• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.546-547
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• 2002

Ni thin film on the PMN-PT crystal wafer were deposited by using E-beam evaporator technique. Deposited film was patterned by UV-lithography and etching and was in-diffused at 300~600C. Diffusion profile of Ni ions in PMN-PT was measured by secondary ion mass spectroscopy (SIMS).

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1537-1539
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• 1997

In this study, the dielectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ Ceramics have been investigated as a addition of the amount of $MnO_2(0{\leq}x{\leq}0.9wt%)$. The Temperature-dependant dielectric characteristics of 0.9PMN-0.1PT relaxor ferroelectric system were improved by enhencing the extent of the diffuse phase transition(DPT). The maximum dielectric permittivity decreased by substitution $MnO_2$ and the dielectric loss decreased with increasing $MnO_2$ substitution amount. It is expected decreasing in inner heat energy for temperature with increasing $MnO_2$ substitution.

• Journal of the Korean Ceramic Society
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• v.34 no.6
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• pp.569-576
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• 1997

Electrically-induced strain and polarization studies of the (1-x)Pb(Mg1/3Nb2/3)O3-PbZrO3 crystalline solutions have been done. Dielectric constants with temperature were investigated for 0$\leq$x$\leq$0.95. With increasing PbZrO3 content the transition maxima were found to move to higher temperature region and DPT (Diffused Phase Transition) properties were decreased for x$\leq$0.60. Phase transition between ferroelectric states and antiferroelectric states was confirmed for 0.93$\times$10-3 for 0.4

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.95-98
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• 1998

완화형 강유전체인 0.9MPb*Mg$_{1}$3/Nb$_{2}$3/)O$_{3}$-0.1PbTiO$_{3}$에서 강유전-상유전 상전이에 수반되는 relaxation거동을 살펴보기위해 낮은 전계에서 측정된 유전특성과 높은 전계에서 측정된 전계유기 분극 거동 등을 조사하였다. -50-9$0^{\circ}C$의 상전이 온도범위에 걸쳐 1V/mm의 낮은 전계에서 측정된 유전특성의 온도의존성을 구하고 수 kVmm의 강전계하에서 발생된 분극의 온도의존성을 관찰하였다. 이 모든 결과들은 Vogel-Fulcher관계식에 비교적 정확하게 일치되었으며 그 결과 T$_{f}$ 는 294.6˚K로 나타났다. 본 연구결과를 통하여 Vogel-Fulcher관계식에 의한 주파수 의존성은 낮은 전계하에서의 유전특성 뿐 아니라 강전계하에서의 여러물성들도 동일하게 적용되는 것을 확인할 수 있었다.

• Korean Journal of Materials Research
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• v.7 no.7
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• pp.547-558
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• 1997

Pb(Mg$_{1}$3/Nb$_{2}$3)O$_{3}$[PMN]-PbTiO$_{3}$[PT]계 고용체의 상경계조성(MPB)영역에 대해 La을 첨가하여 변성시킨 La변성 (1-x)PMN-xPT(x=0.35) 고용체를 만들어 온도-유전율 특성, 전계유기 분극특성 및 변위특성을 조사하였다. PMN-PT의 상경영역의 조성인 x=0.35에 대해 La함량을 0-10at%까지 변화시켰다. PMN-PT계 고용체에서 PT 의 함량이 증가함에 따라 전계유기변위 및 히스테리시스 특성이 모두 증가하였다. 전계유기변위 값 $\varepsilon$ 는 능면정과 정방정의 공존영역인 MPB(x=0.35)조성에서 가장 높은 값($\varepsilon$ = 2 x $10^{-3}$)을 보여 주었다. MPB조성에 대해 La을 첨가한 계의 전계유기변위를 조사한 결과 La의 첨가량이 적을 때 (La=0-5at%)는 La의 함량이 증가함에 따라 히스테리시스 특성이 감소하였고 $\varepsilon$ 은 증가하여 고성능의 액튜에이터 재료에 적합한 조성물로 기대된다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.3
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• pp.164-167
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• 2016

In this study, in order to develop relaxor ferroelectric ceramics for refrigeration device application with large electrocaloric effect, PLZT(8/65/35) composition was fabricated using conventional solid-state method. The Curi temperature of this composition PLZT ceramics was $230^{\circ}C$, and the P-E hysteresis loops of the PLZT ceramics as a fuction of temperature became slim by degrees with higher temperatures. The maximum value of ${\Delta}T$ of $0.243^{\circ}C$ in ambient temperature of $215^{\circ}C$ with 30 kV/cm was appeared. It is considered that PLZT ceramics possess the possibility of refrigeration device application.

