Resonance-antiresonance Method Research Articles

Measurement of Piezoelectric Characteristics of Diode Structures Using the «Obzor-103» Vector Analyzer

The results of the study of semiconductor film heterostructures CdS-Cu2S and CdS-ZnS-Cu2S by the resonance-antiresonance method are presented. The semiconductor heterostructures CdS-Cu2S and CdS-ZnS-Cu2S applied on a molybdenum basis were used as samples. The molybdenum base was used as the first current contact. A degenerate p-type Cu2S semiconductor was used as the second current contact. Piezoelectric devices include piezoelectric transducers, based on piezoelectric elements made of the material having a direct or reverse piezoelectric effect.The advantages and disadvantages of resonance antiresonance have been demonstrated. Measurements of the amplitude-frequency characteristics were performed using the vector analyzer "Obzor - 103". The methods of sample research and the procedure of measurements of complex reflection and transmission coefficients with the help of measuring complex "Obzor - 103" are presented. The scheme of measurement of the complex reflection coefficient S11 and the complex transmission coefficient S21 of the four-pole in the 50 Ohm path is presented. Appropriate definitions of complex display and transmission coefficients are given. Using the "Obzor - 103" vector analyzer, the complex reflection coefficients of the S11 samples were measured and the resonance bands from 883 to 1273 MHz were recorded.Based on the determined values of the resonance and anti-resonance frequencies, the figure of merit of the investigated heterostructures and capacitance values were calculated. The calculation was performed using additional data obtained from the study of the samples using the emitter meter "E7-20" under conditions close to the resonance. Comparison of the calculated values shows a significant difference in the behavior of the samples based on CdS and ZnS. Compared to the capacity and figure of merit for the piezoceramic elements presented in OST II 0444-78.The structures studied by us showed significantly lower values of quality and capacity. The much lower values of the figure of merit are explained by the fact that in our work we investigated thin-film structures rather than the volumetric piezo-ceramic elements, the values of which are given in OST II 0444-78.The highest Q-values (~ 62) were obtained for the CdS-ZnS-Cu2S heterostructure. For structures with CdS films, the Q-values is less than 27.94. The Q-value of 62.65 for the CdS-ZnS-Cu2S structure is quite large, even compared to the value for a well-known piezoceramic such as CTS-19, whose Q-value is 60 and which is a bulk material. Thus, studies conducted to evaluate the piezoelectric properties of heterostructures with CdS-Cu2S and CdS-ZnS-Cu2S semiconductor films demonstrate the presence of the piezoelectric properties of these structures and the prospects for their developmentThe results obtained are new and show the prospect of research on semiconductor heterostructures for the development of new piezoelectric devices.

Energy Integration Method for Calculating k eff and its Application in Design Optimization of Disk Resonators via Convex Edge

Piezoelectric resonators have been extensively used as filters, actuator, and sensors. The effective electromechanical coupling coefficient ( [Formula: see text] is the most useful parameter to evaluate the electromechanical conversion efficiency of piezoelectric resonators. However, even for simple geometry piezoelectric resonators, such as disks, the coupling between different modes makes the resonant characteristics very complex. The coupling causes low electromechanical coupling efficiency of the intended mode. We propose a finite-element-based energy integration method to calculate [Formula: see text] of piezoelectric resonators. This method is more accurate than the conventional resonance-antiresonance method and provides a powerful tool for the design optimization of pure mode resonators. A special case studied here is the fundamental thickness extensional (TE) mode of PZT-8 disks in the aspect ratio range of 2-20. Our results showed that multimode coupling near this mode can be greatly suppressed by modifying the edge surface of the disk to a convex shape. Such an optimized design could enhance [Formula: see text] of the fundamental TE mode by as much as 10%-45% depending on the aspect ratio.

