Time-resolved characterization of domain switching in ferroelectrics using X-ray and neutron diffraction

Ferroelectric materials, characterized by their high dielectric constants, piezoelectricity, and pyroelectricity, find numerous applications in electronic products such as computer memory, highly sensitive sensors, and sonar devices. Additionally, they hold potential applications in fields like solid-state refrigeration, with their performance often closely linked to their microstructural evolution, including phase transitions and domain switching. Phase-field methods serve as highly advantageous tools for exploring, revealing, and predicting mesoscale ferroelectric domain evolution. Within ferroelectric phase-field models, diverse types of domain structures of ferroelectric materials, such as bulk single crystals and thin films, can be simulated by setting different mechanical and electrical boundary conditions. Various types of ferroelectric phase transitions can also be studied by setting conditions in the models such as temperature variations and the application of external electric fields. Furthermore, by applying external electrical or mechanical stimuli in the phase-field models, behaviors such as ferroelectric domain switching can be observed. Here we first outline the fundamental framework of phase-field models, followed by a comprehensive overview of various phase transitions in ferroelectric materials, including ferroelectric-to-paraelectric and antiferroelectric-to-ferroelectric transitions. Additionally, the review summarizes how phase-field models facilitate the induction of ferroelectric domain switching through various experimental stimuli, including electric fields and mechanical fields. This review concludes by summarizing and prospecting potential new applications of the phase-field method in the study of ferroelectric phase transitions and domain switching.

This study investigated the effects of embedding piezoelectric lead zirconate-titanate (PZT) sensors on the tensile strength and fatigue behavior of a quasi-isotropic graphite/epoxy laminate as well as the embedded sensor's voltage degradation under these loading conditions. For this, AS4/3501-6 laminates were fabricated with a lay-up where PZT was inserted into a cut-out area in the two middle plies. Monotonic tensile tests showed that both the average ultimate strength and Young's modulus of the tested laminate with or without PZT were within 4% of each other. The fatigue lives with and without PZT were very close to each other as well. Overall, the sequence of damage in this study agreed with previous investigations of the damage mechanisms for quasi-isotropic laminates. The ranges of modulus reduction in both cases, with and without PZT, were within 5 to 15% of each other during fatigue loading. Delamination growths in both cases during most of the fatigue life were also very comparable to each other. Further, this study showed that the embedded PZT would maintain a steady voltage output indefinitely when mechanically cycled within its operational strain limit. It thus appears that the embedment of PZTs in a cut-out area of plies of quasi-isotropic graphite/epoxy laminates would not affect their monotonic tensile and fatigue behavior.

In this study, a generalized inverse-pole-figure (IPF) method has been suggested to analyze domain switching in polycrystalline ferroelectrics including composition of morphotropic phase boundary (MPB). Using the generalized IPF method, saturated domain orientation textures of single-phase polycrystalline ferroelectrics with tetragonal and rhombohedral symmetry have been analytically calculated and the results have been confirmed by comparison with the results from preceding studies. In addition, saturated domain orientation textures near MPBs of different multiple-phase polycrystalline ferroelectrics have been also analytically calculated. The results show that the generalized IPF method is an efficient method to analyze not only domain switching of single-phase polycrystalline ferroelectrics but also MPB of multiple-phase polycrystalline ferroelectrics.

Raman analysis of ferroelectric switching in niobium-doped lead zirconate titanate thin films

Time-resolved characterization of domain switching in ferroelectrics using X-ray and neutron diffraction

To improve the compatibility between the sensor material and civil engineering structural material, a new functional cement-based composite for smart structure applications has been studied. Piezoelectric lead zirconate titanate (PZT) fibres, fabricated using a slurry method, are embedded in a cement matrix to form PZT/cement 1–3 composites. By incorporating PZT fibres into the cement matrix, composites with low PZT volume fractions ranging from 0.05 to 0.22 have been fabricated. The 1–3 composites have good piezoelectric properties that agree quite well with theoretical modeling. The thickness electromechanical coupling coefficient of the composites could reach ∼0.5 even for low volume fraction of PZT. These composites have potential to be used as sensors in civil structure health monitoring systems.

