Piezoelectric Voltage Constant G33 Research Articles

Biodegradable ferroelectric molecular crystal with large piezoelectric response.

Transient implantable piezoelectric materials are desirable for biosensing, drug delivery, tissue regeneration, and antimicrobial and tumor therapy. For use in the human body, they must show flexibility, biocompatibility, and biodegradability. These requirements are challenging for conventional inorganic piezoelectric oxides and piezoelectric polymers. We discovered high piezoelectricity in a molecular crystal HOCH2(CF2)3CH2OH [2,2,3,3,4,4-hexafluoropentane-1,5-diol (HFPD)] with a large piezoelectric coefficient d33 of ~138 picocoulombs per newton and piezoelectric voltage constant g33 of ~2450 × 10-3 volt-meters per newton under no poling conditions, which also exhibits good biocompatibility toward biological cells and desirable biodegradation and biosafety in physiological environments. HFPD can be composite with polyvinyl alcohol to form flexible piezoelectric films with a d33 of 34.3 picocoulombs per newton. Our material demonstrates the ability for molecular crystals to have attractive piezoelectric properties and should be of interest for applications in transient implantable electromechanical devices.

Piezoelectric response enhancement of w-AlN by Hf (or Zr) and Sc co-alloying: A first principles study

In this report, rigorous calculations based on density functional theory have been performed to study the piezoelectric and elastic properties of wurtzite aluminum nitride (w-AlN) with single- and co-alloying by Hf (or Zr) and Sc. It is found that the (HfSc)0.375Al0.625N and (ZrSc)0.375Al0.625N with stable wurtzite phase, exhibit a piezoelectric coefficient d33 as large as 49.18 pC/N and 47.00 pC/N, respectively. However, the piezoelectric voltage constant g33 and electromechanical coupling constant k233 of HfAlN, ZrAlN, HfScAlN, and ZrScAlN are smaller than that of the ScAlN counterpart, which is due to the large dielectric constant ε33 of Hf (or Zr) alloying samples. Furthermore, the internal parameter u and the bond angle α were calculated to elucidate the brittle-to-ductile transformation in alloying w-AlN crystal structure. Electronic structure calculations show that the bandgap decreases almost linearly concerning the increase of alloying concentration, and the Hf (or Zr) alloying compounds become n-type semiconductors due to the existing high-charge states.

Electrical output performance of PZT-5H under the superposition of temperature, temperature change rate and pulse stress

The static pyroelectric coefficient of PZT-5H thin slice was measured. The effects of temperatures, temperature change rates and pulse stress on the discharge characteristics of PZT under different electrical boundary conditions (open circuit and short circuit) were investigated by an improved split Hopkinson pressure bar system; The effects of temperature change rate and the pulse stress on dynamic piezoelectric coefficient and discharge characteristics of PZT were analyzed. The results show that the static pyroelectric coefficient of the piezoelectric ceramics is 4.16 × 10−8 C/cm2·°C. The piezoelectric voltage constant g33(σ, ∂ΔT), piezoelectric strain constant d33(σ, ∂ΔT), elastic compliance coefficient S and electromechanical coupling coefficient k were obtained by experiments at the given temperature and different temperature change rates.

Piezoelectric Properties of 0-3 Composite Films Based on Novel Molecular Piezoelectric Material (ATHP)2PbBr4.

Since their discovery, ferroelectric materials have shown excellent dielectric responses, pyroelectricity, piezoelectricity, electro-optical effects, nonlinear optical effects, etc. They are a class of functional materials with broad application prospects. Traditional pure inorganic piezoelectric materials have better piezoelectricity but higher rigidity; pure organic piezoelectric materials have better flexibility but havetoo small a piezoelectric coefficient. The material composite, on the other hand, can combine the advantages of both, so that it has both flexibility and a high piezoelectric coefficient. In this paper, a new molecular piezoelectric material (C5H11NO)2PbBr4 with a high Curie temperature Tc and a large piezoelectric voltage constant g33, referred to as (ATHP)2PbBr4, was used to prepare a 0-3 type piezoelectric composite film by compounding with an organic polymer material polyvinylidene fluoride (PVDF), and its ferroelectricity was investigated. The results show that the 0-3 type (ATHP)2PbBr4 piezoelectric composite film has good ferroelectricity and piezoelectricity, and the calculated piezoelectric voltage constant g33 after polarization is about 358.6 × 10−3 Vm/N, which is higher than that of PVDF material, and is important for the fabrication of high-performance piezoelectric sensors.

