• 제목/요약/키워드: Perovskite Phase

검색결과 524건 처리시간 0.026초

저온 동시소결을 위한 Ni-Zn-Cu 폐라이트와 Pb(Fe1/2Nb1/2)O3에서의 열적 거동 및 계면층 특성 (Interfacial Layer and Thermal Characteristics in Ni-Zn-Cu Ferrite and Pb(Fe1/2Nb1/2)O3 for the Low Temperature Co-sintering)

  • 송정환
    • 한국전기전자재료학회논문지
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    • 제20권10호
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    • pp.873-877
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    • 2007
  • In order to apply a complex multilayer chip LC filter, this study has estimated the interfacial reaction and coupling properties of dielectric materials $Pb(Fe_{1/2}Nb_{1/2})O_3$ and Ni-Zn-Cu ferrite materials through low-temperature co-sintering (LTCS). PFN powders were fabricated using double calcinated at $700^{\circ}C$ and then $850^{\circ}C$. While the perovskite phase rate was found to be 91 %, after heat treatment at $900^{\circ}C$ for 6h, the perovskite phase rate and density exhibited a value of 100 % and 7.46$g/cm^3$, respectively. The PFN/Ni-Zn-Cu ferrite, PFN/CUO (or $Pb_2Fe_2O_5$) and ferrite/CuO (or $Pb_2Fe_2O_5$) were mechanically coupled through interfacial reactions after the specimen was co-sintered at $900^{\circ}C$ for 6 h. No intermediate layer exists for the mutual coupling reaction. This result indicates the possibility of low-temperature co-sintering without any interfacial reaction layer for a multilayer chip LC filter.

스크린 프린팅법으로 제작한 BSCT 후막의 구조적 특성과 유전적 특성 (Structural and dielectric properties of the BSCT thick films fabricated by the screen printing method)

  • 노현지;이성갑;이창공;남성필;이영희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.167-167
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    • 2008
  • The barium strontium calcium titanate powders were prepared by sol-gel method. Ferroelectric $(Ba_{0.54}Sr_{0.36}Ca_{0.1})TiO_3$(BSCT) thick films were fabricated by the screen-printing method on alumina substrate. And we investigated the structural and dielectric properties of BSCT thick films with the variation of sintering temperature. As a result of thermal analysis, BSCT polycrystalline perovskite phase was formed at around $660^{\circ}C$. The results of X-ray diffraction analysis were showed a cubic perovskite structure without presence of the second phase in all BSCT thick films. The average grain size and the thickness of the specimen sintered at $1450^{\circ}C$ were about 1.6 mm and 45 mm, respectively. The relative dielectric constant increased and the dielectric loss decreased with increasing the sintering temperature, the values of the BSCT thick films sintered at $1450^{\circ}C$ were 5641 and 0.4% at 1kHz, respectively.

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용융염 합성법에 의한 $Pb(Sc_{1/2}Ta_{1/2})O_3$의 제조 (Preparation of $Pb(Sc_{1/2}Ta_{1/2})O_3$, by the molten salt synthesis method)

  • 박경봉;김태희
    • 한국결정성장학회지
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    • 제15권3호
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    • pp.99-103
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    • 2005
  • NaCl-KCl을 flux로 사용한 용융염 합성법을 이용하여 $Pb(Sc_{1/2}Ta_{1/2})O_3$, 분말을 제조하였다. $700^{\circ}C$에서 $800^{\circ}C$의 온도범위에서 상형성 및 분말 상태의 변화를 조사하였다. 용융염 합성법으로 $750^{\circ}C$ 2시간 하소하였을 때, 순수한 페로브스카이트 구조를 가진 $Pb(Sc_{1/2}Ta_{1/2})O_3$ 상이 형성되었으며, 평균 입자 크기는 $0.5\{mu}m$ 이하이고 입방체와 유사한 형상을 갖는 분말이 제조되었다. DIA, X-선 회절 분석, 미세구조 변화를 통해 합성된 분말의 특성을 고찰하였다.

