Single Crystals Of Pb Research Articles

In vivo flexible energy harvesting on porcine heart via highly-piezoelectric PIN–PMN–PT single crystal

One of the main challenges with implantable biomedical devices is the replacement surgeries of depleted batteries for elderly patients. This not only poses medical risks but also results in financial burdens. Consequently, there is a growing need for self-powered in vivo electronics that can convert the biomechanical movements of organs into usable electric energy. Notably, a previously reported in vivo flexible energy harvester generated relatively low current output from a living porcine heart, restricting its ability to operate self-powered electronic devices. In this study, a high current output implantable flexible energy harvester was demonstrated by adopting a highly-piezoelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) film. The in vivo flexible energy harvester generated a short-circuit output current of 20 µA (corresponding to a current density of 3.08 µA/mm3) from the contraction and relaxation of a porcine heart. This recorded in vivo output current density was attributed to its outstanding piezoelectric charge coefficient of the single crystal PIN-PMN-PT, optimized Ni stressor assisted exfoliation as well as the implementation of a metal-insulator-metal (MIM) structure. Moreover, the flexible energy harvester was also demonstrated as a self-powered cardiac sensor to monitor irregular heartbeats by observing heart rate variations due to drug administration in a porcine heart. Additionally, output performance evaluation was conducted with the chest closed to further assess the feasibility of practical in vivo harvesting. Finally, the single crystal harvester exhibited biocompatibility, showing no signs of cytotoxicity based on cell viability assessments and histological characterizations. These results underscore the potential of the flexible PIN-PMN-PT energy harvesting device as a sustainable power source for self-powered in vivo biomedical electronics.

Domain patterning in nonpolar cut PMN–PT by focused ion beam

The formation of the ferroelectric domain structure as a result of irradiation by focused ion beam of [100]-cut 0.61Pb(Mg[Formula: see text]Nb[Formula: see text]O3–0.39PbTiO3 (PMN–PT) single crystals covered by surface artificial dielectric layer and with free surface was investigated. The dot irradiation resulted in formation of the wedge-like domains grown along [00[Formula: see text]] direction. For irradiation of the free surface, the domains are mainly located under the surface, while at the irradiated surface with an artificial dielectric layer the domains are located at the surface. It was shown that the subsurface wedge-shaped part of the domain is unstable and completely disappears after a month due to spontaneous backswitching under the action of the residual depolarization field. The revealed nonlinear dose dependence of the domain sizes was attributed to the distribution of the electric field using the point charge model. The domain interaction for the distance between irradiated dots below 30[Formula: see text][Formula: see text]m has been revealed in all samples. It was shown that the decrease of the distance between irradiated dots in the created domain row leads to an increase in the length of the central domains, which is explained by the contribution of all injected charges to the switching field.

Enhanced piezoelectric and optical properties of tetragonal Sm‐doped Pb(In1/2Nb1/2)–Pb(Mg1/3Nb2/3)–PbTiO3 crystals

AbstractRelaxor ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) has received extensive research and attention due to its excellent piezoelectric, electromechanical, and other properties. In particular, tetragonal relaxor ferroelectric single crystals have shown greater application potential in high‐temperature devices due to their higher Curie temperature and better stability. However, the low piezoelectric performance of tetragonal crystals also greatly limits its application, and research on its optical properties is not sufficient. In this paper, the tetragonal phase Sm–PIN–PMN–PT single crystal was obtained by the Bridgman method, and its piezoelectric and electro‐optical properties are studied. At the same time, we gave a complete set of piezoelectric, dielectric, and elastic coefficient matrices. The results show that the crystal has excellent piezoelectric and electromechanical properties. The piezoelectric coefficient can reach 905pC/N, the electromechanical coupling coefficient k33 is 85%, and the kt is 72%. The transmittance of the sample polarized along [001] direction can reach 66%. The effective electro‐optical coefficient γc is 60 pm/V at room temperature and can reach 86 pm/V at 70°C. It has a wide operating temperature range and stable performance with frequency variation, which has certain reference significance for application in new electro‐optical devices.

