Search Results (103)

Relaxor ferroelectric single crystals, such as Pb(In₁/₂Nb₂/₃)O₃–Pb(Mg₁/₂Nb₂/₃)O₃–PbTiO₃, possess extraordinary electro-optic (EO) coefficients, offering immense potential for next-generation integrated modulators. However, the application of PIN-PMN-PT in fiber-optic gyroscopes (FOGs) is hindered by the challenge of fabricating high-quality optical waveguides with strict mode selectivity, as conventional diffusion typically excites multi-mode propagation. Here, the fabrication of high-quality, mode-selective waveguides is achieved in rhombohedral PIN-PMN-PT via a nickel in-diffusion technique. The resulting graded-index structures exhibit a Gaussian profile with a maximum refractive index change (∆n) of 1.53% while preserving the single crystal structure. Under specific processing conditions, we achieve precise mode selectivity, enabling exclusive transverse electric (TE) mode transmission. This mode selectivity fulfills the requirements for single-mode Y-branch geometries, establishing a robust platform for ultra-compact, low driving voltage modulators and advancing the miniaturization of inertial navigation and integrated photonic systems. Full article

In low-amplitude and low-frequency vibration environments, the energy harvesting efficiency of self-powered wireless sensor nodes is insufficient, limiting their long-term autonomous operation. To address this issue, a micro piezoelectric–electromagnetic hybrid energy harvester is designed, aiming to enhance energy capture efficiency through structural integration and parameter optimization. The study is conducted entirely through numerical simulations. A coaxial integrated architecture is adopted, combining a piezoelectric cantilever beam array with an electromagnetic induction module. The piezoelectric layer uses lead magnesium niobate–lead titanate (PMN-PT) solid solution material with a thickness of 0.2 mm. The electromagnetic module employs copper wire coils with a diameter of 0.08 mm, winding 1500–3000 turns, paired with N52-type neodymium–iron–boron (NdFeB) permanent magnets. To improve energy conversion efficiency, the optimization parameters include the length-to-thickness ratio of the cantilever beam, the mass of the tip mass, the number of coil turns, and the spacing of the permanent magnets. Each parameter is set at four levels for orthogonal experiments. A multi-physics coupling model is established using ANSYS Workbench 2023, covering structural dynamics, piezoelectric effects, and the electromagnetic induction module. The mesh size is set to 0.1 mm. The energy output characteristics are analyzed under vibration frequencies of 0.3–12 Hz and amplitudes of 0.2–1.0 mm. Simulation results show that the optimized hybrid harvester achieves 45% higher energy conversion efficiency than a single piezoelectric structure and 31% higher than a traditional separated hybrid structure within the 0.3–12 Hz low-frequency range. Under a 6 Hz frequency and 0.6 mm amplitude, the output power density reaches 3.5 mW/cm³, the peak open-circuit voltage is 4.1 V, and the peak short-circuit current is 1.3 mA. Under environmental conditions of 20–88% humidity and −15–65 °C temperature, the device maintains over 94% stability in energy output. After 1.2 million vibration cycles, structural integrity remains above 96%, and energy conversion efficiency decreases by no more than 5%. The proposed coaxial hybrid structure and multi-parameter orthogonal optimization method effectively enhance energy harvesting performance in low-amplitude, low-frequency environments. The simulation design parameters and analysis procedures provide a reference for the development of similar micro hybrid energy harvesters and support the performance optimization of self-powered wireless sensor nodes. Full article

