Piezoelectric Ceramic Pb Research Articles

Improved Tunability in Metglas/Ferrite/PZT Magnetoelectric Tunable Inductors

A tunability-improved magnetoelectric (ME) inductor in the symmetrical composite consisting of spinel Ni–Zn ferrite Ni0.8Zn0.2Fe2O4(NZFO) platelet and piezoelectric ceramics Pb(Zr, Ti)O3 (PZT) slab with Metglas foils laminated was fabricated and systemically characterized. To further improve the tunability in conventional ferrite/PZT inductors, a methodology of Metglas foils laminated with high permeability and magnetostriction was introduced, and thus, significant improvement in inductance tunability was realized. Experimental results show that tunability reaches its maximum in Metglas/ferrite/PZT composite at $L = 2$ and $E = 8$ kV/cm application, exhibiting an enhancement factor of 3.25 times relative to NZFO/PZT/NZFO laminate. Therefore, versatile flexibility on tuning methodology as well as the adjustable range was introduced to provide great potentials for practical applications in compact and power-efficient integrated circuits.

A Passive Electric Current Sensor Based on Ferromagnetic Invariant Elastic Alloy, Piezoelectric Ceramic, and Permalloy Yoke

This paper presented a passive current sensor in an electric power grid. The sensor consists of an iron–nickel-based ferromagnetic invariant elastic alloy (FIEA) beam with high quality factor ( $Q$ -factor), piezoelectric ceramic Pb(Zr,Ti)O3 (PZT8), and a Permalloy yoke. The beam bends in the magnetic field of a current-carrying wire as a result of the magnetostriction of the FIEA, and the PZT8 produces a voltage proportional to the electric current in the wire. The electric current sensitivity is potentially improved due to the high $Q$ -factor of the FIEA/PZT8 beam and the concentration effect of the Permalloy yoke. Experimental data are taken to evaluate the feasibility of the current sensor. At the power frequency of 50 Hz, the sensor shows the linear sensitivities of 300.5, 177.9, 119.2, and 88.8 mV/A from 0.2 to 5 A when the separating distances are 6, 10, 15, and 20 mm, respectively. The performances indicate that the proposed device is promising for power-frequency current sensing applications.

A small linear ultrasonic motor utilizing longitudinal and bending modes of a piezoelectric tube

A small linear ultrasonic motor which consists of a piezoelectric ceramic Pb(Zr,Ti)O3 (PZT) tube (outside diameter 5 mm, inside diameter 3 mm, length 15 mm, acts as stator) and a shaft (acts as slider) has been developed. The outer surface electrode of the PZT tube is divided into 4 parts to excite longitudinal-bending (L1-B2) modes, which could be then used to produce linear motion. The motor shows a high power (force) density. It has a no-load speed of 0.14 m/s, a stall force of 0.3 N, and a maximum output power of 9.3 mW under an applied voltage of 100 Vpp. The method for further improving the performance has been discussed. The proposed motor can be further miniaturized because of its simple structure, and it has potential to be applied to medical microrobots, endoscopes, or micro laparoscopic devices, etc.

Note: A high-sensitivity current sensor based on piezoelectric ceramic Pb(Zr,Ti)O3 and ferromagnetic materials

An electric current sensor using piezoelectric ceramic Pb(Zr,Ti)O3 (PZT) sandwiched between two high permeability cuboids and two NdFeB magnets is presented. The magnetic field originating from an electric wire is augmented by the high permeability cuboids. The PZT plate experiences an enhanced magnetic force and generates voltage output. When placed with a distance of d = 5.0 mm from the wire, the sensor shows a flat sensitivity of ∼5.7 mV/A in the frequency range of 30 Hz-80 Hz and an average sensitivity of 5.6 mV/A with highly linear behavior in the current range of 1 A-10 A at 50 Hz.

Microstructure, temperature stability and electrical properties of ZnO-modified Pb(Ni1/3Nb2/3)O3–Pb(Fe1/2Nb1/2)O3–Pb(Zr0.3Ti0.7)O3 piezoelectric ceramics

Quaternary piezoelectric ceramics Pb(Ni1/3Nb2/3)O3–Pb(Fe1/2Nb1/2)O3–Pb(Zr0.3Ti0.7)O3–xZnO (PNN–PFN–PZT–xZ, x=0.0–0.08 in molar ratio) were prepared by the conventional mixed-oxide method. The effects of ZnO content on the microstructure and piezoelectric properties were systematically investigated. Increasing ZnO additive promotes the phase structure transformation from rhombohedral to tetragonal, indicating the presence of the morphotropic phase boundary in the ZnO-modified PNN–PFN–PZT system. The results show that ZnO doping significantly improves the coercive field (Ec), Curie temperature (Tc), and temperature stability (Δfr/fr 30 °C, Δd31/d31 30 °C) of the PNN–PFN–PZT–xZ ceramics, although the piezoelectric constant (d33, d31) decreases slightly with increasing ZnO content. Taking into consideration the piezoelectric property and temperature stability, the obtained ceramic sample with x=0.04 exhibited favorable properties, which are listed as follows: d33=810 pC/N, kp=0.647, εr=6243, tan δ=2.74%, Ec=4.7 kV/cm, and Tc=136 °C.