The unexpected diffuse phase transition in relaxor-PbTiO3 ferroelectrics via acceptor modification

The diffuse phase transition (DPT) and domain structure are essential to the functional properties of relaxor ferroelectrics and are extremely sensitive to the ion doping. The utilization of acceptor doping has been observed to be an effective method in enhancing the high-power properties of relaxor ferroelectric materials. The present study aims to examine the acceptor-doped DPT and domain structure in single crystals of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3. An unexpected physical phenomenon was identified in which Mn-doping increased dielectric diffusion and lowered domain size while suppressing dielectric relaxation. Traceability investigations suggest that Mn-doping inhibited the growth of polar nanoregions by enhancing random electric fields, which increases dielectric diffusion while decreasing the domain size. Meanwhile, Mn doping redistributes the relaxation time function, which results in a reduction in dielectric relaxation. The current research deepens the understanding of the physical basis of DPT and can be applied to the development of high-performance piezoelectric materials.

Comparative analysis of crystallographic phase stability of single and poly-crystalline lead nitrate at dynamic shocked conditions

In the present work, we report the crystallographic structural stability of the poly-crystalline lead nitrate samples at shocked conditions with which a systematic comparison is made for the previously reported single-crystalline lead nitrate crystal at shocked conditions. X-ray diffractometry (XRD) and Raman spectroscopic measurements have been performed to assess the crystallographic structural stability of poly-crystalline Pb(NO3)2 samples at shocked conditions and the observed XRD and Raman results disclose that the title poly-crystalline samples retain the original crystallographic structure even at 100 shocked conditions interacting with the shock waves of 2.2 Mach number. But the single crystals of Pb(NO3)2 undergo crystalline to amorphous phase transition at shocked conditions. Based on the observed results, poly-crystalline samples have higher-structural stability than that of single crystals. The outcome of this work provides glimpses of possible further contributions to crystal engineering for the design of new materials with specific physical and chemical properties.

Pure- and Pseudo-Lateral-Field-Excitation Characteristics of Relaxor Ferroelectric Single Crystal PMN-PT.

The relaxor ferroelectric single crystal (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) has high piezoelectric constants, and thus has a good application prospect in the field of highly sensitive piezoelectric sensors. In this paper, for relaxor ferroelectric single crystal PMN-PT, the bulk acoustic wave characteristics on pure- and pseudo-lateral-field-excitation (pure- and pseudo-LFE) modes are investigated. LFE piezoelectric coupling coefficients and acoustic wave phase velocities for PMN-PT crystals in different cuts and electric field directions are calculated. On this basis, the optimal cuts of pure-LFE and pseudo-LFE modes of relaxor ferroelectric single crystal PMN-PT are obtained, namely, (zxt)45° and (zxtl)90°/90°, respectively. Finally, finite element simulations are carried out to verify the cuts of pure-LFE and pseudo-LFE modes. The simulation results show that the PMN-PT acoustic wave devices in pure-LFE mode have good energy-trapping effects. For PMN-PT acoustic wave devices in pseudo-LFE mode, when the device is in air, no obvious energy-trapping emerges; when the water (as a virtual electrode) is added to the surface of the crystal plate, an obvious resonance peak and the energy-trapping effect appears. Therefore, the PMN-PT pure-LFE device is suitable for gas-phase detections. While the PMN-PT pseudo-LFE device is suitable for liquid-phase detections. The above results verify the correctness of the cuts of the two modes. The research results provide an important basis for the development of highly sensitive LFE piezoelectric sensors based on relaxor ferroelectric single crystal PMN-PT.

Magnetic and Electrical Characteristics of Nd3+-Doped Lead Molybdato-Tungstate Single Crystals.

Single crystals of Pb1-3x▯xNd2x(MoO4)1-3x(WO4)3x (PNMWO) with scheelite-type structure, where ▯ denotes cationic vacancies, have been successfully grown by the Czochralski method in air and under 1 MPa. This paper presents the results of structural, optical, magnetic and electrical, as well as the broadband dielectric spectroscopy measurements of PNMWO single crystals. Research has shown that replacing diamagnetic Pb2+ ions with paramagnetic Nd3+ ones, with a content not exceeding 0.01 and possessing a screened 4f-shell, revealed a significant effect of orbital diamagnetism and Van Vleck's paramagnetism, n-type electrical conductivity with an activation energy of 0.7 eV in the intrinsic area, a strong increase of the power factor above room temperature for a crystal with x = 0.005, constant dielectric value (~30) and loss tangent (~0.01) up to room temperature. The Fermi energy (~0.04 eV) and the Fermi temperature (~500 K) determined from the diffusion component of thermopower showed shallow donor levels.