Biopsy procedures are essential for definitive cancer diagnosis but remain limited by the risk of accidental blood vessel puncture, which can lead to hemorrhage and procedural failure. Conventional imaging guidance often provides insufficient vascular contrast, making vessel avoidance during needle insertion challenging. A rotational oblique spectral ultrasound (ROSUS) imaging system was developed to improve vessel detection and needle guidance during biopsy procedures. The device integrates a high-frequency PMN-PT 1–3 composite transducer mounted at a 45° angle within the 18-gauge needle tip, enabling simultaneous forward- and side-looking capability. By combining synchronized rotational–axial scanning with multifrequency signal ratio (MFSR) processing, ROSUS achieved volumetric images with blood–tissue contrast ratio improvement over 1.2 dB compared to conventional B-mode signal processing while maintaining high spatial resolution of 85 µm and 424 µm in axial and lateral directions, respectively. These results demonstrate that frequency-domain spectral processing can improve vessel and tissue differentiation, offering an 18-gauge needle-integrated platform for safer and more accurate biopsy needle-based procedures. Full article

Alternating-current poling (ACP) is becoming a mainstream method because of its stronger ability in promoting the piezoelectric performance of ferroelectric single crystals than that of direct-current poling (DCP). A novel approach was developed by incorporating alternating-current poling and direct-current poling as modified alternating-current poling (MACP). According to the comparison of performance differences between AC-poled and DC-poled single crystals, the properties of MACP single crystals under specific conditions were systematically investigated. The improvement of single crystal performance by MACP is manifested by the multi-peak increase in piezoelectric coefficient ($d_{33}$) and relative dielectric permittivity (${\epsilon }_{33}^T/{\epsilon }_0$), and the coupling factor ($k_t$) value under higher DC bias is higher than that under DC polarization, rather than a direct superposition of DCP and ACP. Two optimal polarization windows were found: 0.2–0.25 kV/mm and 0.35–0.6 kV/mm. Compared with DCP, MACP increases the $d_{33}$, ${\epsilon }_{33}^T/{\epsilon }_0$ and $k_t$, of single crystals by up to 45.67%, 21.62%, and 24.54%, respectively. This significant performance improvement, combined with its complexity, provides a new direction for customizing the performance of single crystals. Full article

Gas pipelines are a critical means of transportation in industrial production. To detect gas pipeline leaks, ultrasonic transducers with specific center frequencies and high sensitivity are required. This paper proposes a novel air-coupled ultrasonic transducer design based on a horn-type matching layer and a bending-mode type of piezoelectric material, specifically tailored for gas leak detection scenarios. The transducer design is optimized by the finite element method, focusing on the basic components of the piezoelectric bimorph, the horn and the supporting tube. First, the influence of various dimensional parameters of the piezoelectric bimorph on the bending vibration mode was analyzed. Then, the effects of the other two components, the horn and the supporting tube, on the piezoelectric bimorph vibration mode were investigated. A parametric scan on the dimensions of these components was conducted to optimize the transducer’s output. Finally, ultrasonic transducers using PMN-PT and PZT were fabricated and tested. The results show that the sensitivity of those transducers surpasses that of similar commercial transducers, especially the PMN-PT one with a center frequency of 40 kHz and a peak receiving sensitivity of −51.1 dB. This transducer, benefiting from the high-performance piezoelectric material and the bending vibration mode, proves to be a promising candidate for high-precision leak detection in gas pipelines. Full article

High-strength bolts play an essential role in connecting steel structural components across bridges, buildings, and machinery, thanks to their low cost and broad adaptability. However, prolonged exposure to complex loading and harsh environments can cause loosening, which increases the risk of structural distortion or catastrophic collapse. Conventional monitoring tools, such as strain gauges or fiber-optic sensors, often suffer from high expense, short service life, and poor early-warning performance. To overcome these challenges, this study presents a novel surface-mounted piezoelectric sensor built on lead magnesium niobate–lead titanate (PMN-PT) single crystals, selected for their superior piezoelectric constants, energy density, and low-frequency sensitivity. The sensor integrates a PMN-PT wafer, monolithic washer, epoxy resin encapsulation, and shielded cabling. It was experimentally validated through waterproofing and electrical tests across five working conditions, maintaining capacitance stability within 3.25% and infinite insulation resistance. Preload monitoring experiments were conducted using a time-reversal method, and a tightening index based on focused signal amplitude was proposed to quantify bolt-loosening conditions. Results confirmed a strong linear association (R² = 0.986) between the focused signal amplitude and preload torque (0–120 N·m), with a maximum error of only 5.7% in validation trials under unknown torque. Overall, this PMN-PT-based sensor offers a cost-efficient, sensitive, and durable solution for early detection of bolt loosening in steel structures. Full article

