• 한국세라믹학회지
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• 제26권6호
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• pp.755-762
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• 1989

A pyroelectric ceramic material based on Pb(Sn1/2Sb1/2)O3 modified PZT system is studied as a function of the amount of Pb(Sn1/2Sb1/2)O3 and PbTiO3. With increasing the Pb(Sn1/2Sb1/2)O3 amount the dielectric constant increases up to 10mol% and then decreases, but the pyroelectric coefficient decreases and as the PbTiO3 contents increase in the 10mol% added PZT system, the dielectric constant increases but the infrared sensitivity decreases. The good pyroelectric material has low dielectric constant and no pyrochlore phase, but does not depend in the amount of remanent dipole, and its composition sites around ferroelectric-to-antiferroelectric phase boundary.

• 한국전기전자재료학회논문지
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• 제20권12호
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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.

• Transactions on Electrical and Electronic Materials
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• 제6권2호
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• pp.35-38
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• 2005

Pb(Zr$_{0.8}$Ti$_{0.2}$)O$_{3}$ powders, prepared by the sol-gel method, were mixed with an organic vehicle and the PZT thick films were fabricated by the screen-printing techniques on Pt/Ah03 substrates. The structural properties were examined as a function of sintering temperature. The particle size distribution of the PZT powder derived from the sol-gel process is uniform with the mean particle size of about 2.6 m. As a result of the DTA, the formation of the polycrystalline perovskite phase was observed at around $890^{circ}$CC. In the X-ray diffraction analysis, all PZT thick films showed a perovskite polycrystalline structure without a pyrochlore phase. The perovskite crystallization temperature of PZT thick films was about $890^{circ}$C. The average thickness of the PZT thick films was approximately 80-90 m.

• 한국분말재료학회지
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• 제17권1호
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• pp.59-64
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• 2010

8 mol% Y-doped $SrTiO_3$ powder was synthesized by Pechini method from titanium isopropoxide, strontium nitrate, yttrium nitrate, citric acid and ethylene glycol. A $Y_2Ti_2O_7$ pyrochlore phase-free perovskite powder was obtained by calcining a polymeric resin, which was prepared from a precursor solution, at $500^{\circ}C$ in an air atmosphere. Low temperature calcination could lead to a fine-grained microstructure. In the case of a solid-state reaction, an extended heat-treatment at high temperature in a reduced atmosphere needed to obtain a single phase perovskite $SrTiO_3$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.246-247
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• 2007

(Ba,Sr,Ca)$TiO_3$ powders, which were prepared by sol-gel method using a solution of Ba-acetate, Sr-acetate and Ca-acetate and Ti iso-propoxide, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen-printing techniques on high purity alumina substrates. The structural and dielectric properties were investigated for various $Dy_2O_3$ doping contents. As a result of thermal analysis, the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure and no pyrochlore phase was observed. The average grain size of the specimens decreased with.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.311-314
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• 1999

Ferroelectric PZT heterolayered thin films were fabricated by spin coating method on the Pt/Ti/SiO$_2$/Si substrate using PZT(10/90) and PZT(90/10) metal alkoxide solutions. All PZT heterolayered films showed a homogeneous grain structure without presence of the rosette structure. It can be assumed that the lower PZT layers a role of nucleation site or seeding layer for the formation of the upper PZT layer. Zr and Ti diffusion into the Pt electrode were mainly distributed at the surface of Pt electrode beneath the PZT/Pt interface. The PZT/Pt interfacial layer showed a microstructure characterized by a grain phase surrounded by a Pb-deficient pyrochlore matrix phase. The relative dielectric constant and the dielectric loss of the PZT-6 film were 567 and 3.6, respectively.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.174-176
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• 2012

Piezoelectric 0.93(Na0.5K0.5)NbO3-0.07BiTiO3 (NKN-BTO) ceramics were fabricated by the mixed-oxide method and their structural and dielectric properties was investigated with the variation of sintering temperature. All specimens were crystallized in the perovskite single phase without any formation of a second phase such as pyrochlore. The average grain size of the NKN-BTO specimen sintered at 1130 ℃ is 0.32 ㎛. The specimen sintered at 1100 ℃ showed the highest relative density of 98%. Electromechanical coupling factor, relative dielectric constant and dielectric loss of the NKN-BTO specimens sintered at 1110 ℃ were 0.31, 1222 and 0.02, respectively. Curie temperature of the specimen sintered at 1110 ℃ was 445 ℃.