Fabrication and analysis of high-performance piezoelectric MEMS generators

In this paper, we have designed a fabrication process for microgenerators by bonding a piezoelectric ceramic Pb(Zr,Ti)O3 (PZT) plate to a silicon on insulator (SOI) wafer. The key techniques of the process include the low-temperature bonding technique using conductive epoxy resin, thinning of the bulk PZT using mechanical lapping and wet-etching combined method, and the micromachining of bulk ceramics by dicing. Through the development and optimization of the process, a piezoelectric MEMS power generator array was successfully fabricated. The typical device is selected to characterize the output performance of the microgenerators, while the composite beam dimension of PZT and silicon layer is about 3080 µm × 800 µm × 31 µm and the dimension of Ni proof mass is about 900 µm × 800 µm × 450 µm. The experimental results show that the output voltage, output power and power density of this device are 2.72 VP-P, 11.56 µW and 28 856.7 µW cm−3 at the resonant frequency of 514.1 Hz when it matches an optimal resistive load of 70 kΩ under the excitation of 1g acceleration. The output performance of this device is higher, compared with that of other reported MEMS power generators, which demonstrates that this novel technique has great potential to fabricate high-performance piezoelectric MEMS energy harvester.

Piezoelectric MEMS generator based on the bulk PZT/silicon wafer bonding technique

AbstractA MEMS‐based piezoelectric energy harvester was fabricated by bonding a piezoelectric ceramic Pb (Zr,Ti)O3 (PZT) plate to silicon wafer. The generator structure of a trapezoidal shape composite cantilever beam with nickel metal mass was designed. The novel fabrication techniques to obtain PZT thick film with excellent piezoelectric properties, including a low‐temperature PZT—Si bonding using epoxy resin as the intermediate adhesive layer and thinning of the bulk PZT ceramics by mechanical lapping and polishing method, were carried out. A piezoelectric MEMS power generator array was successfully fabricated and the measurement results for a microgenerator with typical dimension were also presented. The test result shows that this novel technique has great potential to fabricate high‐performance piezoelectric MEMS energy harvester.

Eddy current induced magnetoelectricity in a piezoelectric unimorph bender

Here, we report on a magnetoelectric (ME) coupling in a simple piezoelectric unimorph bender induced by the eddy currents within the silver electrodes of the piezoelectric ceramic Pb(Zr,Ti)O3 (PZT) subjected to ac magnetic flux. Eddy currents and the applied magnetic field generate Lorentz forces in the metal electrode acting on the PZT. A magnetically induced piezoelectric current linear versus dc magnetic biases is obtained at the ceramic electrodes. ME coupling is finally achieved with only one piezoelectric bender: (i) no magnetic phase is required, (ii) no ac current supply is necessary, eddy currents in electrodes are sufficient to generate Lorentz forces.

Single crystal growth in PMN-PT and PMN-PZT

Single crystal growth of lead-based piezoelectric ceramics Pb(Mg1/3Nb2/3)0.68Ti0.32O3 (PMN-32PT) and Pb(Mg1/3Nb2/3)0.42(Ti0.638Zr0.362)0.58O3 (PMN-37PT-21PZ) ceramics via templated grain growth (TGG) was investigated. (001)- and (111)-oriented BaTiO3 (BT) single crystals and (001)-oriented SrTiO3 (ST) single crystals (of approximately 2.5 × 2.5 × 1 mm) were utilized as seeds for the growth experiments. The piezoelectric single crystals were produced in a process that involves at first hot pressing of single crystal in cold isostatically pressed ceramics followed by subsequent sintering of the samples. Growth of (001)-oriented single crystals with BT seeds was observed in both PMN-32PT and PMN-37PT-21PZ matrices. The measured growth lengths were up to 140 and 65 μm, respectively. The grown (001)-oriented single crystals grown were rectangular. The measured growth lengths of the pyramidal-shaped (111) BT single crystals were up to 1 mm, which is much larger than the growth lengths of the (001) single crystals. Experiments on (001) ST-seeded single crystals were not successful. No single crystal growth was observed due to the dissolution of the ST single crystals in the PMN-PZT matrix. The differences were explained by defect-chemical considerations.

Acoustic transducers with a perforated damping backplate based on PZT/silicon wafer bonding technique

This paper reports on a membrane-type acoustic transducer fabricated by bonding a piezoelectric ceramic Pb(Zr,Ti)O 3 (PZT) plate to a silicon on insulator (SOI) wafer. A special Si backplate with perforated acoustic holes is also bonded to the membrane to broaden the acoustic frequency spectrum. Key techniques in the fabrication include a low-temperature bonding technique using a spin-on polymer, design of electrode interconnect, chemical mechanical polishing (CMP) for thinning down the bulk PZT, and deep reactive ion etching bulk micromachining of silicon. High quality integrated transducers on SOI wafer have been successfully demonstrated and the fabrication and measurement results are presented.