Bridges play a key and controlling role in transportation systems. Steel bridges are favored for their high strength, good seismic performance, and convenient construction. As important node connectors of steel bridges, high-strength bolts are extremely susceptible to damage such as corrosion and loosening. Therefore, accurate identification of bolt loosening is crucial. First, a new type of adhesive piezoelectric sensor is designed and prepared using PMN-PT piezoelectric single-crystal materials. The PMN-PT sensor and polyvinylidene fluoride (PVDF) sensor are subjected to steel plate fixed frequency load and swept frequency load tests to test the performance of the two sensors. Then, a steel plate component connected by high-strength bolts is designed. By applying exciter square wave load to the structure, the vibration response characteristics of the structure are analyzed to identify the loosening of the bolts. In addition, a piezoelectric smart washer sensor is designed to make up for the shortcomings of the adhesive piezoelectric sensor, and the effectiveness of the piezoelectric smart washer sensor is verified. Finally, a bolt loosening index is proposed to quantitatively evaluate the looseness of the bolt. The results show that the sensitivity of the PMN-PT sensor is 21 times that of the PVDF sensor. Compared with the peak stress change, the natural frequency change is used to identify the bolt loosening more effectively. Piezoelectric smart washer sensor and bolt loosening indicator can be used for bolt loosening identification. Full article

For relaxor ferroelectric single crystal (1 − x)Pb(Mg_1/3Nb_2/3)O₃ − xPbTiO₃ (PMN-PT), through reasonable component regulation and electric field polarization, an orthogonal mm² point group structure can be obtained, which has high piezoelectric constants and is, therefore, a desired substrate material for lateral-field-excited (LFE) bulk acoustic wave (BAW) devices. In this work, acoustic wave resonance characteristics of (zxt) 45° PMN-PT BAW devices with LFE are investigated. Firstly, Mindlin first-order plate theory is used to obtain vibration governing equations of orthorhombic crystals excited by a lateral electric field. By analyzing the electrically forced vibrations of the finite plate, the basic vibration characteristics, such as motional capacitance, resonant frequency, and mode shape are obtained, and influences of different electrode parameters on resonance characteristics of the device are investigated. In addition, the effects of the structure parameters on the mass sensitivity of the devices are analyzed and further verified by FEM simulations. The model presented in this study can be conveniently used to optimize the structural parameters of LFE bulk acoustic wave devices based on orthorhombic crystals, which is crucial to obtain good resonance characteristics. The results provide an important basis for the design of LFE bulk acoustic wave resonators and sensors by using PMN-PT orthorhombic crystals. Full article

The morphotropic phase boundary (MPB) with multiphase coexistence serves as a critical region for piezoelectric materials, but the individual contributions of various microscopic mechanisms to the overall electromechanical response remains a challenge for further subdivision. Here, we systematically investigate the microscopic origins of outstanding piezoelectricity in <001>-oriented Pb(Mg_1/3Nb_2/3)O₃-30PbTiO₃ (PMN-30PT) single crystals and quantitatively identify the dominant factors for giant electrostrain and ultrahigh piezoelectric coefficient. Large electrostrain arises predominantly from polarization rotation within the easily distorted monoclinic phase and the high-energy-barrier monoclinic-to-tetragonal phase transition, enabled by a synergistic interplay of broad electric field adaptability and high strain sensitivity. In contrast, the peak piezoelectric coefficient (d₃₃ > 2100 pC/N) is attributed to the low-energy-barrier rhombohedral-to-monoclinic phase transition, which facilitates polarization rotation. Furthermore, the critical yet distinct roles of monoclinic phase compared to piezoelectric and electrostrain have been confirmed. By the quantitative segmentation of various microscopic factors, this work provides fundamental insights into the design of high-performance piezoelectrics. Full article

