• Journal of the Korean Ceramic Society
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• v.54 no.2
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• pp.150-157
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• 2017

Three types of piezoelectric single crystals [PMN-PT (Generation I $[Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3]$), PMN-PZT (Generation II $[Pb(Mg_{1/3}Nb_{2/3})O_3-Pb(Zr,Ti)O_3]$), PMN-PZT-Mn (Generation III)] were grown by the solid-state single crystal growth (SSCG) method, and their dielectric and piezoelectric properties were measured and compared. Compared to (001) PMN-PT and PMN-PZT single crystals, the (001) PMN-PZT-Mn single crystals exhibited a higher transition temperature between the rhombohedral and tetragonal phases ($T_{RT}=144^{\circ}C$), as well as a higher coercive electric field ($E_C=6.3kV/cm$) and internal bias field ($E_I=1.6kV/cm$). The (011) PMN-PZT-Mn single crystals showed the highest coercive electric field ($E_C=7.0kV/cm$), and the highest stability of $E_C$ and $E_I$ during 60 cycles of polarization measurement. These results demonstrate that both Mn doping (for higher electromechanical quality factor ($Q_m$)) and a (011) crystallographic orientation (for higher coercive electric field and stability) are necessary for high power transducer applications of these piezoelectric single crystals. Specifically, the (011) PMN-PZT-Mn single crystal (Gen. III) had the highest potential for application in the fields of SONAR transducers, high intensity focused ultrasound (HIFU), ultrasonic motors, and others.

• Journal of Sensor Science and Technology
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• v.29 no.1
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• pp.45-50
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• 2020

Magnetoelectric (ME) composites were designed using the PMN-PZT single crystal and Ni foils; the properties and magnetic-field sensitivities of ME composites with different piezoelectric vibration modes (i.e., 31, 32, and 36 modes that depend on the crystal orientation of the single crystal) were compared. In the off-resonance condition, the ME coupling properties of the ME composites with the 32 and 36 piezoelectric vibration modes were better than those of the ME composites with the 31 piezoelectric vibration mode. However, in the resonance condition, the ME coupling properties of the ME composites were almost similar, irrespective of the piezoelectric vibration mode. Additionally, in the off-resonance condition (at 1 kHz), the magnetic-field sensitivity of the ME composites with the 36 piezoelectric vibration mode was up to 2 nT and those of the ME composites with the 31 and 32 piezoelectric vibration modes were up to 5 nT. These magnetic-field sensitivities are similar to those offered by conventional high-sensitivity magnetic-field sensors; the potential of the proposed sensor to replace costly and bulky high-sensitivity magnetic field sensors is significant.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.890-897
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• 2014

This work investigated the electromechanical performance of a cantilevered vibration energy harvester incorporating the single crystal PMN-PZT, manufactured with the most recent technology of solid-state single crystal growth. The performances of single crystal PMN-PZTs with two different crystallographic axes such as [011] and [001] are compared with those of PZT ceramics. From the investigations, it is shown that the [001]-poled PMN-PZT is advantageous for the excitations containing single dominant frequency component, while the single crystal [011]-$d_{32}$ is superior in terms of the energy storage density and energy conversion efficiency.

• Journal of the Korean Ceramic Society
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• v.52 no.1
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• pp.77-82
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• 2015

The effect of the electrode type on the dielectric and piezoelectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbZrO_3-PbTiO_3$ (PMN-PZT) single crystals was investigated in an effort to improve their properties for various piezoelectric applications. First, three different types of PMN-PZT single crystals [PMN-PZT-A (piezoelectrically soft type; dielectric constant ~ 10,000), PMN-PZT-B (piezoelectrically soft type; phase-transition temperature between the rhombohedral and tetragonal phases ($T_{RT}$) ~ $145^{\circ}C$), PMN-PZT-C (piezoelectrically hard type; high mechanical quality factor ($Q_m$) ~ 1,000)] were fabricated using the solid-state single crystal growth (SSCG) method. Then, four different types of electrodes [sputtered Au, sputtered Cr/Au, sputtered Ti/Au, and fired Ag] were formed on the single crystals, and their dielectric and piezoelectric properties were measured. The single crystals with a sputtered Ti/Au electrode showed the highest dielectric and piezoelectric constants but the lowest coercive electric field ($E_C$). The single crystals with a fired Ag electrode showed the lowest dielectric and piezoelectric constants but the highest coercive electric field ($E_C$). This dependence on the type of electrode was most significant in the piezoelectrically hard PMN-PZT-C single crystals. However, the effects of the electrode type on the phase transition temperatures ($T_C$, $T_{RT}$) and dielectric loss were negligible. These results clearly demonstrate that it is important to select an appropriate electrode so as to maximize the dielectric and piezoelectric properties of single crystals in each type of piezoelectric application.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.545-550
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• 2013

