Single Crystals Of Pb Research Articles

Enhancement of Magnetoelectric Conversion Achieved by Optimization of Interfacial Adhesion Layer in Laminate Composites.

We report the effect of epoxy adhesion layers with different mechanical or physical property on a magnetoelectric (ME) composite laminate composed of FeBSi alloy (Metglas)/single-crystal Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3/Metglas to achieve an improved ME conversion performance. Through theoretical simulation, it was revealed that the Young's modulus and the thickness of interfacial adhesives were major parameters that influence the conversion efficiency in ME composites. In the experimental evaluation, we utilized three epoxy materials with a distinct Young's modulus and adjusted the average thickness of the adhesion layers to optimize the ME conversion. The experimental results show that a thin epoxy layer with a high Young's modulus provided the best performance in the inorganic-based ME conversion process. By tailoring the interfacial adhesion property, the ME laminate generated a high conversion coefficient of 328.8 V/(cm Oe), with a mechanical quality factor of 132.0 at the resonance mode. Moreover, we demonstrated a highly sensitive alternating current magnetic field sensor that had a detection resolution below 10 pT. The optimization of the epoxy layers in the ME laminate composite provided significant enhancement of the ME response in a simple manner.

Fabrication of PMN-PT/Epoxy 2–2 Composite Ultrasonic Transducers and Analysis Based on Equivalent Circuit Model

Single-crystal (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN-PT) has great potential for use in ultrasonic applications; however, it is challenging to achieve both broad bandwidth and high sensitivity owing to the mismatch in acoustic impedance between the piezoelectric materials and loading medium. Fabrication of a matching layer for transducers is challenging owing to the increase in the center frequency of the transducer. In this study, a 2–2 PMN-PT-crystal composite was designed and fabricated, exhibiting desirable piezoelectric properties and lower acoustic impedance compared with single-crystal PMN-PT. Transducers based on the 2–2 PMN-PT composite were fabricated and analyzed in detail to investigate their sensitivity and bandwidth. Moreover, the effects of a backing layer on the transducer were investigated. The measured results showed that the bandwidth improved from 21.28% to 35.54% at the cost of reduced sensitivity of the transducer. Systematic analysis of this phenomenon using an equivalent circuit based on the Mason model is presented.

Relation between Fractal Inhomogeneity and In/Nb-Arrangement in Pb(In1/2Nb1/2)O3

Relaxor ferroelectrics show substantial responses to electric fields. The key difference from normal ferroelectrics is a temperature-dependent inhomogeneous structure and its dynamics. The lead-based complex perovskite Pb(In1/2Nb1/2)O3 is an intriguing system in which the inhomogeneous structure can be controlled by thermal treatment. Herein, we report investigations of the phase transitions in single crystals of Pb(In1/2Nb1/2)O3 via changing the degree of randomness in which In and Nb occupy the B site of the ABO3 perovskite structure. We studied the dynamic properties of the structure using inelastic light scattering and the static properties using diffuse X-ray scattering. These properties depend on the degree of randomness with which the B site is occupied. When the distribution of occupied In/Nb sites is regular, the antiferroelectric phase is stabilised by a change in the collective transverse-acoustic wave, which suppresses long-range ferroelectric order and the growth of the inhomogeneous structure. However, when the B site is occupied randomly, a fractal structure grows as the temperature decreases below T*~475 K, and nanosized ferroelectric domains are produced by the percolation of self-similar and static polar nanoregions.

Specific heat of a PIN-PMN-PT single-crystal up to 500K

The temperature dependence of the specific heat of the single crystal Pb(In[Formula: see text]Nb[Formula: see text])O3-Pb(Mg[Formula: see text]Nb[Formula: see text])O3-PbTiO3 (PIN-PMN-PT) was obtained at 80–500[Formula: see text]K by means of ac-calorimetry, and comparison with the calorimetric data for PMN was made, allowing one to determine absolute values of the specific heat of PIN-PMN-PT. For the high-temperature region ([Formula: see text][Formula: see text]K), the background heat capacity was calculated, the anomalies of the heat capacity for both compounds were determined, and the hump of the temperature dependence of specific heat PIN-PMN-PT was detected for the first time.