[011] poled relaxor-PT single crystals provide superior piezoelectric constants and electromechanical coupling factors in the 32 crystal directions, and also exhibit high electrical stability under compressive stresses and temperature changes. In particular, Mn-doped Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (Mn:PIN-PMN-PT) single crystals show a superior coercive field (E_C ≥ 8.0 kV/cm) and mechanical quality factor (Q_m ≥ 1030), making them suitable for high-power transducers. The high-power characteristics of [011] poled single crystals have been verified from a material perspective; thus, further investigation is required from a transducer perspective. In this study, the high-power characteristics of piezoelectric transducers based on [011] poled PIN-PMN-PT and [011] poled Mn:PIN-PMN-PT single crystals were investigated. To analyze the driving limits of the single crystals, the polarization–electric field (P–E) curves, as a function of the driving electric field, were measured. The results showed that [011] poled Mn:PIN-PMN-PT single crystals demonstrate lower energy loss and THD (Total Harmonic Distortion), directly relating to the driving efficiency and linearity of the transducer. Additionally, [011] poled Mn:PIN-PMN-PT crystals provide excellent stability under the compressive stress and temperature changes. To analyze the high-power characteristics of [011] poled single-crystal transducers, two types of barrel-stave transducers, based on [011] poled PIN-PMN-PT and [011] poled Mn:PIN-PMN-PT, were designed and fabricated. The changes in the impedance and transmitting voltage response with respect to the driving electric fields were measured, and the energy loss and THD of the transducers with respect to the driving electric fields were examined to assess the driving limit of the [011] poled single-crystal transducer. The high-power characteristic tests confirmed the stability of [011] poled Mn:PIN-PMN-PT single crystals and verified their potential for high-power transducer applications. Full article

Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ single crystals (PMN-PT SCs) are widely utilized in high-performance piezoelectric devices due to their exceptional piezoelectric properties. Among the various post-processing techniques for domain engineering in PMN-PT SCs, alternating current polarization (ACP) has become a widely adopted method for enhancing piezoelectric performance. This study proposes a new ultrahigh-temperature field-cooling polarization (UFCP) technique, combining direct current polarization (DCP) and ACP with field cooling above the Curie temperature. Dielectric spectra indicate that the UFCP method promotes electric field-induced phase transitions above the Curie point, forming a stable multiphase configuration. The transverse piezoelectric coefficient $d_{31}$ of UFCP SCs is $1126\mathrm{p}\mathrm{C}/\mathrm{N}$, and the electromechanical coupling factor $k_{31}$ is 0.559. Compared with traditional DCP, UFCP increases $d_{31}$ by 68.6%, the mechanical quality factor $Q_m$ by 16.7%, and the piezoelectric figure of merit (FOM) by 98.3%. Furthermore, under high-power excitation with a root-mean-square voltage of $15\mathrm{V}$, UFCP achieves a 343% increase in power and a 130.5% improvement in the FOM compared with DCP, demonstrating its potential for enhancing high-power performance in practical applications. Full article

Existing tunable optical metasurfaces based on the electro-optic effect are either complex in structure or have a limited phase modulation range. In this paper, a simple rectangular metasurface structure based on a Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) crystal with high electro-optic coefficient of 120 pm/V was designed to demonstrate its electrically tunable performance in the optical communication band through simulations. By optimizing the structure parameters, a tunable metasurface was generated that can induce a complete 2π phase shift for beam deflection while maintaining relatively uniform transmittance. Simulations further demonstrated the electrical tunability of the beam deflection direction and operating wavelength of the metasurface. This tunable optical metasurface, with its simple and easily fabricated structure, can promote the development and application of multifunctional and controllable metasurfaces. Its adjustable beam deflection direction and operating wavelength may find applications in fields such as optical communication systems and imaging. Full article