Elastic properties and frequency characteristics of a piezo-active 3–0-type corundum-containing composite

A 3–0-type composite, that contains the PZT-type ferroelectric and corundum ceramics, is characterised as a piezoelectric material with relatively stable resonance frequencies for the planar and thickness modes of oscillation. The 3–0-type composite is manufactured by solid state sintering, the resulting composite microgeometry is studied by electronic microscopy, and parameters of the composite are measured by using the resonance-antiresonance method. It is observed that almost equal volume fractions of corundum mc and air pores mp are detected in the composite samples at 0.05 < mc < 0.18. The presence of both the corundum inclusions and air pores at an almost equal volume fraction influences the elastic properties and resonance frequencies. Experimental results on the elastic properties and frequency characteristics of the composite are interpreted in terms of a model that takes into account the electromechanical interaction between the 3–0 ferroelectric ceramic/corundum and 3–0 ferroelectric ceramic/pore regions. Effective electromechanical properties and related parameters of the composite are evaluated in terms of the effective field method and dilute approximation. The studied 3–0-type composite has potential to be applied as an active element of piezoelectric transducers, sensors, and other piezotechnical devices.

Quenching effects on piezoelectric properties and depolarization temperatures of (Bi0.5Na0.5)TiO3-based solid solution systems

Lead-free ferroelectric and piezoelectric ceramics, (Bi0.5Na0.5(1−x)Li0.5x)TiO3 and (1 − y)(Bi0.5Na0.48Li0.02)TiO3–yBaTiO3 (abbreviated as BNLT100x and BNLBT4-100y, respectively), were fabricated by a quenching procedure after sintering, and then their electrical properties were investigated with the aim of increasing their depolarization temperature Td. From the measurements by a resonance–antiresonance method, the electromechanical coupling factors k33 of BNLT100x and BNLBT4-100y were exactly the same after the quenching treatment as compared with the nonquenched one. The Td of all BNLT100x quenched from 1100 °C reached around 240 °C, and they are almost 60 °C higher for x = 0, 0.02, 0.04, and almost 80 °C higher for x = 0.08 than those of nonquenched ceramics. We also found, from the measurement on BNLBT4-100y quenched from 1100 °C, that the Td values were enhanced to higher temperature by the quenching treatment, even in the case of rhombohedral side (100y < 6), tetragonal side (100y > 6), and MPB composition (100y = 6). Moreover, we confirmed that the rhombohedrality 90-α and the tetragonality c/a values were enhanced by the quenching treatment. This result revealed that, even in the tetragonal symmetry, the lattice distortion (tetragonality) could also be stabilized by the quenching treatment in BNT-based solid solution ceramics.

Investigation of La3+ Doping Effect on Piezoelectric Coefficients of BLT Ceramics

AbstractEffects of La3+admixture in barium lanthanum titanate (BLT) ceramics system with colossal permittivity on performance of prospective piezoelectric cold plasma application were studied. Usage of cold atmospheric pressure plasma appears promising in terms of industrial and healthcare applications. Performed investigation provide consistent evaluation of doping lanthanum amount on piezoelectric coefficients values with simultaneous capability of charge accumulation for effective plasma generation. Modification of ferroelectric materials with heterovalent ions, however with the lower radii than the original atoms, significantly affects their domain mobility and consequently electromechanical properties. To determine the piezoelectric coefficients, the resonance-antiresonance method was implemented, and values of piezoelectric and dielectric parameters were recorded. Finally the results indicated that addition of 0.4 mol.% of La3+ions to the ceramic structure maximally increased the values of piezoelectric coefficient tod33= 20 pC/N and to huge dielectric constant toε33T= 29277.

Quenching effects for piezoelectric properties on lead-free (Bi1/2Na1/2)TiO3 ceramics

Lead-free ferroelectric and piezoelectric ceramics, (Bi0.5Na0.5)TiO3 (BNT), were fabricated by a quenching procedure after sintering, and then their electrical properties were investigated with the aim to increase their depolarization temperature Td. From the measurement of the temperature dependence of dielectric properties, Td increased with increasing quench temperature. The Td of a BNT sample quenched from 1100 °C was 223 °C, which was almost 50 °C higher than that prepared by the ordinary cooling process. From the measurement of P–E hysteresis loops, both the remanent polarization Pr and the coercive field Ec of BNT samples prepared by ordinary firing were almost the same as those quenched from 1100 °C. Additionally, from the measurements by a resonance–antiresonance method, the electromechanical coupling factor k33 of ordinarily fired BNT was 0.45, and that of the quenched BNT was 0.46. From these results, it is clarified that the quenching procedure is an effective way to increase the Td of BNT ceramics without deteriorating ferroelectric and piezoelectric properties.

