• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.117-118
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• 1992

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.11
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.46-50
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• 1996

In this paper, xPb(Zn$\_$1/3/Nb$\_$2/3/)O$_3$-yPbTiO$_3$-zPbZrO$_3$-zPbZrO$_3$ (0.5wt%)MnO$_2$ ceramics were fabricated by the mixed oxide method sintered at 1250$^{\circ}C$ for 2[hrs] and then the dielectric and pyroelectric properties were investigated. In 0.10PZN-0.45PT-0.47PZ sample, dielectric constant was 829 and in the case of 01.5PZN-0.45PT-0.40PZ sample, pyroelectric current and pyroelectric coefficient were 0.95 x 10$\^$-7/ [A] and 7.6 x 10$\^$-1/ [C/$\textrm{cm}^2$$.$$^{\circ}C$]. Figure of merits of pyroelectric current and voltage and detectivity, in same sample, has shown good properties, that were 2.4 x 10$\^$-8/[C$.$cm/J], 5.5 x 10$\^$-11/[C$.$cm/J], 1.6 x 10$\^$-8/ [C$.$cm/J].

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.1-5
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• 1995

In this study, a piezoelectric fan was fabricated using piezoelectric element of 0.13PZN-0.41PZ-0.46PT prepared by extruding method. The sizes of the piezoelectric element and the piezoelectric fan were adjust to utilize commercial ac source(100V, 6OHz). The size of the piezoelectric element was $0.26{\times}19.5{\times}45$mm and the resonant frequency and the electromechanical coupling coefficient were 31.26KHz, 31.58% respectively. The size of the piezoelectric fan was $0.62{\times}19.5{\times}78.5$mm and the maximum displacement was 40mm.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.1
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• pp.50-55
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• 1992

Piezoelectric Buzzer which has been generally used requires about 30kV/cm poling process and has the aging effects. In this study, 0.85 PZN - 0.10 BT - 0.05 PT system ceramics with additives of 0 - 2 wt% YS12TOS13T were fabricated and investigated on electromechanical coupling coefficient(kS1pT), electric field induced charge coefficient(dS131T), and sound level. As the results, in the 0.4 wt% YS12TOS13T added composition ceramics compared with the basic, kS1pT was increased from 0.355 to 0.39 and induced piezoelectric d constant increased from 204 to 220 x 10S0-12T (C/N) and sound level of electrostrictive Buzzer has the highest value of 71.5 dB under 8kV/cm bias electric field.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.21-21
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• 2003

Pb(Zn/sub 1/3/Nb/sub 2/3/)O₃(PZN)은 전형적인 완화형 강유전체로서 급격하게 상전이를 일으키는 것이 아니라 온도에 따라 완만하게 변화하는 물질이다. 완화형 강유전체의 경우, 저온에서는 ㎛ 이상의 거시분역이 존재하고 일반적인 강유전체와 유사한 특성을 가지지만, 온도가 증가하면서 거시분역이 불안정해 지고 크기가 자가져서 수 nm 크기의 미소 극성 영역으로 나뉘는데, 이때 결정구조, 유전율, 유전 손실등의 온도와 주파수에 따른 변화를 관찰하여 강유전 상전이 현상의 특징을 살펴보고자 하였다. 이를 위해 본 연구에서는 융제법에 의해 PZN-xPT 단결정을 성장시킨 후 온도에 따른 결정구조를 변화를 측정하고, 이러한 결정구조의 변화가 강유전 특성에 미치는 영향에 대해 알아보았다. 순수한 PZN은 전형적인 완화형 강유전체의 상전이거동을 나타내었으며, PT의 함량이 증가하면서 점차 일반적인 강유전체로 전이하는 것이 관찰되었다. 그러나 PZN-0.12PT의 경우도 완전한 일반적 강유전체는 아니었으며 완화형거동을 일부 나타내었다. 모든 조성에서 온도가 감소하면서 국부적인 응력의 증가가 관찰되었으며, 응력의 인가 정도는 H 함량에 따라 증가하였다. 이상의 변화는 순수한 PEW에서 나타나는 미소분역들이 온도의 감소와 H 양의 증가에 따라 정전기적 상호작용을 일으키면서 강유전분역으로 성장하기 때문이었으며, Vogel-fulture식에 따른 유전율 최대온도와 측정주파수간의 관계는 분역들간의 상호작용을 됫받침해주었다.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.934-942
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• 1990

The quarternary system ceramics 0.5[yPb(Zn1/3Nb2/3)O3-(1-y)Pb(Ni1/3Nb2/3)O3]-0.5[xPbTiO3-(1-x)PbZrO3](PZN-PNN-PT-PZ) was fabricated by the columbite precursor method to obtain a stabilized perovskite structure and by conventional method to evaluate the efficiency of the former methd. Dielectric and piezoelectric properties were investigated and the stability of the perovskite phase was studied as a function of PZN and PT contents and firing temperature. In the samples prepared by the columbite precursor method, the pyrochlore phase, which is detrimental to both the dielectric and piezoelectric properties, was not observed in the absence of PZN, and electric properties were improved even when fabricated at low temperature. By adding PZN, some pyrochlore phase appeared and the morphotropic phase boundary of the samples shifted to more Zr-rich composition. The temperature dependence of piezoelectric constant decreased with the addition of PZN, due to the rising of the Curie point.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.41-44
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• 1998

(1-X)LTC-XHTC composites were manufactured with the variation of X in the range of 0.3 $\leq$X $\leq$0.6 and its dielectric properties were investigated. Here, LTC and HTC are PZN-BT-PT -based ceramics with quire temperature(Tc) of 100。 C-3$0^{\circ}C$, respectively. 0.6HTC-0.4LTC composite ceramics show excellent values of $\Delta$$\varepsilon$$_{r}$/$\varepsilon$[%] which were -7.1% at -2$0^{\circ}C$ and -12% at 5$0^{\circ}C$, respectively. It is thought that composite ceramics with above results can be applied to electrostrictive actuator, high voltage ceramic capacitor etc.mic capacitor etc.r etc.c.

• Electrical & Electronic Materials
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• v.9 no.4
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• pp.351-356
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• 1996

The quartemary system ceramics 0.5[xPb(Zn$_{1}$3/Nb$_{2}$3/)O$_{3}$-(1-x)Pb(Ni$_{1}$3/Nb$_{2}$3/)O$_{3}$]-0.5[yPbTiO$_{3}$-(1-y) PbZrO$_{3}$ for piezoelectric actuators were prepared bv the were added to the raw materials up to 5 mole. Sintering temperature was varied form 1000.deg. C to 1200.deg. C. Sintering characteristrics, dielectric and piezoelectric properties were then investigated. Piezoelectric properties of sample prepared by the molten salt method were improved compared to those prepared by the conventional method. Addition of PZN shifted morphotropic phase boundary to more Zr-rich composition and decreased the piezoelectric properties.

• Journal of the Korean Ceramic Society
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• v.29 no.9
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• pp.675-680
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• 1992

The purpose of this investigation was to study the stability of perovskite structure, the variation of electrical properties and a microstructure with varing amount of PbTiO3 additive in PZN-PT-BT system. The results are as follows: 1. The pyrochlore phase was reduced as the amount of PbTiO3 additive was increased and completely eliminated at 0.15PT in PZN-PT-BT system. 2. The aging rate was increased in proportion to tetragonality because the internal stress was increased in proportion to tetragonality. 3. On increasing the amount of PbTiO3 additive, the Curie temperature was increased in proportion to tetragonality. 4. As the amount of PT in the composition increase, the variation of dielectric constant was sharpened and the diffuseness of the transition decreased.