Energy harvesting plays an important role in advancing personalized wearables by enabling continuous monitoring, enhancing wearable functionality and facilitating sustainable solutions. We aimed to develop a flexible piezoelectric energy harvesting system based on inorganic piezoelectric materials that convert mechanical energy into electricity to power a wide range of mobile and portable electronic devices. There is significant interest in flexible piezoelectric energy harvesting systems that use inorganic piezoelectric materials due to their exceptional physical features and prospective applications. Herein, we successfully demonstrated a flexible piezoelectric nanogenerator (PENG) designed by the co-doped rare-earth element ceramics (RE-PMN-PT) embedded in PVDF and PDMS composite film and attained a significant output performance while avoiding electrical poling process. The impact of dielectric characteristics on the electrical output of nanogenerators was investigated, together with the structure of the composites. The Sm/La-PMN-PT particles effectively amplify both the voltage and current output, showcasing their potential to power portable and wearable devices, as demonstrated by their capacity to illuminate LEDs. The maximal output power of 2 mW was correlated with the high voltage (220 V) and current (90 µA) of Sm/La-PMN-PT/PVDF, which demonstrated that the device has the potential for energy harvesting in biomedical applications. Full article

This paper studies the structural parameters and electrophysical properties (dielectric and piezo electric, as well as currents of thermostimulated depolarization) of samples of composition 0.20BiScO₃·0.45PbTiO₃·0.35PbMg_1/3Nb_2/3O₃ (or in short 0.20BS·0.45PT·0.35PMN) obtained by ceramic and melt-hardening methods of synthesis. In the ceramic method, the samples were obtained from the starting oxides by two-stage firing. In the melt method, amorphous precursors were first obtained from heat-treated and non-heat-treated starting oxide mixtures by melting and subsequent quenching under sharply gradient temperature conditions. Samples were obtained after grinding, pressing, and thermal annealing of the synthesized precursors, and four types of samples differing in size and shape of the intermediate precursor particles (crystallites) were obtained. The X-ray phase analysis showed that the predominant phase in the studied samples is the perovskite phase; in both types of samples, up to 5 wt.% of impurity phase with pyrochlore structure was also present. The samples of 0.20BS·0.45PT·0.35PMN exhibit dielectric properties characteristic of relaxor ferroelectrics, and the polarized samples exhibit a pronounced piezo effect with a piezo modulus value of d₃₃~200 pC/N. A comparative analysis of the properties of the samples obtained by different methods has been carried out. The essential advantage of the melt method is that its use allows obtaining varieties of four kinds of ferroelectric relaxors and reduces the time of synthesis of samples by 2–3 times. Full article

The inevitable feedback between the environmental and energy crisis within the next decades can probably trigger and/or promote a global imbalance in both financial and public health terms. To handle this difficult situation, in the last decades, many different classes of materials have been recruited to assist in the management, production, and storage of so-called clean energy. Probably, ferromagnets, superconductors and ferroelectric/piezoelectric materials stand at the frontline of applications that relate to clean energy. For instance, ferromagnets are usually employed in wind turbines, superconductors are commonly used in storage facilities and ferroelectric/piezoelectric materials are employed for the harvesting of stray energy from the ambient environment. In this work, we focus on the wide family of ferroelectric/piezoelectric materials, reviewing their physical properties in close connection to their application in the field of clean energy. Among other compounds, we focus on the archetypal compound Pb(Zr,Ti)O₃ (or PZT), which is well studied and thus preferred for its reliable performance in applications. Also, we pay special attention to the advanced ferroelectric relaxor compound (1−x)Pb(Mg_1/3Nb_2/3)O₃−xPbTiO₃ (or PMN-xPT) due to its superior performance. The inhomogeneous composition that many kinds of such materials exhibit at the so-called morphotropic phase boundary is reviewed in connection to possible advantages that it may bring when applications are considered. Full article