The Influence of DC Electric Field on Piezoelectric Coefficients of PZT Ceramics

The paper deals with the non-linear properties of the piezoelectric ceramics Pb(Zr x Ti 1 − x )O 3 (PZT) at room temperature. The influence of DC electric field on the material parameters, such as piezoelectric coefficients d 31 and d 33 of PZT ceramics, was studied using the resonance method. The dependence of the resonance and antiresonance frequencies of PZT resonators on DC electric field was measured. Hydrostatic piezoelectric coefficients d h , calculated from d 33 and d 31 piezoelectric coefficients, were compared with d h coefficients, that were measured directly by dynamic hydrostatic method. Electric field limits for application on PZT ceramics were determined. A remarkable influence of the DC electric field on d 31 and d 33 piezoelectric coefficients values was exhibited for soft PZT ceramics (APC 850 and APC 856).

Textured PMN–PT and PMN–PZT

A promising way to improve the performance of piezoelectric ceramics is grain orientation by templated grain growth. In this work lead‐based piezoelectric ceramics Pb(Mg1/3Nb2/3)0.68Ti0.32O3 (PMN–32PT) and Pb(Mg1/3Nb2/3)0.42(Ti0.638Zr0.362)0.58O3 (PMN–37PT–21PZ) ceramics were textured via templated grain growth process. For texturization (001)‐oriented BaTiO3 (BT) platelets (approximately 10 μm × 10 μm × 2 μm) were utilized as templates. The texturized ceramics were accomplished by aligning the templates by tape casting. The template growth into the matrix resulted in textured ceramics with Lotgering factors between 0.94 and 0.99 for both compositions. Consequences of the texture are enhanced dielectric and piezoelectric properties. Unipolar strain‐field measurements of textured ceramics showed 0.25% strain s33 at 3 kV/mm. Large signal d33* of up to 878 pm/V were determined directly from strain measurements. Compared with randomly oriented ceramics in texturized samples unipolar strain s33 and large signal d33* was enhanced by a factor of up to 1.8.

Electromechanical coupling coefficient of 0.70Pb(Mg1∕3Nb2∕3)O3–0.30PbTiO3 single crystal resonator with arbitrary aspect ratio

Based on mode coupling theory and the fundamental energy ratio definition of the electromechanical coupling coefficient, a unified formula has been derived to calculate the effective electromechanical coupling coefficient keff of 0.70Pb(Mg1∕3Nb2∕3)O3–0.30PbTiO3 (PMN-30%PT) ferroelectric single crystal cylindrical resonator with arbitrary aspect ratio. The keff dependence on resonator aspect ratio of PMN-30%PT crystal shows similar characteristics as that of the conventional piezoelectric ceramics Pb(ZrxTi1−x)O3 (PZT). However, compared to PZT-5 ceramics, PMN-30%PT single crystal has a smaller aspect ratio where the keff changes dramatically and there is also a stronger coupling between thickness and radial modes causing much larger mode splitting.

Effect of addition of MnO 2 on piezoelectric properties of PNW–PMS–PZT ceramics

The piezoelectric ceramics Pb(Ni 1/2W 1/2)O 3–Pb(Mn 1/3Sb 2/3)O 3–Pb(Ti 1/2Zr 1/2)O 3– x wt% MnO 2 (abbreviated as PNW–PMS–PZT) were prepared by traditional ceramics process. The phase structure of ceramics sintered at 1150 °C was analyzed. Results show that the pure perovskite phase is in ceramics specimens. The effect of MnO 2 doping on dielectric and piezoelectric properties was investigated. When the content of MnO 2 was less than 0.2 wt%, dielectric constant ɛ r, piezoelectric constant d 33 and mechanical quality factor Q m increased, dielectric loss tan δ decreased. When the content of MnO 2 was more than 0.2 wt%, ɛ r, d 33 and Q m decreased, tan δ increased with increasing amount of MnO 2. k p and T c decreased all the while with the amount of MnO 2 increased. The piezoelectric ceramics with 0.2 wt% MnO 2 is suited for high-power piezoelectric transformer, and properties were ɛ r = 2138, tan δ = 0.0058, k p = 0.613, Q m = 1275, d 33 = 380 pC/N, T c = 205 °C.

A transmission electron microscopy study of ferroelectric domains in a modified lead zirconate titanate ceramic

Microstructures of a modified PZT piezoelectric ceramic Pb(Mg1/3Nb2/3)A(Mn1/3Nb2/3)BZrCTiDO3 with A = 0.059, B = 0.066, C = 0.459 and D = 0.416 were investigated using transmission electron microscopy. Labyrinthic domain configurations were observed. In situ observations during heating were carried out in an electron microscope. The effect of electron beam irradiation on the ferroelectric-to-paraelectric phase transition was studied. An essentially one-dimensional array of microdomains and a vein configuration of microdomains were observed in the modified PZT piezoelectric ceramic specimen.