Deterministic magnetic moment rotation in antiferromagnetic material by piezoelectric strain modulation

Antiferromagnetic (AFM) spintronic devices play a vital role in the development of novel spintronic devices due to their attractive features. Herein, the interfacial state manipulation of the AFM IrMn material is investigated by combining a ferroelectric single crystal Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) with an electric field (E-field)-controlled magnetic moment arrangement of the IrMn film. A PMN-PT/Cu/IrMn/NiFe heterostructure is chosen to confirm the deterministic manipulation of AFM interfacial states and its angle of magnetic moment rotation. The appropriate thickness of the Cu layer is selected to disrupt the strain-mediated magnetoelectric coupling between the NiFe layer and PMN-PT substrate. The NiFe film reference layer can reflect the variation in AFM interfacial states via the exchange bias. When the E-field is applied, an in-plane piezoelectric strain is produced. If IrMn responds to the strain, its magnetic moment rotates from [001] to [1−10] depending on the crystal orientation of PMN-PT. Based on the experimental results and theoretical analyses, a rotation in the magnetic moment of the IrMn layer by ~20° is confirmed. This work provides convincing evidence for the manipulation of E-field-controlled AFM interfacial states and describes a reliable method for achieving the rotation angle of AFM moments, which can help to accelerate the development of AFM spintronic devices.

The Zn1-xPbxCr2Se4-Single Crystals Obtained by Chemical Vapour Transport-Structure and Magnetic, Electrical, and Thermal Properties.

Monocrystalline chalcogenide spinels ZnCr2Se4 are antiferromagnetic and semiconductor materials. They can be used to dope or alloy with related semiconducting spinels. Therefore, their Pb-doped display is expected to have unique properties and new potential applications. This paper presents the results of dc and ac magnetic measurements, including the critical fields visible on the magnetisation isotherms, electrical conductivity, and specific heat of the ZnCr2S4:Pb single crystals. These studies showed that substituting the diamagnetic Pb ion with a large ion radius for the Zn one leads to strong short-range ferromagnetic interactions in the entire temperature range and spin fluctuations in the paramagnetic region at Hdc = 50 kOe.

Electric-field control of nonlinear THz spintronic emitters

Energy-efficient spintronic technology holds tremendous potential for the design of next-generation processors to operate at terahertz frequencies. Femtosecond photoexcitation of spintronic materials generates sub-picosecond spin currents and emission of terahertz radiation with broad bandwidth. However, terahertz spintronic emitters lack an active material platform for electric-field control. Here, we demonstrate a nonlinear electric-field control of terahertz spin current-based emitters using a single crystal piezoelectric Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) that endows artificial magnetoelectric coupling onto a spintronic terahertz emitter and provides 270% modulation of the terahertz field at remnant magnetization. The nonlinear electric-field control of the spins occurs due to the strain-induced change in magnetic energy of the ferromagnet thin-film. Results also reveal a robust and repeatable switching of the phase of the terahertz spin current. Electric-field control of terahertz spintronic emitters with multiferroics and strain engineering offers opportunities for the on-chip realization of tunable energy-efficient spintronic-photonic integrated platforms.

Highly Linear and Wide Non-Resonant Two-Degree-of-Freedom Piezoelectric Laser Scanner.

Laser scanners with mechanically driven mirrors have exhibited increasing potential for various applications, such as displays and laser radar. Resonant scanners are the predominantly used scanners; however, non-resonant scanners are required for applications where point-to-point driving is desirable. Because a non-resonant drive cannot amplify the drive angle owing to the resonance phenomenon, high values are difficult to achieve for the main performance metrics of the scanners: mirror area, drive angle, and operating frequency. In this paper, we present a two-axis scanner with a piezoelectric actuator made of a piezoelectric single-crystal Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 as the actuation force source. The scanner contains a circular mirror with a diameter of 7 mm and achieves an average static mechanical deflection angle amplitude of 20.8° in two axes with a resonant frequency of 559 Hz. It is equipped with a transmission mechanism that can decouple each axis to achieve high linearity; in our study, the nonlinearity error was less than 1°.