Piezoelectric PMN-29PT single crystal multilayer actuators [100 $mm^2$ in cross section and 22 mm in length] are designed and fabricated by stacking square plates [$10{\times}10{\times}0.5(t)\;mm^3$] of PMN-29PT single crystals having a $d_{33}$ of about 1,500 pC/N. The characteristics of PMN-29PT multilayer actuators are compared with those of P-025.40P multilayer PZT ceramic actuators [490 $mm^2$ in cross section and 60 mm in length] produced by PI in Germany. Even though the total volume of the PMN-29PT single crystal multilayer actuator is only about 7.5% of that of the P-025.40P ceramic multilayer actuator, PMN-29PT single crystal multilayer actuators are expected to show very similar properties to P-025.40P ceramic actuators in terms of static stroke and blocking force. Therefore, on the basis of their smaller mass and volume compared to the conventional PZT ceramic multilayer actuators, piezoelectric PMN-29PT single crystal multilayer actuators have significant potential regarding the development of various high performance actuators for aerospace subsystems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.539-543
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• 2014

This work investigated the electromechanical performance of a cantilevered vibration energy harvester incorporating the single crystal PMN-PZT, manufactured with the most recent technology of solid-state single crystal growth. Single crystal PMN-PZTs with two different crystallographic axes such as [011] and [001] were considered. For the [011] orientation, because material properties such as the stiffness, piezoelectric strain coefficients are not the same in the directions normal to the crystallographic axis, the effects of the transversely anisotropy on the magnitude and frequency bandwidth of output power were also analyzed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.17-17
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• 2009

Piezoelectric single crystals in the ternary MPB PMN-PZ-PT system with high $T_cs$ ($T_c$ > $200\sim300^{\circ}C$) and $E_cs$($E_c$>5~10 kV/cm) were fabricated by the cost-effective solid-state crystal growth (SSCG) technique. Chemically uniform PMN-PZT single crystals were successfully grown up to 60 mm by the SSCG method and their dielectric and piezoelectric properties characterized. Compared to Bridgman PMN-PT single crystals, the high $T_c/E_c$ PMN-PZT single crystals were found to exhibit a much wider usage range with respect to electric field as well as temperature, and thus become best candidates for medical transducers, actuators, and naval applications.

• ETRI Journal
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• v.31 no.6
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• pp.688-694
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• 2009

In this paper, we present the results of a preliminary study on the piezoelectric energy harvesting performance of a Zr-doped $PbMg_{1/3}Nb_{2/3}O_3-PbTiO_3$ (PMN-PZT) single crystal beam. A novel piezoelectric beam cantilever structure is used to demonstrate the feasibility of generating AC voltage during a state of vibration. The energy-harvesting capability of a PMN-PZT beam is calculated and tested. The frequency response of the cantilever device shows that the first mode resonance frequency of the excitation model exists in the neighborhood of several hundreds of hertz, which is similar to the calculated value. These tests show that several significantly open AC voltages and sub-mW power are achieved. To test the possibility of a small scale power source for a ubiquitous sensor network service, energy conversion and the testing of storage experiment are also carried out.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1034-1038
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• 2007

In order to develop the composition ceramics capable of being sintered at low temperature with high piezoelectric properties for multilayer piezoelectric actuator application, PZW-PMN-PZT system ceramics were manufactured according to sintering aid $Li_2CO_3$ addition and their microstructural, dielectric and piezoelectric properties were investigated. The crystal structure of the specimens showed a perovskite phase and no pyrochlore or other second phase was detected. At the sintering temperature of $900\;^{\circ}C,\;0.2\;wt%Li_2CO_3$ added specimen showed a optimum values of kp = 0.562, $d_{33}\;=\;360\;pC/N$ and Qm = 1184, respectively.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.127-132
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• 2005

Transducers for implantable hearing aids need to be small and to have good performance in frequency responses and vibration properties. From this viewpoint, we Proposed a multi-layer actuator with the piezoelectric single crystal, PMN-PT. for the implantable hearing aid. and verified its adequacy through finite element analyses and experiments. PMN-PT multi-layer actuator samples were fabricated by stacking fourteen layers of the PMN-PT crystal. Each layer were $0.2{\cal}mm$ thick and the actuator sample was $2.8{\cal}mm$ thick in total. We evaluated the performance of the PMN-PT actuator through impedance analyses and vibration displacement measurements, and compared the result with that of a PZT actuator. Results of all the process confirmed the feasibility of the PMN-PT actuator as a good transducer for an implantable hearing aid.