• 소성∙가공
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• 제11권7호
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• pp.569-574
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• 2002

Recently, thick PZT films are required for the cases of micro piezoelectric devices with high driving force, high breakdown voltage and high sensitivity, and so on. In this work, thick PZT films were fabricated by Sol-Gel multi-coating method. Microstructures, and electrical properties of films were investigated by XRD, FESEM, impedance analyzer, and P-E hysteresis. PZT films with 2.7$mu extrm{m}$ to 4.4${\mu}{\textrm}{m}$ thickness were fabricated. Dielectric constant, loss, remnant polarization and coercive field of them were 880~1650 at 1kHz, 2~3% at 1kHz, 26~32 $\mu$C/$ extrm{cm}^2$, and 33~60kV/cm, respectively. Also a transverse piezoelectric coefficient $(e_{31,f})$ measurement system was fabricated and tested for thick film samples.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1326-1331
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• 2003

Thick PZT films are required for the cases of micro actuators and sensors with high driving force, high breakdown voltage and high sensitivity, and so on. In this work, thick PZT films were fabricated by Sol-Gel multi-coating method. Total 8 types of samples using thick PZT films with thicknesses, about $1{\mu}m$ and $2{\mu}m$, and Pt top electrodes shapes for measuring transverse piezoelectric coefficient ($e_{31,f}$) were fabricated using MEMS processes. They were characterized by fabricated e31,f measurement system before and after poling. $e_{31,f}$ values of samples after poling were higher than before poling. Those of $2{\mu}m$ thick PZT films were also higher than $1{\mu}m$ thick PZT films. And those with long electrodes as top electrodes were also higher than shorter.

• 한국전기전자재료학회논문지
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• 제15권12호
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• pp.1054-1059
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• 2002

A great deal of research has been done in the field of characterization for piezoelectric thin films after the first report on the measurement for the piezoelectric coefficient of thin films in 1990. The main idea of this research is to provide a distinctive solution for the measurement and standardization of both the longitudinal and the transverse piezoelectric d-coefficients, d33 and d31, of ferroelectric thin films. In general, to get these two coefficients of thin films, two different measuring systems are required. Here, we propose the improved method for the evaluation of these two coefficients with single equipment and with the relatively convenient procedure. The two-step loading process of applying the both positive and the negative pressure has been introduced to acquire the piezoelectric coefficients. These results have been calibrated for both the longitudinal and 4he transverse piezoelectric d-coefficients, d33 and 431, of thin films by comparison with the virtual standard created from FEM. In this experiments, we have obtained d33 of 331pC/N and 031 of -92.2pC/N for the PZT thin films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.916-919
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• 2000

A great deal of research has been done in the field of characterization for piezoelectric thin films after the first report on the measurement for the piezoelectric coefficient of thin films in 1990. The main idea of this research is to provide a distinctive solution for the measurement of both the longitudinal and the transverse piezoelectric d-coefficients, d$\sub$33/ and d$\sub$3l/, of ferroelectric thin films and also thick films. In general, to get these two coefficients of thin films, two different measuring systems are required. Here, we propose the improved method for the evaluation of these two coefficients with single equipment and with the relatively convenient procedure. The two-step loading process of applying the both positive and the negative pressure has been designed to acquire the piezoelectric coefficients. These results have beer calibrated for both the longitudinal and the transverse piezoelectric d-coefficients, d$\sub$33/ and d$\sub$31/, of thin films. In the first stage of the experiments, we have obtained d$\sub$33/ of 108pC/N and d$\sub$31/ of 57pC/N for the PZT thin films.

• Advances in aircraft and spacecraft science
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• 제2권3호
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• pp.275-302
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• 2015

Theoretical and numerical assessments of approximate evaluations and simplified analyses of piezoelectric structures transverse shear modal effective electromechanical coupling coefficient (EMCC) are presented. Therefore, the latter is first introduced theoretically and its approximate evaluations are reviewed; then, three-dimensional (3D) and simplified two-dimensional (2D) plane-strain (PStrain) and plane-stress (PStress) piezoelectric constitutive behaviors of electroded shear piezoceramic patches are derived and corresponding expected short-circuit (SC) and open-circuit (OC) frequencies and resulting EMCC are discussed; next, using a piezoceramic shear sandwich beam cantilever typical benchmark, a 3D finite element (FE) assessment of different evaluation techniques of the shear modal effective EMCC is conducted, including the equipotential (EP) constraints effect; finally, 2D PStrain and PStress FE modal analyses under SC and OC electric conditions, are conducted and corresponding results (SC/OC frequencies and resulting effective EMCC) are compared to 3D ones. It is found that: (i) physical EP constraints reduce drastically the shear modal effective EMCC; (ii) PStress and PStrain results depend strongly on the filling foam stiffness, rendering inadequate the use of popular equivalent single layer models for the transverse shear-mode sandwich configuration; (iii) in contrary to results of piezoelectric shunted damping and energy harvesting popular single-degree-of-freedom-based models, transverse shear modal effective EMCC values are very small in particular for the first mode which is the common target of these applications.

