both mechanical as well as magnetic energies. Dual energy harvester is realised with the help of Lead Zirconium Titanate (PZT) thin film and nickel (Ni) foil. Ferroelectric PZT has been grown with the help of chemical solution deposition technique under optimised conditions on Nickel cantilevers. The effect of damping mass on the resonating frequency of the PZT-60/Ni dual cantilever has been studied. The maximum power and voltage generated by dual energy harvester at the matching load impedance of 100 kΩ under resonance condition were about 117 × 102 mW/m3 and 52 mV respectively corresponding to an applied acceleration of 1.0 g. A change of about 0.5 mV/Oe voltage was achieved for PZT-60/Ni cantilever in the presence of magnetic field. The dual energy harvester prepared with the help of chemical solution technique is found to have profound response and hence enables the realization of self powered electronic devices by scavenging an ambient magnetic and mechanical energies for various wireless electronic applications ranging from medical implant to health monitoring areas.

Photodegradation of Phenol under Visible Light Irradiation Using Cu-N-codoped ZrTiO<sub>4</sub> Composite as a High-Performance Photocatalyst

Codoping of nitrogen and copper into zirconium titanate composite (Cu-N-codoped ZrTiO4) was carried out through a sol-gel process. This study aimed to investigate the effect of copper and nitrogen dopants on the photocatalytic activity of ZrTiO4 composite in degrading phenol. To prepare the composite, an aqueous suspension of zirconia (ZrO2) alongside a fixed amount of urea and various amount of copper sulfate was added dropwise into diluted titanium(IV) tetraisopropoxide (TTIP) in ethanol. The composites were calcined at temperatures of 500, 700, and 900 °C. Fourier-transform infrared spectrophotometry (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray (SEM-EDX) mapping, and specular reflectance UV-visible spectrophotometry (SR UV-vis) were used for their characterization of composite. The photocatalytic activity was evaluated by adding the composite into a 10 mg L−1 phenol solution for various irradiation time spans. The remaining concentration of phenol solution was determined by absorption at 269 nm. Cu-N-codoped ZrTiO4 composite containing 5% Cu calcined at 500 °C demonstrated the highest observed rate constant and a significant band gap decrease from 3.13 to 2.68 eV.

Effective-performance of inorganic and organic (barium zirconium titanate/polyvinylidene fluoride) piezoelectric composite for energy harvesting and self-powered smart IoT-based electronics

In the context of the rapidly advancing fields of energy harvesting and the Internet of Things (IoT), flexible piezoelectric materials have received significant attention for powering and providing sensing signals to electronic devices. In this study, piezoelectric barium zirconium titanate (BZT) material was synthesized via a solid-state reaction method at high temperatures. The synthesized BZT was incorporated as a filler in the PVDF polymer matrix to design a flexible piezoelectric device using a solvent-casting method. Structural analyses verified the formation of the tetragonal structure (P4mm) of BZT and the successful composite with PVDF. Piezoelectric properties of PVDF and BZT/PVDF were tested under mechanical force, revealing that the BZT/PVDF composite exhibited higher voltage output compared to PVDF under applied load. Furthermore, the BZT/PVDF composite demonstrated excellent stress tolerance and enhanced piezoelectric performance under varying loads. Notably, the BZT/PVDF composite showed impressive energy harvesting capabilities during finger tapping, storing electrical energy in capacitors, to power electronic watch, calculator, mini-speaker, and illuminating LEDs. The composite also exhibited potential for monitoring and harvesting energy from human motion. Additionally, BZT/PVDF was utilized as a smart lab alarm (SLA) system for the safety of human beings, enhancing safety in laboratories by signaling potential contact between BZT/PVDF and human beings in hazardous areas. These findings indicate the flexible BZT/PVDF composite as a promising solution for lead-free energy harvesting and self-powered smart IoT-based electronics.

Measurements of nonlinear electric-acoustic interactions in lead zirconium titanate

When electric and acoustic waves simultaneously pass through a piezoelectric material, nonlinearities can arise. The electric and acoustic waves can mix, generating a signal consisting of both sum and difference spectral components. Here we present a method of directly measuring the nonlinearly mixed electric-acoustic signal using a vector network analyzer (VNA). In normal VNA operation, sources and receivers operate at the same frequency. In our measurements, we employ a frequency offset mode, where receivers in the VNA can be tuned to a frequency different from the source frequency. Here, we measure at the expected mixing product frequency of the electrical and acoustic signals we introduce into the measurement to capture nonlinear electric-acoustic mixing. We present measurements of electric-acoustic mixing in a block of lead zirconium titanate (PZT) mounted on top of an electric co-planar waveguide connected to the VNA. The results show the presence of many coupled electric-acoustic modes. To interpret these modes, we characterized the PZT block with modal analysis and finite element simulations. Some of the observed nonlinear electric-acoustic modes directly correlated with the mechanical modes of the block, while others did not. Overall, this method allows for direct probing of non-linear electric-acoustic mixing in materials and devices.