• Journal of the Korean Ceramic Society
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• v.37 no.1
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• pp.12-20
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• 2000

Dielectric property of Ba-modified 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 ceramics having compositions near the morphotropic phase boundary was investigated. For the specimens having Ba contents between 0 and 20 at%, the average transition temperature was decreased linearly with increasing Ba contents and the degree of hysteresis was also decreased with increasing Ba contents. The maximum dielectric constants (K), electric field induced polarization(P) and electrically-induced strain(S) were found to exihibit a maximum value at∼3 at% of Ba. The increase of S and the decrease of hysteresis by minor additions of Ba impurities indicated the development of new higher perfomance actuator materials. The composition of Ba-PMN-PT (10/65/35) may be appropriate for capacitor materials because of low hysteresis and high polarization.

• Journal of the Korean Ceramic Society
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• v.37 no.1
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• pp.63-69
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• 2000

Electrically-induced strain(S) and polarization(P) for Pb(Sc1/2Nb1/2)O3-PbTiO3(1-x)PSN-xPT) crystalline solutions were studied. From the compositional dependence of S and P we could observe two maximum values at x=0.10 and x=0.425. It is considered that PSNT10(x=0.10) composition is the structural phase boundary to indicate the variable order-disorder[VOD] region. PSNT(x=0.425) composition is the morphotropic phase boundary[MPB] to indicate the rhombohedral to tetragonal phase transition. Higher S (0.437%) and P (0.3974$\mu$C/$\textrm{cm}^2$) values were attained by the La substitution (5 wt%) at Pb site in the MPB composition of 57.5PSN-42.5PT.

• Korean Journal of Materials Research
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• v.6 no.4
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• pp.349-356
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• 1996

완화형 강유전체의 가장 대표적인 PMN계에서 첨가제의 종류와 함량, 측정온도, 인가 전계의형태 등의 변화에 따른 전계인가 변화특성을 광법위하게 조사하였다. Columbite precursor법에의해 분말을 준비하고 고상소결방법에 의하여 모든 시편을 제조하였다. 순수한 PMN에 첨가제로서 PbTiO3와 Pb(Zr, Ti)O3를 첨가한 경우에 완전한 perovskite 구조의 고용체가 형성되었음을 알 수 있었다. T$\varepsilon$max이상에서는 변위의 이력이 크게 발생하는 강유전체의 거동을 보여주었다. 양방향으로 전계를 인가하여 변위를 이용하면 발생 strain은 실온 근방에서 온도에 대하여 안정적이지만 단방향 전계에 따른 변위는 온도에 따라 크기가 변한다는 것을 알 수 있었고 유전상수가 큰 경우가 전왜의 크기 또한 큰 것을 알 수 있었다. 0.9MN-0.1PT와 0.8PMN-0.2PZT의 경우 최대가 되는 온도는 유전율이 최대가 되는 온도보다 더 낮은 온도에서 나타났다.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.159-163
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• 2002

A single phase perovskite relaxor ferroelectric PMN-PT-BT was prepared by a single calcination and the modified mixed oxide process. It was accomplished by ball-milling PbO, $Nb_2O_5,\;Ti(OC_3H_7)_4,\;BaCO_3,\;and\;Mg(NO_3)_2$ instead of MgO, removing the solvent, and then followed by calcination at 900$^{\circ}C$ for 2h. The specimen sintered at 1100$^{\circ}C$/2h showed the sintered density of 7.83 g/$cm^3$, room temperature dielectric constant of 22000, and dielectric loss of 2.5%. Addition of 1.0 mole% (0.3 wt%) of Ag as $AgNO_3$ and followed by calcination at 550$^{\circ}C$/2h lowered the sintering temperature to 900$^{\circ}C$. It still showed the sintered density of 7.88 g/$cm^3$, room temperature dielectric constant of 20000 and dielectric loss of 2.4%.