• E2M - 전기 전자와 첨단 소재
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• 제8권1호
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• pp.27-34
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• 1995

The analysis of nonlinear equivalent circuit and the resonance characteristics of input current and output voltage were simulated, and their electrical properties are discussed in the transverse-type piezoelectric ceramic transformer. The nonlinear resonance characteristics of input current and output voltage showed by the thermal effect due to a higher driving current, the nonlinearity increased greatly as driving current increased. When load resistor was 100[M.ohm.], the nonlinear coefficient was -1.3. The nonlinear resonance curve of input current and output voltage for a variation of input voltage and load resistor agreed with the discussed theory. The output voltage increased nearly proportioned to input voltage when load resistors were below 50[M.ohm.], the voltage step-up ratio decreased when a load resistor was 100[M.ohm.] and their maximum value was 950.

• 한국전기전자재료학회논문지
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• 제14권11호
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• pp.892-897
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• 2001

Variations of dielectric and piezoelectric properties and associated phase transformation of <001> -oriented rhombohedral 0.92Pb (Zn$\sub$1/3/Nb$\sub$2/3/)O$_3$-0.08PbTiO$_3$ single crystals were investigated. The longitudinal strain level was found to abruptly increase at 15 kV/cm, corresponding to that where an induced phase appears within a multidomain matrix. Drastic decreases in the dielectric constant, transverse coupling, and transverse piezoelectric coefficient associated with the E-field induced phase were the result of increased crystal anisotropy in PZN-PT crystals. By contrast, the thickness coupling increased from 53 % at 0 kV/cm to 64 % at 45 kV/cm, also associated with this phase transition under the E-field. The measured dielectric and piezflelectric properties found for the induced phase state were nearly identical to those of <001> poled tetragonal (1-x)PZN-xPT (x>0.1) crystals. Based on these results, it is evident that the symmetry of induced phase is tetragonal.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.965-968
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• 2004

Effective transverse Piezoelectric Coefficients $(e_{31,f})$ of thick PZT $(Pb(Zr_{0.52}Ti{0.48}Ti_{0.48})O_3)$ films on $SiN_x/Si$ substrates were measured with PZT thicknesses and top electrode dimensions. $e_{31,f}$ is one of important Parameters characterizing Piezoelectricity of PZT films. Thick PZT films have been used as various sensors and actuators because of their high driving force and high breakdown voltage. Thick PZT films were fabricated on Pt/Ta/$SiN_x$/Si substrates using sol-gel method. Thicknesses of PZT films were $1{\mu}m$ and $1.8{\mu}m$. $|e_{31,f}|$ values of $1.8{\mu}m$-thick-PZT films were higher than those of $1{\mu}$-thick-PZT films. Maximum $|e_{31,f}|$ of $1.8{\mu}$-thick-PZT films was about $50^{\circ}C/m^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.393-397
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• 2001

A linear ultrasonic motor was designed by a combination of the first longitudinal and fourth bending mode, the motor consisted of a straight aluminum alloys bar bonded with a piezoelectric ceramics element as a driving element. That is, L$_1$-B$_4$ linear ultrasonic motor can be constructed using a multi-mode vibrator of longitudinal and bending modes. The simulation with variation of material characteristics of piezoceramic were performed as use of finite element analysis ANSYS 5.5, such as elastic compliance, piezoelectric constant, electro-mechanical coupling coefficient, poisson's ratio and density. The results of simulation, elastic compliance constant s$_{11}$ and piezoelectric constant d$_{31}$ had the most of influence on the elliptic-motion. This results consist with using transverse effect of material. The used motor were piezoceramics of 4 layers, and the dimensions were 65$\times$5$\times$3.5mm(LxWxt).).

• 대한전자공학회논문지
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• 제11권6호
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• pp.1-15
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• 1974

본 연구는 탄성파 지연선에 이용되는 탄성표면파중에서 SH표면파 모우드에 대하여 이론적 해석을 하였으며 그 결과 전기-기계적 결합계수가 크며 또한 여전 매질내 깊이 방향으로 아주 작은 감쇠률을 갖고 표면을 따라 전파됨을 알았단. 예로서 PZT-4인 경우 에너지의 80%가 감쇠되는 깊이는 190파장이 된다. 또한 탄성표면파 지연선을 하나의 계단자강으로서 취급하여 삽입손실를 구하였으며 특히 SH표면파 모우드와 같이 전기-기계론 결합계수가 큰 경우는 인터디지탈 트랜스듀셔의 전극폭과 윤극간 간격 사이의 비에 따라 중심 주파수가 현저히 달라진다. 그리고 탄성파 지연선의 온도계수를 벌크파인 종파, 횡파에 대하여 구하였으며 LiTaO2 Z축방향 전파의 횡파는 지연시간의 온도계수가 5.4X10-6/℃로 아주 작아짐을 알았다. 또한 LiNbO3의 130°, 64° 로테이트 Y캇트, X전파의 탄성표면파의 온도계수가 이론치와 잘 일치함을 실험적으로 확인하였다.