A study of the piezoelectric resonance in organic single crystal: glucuronic acid γ-lactone

An organic nonlinear optical material, namely glucuronic acid γ-lactone or glucuronolactone, was crystallized from aqueous solution. Crystals of large dimensions and full morphology were obtained by slow-cooling method in a custom-built solution growth setup. CHN analysis and X-ray diffraction confirmed the phase formation in the grown crystal. High-resolution XRD studies followed by Rietveld refinement yielded accurate lattice parameters which compared well with the reported values. UV–Vis spectrum recorded for a b-plate of 2 mm thickness revealed the low UV-cutoff at 250 nm. Dielectric constant and dielectric loss were monitored as a function of frequency. Piezoelectric resonance peaks were observed in the range 0.2–1.5 MHz which are dependent on the plate thickness. The temperature dependence of the resonance peak frequency was studied. Piezoelectric coefficients were estimated by resonance–antiresonance method.

Complete electroelastic set for the (YXt)-45° cut of a KNbO3 single crystal

A complete and consistent set (elastic, dielectric, and piezoelectric tensors) of a commercial lead-free (YXt)-45° cut KNbO3 single crystal is reported. These data were obtained using several samples and the resonance-antiresonance method. Particular attention was paid to the consistency of this delivered database. A genetic algorithm with an appropriate criterion was used. Electromechanical characterization revealed a high thickness coupling factor of approximately 60%. These properties make this single crystal a good candidate for several applications such as medical imaging. This complete set provides a basis for simulation designs of such devices integrating this piezoelectric lead-free material, especially for ultrasonic transducers.

Characterization of potassium-modified Li0.12Na0.88Nb0.97Sb0.03O3 lead-free piezoceramics

Potassium modified Li0.12Na0.88Nb0.97Sb0.03O3 (LNNS) based piezoceramics were synthesized by solid state sintering methods. In this work, the substitution of voluminous K+ ions induced a phase transition from orthorhombic to pseudo-tetragonal structure. This transition increased the rattling space in BO6 octahedra, leading to an increase of Curie-temperature (TC). The dielectric behavior above TC was also studied and followed the well-known Curie–Weiss law. The para-ferroelectric phase transition shows the typical displacive ferroelectric behavior and belongs to the first-order phase transition. A set of material constants was characterized by using a resonance–antiresonance method in LNN-based piezoceramics. It was found that the potassium-modifications make a ‘softening’ effect on LNNS-based piezoceramics. Additionally, high piezoelectric voltage coefficient (g33 ∼ 50 mV m/N) was found in LNNS-based ceramics.

Effect of Sintering Temperature on the Electromechanical Properties of (1-x)Pb(ZryTi1-y)O3-xSm(Fe3+0.5, Nb5+0.5)O3 Ceramics

The effect of sintering temperature on the structure and piezoelectric properties of (1-x)Pb(Zry Ti1-y)O3-xSm(Fe3+5+0.5)O3[PZT-SFN] sintered samples, with 0.47≤ y≤ 0.57, was investigated. The samples structure was determined by X-ray diffractometry and the piezoelectric properties by the resonance–antiresonance method. A morphotropic phase boundary (MPB) with optimum piezoelectric properties was found around 0.51≤ y≤ 0.55. The electromechanical coupling factor was maximum for the two samples where y=0.53, kp = 0,63 and y=0.55, kp = 0,631.

Measurements of Acoustical Physical Constants of La3Ta0.5Ga5.3Al0.2O14 Single Crystals at High Temperatures

The dielectric, elastic, and piezoelectric constants of langasite family single-crystal La3Ta0.5Ga5.3Al0.2O14 (LTGA) were measured by combing plane-wave ultrasonic microspectroscopy (PW-UMS) technology with the resonance–antiresonance method in a range from room temperature to 1000 °C. The influence of dielectric loss at high temperatures on resonance and antiresonance frequencies was discussed. At room temperature, the piezoelectric constants d11 and d14 were 6.62 and -4.65 pC/N, respectively. d11 increased to 7.5 pC/N at 1000 °C. The electromechanical coupling factor k12 was about 16.8% in the entire temperature range. All the necessary parameters of the LTGA crystal for acoustic wave applications at high temperatures were determined in this research.