Electric-field tuning of ferromagnetic resonance in CoFeB/MgO magnetic tunnel junction on a piezoelectric PMN-PT substrate

We investigated the strain-induced modulation of in-plane magnetic anisotropy in single crystal Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) with a (011) orientation/seed layer/IrMn/CoFeB/MgO/CoFeB/capping layer structure using spin-torque ferromagnetic resonance (ST-FMR) at room temperature. An in-plane biaxial strain is produced by an electric field applied across the substrate, which results in the tuning of the magnetic anisotropy of the CoFeB layer. As the change in the electric field value progresses, the MR loop becomes slanted, indicating the change in the easy axis direction. A strain-induced FMR frequency shift dependence of 145 MHz⋅cm⋅kV−1 is obtained by analyzing the experimental FMR spectra. An analytical model of the potential dynamic mechanism based on the strain induced reorientation of magnetization was discussed. Our results suggest that PMN-PT based magnetic tunnel junctions can have applications in electric-field driven spintronic devices.

Solution synthesis of lead seeded germanium nanowires and branched nanowire networks and their application as Li-ion battery anodes

Herein, we report the high density growth of lead seeded germanium nanowires (NWs) and their development into branched nanowire networks suitable for application as lithium ion battery anodes. The synthesis of the NWs from lead seeds occurs simultaneously in both the liquid zone (solution–liquid–solid (SLS) growth) and solvent rich vapor zone (vapor–liquid–solid (VLS) growth) of a high boiling point solvent growth system. The reaction is sufficiently versatile to allow for the growth of NWs directly from either an evaporated catalyst layer or from pre-defined nanoparticle seeds and can be extended to allowing extensive branched nanowire formation in a secondary reaction where these seeds are coated onto existing wires. The NWs are characterized using TEM, SEM, XRD and DF-STEM. Electrochemical analysis was carried out on both the single crystal Pb–Ge NWs and the branched Pb–Ge NWs to assess their suitability for use as anodes in a Li-ion battery. Differential capacity plots show both the germanium wires and the lead seeds cycle lithium and contribute to the specific capacity that is approximately 900 mAh g−1 for the single crystal wires, rising to approximately 1100 mAh g−1 for the branched nanowire networks.

High composition uniformity of 4″ of PIN-PMN-PT single crystals grown by the modified Bridgman method

Relaxor based ferroelectric single crystals Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) with composition near morphotropic phase boundary exhibit extraordinary piezoelectric properties. Due to the composition segregation during crystal growth, the composition and properties of PIN-PMN-PT single crystal boules are poor uniformity. In this work, uniformity of dielectric and piezoelectric properties of the crystal boules with 4″ diameter by 100mm long were clearly improved along the crystal growth direction by the modified Bridgman method. For 70% length of the boule, TRT and Tc were around 100°C and 160–180°C along the growth direction, respectively. The variety of piezoelectric constant d33 is about 1500-1800pC/N in the same range of the boule. So that PIN-PMN-PT crystals will be more cost-effective and beneficial for ultrasonic applications in higher temperature region.

Investigation on unidirectional growth of 1,3,5-Triphenylbenzene by Sankaranarayanan-Ramasamy method and its characterization of lifetime, thermal analysis, hardness and etching studies

An organic single crystal of 1,3,5-Triphenylbenzene (3PB) has been grown from solution by unidirectional Sankaranarayanan-Ramasamy (SR) method within a period of 72 days. The size of grown crystal was 40 mm length and 30 mm diameter. The solubility of 3PB material was determined in five various solvents with different temperatures and tetrahydrofuran (THF) was used as a suitable solvent for bulk crystallization. Metastable zone width of the solution was determined to optimize the growth period. Cell parameters of the grown 3PB crystal were confirmed by single crystal X-ray diffraction and it belongs to orthorhombic crystal system. The density of the grown 3PB crystal was found to be 1.240 g/cm3 by floatation method. Optical studies reflect the transmittance ability of crystal in entire visible and NIR region. The refractive index of the grown 3PB crystal was found to be 1.618. Fluorescence emission spectrum was recorded and emission peak observed at 360 nm. Prompt and delayed fluorescence lifetime of 3PB single crystal has been calculated at 12 ns and 30 ns respectively. Thermogravimetric/Differential thermal analysis (TG/DTA) measurement was performed to the grown crystal and it was stable up to 164 °C. Vicker’s microhardness value (Hv) was calculated with varying load ranging from 25 to 100 g and the Mayer’s index was found to be 4.5, showing that the grown crystal belongs to a soft material category. Growth pattern and the surface defect were examined by the optical microscope. The microstructure of the crystal surface shows the regular shapes of etch pits which are in triangular shape.

Shear-Mode-Based Cantilever Driving Low-Frequency Piezoelectric Energy Harvester Using 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3.