RF 스퍼터링법에 의한 SBT박막의 강유전체 특성 (Ferroelectric Properties of SBT Thin Film by RF Sputtering)

  • 김태원;오열기;김원종;조춘남;김진사;최운식;김충혁;심상흥;이준웅
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 추계학술대회 논문집
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    • pp.217-220
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    • 2000
  • The SrBi$_2$Ta$_2$O$\_$9/(SBT) thin films are deposited on Pt-coated electrode(Pt/TiO$_2$/SiO$_2$/Si) using RF sputtering method. The SBT thin films deposited on substrate at 400-500[$^{\circ}C$]. SBT thin film deposited on Pt-coated electrodes have the cubic perovskite structure and polycrystalline state. With increasing annealing temperature from 600[$^{\circ}C$] to 850[$^{\circ}C$], flourite phase was crystallized to 650[。 and Bi-layered perovskite phase was crystallize ed above 700[$^{\circ}C$]. The maximum remnant polarization and the coercive electric field is 11.73[${\mu}$C/$\textrm{cm}^2$], 85[kV/cm] respectively at annealing temperature of 750[$^{\circ}C$]. The fatigue characteristics of SBT thin films deposited on Pt/TiO$_2$/SiO$_2$/Si substrate did not change up to 10$\^$10/ switching cycles.

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Annealing Effects of Laser Ablated PZT Films

  • Rhie, Dong-Hee;Jung, Jin-Hwee;Cho, Bong-Hee;Ryutaro Maeda
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 하계학술대회 논문집
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    • pp.528-531
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    • 2000
  • Deposition of PZT with UV laser ablatio was applied for realization of thin film sensors and actuators. Deposition rate of more than 20nm/min was attained by pulsed KrF excimer laser deposition, which is fairly better than those obtained by the other methods. Perovskite phase was obtained at room temperature deposition with Fast Atom Beam(FAB) treatment and annealing. Smart MEMS(Micro electro-mechanical system) is now a suject of interest in the field of micro optical devices, micro pumps, AFM cantilever devices etc. It can be fabricated by deposition of PZT thin films and micromachining. PZT films of more than 1 micron thickness is difficult to obtain by conventional methods. This is the reason why we applied excimer laser ablation for thin film deposition. The remanent polarization Pr of 700nm PZT thin film was measured, and the relative dielectric constant was determined to about 900 and the dielectric loss tangent was also measured to be about 0.04. XRD analysis shows that, after annealing at 650 degrees C in 1 hour, the perovskite structure would be formed with some amount of pyrochlore phase, as is the case of the annealing at 750 degrees C in 1 hour.

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Co 및 Ti가 치환된 Layered perovskite의 SOFC 전극에 대한 적용성 연구 (Application of Layered Perovskites Substituted with Co and Ti as Electrodes in SOFCs)

  • 김찬규;신태호;남중현;김정현
    • 신재생에너지
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    • 제18권2호
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    • pp.40-49
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    • 2022
  • In this study, the phase and electrochemical properties of Co and Ti substituted layered perovskites SmBaCo2-xTixO5+d (x=0.5, 0.7, 1.0, 1.1, 1.3, and 1.5) were analyzed, and their application as electrodes in solid oxide fuel cells (SOFCs) were evaluated. After calcination at 1300℃ for 6 h, a single phase was observed for two compositions of the SmBaCo2-xTixO5+d oxide system, SmBaCoTiO5+d (x=1.0) and SmBaCo0.9Ti1.1O5+d (x=1.1). However, the phases of SmBaCoTiO5+d (SBCTO) and SmTiO3 coexisted for compositions with x≥1.3 (Ti content). In contrast, for compositions of x≤0.7, the SmBaCo2O5+d phase was observed instead of the SmTiO3 phase. To evaluate the applicability of these materials as SOFC electrodes, the electrical conductivities were measured under various atmospheres (air, N2, and H2). SBCTO exhibited stable semi-conductor electrical conductivity behavior in an air and N2 atmosphere. However, SBCTO showed insulator behavior at temperatures above 600℃ in a H2 atmosphere. Therefore, SBCTO may only be used as cathode materials. Moreover, SBCTO had an area specific resistance (ASR) value of 0.140 Ω·cm2 at 750℃.

Pb(Mg1/3Nb2/3)O3계의 유전성에 미치는 BaTiO3첨가량 및 열처리 온도의 영향 (PMN-BaTiO3계 세라믹스의 합성 및 유전성) (Influence of BaTiO3 Content and Firing Temperature on the Dielectric Properties of Pb(Mg1/3Nb2/3)O3 Ceramics)

  • 윤기현;강동헌
    • 한국세라믹학회지
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    • 제26권2호
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    • pp.249-257
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    • 1989
  • Dielectric properties and the stability of the perovskite phase in the Pb(Mg1/3Nb2/3)O3 system have been investigated as a function of amount of BaTiO3 and firing temperature. In the specimens fired at 120$0^{\circ}C$, the pyrochlore phase was eliminated by the addition of 10-15m/o BaTiO3 and also the dielectric constant increased. However, the dielectric constant decreased with further addition of BaTiO3 even though no pyrochlore phase was found to be present. The reducing tendency of the pyrochlore phase decreased with lowering the firing temperature in the system of Pb(Mg1/3Nb2/3)O3 with BaTiO3. Dielectric properties in PMN ceramics were affected by the character of the BaTiO3 rather than the pyrochlore phase.