• 한국세라믹학회지
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• 제35권5호
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• pp.458-464
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• 1998

Variations of reaction sequence of $Pb(Zn_{0.6}Mg_{0.4})_{1/3}Nb_{2/3}O_3$[PZMN] with precusor mixing methods were ex-amined using X-ray diffraction and dielectric characteristics. In the present study three different types of precursor mixing methods (oxide mixing PbO+$ZnNb_2O_6+MgNb_2O_6$[Zn+MN] and PbO+(Zn,Mg)$Nb_2O_6$[ZMN] precursor mixing) were adopted. When the oxide mixing method was used for the PZMN synthesis a Zn-rich perovskite phase and pyrochlore phase were formed. Compared with PbO+ZN+MN precursor mixing method the PbO-ZMN precursor led to a lowering of the formation temperature for perovskite sin-gle phase. These variation of composition and formation temperature of the perovskite phase were dis-cussed in terms of the difference in the solid-reaction requence between these three different types of pre-cursor mixing.

• 한국진공학회지
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• 제7권1호
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• pp.17-23
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• 1998

RF magnetron co-sputtering법으로 PFN[$Pb(Fe_{0.5}Nb_{0.5}O_3(PFN)$]박막을 제조한 후 급속 열처리(rapid thermal annealing, RTA)하여 XRD(s-ray diffractometer)를 통한 박막의 상변 태 및 전기적 특성에 대하여 연구하였다. $SiO_2$/Si, ITO/glass, 및 Pt/Ti/$SiO_2$/Si기판에 PFN 박막을 증착시켰다. 기판의 변화에 따른 증착된 PFN박막의 조성변화는 관찰할 수 없었다. ITO/glass기판을 사용한 경우와 $SiO_2$/Si기판을 사용하여 증착시킨 PFN박막의 결정구조를 분석한 결과 ITO/glass기판에 증착한 시편이 perovskite상으로의 결정화가 더욱 우세하였다. 이는$SiO_2$기판의 경우 Pb의 확산에 의해 결정화가 잘 되지 못하기 때문이다. Pt/Ti/$SiO_2$/Si 기판 위에 증착시킨 PFN박막의 경우 perovskite상과 pyrochlore상이 공존하였다. Perovskite 상으로의 상변태에 대한 중요한 변수로는 열처리 온도와 Pb의 함량인 것이 확인되었으며, Pb의 함량이 화학양론적 조성비에 비해 5-10%정도 과량일수록 perovskite상으로의 상변태 온도가 낮아지고 상전이 정도가 향상되는 것으로 나타났으며, 급속 열처리 후 XRD를 이용 한 결정성 분석결과를 통해 결정한 perovskite상으로의 상전이 최저온도는 $500^{\circ}C$였다. Pb/(Fe+Nb)의 조성비가 1.17인 경우의 박막을 질소 분위기 하에서 $600^{\circ}C$로 30초간 급속열 처리 하였을 때 낮은 누설 전류 값과 1kHz에서 88의 유전 상수 값, 2.0$\mu$C/$\textrm{cm}^2$의 잔류 분극 값과 144kV/cm의 항전계 값을 얻었다.

• 한국세라믹학회지
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• 제32권6호
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• pp.748-760
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• 1995

Pyroelectric properties, figure of merits, and the other properties of the Pb(Zn1/3Nb2/3)O3-Pb(Fe1/2Nb1/2)O3 system, as expected to have excellent pyroelectric properties in the operating temperature range of pyroelectric type infrared sensor, were investigated. In the Pb(Zn1/3Nb2/3)O3-Pb(Fe1/2Nb1/2)O3 system, suppression of the pyrochlore phase depended on sintering condition, as like sintering temperature, holding time, sintering atmosphere. The specimen, sintered by the same composition atmosphere powder at 105$0^{\circ}C$ for 1.5h, possessed the best physical property. It was found that the piezoelectric parameters were mainly depended on the amount of spontaneous polarization and then the 0.2PZN-0.8PFN showed the best pyro- and piezoelectric properties. In terms of the experimental method, two pyroelectric-testing methods, i.e. static and dynamic methods, had a same tendency. Also the result of pyroelectric testing by the static method indicated that the diffuse phase transitiion resulted in the temperature difference of phase transition between dielectric constant and pyroelectric coefficient.