High-Performance Piezoelectric Characteristics of Sm Substituted Pb(Ni,Nb)O3-Pb(Zr,Ti)O3-Pb(Mg,W)O3 System Ceramics for Ultrasonic Transducer Application

In this paper, in order to develop composition ceramics for an acoustic emission sensor application for nondestructive testing, Pb(Ni,Nb2/3)O3-Pb(Zr,Ti)O3-Pb(Mg,W)O3 [PNN-PZT-PMW] system ceramics were manufactured by conventional mixed oxide method using Li2CO3 and CaCO3 as sintering aids. Their microstructural, dielectric and piezoelectric properties were also investigated. At x = 0.0075 Sm, the substituted specimen sintered at 980 (°C), and high values of piezoelectric properties appeared: the dielectric constant (εr) of 2824, piezoelectric coefficient d33 of 630 [pC/N], planar electromechanical coupling factor kp of 0.665, piezoelectric voltage constant g33 of 25.2 [mV.m/N], and high Curie temperature (Tc) = 270 (°C), respectively. These values were applicable for devices such as acoustic emission sensor and ultrasonic transducer.

Grain size effect on piezoelectric properties of BaTiO3 ceramics

We demonstrated the grain size effect on piezoelectric properties of pure BaTiO3 ceramics. BaTiO3 ceramics with various grain sizes were prepared by conventional and two-step sintering methods. The piezoelectric strain constant d33 increased with decreasing grain size when the grain size was more than 1.2 µm, whereas it decreased when the grain size was below 1.2 µm. The maximum d33 was 460 pC/N, which is approximately three times larger than that of coarse BaTiO3 ceramics. The increase in d33 was well explained by the domain-wall contribution, while the decrease in d33 was understood as the grain boundary effect. On the other hand, the piezoelectric voltage constant g33 increased with decreasing grain size down to 0.6 µm. The piezoelectric constants d33 and g33, and the mechanical quality factor Qm can be controlled by the grain size of BaTiO3 ceramics.

Flexible Semitransparent Energy Harvester with High Pressure Sensitivity and Power Density Based on Laterally Aligned PZT Single-Crystal Nanowires.

A flexible semitransparent energy harvester is assembled based on laterally aligned Pb(Zr0.52Ti0.48)O3 (PZT) single-crystal nanowires (NWs). Such a harvester presents the highest open-circuit voltage and a stable area power density of up to 10 V and 0.27 μW/cm2, respectively. A high pressure sensitivity of 0.14 V/kPa is obtained in the dynamic pressure sensing, much larger than the values reported in other energy harvesters based on piezoelectric single-crystal NWs. Furthermore, theoretical and finite element analyses also confirm that the piezoelectric voltage constant g33 of PZT NWs is competitive to the lead-based bulk single crystals and ceramics, and the enhanced pressure sensitivity and power density are substantially linked to the flexible structure with laterally aligned PZT NWs. The energy harvester in this work holds great potential in flexible and transparent sensing and self-powered systems.

Enhanced structural, dielectric, ferroelectric, and piezoelectric properties of (1−x)Ba0.9Sr0.1TiO3–(x)Ba0.7Ca0.3TiO3 ceramics derived using mechano‐chemical activation technique

AbstractThe effect of Ba0.7Ca0.3TiO3 (BCT) substitution on the structural, dielectric, ferroelectric, and piezoelectric properties of mechano‐chemically synthesized lead‐free (1−x)Ba0.9Sr0.1TiO3‐(x)Ba0.7Ca0.3TiO3 (x=0.0, 0.10, 0.20, 0.35, and 0.50) ceramics have been investigated. XRD patterns confirms the formation of tetragonal phase with P4mm space group. The results indicate a strong influence of BCT substitution on the structural and electrical properties of Ba0.9Sr0.1TiO3 (BST) ceramic. BST–BCT ceramic for x=0.35 have shown high dielectric constant εm~21 800, high remnant polarization Pr~10.16 μC/cm2, large piezoelectric charge constant D33~293 pC/N, large piezoelectric voltage constant g33~5.80 mV·m/N, and highest dielectric breakdown strength Ebd~224 kV/cm among the five synthesized samples. The correlation between structural, dielectric, ferroelectric, and piezoelectric properties of the BST ceramic with increasing BCT content have been systematically described on the basis of domain wall motion and grain size effect.