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마이크로파 공정으로 제조된 $LaMnO_3$ 페롭스카이트형 촉매에서 벤젠의 연소반응 (Combustion Characteristics of Benzene over $LaMnO_3$ Perovskite-type Catalysts Prepared Using Microwave-assisted Process)

  • 정원영;홍성수
    • 공업화학
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    • 제24권5호
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    • pp.507-512
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    • 2013
  • 페롭스카이트형 산화물을 마이크로파 공정으로 합성하여 XRD, XPS, BET 및 $H_2-TPR$ 등에 의해 특성분석을 하였고, 벤젠의 연소반응에서의 활성을 조사하였다. 대부분의 촉매들은 페롭스카이트 결정구조를 잘 가지고 있었으며 21 nm 에서 35 nm의 크기를 나타내었다. $LaMnO_3$ 촉매가 가장 높은 활성을 보여주었고 $250^{\circ}C$에서 거의 100%의 전환율을 나타내었으며, 마이크로파 공정으로 제조한 촉매가 기존의 졸-겔법으로 제조한 촉매에 비해 높은 활성을 보여주었다. 또한 소성온도가 증가함에 따라 연소반응의 활성이 증가하였다. 모든 촉매들의 산화환원 성질을 측정한 수소 승온환원 실험 결과는 벤젠의 연소반응의 순서와 잘 일치하였다.

ECR PECVD법에 의한 페로브스카이트상(Pb, La)$\textrm{TiO}_3$ 박막 증착 연구 (A Study on the Fabrication of Perovskite (Pb, La)$\textrm{TiO}_3$ Thin Films by ECR PECVD)

  • 정성웅;박혜련;이원종
    • 한국재료학회지
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    • 제7권1호
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    • pp.33-39
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    • 1997
  • ECR PECVD법에 의해 $Pt/Ti/SiO_{2}/Si$ 다층 기판 위에 $480^{\circ}C$에서 순수한 페로브스카이트상의 PLT박막을 증착하였다. PLT 박막 증착전 ECR산소 플라즈마내에서의 $Pb(DPM)_{2}$ pre-flowing처리는 $Pb(DPM)_{2}$의 공급을 안정화시켜주며 박막증착초기에 Pb성분이 풍부한 분위기를 조성해 줌으로써 페로브스카이트 핵생성을 용이하게 하여 PLT박막 특성을 향상시켰다. Ti-source 유입량을 변화시킬 때 PLT박막의 증착특성, 조성, 결정상 그리고 전기적 특성을 관찰하였다. PLT박막은(100)으로 우선 배향되었으며 화학양론비가 잘 맞는 경우 높은 페로브스카이트 X-선 회절강도와 높은 유전율을 나타내었다.

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Hot-air 공정을 이용한 무기 CsPbl2Br 페로브스카이트 태양전진 제작 연구 (Study of Inorganic CsPbI2Br Perovskite Solar Cell Using Hot-air Process)

  • 김리나;이동건;강동원;김은도;김제하
    • Current Photovoltaic Research
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    • 제10권4호
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    • pp.101-106
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    • 2022
  • We prepared a CsPbI2Br solution using Cesium iodide (CsI), Lead (II) bromide (PbBr2) and Lead (II) iodide (PbI2) materials into a polar solvent mixture of N,N-dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO). A simple spin coating technique was used for the fabrication of CsPbI2Br absorber layer in the solution process. In order to prepare uniform coating of absorber film we adopted a hot-air process in assocation with the spin coating. It was confirmed that the thin film manufactured by the hot-air process had a higher absorption rate than that without it, and the optical band gap was measured 1.93 eV. The thin film of absorber was uniformly prepared and revealed the Black α-Cubic crystal phase as proved through X-ray diffraction analysis. Finally, a perovskite solar cell having an n-i-p structure was manufactured with a CsPbI2Br perovskite absorption layer. From the solar cell, we obtained a power conversion efficiency (PCE) of 5.97% in a forward measurement.