• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.174.1-174
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• 2002

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1028-1030
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• 1995

In the fields of the optics, precise machine, semiconducting processing, the micro-positioning actuators are required for the control of position in the submicron range. In this study, $Pb(Ni_{1/3}Nb_{2/3})O_3-Pb({Zn}_{1/3}Nb_{2/3})O_3-Pb({Zr}_{1/2}Ti_{1/2})O_3$ ceramics were fabricated by solid state reaction. The structural, dielectric and electric properties were investigated for sintering condition. The specimen sintered at $1,150(^\circ}C)$ for 1hr, had the highest density and dielectric contant. The resistivity, dielectric and density were increased with increasing PZN contents.

• Progress in Superconductivity
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• v.3 no.1
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• pp.74-77
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• 2001

We have fabricated a high-Tc superconductive transistor with polyvinylidene fluoride (PVDF) gate electrode on MgO bicrystal Josephson junction by spin-coating method. The PVDF ferroelectric film is found to be suitable fur a gate electrode of the superconductive transistor since it has not only small leakage current but also high dieletric constant at low temperature. For the application of superconducting-FET, we investigated millimeter wave properties (60 GHz band) of the Josephson junction with PVDF gate electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.213-216
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• 1995

Strontium niobate, $Sr_2Nb_2O_{7}$ was prepared by the molten stilt synthesis (MSS) and the chemical coprecipitation method (CCP). Single phase $Sr_2Nb_2O_{7}$ was obtained by MSS and CCP at $750^{\circ}C$ and $800^{\circ}C$, respectively. An intermediate phase of composition, $Sr_{5}Nb_4O_{15}$, appeared at $700^{\circ}C$ when CCP method was employed. The resulting powder was observed to have finer particles and more uniform distribution of particle sizes, as compared to those obtained through the conventional method. Such powder characteristics allowed the use of a much lower sintering temperature of $1400^{\circ}C$. Grain-orientation along (0k0) direction, which is advantageous for improving dielectric properties, was also observed. The sintering characteristics and the dielectric properties prepared by MSS and CCP, were better than those by the conventional method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.60-60
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• 2008

We manufactured Liquid Crystal Polymer (LCP) and (1-x)$BaTiO_3-xSrTiO_3$(BST) ceramic composites and investigated dielectric properties to use as embedded capacitor in printed circuit boards and replace LTCC substrates. The dielectric properties of these composites are varied with volume fraction of BST and ratios of BT/ST. Dielectric constants are in the range of 3~28. In addition, we could get low TCC and High Q value that could not achieve in other ceramic-polymer composites. Especially, in composite with x=0.4 and 50vol% BST, the dieletric constant and Q-value are 27 and 300, respectively. And more TCC is -116~145ppm/$^{\circ}C$ in the temperature range of -55~$125^{\circ}C$. We think that this composites can be used high-Q substrate material like LTCC and embedded temperature compensation capacitor in printed circuit boards.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.232-233
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• 2007

We manufactured Liquid Crystal Polymer (LCP) and (1-x)CaTiO3-xLaAlO3 (CT-LA) ceramic composites and investigated dielectric properties to use as embedded capacitor in printed circuit boards and replace LTCC substrate. The dielectric properties of these composites are varied with volume fraction of CT-LA and ratios of CT/LA. Dielectric constants are in the range of 3~15. In addition, we could get low TCC and High Q value that could not achieve in other ceramic-polymer composites. Especially, in composite with x=0.01 and 30 vol% CT-LA, the dieletric constant and Q-value are 10 and 200, respectively. And more TCC is $-28{\sim}300ppm/^{\circ}C$ in the temperature range of $-55{\sim}125^{\circ}C$. We think that this composites can be used high-Q substrate material like LTCC and embedded temperature compensation capacitor in printed circuit boards.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.460-463
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• 2003

In this paper, we present the properties of water absorption of elastic epoxy for high voltage. The ratio of water absorption shows linearly increase according to ${\sqrt}t$ till 66 hours. And rigid epoxy is 0.053 [%], elastic epoxy at addictives 35 [phr] is 0.309 and it at addictives 70 [phr] is 0.44 [%]. The reason where absorption of elastic epoxy is high is because of micro void. It can be confirmed by SEM analysis. Dieletric constant increased linearly by addictives' concentration and tans is also increased by addictives' concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.60-63
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• 1997

Dieletric ailed piezoelectric properties of Pb[$Zr_{0.45}$/ $Ti_{0.5-x}$/L $u_{x}$ (M $n_{1}$3//S $b_{2}$3)$_{0.05}$] $O_3$(0$\leq$x $\leq$0.03) were investigated. The partial substitution of $Ti^{4+}$ by a L $u^{3+}$ permitted improvement of the piezoelectric constant( $d_{33}$ ), electromechanical coupling factor ( $k_{p}$ ) and dielectric constant($\varepsilon$$_{33}$ /Sup T/). The dielectric loss(tan $\delta$ ) increased and mechanical quality factor(Qm) decreased with an increase of x were observed. A new piezoelectric material for actuator application was developed at x=0.02 with $d_{33}$ =370$\times$10$^{-2}$ /C/N, $k_{p}$ =58.5%, $\varepsilon$$_{33}$ $^{T}$ =1321, $Q_{m}$ =714 and tan $\delta$ =0.98%.%..%.%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.54-58
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• 1996

In this paper, the structure, dieletric and piezoelectric properties of Pb(Fe$_{\frac{1}{2}}$/Sb$_{\frac{1}{2}}$$O_3$+ Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$system ceramics were investigated and the effects of donor Nb$^{+5}$ on these properties were characterized for the application of the actuator. In xPb(Fe$_{\frac{1}{2}}$Sb$_{\frac{1}{2}}$)O$_3$+ (1-x) Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$system ceramics, tetragonality decreased as x and Nb$_2$O$_{5}$ wt% were increased. In 0.05Pb(Fe$_{\frac{1}{2}}$Sb$_{\frac{1}{2}$}$)O$_3$+ 0.95 Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$system, grain size was smallest but showed best dielectric and piezoelectric properties. The specimen sintered at 120$0^{\circ}C$ in 0.05pb(Fe$_{\frac{1}{2}}$Sb$_{\frac{1}{2}}$ )O$_3$+ 0.95 Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$+ Nb$_2$O$_{5}$ 0.6wt% exihibited best piezoeletric properties such as $K^{p}$ =64%, d$_{33}$ =490 [$\times$10$^{-12}$ C/N] and strain was 1320[$\times$10$^{-6}$ Δ$\ell$/$\ell$]at AC 6kV/cm

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.101-106
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• 1999

Pb$(Zr_{0.5},Ti_{0.5})O_3$ thin films were prepared on $Pt/Ti/SiO_2/Si$substrates by spin-coating. The sol was sonicated in an ultrasonic bath to promoto homogenization and the results were compared with untreated case. In the case of PZT thin films prepared from sonicated sol, only perovskite phase was obtained at $550^{\circ}C$ and "rosette" structures in the films disappeared. Dieletric constants (10kHz), remnant polarization, and coercive field of the films prepared from untreated and sonicated sol were 335 and 443, 12.3 and17.7$\mu$C/$\textrm{cm}^2$, 168.4 and 153.5 kV/cm. Electrical properties were improved by introduction of the sonication processon process