Energy harvesting from external mechanical excitation has become a hot interest area, and relaxor piezoelectric single crystal ( 1 - x )Pb(Mg1/3Nb2/3)O3- x PbTiO3 (PMN- x PT or PMN-PT) has attracted continuous attention due to the well-known ultrahigh shear-mode electromechanical response. To exploit the low-frequency application of excellent shear-mode performance of the PMN-PT single crystal, we proposed a Shear-mode-based CANtilever Driving Low-frequency Energy harvester. The device is composed of two symmetrically assembled sandwich structures and a cantilever, in which sandwich structures can be driven by the cantilever. An analytical method was used to illustrate the high output mechanism, and a finite-element method model of the device was also established to optimize the generated electric energy in this device. The electrical properties of the device under different excitation frequencies and load resistances were studied systematically. The maximum voltage and power density at resonance frequency (43.8 Hz) were measured to be 60.8 V and 10.8 mW/cm(3) under a proof mass of 13.5 g, respectively. Both theoretical and experimental results demonstrate the considerable potential of the resonance-excited shear-mode energy harvester applied to wireless sensors and low-power portable electronics.

Energy scavenging based on a single-crystal PMN-PT nanobelt.

Self-powered nanodevices scavenging mechanical energy require piezoelectric nanostructures with high piezoelectric coefficients. Here we report the fabrication of a single-crystal (1 − x)Pb(Mg1/3Nb2/3)O3 − xPbTiO3 (PMN-PT) nanobelt with a superior piezoelectric constant (d33 = ~550 pm/V), which is approximately ~150%, 430%, and 2100% of the largest reported values for previous PMN-PT, PZT and ZnO nanostructures, respectively. The high d33 of the single-crystalline PMN-PT nanobelt results from the precise orientation control during its fabrication. As a demonstration of its application in energy scavenging, a piezoelectric nanogenerator (PNG) is built on the single PMN-PT nanobelt, generating a maximum output voltage of ~1.2 V. This value is ~4 times higher than that of a single-CdTe PNG, ~13 times higher than that of a single-ZnSnO3 PNG, and ~26 times higher than that of a single-ZnO PNG. The profoundly increased output voltage of a lateral PNG built on a single PMN-PT nanobelt demonstrates the potential application of PMN-PT nanostructures in energy harvesting, thus enriching the material choices for PNGs.

Note: High-power piezoelectric transformer fabricated with ternary relaxor ferroelectric Pb(Mg1/3Nb2/3)O3–Pb(In1/2Nb1/2)O3–PbTiO3 single crystal

A plate-shaped piezoelectric transformer was designed and fabricated using ternary relaxor ferroelectric single crystal Pb(Mg(1/3)Nb(2/3))O3-Pb(In(1/2)Nb(1/2))O3-PbTiO3. Both the input and output sections utilized the transverse-extensional vibration mode. The frequency and load dependences of the electrical properties for the proposed transformer were systematically studied. Results indicated that under a matching load resistance of 14.9 kΩ, a maximum output power of 2.56 W was obtained with the temperature rise less than 5 °C. The corresponding power density reached up to 50 W/cm(3). This ternary single-crystal transformer had potential applications in compact-size converters requiring high power density.

Growth and properties of 4-in. diameter ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 by the seed-induced modified Bridgman technique

Growth and quality of single crystals are unusually sensitive to the thermal distribution. In the appropriate thermal field ferroelectric single crystal 23Pb(In1/2Nb1/2)O3–44Pb(Mg1/3Nb2/3)O3–33PbTiO3 (abbr. PIN–PMN–PT, or PIMNT), with 105mm in diameter and 150mm in length, is successfully grown by the modified Bridgman technique. This as-grown crystal shows excellent properties (k33~0.92, d33~2200pC/N, Ec~5.7kV/cm, Tc~185°C, Tr/t~120°C; kt~0.60) near morphotropic phase boundary. In order to suppress the compositional segregation and improve the crystal quality, the controllable orientation growth for specific applications is performed successfully using the same oriented seed. For magnetoelectric applications as-grown <110> oriented PIN–PMN–PT crystal demonstrates its high homogeneity (Δε<±6%, Δtanδ<±14%, ΔTr/t<±3%, ΔTc<±3% and Δkt<±2% in a Φ80mm transverse wafer). These results of single crystal PIN–PMN–PT will greatly meet demands of its devices and promote its applications in the future.