Interface bonding conditions between concrete and steel materials play key roles in ensuring the composite effect and load-carrying capacity of concrete-steel composite structures such as concrete-filled steel tube (CFST) members in practice. A method using both surface wave and electromechanical impedance (EMI) measurement for detecting the existence and the location of inaccessible interface debonding defects between the concrete core and steel tube in CFST members using piezoelectric lead zirconate titanate (PZT) patches as actuators and sensors is proposed. A rectangular CFST specimen with two artificially mimicked interface debonding defects was experimentally verified using PZT patches as the actuator and sensor. By comparing the surface wave measurement of PZT sensors at different surface wave travelling paths under both a continuous sinusoidal signal and a 10-period sinusoidal windowed signal, three potential interface debonding defects are quickly identified. Furthermore, the accurate locations of the three detected potential interface debonding defects are determined with the help of EMI measurements from a number of additional PZT sensors around the three potential interface debonding defects. Finally, the accuracy of the proposed interface debonding detection method is verified with a destructive observation by removing the local steel tube at the three detected interface debonding locations. The observation results show that the three detected interface debonding defects are two mimicked interface debonding defects, and an unexpected debonding defect occurred spontaneously due to concrete shrinkage in the past one and a half years before conducting the test. Results in this study indicate that the proposed method can be an efficient and accurate approach for the detection of unknown interface debonding defects in existing CFST members.

High‐frequency structural analysis so far has been a major issue in dynamic analysis, for which many conventional methods such as finite element method and transfer matrix method are unable to perform well. Since the electromechanical impedance technique for structural health monitoring (SHM) operates at very high frequencies, the reverberation matrix method (RMM), which was just developed a few years ago, is employed to study dynamics of the monitored structures, which are bonded with piezoelectric lead zirconate titanate (PZT) patches. A piecewisely homogeneous Euler–Bernoulli beam model is introduced to approximate the non‐homogeneous beam and only one‐dimensional axial vibration of PZT wafers is considered. The imperfect interfacial bonding between PZT patches and the host beam is investigated based on a shear lag model. Using a hybrid technique combining electromechanical impedance method and RMM, an analytical expression of impedance (or admittance) related to the response of the coupled model of PZT patch‐bonding layer‐host beam system is derived for SHM. The proposed method is examined by comparing with other theoretical methods as well as by means of a test on an intelligent system using a steel beam with two symmetrically installed PZT wafers. It could be further applied to predicting the dynamics of monitored Timoshenko beams, continuous beams, and framed structures as well. Copyright © 2006 John Wiley & Sons, Ltd.

Role of build orientation on quasi-static and dynamic fracture responses of additively manufactured AlF357 and AlSi10Mg alloys

Ferroelectric domain switching on the surface of a lithium niobate thin film can be induced by the tip of a scanning probe microscope, and gives rise to both regular and chaotic spatiotemporal patterns. Moreover, the long-range interactions that govern these phenomena can be tuned by varying temperature, humidity, domain spacing and tip bias.

Ferroelectric domain switching within individual nanoscale grains of a 100 nm thick polycrystalline PbZr0.2Ti0.8O3 thin film has been shown to depend on the relative crystallographic orientation of the adjacent grains. Using Piezoresponse Force Microscopy, the significance of local microstructure on the domain switching was demonstrated. Different regions within grains show different coercive fields under the same external electric field. In addition, neighboring grains also show a collective switching pattern, facilitating/suppressing switching on both sides of the grain boundaries compared to the center of the grain. These experimental observations were supported by numerical simulation demonstrating that changing the crystallographic orientation of a grain affects the switching loop of the neighboring grains. Based on both experimental and numerical simulation, the conclusion can be made that microstructural modulation of the local electric and stress field can significantly affect individual grain switching in polycrystalline thin films.