Investigation of lanthanum substitution in lead-free BNBT ceramics for transducer applications

The influence of lanthanum on structural, dielectric, hysteresis and electric-field-induced strain behavior in lead-free, Bismuth Sodium Barium Titanate (BNBT7) system Bi0.465−xLaxNa0.465Ba0.07TiO3 (x=0.00 to 0.10 in steps of 0.02) near the morphotrophic phase boundary has been investigated. X-ray diffraction confirms the single-phase perovskite structure with co-existence of rhombohedral and tetragonal phases has been observed in all densely packed materials. The diffuse phase transition is evident from the study of the temperature dependence of dielectric constant at different frequencies. All the samples have shown relaxor type behavior. The compositions BNBT7 and lanthanum substituted BNBT7 (x=0.02) have been considered to be suitable for transducer applications on the basis of measured parameters like dynamic piezoelectric constant d*33, 152 and 147 (pm/V), piezoelectric voltage constant g33, 14.36 and 13.37 (10−3mV/N) and coercive field (Ec) is, 14.78 and 9.24 (kV/cm) respectively.

Effect of sintering temperature on structural, dielectric, piezoelectric and ferroelectric properties of sol–gel derived BZT-BCT ceramics

The effects of sintering temperature on the structural, dielectric, piezoelectric and ferroelectric properties of sol–gel derived lead-free 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) piezoelectric ceramics have been reported in this manuscript. BZT-BCT ceramics sintered at 1550°C for 2h resulted in homogeneous and highly dense microstructure with ~96–97% of the theoretical density and grain size of ~10µm. The results indicated a strong influence of the sintering temperature on the structural, dielectric, piezoelectric and ferroelectric properties of BZT-BCT ceramics. BZT-BCT ceramics sintered at 1550°C for 2h resulted in high piezoelectric charge coefficient d33~617pC/N, large planar electromechanical coupling factor kp~54%, large piezoelectric voltage constant g33~11.5mVm/N, high dielectric constant εr~5000, and a low tanδ~0.019. The correlation of dielectric, piezoelectric and ferroelectric properties of the BZT-BCT ceramics with sintering temperature has been explained on the basis of grain size effect and motion of the 90° domain walls.

Square cross-section piezoelectric fiber composites: structure and ferroelectric properties

Square cross-section lead zirconate titanate (PZT5) fibers were fabricated by viscous polymer processing. Fibers were perpendicularly arranged in glass tubes and infiltrated with bisphenol-A epoxy resin E51 to form 1–3 composite structures. Phase, micromorphology, mechanical properties and electric properties were identified for fibers and composites. As a result, PZT5 ceramic fibers sintering at high temperature above 1280 °C have pure trigonal perovskite phase and side length of ~300 μm. A brittle broken mechanism was put forward by the linear stress–strain curves of PZT5 fibers. 1–3 composites with 30 % fiber volume fraction demonstrated closed and saturated P–E loops, high remnant polarization P r of 15.94 μC/cm2 and low coercive field E c of 0.91 kV/mm. Moreover, the composites performed high piezoelectric strain constant d 33, piezoelectric voltage constant g 33 and high anisotropy parameters k t/k p. The acoustic impedance Z was about one-third of PZT5 ceramics. The above performances of PZT5 composites showed an excellent application prospect in the fields of ultrasonic medical imaging systems and nondestructive testing.

Effect of poling process on piezoelectric properties of sol–gel derived BZT–BCT ceramics

Lead free piezoelectric ceramics barium zirconate titanate–barium calcium titanate, [xBZT–(1−x)BCT] (0.48≤x≤0.52), were synthesized by sol–gel method. Calcination of the as-synthesized precursor powders resulted in crystalline powders with single-phase perovskite structure at 700°C, which is significantly lower than that obtained by solid-state reaction. Solid-state sintering at 1450°C resulted in highly dense microstructure with ≥95% of the theoretical density. The effect of electric poling on the piezoelectric properties of the sintered [xBZT–(1−x)BCT] ceramics is studied with varying poling temperatures and poling fields. The results indicated that optimized poling conditions are required in enhancing the piezoelectric properties of [xBZT–(1−x)BCT] ceramics. The morphotropic phase boundary (MPB) composition, 0.5BZT–0.5BCT, showed a high remanent polarization (Pr) of 12.2μC/cm2 and a low coercive field (Ec) of ∼0.14kV/mm. The optimized poling conditions resulted in high piezoelectric charge coefficient d33∼637pC/N, large electromechanical coupling coefficient kp∼59.6%, a large strain of 0.157%, a large piezoelectric voltage constant g33∼29mVm/N for (0.5BZT–0.5BCT) composition. In this report, the excellent piezoelectric properties of the sol–gel derived BZT–BCT ceramics has been analysed and correlated to its structure and poling conditions.