Energy storage and catalytic behaviour of cmWave assisted BZT and flexible electrospun BZT fibers for energy harvesting applications

High-performance lead-free Barium Zirconium Titanate (BZT) based ceramics have emerged as a potential candidate for applications in energy storage, catalysis for electro chemical energy conversion and energy harvesting devices as presented in this work. In the present study hybrid microwave sintered BZT are studied for dielectric, ferroelectric and phase transition properties. BZT ceramic exhibits tetragonal structure as confirmed by the Retvield refinement studies. XPS studies confirms the elemental composition of BZT and presence of Zr. Polarization versus electric field hysteresis loops confirms the ferroelectric behaviour of BZT ceramic. Encouragingly, the BZT showed a moderate energy storage efficiency of 30.7 % and relatively good electro chemical energy conversion (HER). Excellent catalytic activity observed for BZT electrode in acid medium with low Tafel slope 77 mV dec-1. Furthermore, electrospun nanofibers made of PVDF-HFP and BZT are used to make flexible piezoelectric nano generators (PENGs). FTIR studies show that the 16 wt% BZT composite ink exhibits a higher electroactive beta phase. The optimized open-circuit voltage and short circuit current of the flexible PENG exhibits 7Vpp and 750 nA under an applied force of 3N. Thus, flexible and self-powered BZT PENGs are alternative source of energy due to its reliability, affordability and environmental-friendly nature.

Giant piezoresponse in nanoporous (Ba,Ca)(Ti,Zr)O3 thin film.

Lattice strain effects on the piezoelectric properties of crystalline ferroelectrics have been extensively studied for decades; however, the strain dependence of the piezoelectric properties at nano-level has yet to be investigated. Herein, a new overview of the super-strain of nanoporous polycrystalline ferroelectrics is reported for the first time using a nanoengineered barium calcium zirconium titanate composition (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCZT). Atomic-level investigations show that the controlled pore wall thickness contributes to highly strained lattice structures that also retain the crystal size at the optimal value (<30 nm), which is the primary contributor to high piezoelectricity. The strain field derived from geometric phase analysis at the atomic level and aberration-corrected high-resolution scanning transmission electron microscopy (STEM) yields of over 30% clearly show theoretical agreement with high piezoelectric properties. The uniqueness of this work is the simplicity of the synthesis; moreover the piezoresponse d 33 becomes giant, at around 7500 pm V-1. This response is an order of magnitude greater than that of lead zirconate titanate (PZT), which is known to be the most successful ferroelectric over the past 50 years. This concept utilizing nanoporous BCZT will be highly useful for a promising high-density electrolyte-free dielectric capacitor and generator for energy harvesting in the future.

Eco-friendly natural clay bentonite supported zirconium titanate (BT–ZrTiO4): synthesis, characterization and photocatalysis and self-cleaning activities

Eco-friendly natural clay bentonite supported zirconium titanate (BT–ZrTiO4): synthesis, characterization and photocatalysis and self-cleaning activities

Simulation of Self Tuning Shape Memory Alloy Based PZT Energy Harvester

Shape Memory Alloy (SMA) is tuned to match the frequency of excitation with the resonance frequency. Simulation is carried out numerically using COMSOL 5.3 software. This model consists of cantilevered beam without tip mass, PZT layer, Aluminium beam and SMA layer. Lead Zirconium titanate (PZT – 5A) is used as PZT layer for the conversion of energy. Harvesters power frequency response for different frequency ranges are carried out. The maximum output is obtained in excitation frequency with SMA and the results were compared without SMA material. The numerical simulation of the Frequency Response Functions (FRF) was compared with the analytical frequency response functions of the harvester. The maximum difference between the numerical and analytical results is 9.77 % in FRF’s and 1.85 % in resonance frequency. Materials used are Lead Zirconium titanate (PZT – 5A), SMA material and Aluminium beam which reaches the scopes of journal.