Elastic and Piezoelectric Properties of High-Quality Ferroelectric Bi4Ti3O12 Single Crystals

Piezoelectric properties of ferroelectric Bi4Ti3O12 (BiT) single crystals have been investigated by a resonance–antiresonance method. Large and high-quality single crystals of BiT were obtained via top-seeded solution growth under a high oxygen pressure of 0.9 MPa. The elastic and piezoelectric constants in the (11), (12), (13), and (26) modes for BiT single crystals have been determined for the first time. It is shown that BiT has a large d26 constant of 79 pC/N and a large k26 factor of 40%, indicating that BiT is a promising ferroelectric material for application to shear-mode piezoelectric devices.

Analysis of vibration waveforms of electromechanical response to determine piezoelectric and electrostrictive coefficients

We developed a possible method to determine both coefficients of piezoelectricity (d) and electrostriction (M) at the same time by a waveform analysis of current and vibration velocity in the resonance state. The waveforms of the current and vibration velocity were theoretically described using the equations of motion and piezoelectric constitutive equations, considering the dissipation effect. The dissipation factor of the d coefficient and M coefficient is dielectric loss tangent tan δ. The waveforms measured in all of the ceramics, such as Pb(Zr,Ti)O(3) (PZT), Pb(Mg,Nb)O(3) (PMN), and 0.8Pb(Mg(1/3)Nb2/3)O(3)-0.2PbTiO(3) (PMN-PT), were well fitted with the calculated waveform. This fitting produced both the d and M coefficients, which agreed with those determined via the conventional methods. Moreover, the respective contributions of both piezoelectricity and electrostriction to the d value determined in the resonance-antiresonance method were clarified.

Application testing of Sr doping effect of PZT ceramics on the piezoelectric transformer gain and efficiency proposed for MEMS actuators driving

Effect of Sr content in lead zirconate titanate PZT ceramic system on performance of piezoelectric transformer application were studied. Our experiments provide consistent evaluation of doping strontium amount on piezoelctric coefficients values and final voltage gain and efficiency of piezoelectric transformer. Extreme values of these parameters are preferred for MEMS device effective driving. Modification of ferroelectric materials with isovalent ions, however with the bigger radii than the original atoms, significantly affects their properties. Particularly the electromechanical coefficients of (Pb1-xSrx)(Zr0,70Ti0,30)O3, for mole %’s as x = 0.05, 0.10 and 0.15 ceramics exhibit marked increase, if the PSZT material stoichiometry is near the ferroelectric/relaxor phase boundary. To determine the piezoelectric coefficients, the resonance-antiresonance method was implemented. The results indicated that addition of Sr2+ ions in the amount of 5 mol% in the ceramic structure maximally increased the values of piezoelectric parameter to d31 = 8.2 pC/N and mechanical quality factor Qm = 2902. Finally we demonstrated that in spite of the high piezoelectric coefficients for certain material only the practical examination must be applied in order to draw decisive application conclusions due to the complexity of the double energy conversion in such a specific device as the piezoelectric transformer.

Investigation of dielectric, piezoelectric and ferroelectric properties of b-axis grown triglycine sulphate single crystal

Large single crystal of triglycine sulphate (dimension 100 mm along monoclinic b-axis and 15 mm in diameter) was grown using the unidirectional solution growth technique. The X-ray diffraction studies confirmed the growth/long axis to be b-axis (polar axis). The dielectric studies were carried out at various temperatures to establish the phase transition temperature. The frequency response of the dielectric constant, dielectric loss and impedance of the crystal along the growth axis, was monitored. These are typically characterized by strong resonance peaks in the kHz region. The piezoelectric coefficients like stiffness constant (C), elastic coefficient (S), electromechanical coupling coefficient (k) and d 31 were calculated using the resonance-antiresonance method. Polarization (P)-Electric field (E) hysteresis loops were recorded at various temperatures to find the temperature-dependent spontaneous polarization of the grown crystal. The pyroelectric coefficients were determined from the pyroelectric current measurement by the Byer and Roundy method. The ferroelectric domain patterns were recorded on (010) plane using scanning electron microscopy and optical microscopy.