Influence of Strontium Ferrite on Properties of 0-3 Cement-Based Piezoelectric Composites

0-3 cement based piezoelectric composites were fabricated using sulphoaluminate cement as matrix by compressing technique method. The effects of strontium ferrite content on the piezoelectric properties, dielectric properties and acoustic impedance of the composites were studied. The results show that the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composites increase gradually with increaing strontium ferrite content. When the strontium ferrite mass fraction is 0.4%, both of the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composite have the maximum value, and the values are 16.6pC•N-1 and 31.4mV•m•N-1, which are 35% and 19% larger than that of the composite without strontium ferrite doped, respectively. With the strontium ferrite content increase, both of the dielectric constant εr and the dielectric loss tanδ of the composites increase. With the addition of strontium ferrite the acoustic impedance Z increases, but there is no obvious relation between the strontium ferrite content and Z.

Piezoelectric properties of lithium modified silver niobate perovskite single crystals

We report the growth and the piezoelectric properties of lead-free perovskite single crystals of Ag1−xLixNbO3. It possesses a rhombohedral structure with high ferroelectric phase transition (Tc=548K for x=0.086) and large spontaneous polarization (Ps∼40μC∕cm2 for x=0.062) along the ⟨111⟩c direction of pseudocubic perovskite structure for x>0.05–0.06. High quasistatic d33∼210pC∕N and low dielectric constant have lead to a very large value of piezoelectric voltage constant g33∼53.9×10−3Vm∕N for the ⟨001⟩c-cut crystal of this simple perovskite. It has been shown that Li substitution might enhance the piezoelectric coefficient of the crystal. The excellent piezo-/ferroelectricity of this system are considered to be facilitated by the strong polarization nature of both Ag and Li in the perovskite structure. Our findings may stimulate further interests in the development of lead-free piezoelectrics.

An investigation on 1–3 cement based piezoelectric composites

1–3 cement based piezoelectric composites which had good compatibility with civil engineeringstructural materials were fabricated by the cut–fill technique. The piezoelectric, dielectricand ferroelectric properties of the composites were studied. The acoustic impedance of thecomposites was also investigated. The results show that the piezoelectric strain constantd33 and the dielectricconstant ε of the composites increase linearly with the increase of PMNvolume fraction, while the piezoelectric voltage constantg33 presents theopposite trend. The g33 values of the composites are much higher than those of pure PMN. The remnant polarizationPr and thecoercive field Ec of the composite with 27.26% volume fraction of PMN are4.12 µC cm−2 and 4.01 kV mm−1, respectively. By enhancing the PMN volume fraction, the acoustic impedance of thecomposites can be tailored to match that of the civil engineering structural material, i.e.concrete. Therefore, this new kind of composite has potential to be used in civil structurehealth monitoring.

Effects of microstructure on the properties of ferroelectric lead zirconate titanate (PZT) thin films

Lead zirconate titanate (PZT) thin films were prepared with pulsed laser deposition and sol–gel techniques. The PZT films fabricated by these two techniques have similar randomly oriented single perovskite phases, but the film derived from the pulsed laser deposition exhibits a more compact and flat morphology. The dielectric, ferroelectric, and piezoelectric properties of the two kinds of films are comparatively characterized and discussed. It is observed that a denser microstructure would lead to a significantly higher dielectric constant and remanent polarization and a much lower coercive electric field, but only a relatively slight enhancement on the piezoelectric constant. The film with a looser microstructure could have a substantially higher piezoelectric voltage constant g33 due to the much lower dielectric constant. Our results and discussion provide a better understanding of the relationship between the microstructure and the film properties, which is essential in order to tailor the microstructure and hence determine the performance aiming at a specific application.

Micromechanics approach to the magnetoelectric properties of laminate and fibrous piezoelectric/magnetostrictive composites

We use a micromechanics approach to study the magnetoelectric (ME) properties of the piezoelectric/magnetostrictive composite with a 2–2 laminate structure and a 3–1 fibrous structure. It is found that the 3–1 composite has a higher ME coefficient than the 2–2 one, if the volume ratio of piezoelectric material is the same. The reason is that the 3–1 fibrous composite makes use of the longitudinal piezoelectric response and the piezoelectric voltage constant g33 is 2–3 times that of g31. Generally, a smaller volume ratio of the piezoelectric material will generate a higher ME response. The tensile stress at the piezoelectric/magnetostrictive interface of the 3–1 fibrous composite, however, could be high enough to induce plastic deformation or microcracks, which leads to a ME coefficient lower than the theoretically predicted one.

Polarization and piezoelectric properties of ferroelectric grains suspended in a plastic

Abstract Suspended ferroelectric grains may differ from bulk material because of small volume and weak dielectric and elastic interactions. By measurement of the piezoelectric voltage constant g33 it is shown that suspended BaTi03grains 0.5 μm in diameter can be poled to the same degree as coarse grained ceramics. Clamping effects observed in fine grained ceramics therefore must be attributed to interactions between grains.