• Transactions on Electrical and Electronic Materials
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• v.6 no.1
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• pp.6-9
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• 2005

Aging characteristics of 0.2PMN-0.8PZT multilayer ceramic actuators (MCA) has been investigated by applying both triangular wave function for unpoled and unipolar wave for poling. P-E hysteresis loops of the MCA had been distorted after about 90 million cycles running in triangular wave function. Effective electromechanical coupling coefficient was calculated in resonant and anti resonant frequencies. And pseudo-piezoelectric constant $d_{33}$ was also estimated from the strain versus electric field characteristics. The crack growth of MCA was clearly observed along to the boundary between electrode and inactive area. That results were thought due to the internal tensile stress came from both actuation of $d_{33}$ mode and motion of Poisson ratio.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1508-1511
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• 1996

In the fields of the optics, precise machine, semiconducting processing, the micro-positioning actuators are required for the control of position in submicron range. In this study, dielectric properties of 0.5PNN-(0.5-x)PZN-xPZT system ceramics with different PZT mole ratio were investigated. As the amount of PZT incerases, curie temperature was increased. The maximum of dielectric and piezoelectric constant was shown at 0.3 mole ratio of PZT amount. As a results, we have found that the structrue of ceramics with PZT 0.3 mole was morphotropic phase boundary.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1627-1629
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• 1996

Polyvinylidene fluoride( : PVDF) has piezoelectric and pyroelectric. The ${\beta}-PVDF$ manufactured by induced-electric field. In accordance to increasing induced-electric field, the 530 $cm^{-1}$ peak decrease, whereas $510cm^{-1}$ peak increase. The dielectric constant of PVDF thin film is 6.8 and 10 MV/m induced-PVDF thin film is 9.4. The dielectric relaxation characteristic of PVDF thin films correspond to Debye's theory.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.9
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• pp.726-730
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• 2001

Temperature stabilities of dielectric constraints and resonant frequencies of the substrates are very important in piezoelectric ceramics oscillators and filters. In this study, it was investigated temperature stability of the length-extensional vibration mode of Pb(Zr$\_$y/Ti$\_$1-y/)O$_3$+x[wt%]Cr$_2$O$_3$ ceramics. The mode can be utilized in fabricating ultra-small 455 kHz IF devices. Addition of Cr$_2$O$_3$ in morphotrophic phase PZT decreased the variations of dielectric constant, electro-mechanical coupling factor k$\_$31/ and resonant frequency by thermal shock. As additive weight of Cr$_2$O$_3$increased, the temperature coefficient of resonant frequency changed from positive number to negative one. And the composition tith temperature coefficient of resonant frequency was shifted to the one with increased Cr$_2$O$_3$ additive weigh by thermal aging.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.70-71
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• 2004

In this paper, in order to develop the low temperature sintering and dielectric properties for piezoelectric transformer, PMW-PNN-PZT ceramics using $B_2O_3$ as sintering aids were manufactured. With increasing the amount of $B_2O_3$ addition, density were increased up to 10mol% $B_2O_3$ addition and then decreased. The variation rate of dielectric constant according to the change of frequency were decreasing by increasing frequency, and in the sintering $1100^{\circ}C$, 20mol% $B_2O_3$ showed $1.32{\times}10^{-1}/kHz$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.234-237
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• 2000

In this paper, the structural, dielectric and piezoelectric properties of the Pb[(S $b_{1}$2/N $b_{1}$2/)$_{0.035}$- $_Mn_{1}$3/N $b_{2}$3/)$_{0.065}$-(Z $r_{0.49}$, $Ti_{0.51}$)$_{0.90}$] $O_3$ ceramics were investigated with respect to the variation of the milling time. Grain size was decreased as the increase of milling time. As the milling time is increased, the particle size of the powder was decreased. Dielectric constant and electromechanical coupling factor (Qm)were slowly increased with the increase of milling time. The highest value of Qm was 1,497 at milling time 8 hour. Temperature coefficient of resonant frequency(TC $F_{r}$) was moved to positive side with the increase of milling time.e.e.e.e.e.e.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.313-316
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• 2003

The lead zirconate titanate, $Pb(Zr_{0:52}Ti_{0:48})O_3$, films of $0.5\;{\mu}m,\;1\;{\mu}m$ and $2\;{\mu}m$ thickness were fabricated on $Pt/Ti/SiO_2/Si$ substrate by the rf magnetron sputtering method. The PZT films were annealed using by a rapid thermal annealing (RTA) method. The thickness dependence of the film structure, dielectric properties, Polarization-electric field hysteresis loops and capacitance-voltage characteristics were investigated over the thickness range of $0.5\;{\mu}m,\;1\;{\mu}m$ and $2\;{\mu}m$. According to the XRD patterns of the films, (110) peak intensity increases with film thickness increased. The increase of PZT films thickness leads to the decrease of the remanent polarization and the dielectric constant.

• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.42-45
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• 2002

Properties of lead zirconate titanate ferroelectric thin films prepared by rapid thermal annealing/direct insertion thermal annealing were investigated. The remnant polarization (Pr), saturation polarization (Ps), and coercive force (Ec) of typical samples annealed by rapid thermal annealing (RTA) are about 13.7 $\mu$ C/cm$^2$, 27.1 $\mu$C/cm$^2$, and 55.6 kV/cm, respectively. The dielectric constant of the sample is about 786, the dielectric loss tangent is about 2.4% at 1 kHz. Furthermore, ferroelectric, conduction, and piezoelectric properties of the thin films annealed by RTA process and the direct insertion thermal annealing (DITA) process were compared. The influence of temperature in the dry process on the above properties was also investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.346-347
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• 2005

In this study, in order to develop the low temperature sintering ceramics, PZT ceramics adding $MnO_2$, $B_2O_3$ were manufactured, and their piezoelectric and dielectric properties is investigated. The results of this study were gotten such as follows. The electromechanical coupling coefficient(kp) showed good properties on the whole, showed its maximum value 28.266 in specimens sintered at 1200[$^{\circ}C$]. The mechanical quality coefficient(Qm) showed its maximum value 162.61 in specimens sintered at 1200[$^{\circ}C$] and was increased by increasing sintering temperature. The dielectric constant showed the optimum values of 538.903 at specimen sintered at $1000^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.380-381
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• 2006

A technique to control the operating frequency of microstrip antenna by using the X-cut quartz substrate has been investigated experimentally and theoretically. We consider 6, 8 and 10 GHz resonance frequency in three dimensional quartz plates. Equation of linear piezoelectricity are solved for the thickness-shear approximation of X-cut quartz plates. At X-band frequencies, the microstrip antenna was voltage-controllable using the dc electric field dependence of the piezoelectric constant of X-cut quartz. This work demonstrates advantageous application for X-cut quartz plate in microstrip antenna substrates.