Micro-spall damage and subsequent re-compaction of release melted lead under shock loading

Micro-spall is a large-area of liquid cavitation debris cloud formed near the free surface when metal melts during shocking or releasing process. We performed a molecular dynamics simulation to investigate the evolution of micro-spall and the related physical mechanism during the re-compaction process of a single crystal Pb by the second shock wave loading. The temperature and pressure obviously increase during re-compaction process. The ultra-high temperature-rise and local high pressure in the damage area is due to the collision between atoms and the collapse of voids. There is also one more pressure-rise and temperature-rise in the damage region, which is originated from the formation of high-speed internal micro jet and its striking on the back wall of large voids. Due to the uneven distribution of pressure and temperature after the 2nd shock wave passing through the micro spall damage region, the microstructures are also unevenly distributed. Besides, the damage region will swell due to the high temperature-rise during re-compaction process. Therefore, the micro-spall damaged region closed to the free surface is difficult to be compacted to dense state. Because that the voids in the damage region near the free surface are larger for the longer time interval, the temperature-rise originated from the collapse of voids is more severe. The wavefront plane is gradually broadened in the process of re-compaction.

Isotropic single-gap superconductivity of elemental Pb

The unconventional multi-gap superconductivity in elemental Pb were reported previously by surface sensitive tunneling experiments, as well as predicted by several theory works. To obtain bulk evidence for such multiple gap behavior, the thermodynamic critical field $B_{\rm c}$ was measured along three different crystallographic directions ([100], [110], and [111]) in a high-quality Pb single crystal by means of muon spin rotation/relaxation. No difference in temperature evolution of $B_{\rm c}$ for all three directions was detected. The average reduced gap $\alpha=\Delta/k_{\rm B}T_{\rm c}=2.312(3)$ ($\Delta$ is the zero-temperature gap value and $T_{\rm c}$ is the transition temperature) was further obtained by employing the phenomenological $\alpha-$model. Our results imply that the elemental Pb is an isotropic superconductor with a single energy gap.

Wide Two-Degree-of-Freedom Static Laser Scanner with Miniaturized Transmission Mechanism and Piezoelectric Actuation.

In recent years, laser scanners have attracted significant attention for applications such as laser radars. However, the establishment of a two-degree-of-freedom scanner that can quasi-statically drive a large mirror with a large deflection angle has proven to be challenging. In this paper, we propose a laser scanner design and fabrication method by combining two unimorph piezoelectric actuators composed of piezoelectric single-crystal Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 and a miniature translation-rotation conversion mechanism with flexible polyimide hinges. The size of the entire scanner was 32 mm × 12 mm × 10 mm. We successfully demonstrated that the scanner could achieve a large quasi-static mechanical deflection angle amplitude of 20.5° in two axes with a 6-mm-square mirror.

Dynamic scaling hysteresis behavior and field-induced domain transition of 0.16PIN-0.62PMN-0.22 PT single crystals

Due to the good dielectric, piezoelectric and ferroelectric properties, the pseudo-ternary ferroelectric single crystals Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) have been widely concerned and studied. In this study we found that the dynamic hysteresis loop area <A> with electric field E0 and frequency f0 of the 0.16 Pb(In1/2Nb1/2)O3-0.62 Pb(Mg1/3Nb2/3)O3-0.22PbTiO3 (0.16PIN-0.62PMN-0.22 PT) single crystals satisfies the relational equation <A> ∝ E0βf0α. In the <A> ∝ E0β relationship, both linear stages are found correlated with the low electric field in the first stage E0<Ec and the high electric field in the third stage E0 > 3Ec. The hysteresis loop area <A> with frequency f0 relationship satisfies the equation <A> ∝ f0α with roughly linear trend and the hysteresis loop area <A> decreases with increasing frequency f0. Such electric field dependent dynamic hysteresis scaling can be observed by polarized light microscopy.

Hierarchically-structured large superelastic deformation in ferroelastic-ferroelectrics

Large superelastic deformation in ferroelastic-ferroelectrics (FMs) is a complex phenomenon involving multiple mechanisms operating simultaneously. Understanding how these mechanisms contribute corporately is critical to apply this useful property to the intrinsically brittle FMs, which can therefore display both excellent functional and mechanical performance. Here, we have directly observed and quantitatively analyzed in situ in a transmission electron microscope the three main mechanisms of twinning domain, phase transformation and mobile point defect contributing to extremely large superelastic deformation in single-crystal BaTiO3 (5.0% strain) and Pb(Mg1/3Nb2/3)O3-PbTiO3 (10.1% strain). Our results reveal the hierarchical origin of large recoverable strain in “brittle” FMs.