Optimization design for magnetoelectric coupling property of the magnet/bimorph composite

Magnetoelectric (ME) composite as one kind of ME material that can yield a strong coupling effect between magnetic and electric fields at room temperature, has drawn widespread attention for decades due to its rich physics contents and significant technological prospect. Except for traditional magnetostrictive/piezoelectric based ME composites, other ME composites have been reported, among which the magnet/piezo-cantilever composites show super strong ME coupling effect. The magnet/piezo-cantilever composite is generally composed of a piezoelectric cantilever and magnets attached at the free end of the cantilever, which realizes ME coupling by force moment-mediated magnetic torque effect and piezoelectric effect. Recently, various configurations of the magnet/piezo-cantilever composites for obtaining higher ME coupling coefficients have been proposed and demonstrated experimentally. However, few theoretical researches of these magnet/piezo-cantilever composites of different configurations have been carried out, which is of great importance for optimizing the design of ME coupling property of the magnet/piezo-cantilever composites. Here in this paper, a theoretical expression for the low-frequency ME coupling coefficient in the magnet/piezo-cantilever composite is deduced based on piezoelectric constitutive equations by using the theory of elastic mechanics. The typical magnet/bimorph composite is chosen as the theoretical model. Based on the deduced theoretical expression, the dependences of the lowfrequency ME coupling coefficients in the magnet/bimorph composite on material and structural parameters are numerically calculated. The results show that there are optimal thickness values of the piezoelectric layers in the magnet/bimorph composite with different metal thickness values and material constituents for achieving maximal lowfrequency ME coupling coefficients. The thicker the metal layer in the magnet/bimorph composite, the less insensitive the low-frequency ME coupling coefficient to the thickness of the piezoelectric layer will be. And the low-frequency ME coupling coefficient of the magnet/bimorph composite decreases when a metal with higher elastic module is selected for bimorph. For the magnet/bimorph composite consisting of hard piezoelectric ceramics (PZT-4), the low-frequency ME coupling coefficient is higher than that of the composite consisting of the soft counterpart ones (PZT-5 H), which is due to the hard piezoelectric ceramics with higher piezoelectric voltage coefficient than the soft counterpart ones. What is more interesting is that when the piezoelectric material in the magnet/bimorph composite is changed into relaxor ferroelectric single crystals Pb(Zn1/3 Nb2/3)O3-PbTiO3 (PZN-PT), an extremely high low-frequency ME coupling coefficient can be obtained, which is 3.8 and 5 times those of the 13 composites with hard and soft piezoelectric ceramics, respectively. This research gives a theoretical guidance for optimal design and practical applications of the magnet/Bimorph composite.

Infrared light gated MoS₂ field effect transistor.

Molybdenum disulfide (MoS₂) as a promising 2D material has attracted extensive attentions due to its unique physical, optical and electrical properties. In this work, we demonstrate an infrared (IR) light gated MoS₂ transistor through a device composed of MoS₂ monolayer and a ferroelectric single crystal Pb(Mg(1/3)Nb(2/3))O₃-PbTiO₃ (PMN-PT). With a monolayer MoS₂ onto the top surface of (111) PMN-PT crystal, the drain current of MoS₂ channel can be modulated with infrared illumination and this modulation process is reversible. Thus, the transistor can work as a new kind of IR photodetector with a high IR responsivity of 114%/Wcm⁻². The IR response of MoS₂ transistor is attributed to the polarization change of PMN-PT single crystal induced by the pyroelectric effect which results in a field effect. Our result promises the application of MoS₂ 2D material in infrared optoelectronic devices. Combining with the intrinsic photocurrent feature of MoS₂ in the visible range, the MoS₂ on ferroelectric single crystal may be sensitive to a broadband wavelength of light.

Effect of Al and Ce ion concentrations on the optical absorption and luminescence in Gd3(Al,Ga)5O12:Ce3+ epitaxial films

We have studied the effect of Al and Ce ions on the optical absorption and luminescence of singlecrystal (Pb,Gd)3–y Ce y Al x Ga5–x O12 (x = 2.02, 2.09, 2.13, 2.17, 2.22; y = 0.02, 0.06, 0.07) films grown on (111)-oriented single-crystal Gd3Ga5O12 substrates by liquid-phase epitaxy from supercooled high-temperature solutions using solvents of the PbO–B2O3 system and growth charges containing 2.0, 2.1, or 2.2 mol % aluminum oxide and 0.03 or 0.2 mol % cerium oxide. The shift of the absorption bands of the Ce3+ 5d 1 and 5d 2 levels has been determined as a function of Al concentration in the films. The intensity of the Ce3+ luminescence bands of the films has been shown to increase with increasing Al and Ce concentrations.