Underground structures constitute a vital component in infrastructure development. When subjected to dynamic events, these underground structures will result in catastrophic failures. Hence proper understanding of soil-underground structure interaction is essential when designing in seismic-prone areas. Though analytical models estimate the performance of underground structures under dynamic loading conditions, detailed experimental studies provide more insights into the parameters influencing the underground structure’s performance during dynamic conditions. Due to the limitations in model development, time, and cost, 1-g shaking table experiments were preferred by most of the researchers compared to centrifuge and field scale experiments. This paper presents a detailed literature review of experimental studies on tunnel models in 1-g shaking table experiments and critical observations on tunnel-soil interaction under dynamic loading conditions. Discussions on scaling laws, instrumentation scheme, material selection, and other influencing parameters involved in soil tunnel interaction studies in 1-g shaking table testing conditions are presented. Although the 1-g experimental testing conditions have limitations in simulating equivalent ground and testing conditions as compared to centrifuge studies, this paper highlights the possible steps to simulate the tunnel model interaction studies in a better way to minimize the limitations for upcoming future research works.

Purpose This study aims to evaluate the feasibility of using piezoelectric lead zirconate titanate (PZT) sensors to monitor the effects of adding low-density polyethylene (LDPE) beads, made from waste plastic, on carbonation mineralization of modified concrete during accelerated CO2 curing. Design/methodology/approach Two concrete mixtures (P20 and P40) were prepared by replacing 20% and 40% of coarse aggregates with LDPE beads. PZT patches installed in both surface-bonded and embedded configurations were employed to capture electromechanical impedance (EMI) responses experimentally, in the user-defined 250–350 kHz frequency ranges at ten different curing ages of 0, 1, 3, 7, 10, 14, 18, 21, 24 and 28 days from plastic waste admixed-concrete mixes, and were further validated using finite element analysis. Findings The results indicate that carbonation curing significantly influences the EMI responses with increasing plastic waste content in concrete. Embedded PZT sensors exhibited higher sensitivity than surface-bonded sensors, showing maximum root mean square deviation (RMSD) and mean absolute percentage deviation (MAPD) values of up to 39.23% and 75.90%, respectively, for P40 mixes at 28 days curing duration. In contrast, surface-bonded sensors demonstrated lower deviations, with maximum RMSD and MAPD values of 7.69% and 14.28%. Originality/value This study demonstrates that the inert solid plastic additions up to 40% significantly increase the sensitivity of health indices, conclusively showing an intensified carbonation effect due to increased porosity and weak interfaces, which are ultimately correlated to strength gains with higher confidence levels.

Axial stress monitoring in arbitrary cross sections is a challenging task. Stringers are the main axial load carrying components of aircraft skin structures and have typical complex cross sections. This paper investigates the strategy of axial stress monitoring in an arbitrary cross section based on acoustoelastic guided waves using piezoelectric lead zirconate titanate (PZT) sensors. To select appropriate guided wave frequencies and modes sensitive for axial stress monitoring in an arbitrary cross section, the feature guided waves are investigated using acoustoelastic theory combined with the semianalytical finite element method. The mode shapes are derived, which show that these longitudinal-like modes are more sensitive to axial stress. A PZT transducer array is also considered to maximize desired modes. Piezoelectric sensors are used to excite and detect the guided waves in the experiments. Results from acoustoelastic measurements on a T-type stringer are presented, showing the feasibility of this method for axial stress monitoring.

The electro-mechanical impedance (EMI) technique using piezoelectric lead zirconate titanate (PZT) transducers has been shown promising for health monitoring of steel structures. For damage assessment, statistical techniques such as root mean square deviation (RMSD) have been employed to compare the electro-mechanical (EM) admittance signatures acquired before and after damage. However, using the conventional RMSD approach, it is difficult to specify the damage severity and location. To overcome this limitation, a sub-frequency interval approach has been proposed by the authors for the concrete structures. In the present study, this approach is extended and applied to the steel structures. Considering low attenuation of wave and large sensing region of PZTs in steel structures, multiple PZTs are utilized to acquire the EMI signatures of an I-section steel beam. Artificial damage points are induced in the steel beam and the corresponding RMSD values for sub-frequency ranges (RMSD-S) are calculated. To qualitatively study the damage severity and location, a method combining the RMSD-S of multiple PZTs and the logarithmic attenuation of ultrasonic waves is proposed. The results demonstrate that the proposed method is robust and sensitive for damage assessment of steel structures.