Preparation and Piezoelectric Properties of (h00)-Oriented BaTiO3 Ceramics by Tape Casting

(h00)-oriented BaTiO3 ceramics were prepared by tape casting using plate-like BaTiO3 particles as a template. XRD results showed that the degree of orientation of the ceramics is increased from 0.0% to 85.3% by the addition of BaTiO3 template from 0 wt% to 15 wt%, then decreased to 40.7% with further increasing the template to 30wt%. Their piezoelectric properties were measured using a resonance–antiresonance method and d33 meter. It is showed that the piezoelectric properties of oriented samples were increased with increasing degree of orientation. The mass fraction of the template was optimized to achieve improved piezoelectric properties, which was found to be 85.3% with a piezoelectric constant d33 of 320 pC/N.

On the dynamic measurement of constants of piezoelectric single-crystal materials

An error in the estimation of piezoelectric material properties can arise when applying the common measurement procedures in the IEEE Standard to determining constants of piezoelectric materials with exceptionally high coupling coefficients, in particular, single-crystal materials. The probable sources of inaccuracy in the resonance-antiresonance method, when applied to bar samples made of single crystals are considered. An additional method of dynamic measurements that helps to avoid the shortcomings of the resonance- antiresonance method is proposed, and its application is illustrated with examples of measurement of single-crystal piezoelements of different compositions.

Nonlinear Shear Response in (K,Na)NbO&lt;sub&gt;3&lt;/sub&gt;-Based Lead-Free Piezoelectric Ceramics

The piezoelectric shear response of 94.0(Ka0.5, Na0.5)NbO3 (KNN) + 5.0LiNbO3 (LN) + 0.5SrTiO3 (ST) + 0.5BiFeO3 (BF) ceramics was investigated by Laser Doppler Vibrometry (LDV) and resonance-antiresonance method. From resonance-antiresonance method, the piezoelectric d15 constant was obtained to be 273 pC/N. The shear strain obtained by LDV at the frequency of 150kHz showed strong nonlinearity. This suggested that the domain contribution to piezoelectric response in shear mode of KNN-LN-ST-BF ceramics existed at the operational frequency for the shear mode divices.

Intrinsic effect of Mn doping in PZN–12%PT single crystals

In this work we study the influence of manganese doping on the electromechanical properties of PZN–12%PT single crystal. The full electromechanical tensor of doped PZN–12%PT in the tetragonal single domain state is determined by the resonance-antiresonance method. Doping leads to a decrease in the dielectric transverse permittivity ε11T and of the shear piezoelectric coefficient d15. We show by dielectric constant ε33T measurements that the single domain state in doped crystal is stable in plates as thin as 90 μm, whereas it was unstable in plates thinner than 300 μm for the undoped crystals. This intrinsic effect is discussed by using a volume effect model based on the symmetry conforming principle of point defects. [Ren, Nature Mater. 3, 91 (2004)]. Mn doping forces the stability of PZN–12%PT single domain state, which makes the doped crystal a most suitable candidate than the pure crystal for high frequency ultrasonic medical imaging probe.

Molten salt synthesis of (K0.47Na0.47Li0.06)NbO3 lead-free piezoelectric ceramics

(K0.47Na0.47Li0.06)NbO3 (KNLN) lead-free ceramics were prepared by molten salt synthesis (MSS) method using k2CO3-Na2CO3 eutectic mixtures as the flux. The microstructure and piezoelectric properties when sintered at 980–1 030 °C were investigated. The calcined powders were examined by X-ray diffraction. The microstructure of the calcined powders and sintered bodies was observed using a scanning electron microscope (SEM).The piezoelectric constant d33 was measured using a quasi-static piezoelectric d33 meter. The planar coupling coefficient Kp was calculated by resonance-antiresonance method. The experimental data for each sample’s performance indicators were the average values of 8 specimens. The relative densities of sintered specimens are above 97%, and the dielectric loss is below 0.03. It was found that (K0.47Na0.47Li0.06)NbO3 prepared by MSS is compact and lead-free. The piezoelectric constant d33 is 216 pC·N−1 and the planar electromechanical coupling factor Kp is 0.352.