Compositional segregation, structural transformation and property-temperature relationship of high-Curie temperature Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals

Ternary ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) was grown by the modified Bridgman method. The compositional variation of different regions of the crystals was measured, and the segregation regularity of the crystals was proposed. Variations in the dielectric properties and domain structures of the PIN–PMN–PT single crystals were investigated as a function of temperature and composition, and the phase transformation behavior of the crystals was observed. The PIN–PMN–PT crystals showed high Curie temperatures (T C = 160–210 °C), ferroelectric phase transition temperatures (T R–T up to 132 °C) and coercive fields (E C = 6–8 kV/cm) as well as excellent piezoelectric properties (d 33 up to 2,800 pC/N) and electromechanical coefficients (k 33 > 0.90). As the temperature increased, k 33 values remained relatively constant and d 33 increased gradually prior to ferroelectric phase transformation, and these results reflect the wide temperature usage range of PIN–PMN–PT single crystals. The polarization (P r ) and E C of the crystals showed unique trends during the phase transformation process; high P r and E C values can be maintained prior to depolarization, which indicates that the PIN–PMN–PT single crystals are candidate materials for high-power applications. In summary, PIN–PMN–PT single crystals with ultrahigh electric properties, large coercive fields and excellent thermal stability may potentially be applied in harsh environments.

A Reconfigurable Rectified Flexible Energy Harvester via Solid‐State Single Crystal Grown PMN–PZT

A single crystal Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMN-PZT) energy harvester is demonstrated by solid-state crystal growth and an optimized delamination process. The flexible harvester generates an output voltage of 100 V and a current of 20 µA. The advanced reconfigurable rectifying circuit enhanced conversion efficiency of the PMN-PZT harvester is compared to conventional rectifier. Finally, a self-powered military boot is fabricated using the harvester as a demonstration of use in operating consumer electronics.

Beryllium, zinc and lead single crystals as a thermal neutron monochromators

The monochromatic features of Be, Zn and Pb single crystals are discussed in terms of orientation, mosaic spread, and thickness within the wavelength band from 0.04 up to 0.5nm. A computer program MONO written in “FORTRAN-77”, has been adapted to carry out the required calculations. Calculations show that a 5mm thick of beryllium (HCP structure) single crystal cut along its (002) plane having 0.6° FWHM are the optimum parameters when it is used as a monochromator with high reflected neutron intensity from a thermal neutron flux. Furthermore, at wavelengths shorter than 0.16nm it is free from the accompanying higher order ones. Zinc (HCP structure) has the same parameters, with intensity much less than the latter.The same features are seen with lead (FCC structure) cut along its (311) plane with less reflectivity than the former. However, Pb (311) is more preferable than others at neutron wavelengths⩽0.1nm, since the glancing angle (θ∼20°) is more suitable to carry out diffraction experiments. For a cold neutron flux, the first-order neutrons reflected from beryllium is free from the higher orders up to 0.36nm. While for Zn single crystal is up to 0.5nm.

Growth and characterization of ferroelectric Pb(Sc1/2Nb1/2)O3 single crystals

Single crystals of Pb(Sc1/2Nb1/2)O3 were grown by the high-temperature solution method using PbO + B2O3 as flux. The size of the as-grown crystals varies from 1 to 2 mm. X-ray diffraction indicates a pure perovskite phase without B-site ordering. Polarized light microscopy shows that the crystals are of rhombohedral symmetry at room temperature and become cubic at TC = 112 °C on heating. A ferroelectric-to-relaxor phase transition is verified at TC by dielectric spectroscopy. Frequency-dependent permittivity is observed in dielectric measurements, revealing relaxor behavior above TC. Poling the crystal at room temperature does not change TC, but suppresses the permittivity. Typical ferroelectric hysteresis loop is displayed at room temperature, indicating the ferroelectric nature of the rhombohedral phase.

Role of Temperature on Flux Trap Behavior in < 100 > Pb Cylindrical Sample: Polarized Neutron Radiography Investigation

The evolution of flux trap behavior at low temperature (the intermediate state) in high purity Lead samples, both in single crystal with < 100 > orientation and polycrystalline form, is investigated using field cooled (FC) neutron tomography measurements. Reported measurements are carried out for 0∘ and 90∘ sample axis orientation with respect to the external magnetic field. For both< 100 > Pb single crystal as well as polycrystalline sample development of fringe pattern below T <Tc (at 5K) is observed. This shows magnetic field trapped within the sample. On increasing the temperature to 7.5K for T >Tc, fringe pattern inside the sample disappears, indicating that the sample attains a normal state. Further comparison of mosaic spread values for < 100 > Pb crystal and our previously reported < 110 > Pb crystal indicate the feeble role played by dislocations and / or defects [Phys. Rev. B 85 184522 (2012)]. Interestingly, not only the field cooled superconducting state appears distinct for each sample, dependent on the crystal structure - single crystal or polycrystalline, but also on the applied magnetic field orientation with respect to the crystallographic sample axis.