Fabrication of preferentially (001)-oriented Pb(Zr,Ti)O3 films consisting of anisotropic single crystal nanoparticles

Single crystal Pb(Zr,Ti)O3 (PZT) nanoparticles were synthesized via a hydrothermal method using oleic acid. The obtained PZT nanoparticles had a sheet-like structure, and transmission electron microscopy observations revealed that the normal direction of these sheet-like nanoparticles corresponds to the c-axis. PZT films consisting of these nanoparticles were fabricated through the dip-coating method on a Pt/TiOx/SiO2/Si substrate; the sheet-like nanoparticles were aligned with their c-axes parallel to the substrate. Preferentially (001)-oriented PZT film was formed because of the morphology of each single PZT crystal, and this preferential (001)-orientation was maintained even after heat treatment at 600 °C. Local piezoelectric properties were measured via piezoresponse force microscopy with a cantilever as the top electrode, and piezoelectric constant−applied voltage hysteresis loops with high squareness were obtained for the PZT film heated at 600 °C.

Molecular dynamics investigation on complete Mie-Grüneisen equation of state: Al and Pb as prototypes

Molecular dynamics (MD) simulations are carried out to comprehensively investigate the Hugoniot curve, isotherms, isentropes, and internal energy, as well as the Mie-Grüneisen equation of state (EOS) for single-crystal Al and Pb via multi-scale shock technology (MSST) in the open source software Large-scale Atomic/Molecular Massively Parallel Simulator, or LAMMPS. The temperatures (TH and TS) along the Hugoniot curve and isentrope, the entropy increment (ΔSH) along the Hugoniot curve, and the Grüneisen coefficient γ are calculated and discussed based on the linear relation of shock wave velocity and particle velocity. Meanwhile, based on the assumptions that γ is only a function of the specific volume V and the specific heat cV = constant, the typical incomplete Mie-Grüneisen EOS is thermodynamically extended to the complete equations of state (EOSs) utilizing the Hugoniot relation as the reference curve at pressures up to 300 GPa. The incomplete and complete Mie-Grüneisen EOSs show a concave surface in the pressure-specific volume-internal energy (P–V-E), pressure-specific volume-shock Hugoniot temperature (P–V-TH), and pressure-specific volume-entropy increment (P–V-ΔSH) spaces.

Long-range fluctuation of polar nanoregions in relaxor-based (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 ferroelectric single crystals

The long-range fluctuations of polar nanoregions (PNRs) in relaxor-based ferroelectric single crystals (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 with x = 0.29 and 0.33 were investigated by using photon correlation spectroscopy (PCS). Dual relaxation processes for the long-range fluctuation of PNRs were observed in both samples. The relaxation-times cover the range of 6–30 μs and 13–100 μs for the two relaxations which are attributed to the flipping and boundary fluctuation of PNRs, respectively. The temperature dependence of relaxation time for the slow fluctuations varies with similar trend to that for dielectric response. The flipping process of PNRs is deduced to responsible for the large dielectric response.

Improved embedded-atom model potentials of Pb at high pressure: application to investigations of plasticity and phase transition under extreme conditions

Local stress relaxation mechanisms of crystals are a long-standing interest in the field of materials physics. Constantly encountered inelastic deformation mechanisms in metals under dynamic loadings, such as dislocation, deformation twinning and phase transition, have been extensively discussed separately or as some of their combinations. Recently, virtual melting is found to be a dominant local stress relaxation mechanism under extreme strain rates. However, these deformation mechanisms have never been investigated in the same metal at an atomic level due to the lack of high pressure interatomic potentials. In this work, an embedded-atom model potential of Pb is developed and tested for high pressure applications. The developed potential of Pb could not only reproduce many energetic, elastic and defective properties at ambient conditions well, but also correctly describe face-centered cubic (fcc)-hexagonal close packed (hcp) and hcp-body-centered cubic phase transition of Pb under high pressures. Shock Hugoniot, as well as equation of states for fcc and hcp phase, also agrees well with the literature ones up to more than 100 GPa. With the developed potential, non-equilibrium molecular dynamic simulations are conducted to investigate dynamic behaviors of Pb single crystal under ramp-shock compressions. Depending on applied strain rates, dislocation-mediated plasticity, phase transition and virtual melting, constantly reported by experiments or theoretical investigations, are observed in our results. Additionally, a new phase transition mechanism of Pb subjected to the ramp compressions is uncovered.