• 한국세라믹학회지
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• 제37권10호
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• pp.1008-1013
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• 2000

SrTi $O_3$(001) 단결정 기판 위에 졸-겔 스핀코팅으로 $SrBi_2(Ta,Nb)_2O_9$ 박막을 도포하고 그 결정화 과정을 고온 X-선 회절분석 (HTXRD)으로 추적하면서 Pt(111)/Ti/ $SiO_2$/Si 위에 성장한 박막과 비교하였다. SrTi $O_3$(001) 단결정 기판 위에 도포된 $SrBi_2Nb_2O_{9}$ 박막은 fluorite-like phase와 같은 transient phase를 거치지 않고 곧바로 순수한 $SrBi_2Nb_2O_9$ 상으로 결정화가 시작되었으며 결정화가 시작되는 온도인 ${\sim}540^{\circ}C$부터 c축 배향성장하였다. 또한 $SrB i_2(Ta,Nb)_2O_9$ 박막은 Ta/Nb 비에 관계없이 $SrTiO_3$(001) 위에서 모두 $(00{\ell})$로 배향되었으며, 코팅 횟수가 늘어나 필름의 두께가 증가함에 따라 c축 배향성은 미세한 감소를 보였다. $SrBi_2Nb_2O_9/SrTiO_3$단면을 TEM으로 관찰한 결과 $SrBi_2Nb_2O_9$은 대체로 불규칙한 크기의 다결정체로 되어 있었으나 계면 부근에서는 [001]$_{SBN}$//[001]$_{SrTi}$ $O_3$/, [100]$_{SBN}$//[100]$_{SrTi}$ $O_3$/라는 결정학적 관계를 가지며 에피탁샬 성장했음을 알 수 있었다.있었다.

• 한국재료학회지
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• 제11권4호
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• pp.290-293
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• 2001

세라믹 타겟인 Sr$_2$Nb$_2$O$_{7}$ (SNO)과 Bi$_2$O$_3$을 장착한 RF-마그네트론 스퍼터링을 이용하여 SrBi$_2$Nb$_2$O$_{9}$ (SBN) 박막을 p-type Si(100) 기판 위에 증착하였다. 증착시 두 타겟의 파워비를 조절하여 조성의 변화에 따른 SBN 박막의 구조적 및 전기적 특성을 조사하였다. 증착된 SBN 박막은 $700^{\circ}C$의 산소분위기에서 1시간 동안 열처리를 하였으며 상부전극으로 Pt를 증착한 후 산소분위기에서 30분 동안 $700^{\circ}C$에서 전극 후열처리를 실시하였다. 증착된 SBN 박막은 $700^{\circ}C$ 열터리 후에 페로브스카이트 상을 나타냈으며 SNO 타겟과 Bi$_2$O$_3$타겟의 파워가 120 W/100 W 일 때 가장 좋은 전기적 특성을 나타내었다. 이때의 조성은 EPMA(Electron Probe X-ray Micro Analyzer) 분석을 통하여 확인하였으며 Sr:Bi:Nb의 비가 약 1:3:2임을 나타내었다. 이러한 과잉의 Bi조성을 가진 SBN 박막은 3-9 V의 인가전압에서 1.8 V-6.3 V의 우수한 메모리 윈도우 값을 나타내었으며 누설전류 값은 인가전압 5 V에서 1.54$\times$$10^{-7}$ A/$\textrm{cm}^2$였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.346-347
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• 2006

기계적 품질계수(Qm)를 향상시키기 위해 $Y_2O_3$와 $MnO_2$를 첨가함에 따른 $SrBi_2Nb_2O_9$ 세라믹스의 강유전 특성을 알아보았다. 합성분말의 입도를 분석 한 결과 $SrBi_2Nb_2O_9$의 경우 781.27nm였고, $Y_2O_3$와 $MnO_2$를 첨가한 경우 각 각 830.4nm와 981.1nm로 particle size는 증가하였고, 소결 후 소결밀도는 차이가 거의 없었으며, grain size는 $SrBi_2Nb_2O_9$과 $Y_2O_3$를 첨가했을 경우 $1{\mu}m$이하이며 반면, $MnO_2$를 첨가하였을 때 결정립이 성장하여 $3{\sim}4{\mu}m$로 나타났다. 또한, 모두가 $450^{\circ}C$ 이상의 상전이온도를 갖았다.

• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.375-382
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• 2010

A layered perovskite photocatalysts, $SrBi_2Nb_2O_9$ (SBN), was synthesized by the conventional solid-state reaction method and characterized by X-ray diffraction (XRD) and UV-visble spectrophotometry. The results showed that the structure of $SrBi_2Nb_2O_9$ is orthorhombic. Diffuse reflectance spectra for calcined and attrition-milled SBN showed the main absorption edges were less 400 nm, that is ultraviolet region. SBN under micron-sized powder was deposited on the $Al_2O_3$ by room temperature powder spray in vacuum process, so called aerosol deposition (AD), and nano-grained $SrBi_2Nb_2O_9$ photocatalytic thick film was fabricated. AD-deposited SBN thick films were characterized by XRD, scanning electron microscopy (SEM) and UV-visable spectrophotometry, Moreover, it was found that several nano-sized SBN film by AD process can improve the photocatalytic activity under visable reflectance.

• 한국세라믹학회지
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• 제35권10호
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• pp.1040-1048
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• 1998

Ferroelectric properties of{{{{ { { { {SrBi }_{2 }Ta }_{2-x }Nb }_{x }O }_{9 } }} (SBIN) thin films were affected by the amount of Bi content in SBTN. The addition of Bi into the SBTN films could be accomplished by heat treating SBTN/Bi2O3/SBTN het-erostructures fabricated by r.f. magnetron sputtering method. The variation of Bi content was controlled by changing the thickness of the sandwiched Bi2O3 in SBTN/Bi2O3/SBTN heterostructure from 50 to 400$\AA$. As changing the thickness of the sandwiched Bi2O3 in Bi2O3 films was increased from 0 to 100$\AA$ the grain grew faster and the ferroelectric pro-perties were improved. On the other hand when the thickness of Bi2O3 films was thicker than 150$\AA$ the fer-roelectric properties were deteriorated Especially for SBTN thin films inserted by 400$\AA$ Bi2O3 layer a Bi2Phase appeared as a second phase resulting in poor ferroelectric properties. The maximum remanent po-larization (2Pr) and coercive field(Ec) were obtained for the SBTN/Bi2O3/(100$\AA$)/SBTN thin films. In this case 2Pr and Ec were 14.75 $\mu$C/cm2 and 53.4kV/cm at an applied voltage of 3V respectively.

• 한국재료학회지
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• 제13권6호
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• pp.360-364
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• 2003

$Sr_{l}$ $\pm$x/$Bi_{2}$ $\pm$y/$Ta_2$ $O_{9}$ and $Sr_{l}$ $\pm$$Bi_{x}$ $2\pm$y$Nb_2$$O_{9}$ ceramics were prepared by a solid state reaction method. X-ray diffraction analysis indicated that single-phase of Bi-layered perovskite was obtained. According to Sr/Bi content ratio, Curie temperature( $T_{c}$), electromechanical factor($K_{p}$ ) and mechanical quality factor($Q_{m}$ ) were measured. The Curie temperature of SBN(SBT) rose from $414^{\circ}C$(314$^{\circ}C$) to $494^{\circ}C$(426$^{\circ}C$) when Sr/Bi content ratio was increased. In the case of Sr/Bi content ratio = 0.55/2.3, the maximum value of the mechanical quality factor $Q_{m}$ of SBT and SBN were obtained 3320 and 1010, respectively.

• 한국세라믹학회지
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• 제38권11호
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• pp.962-966
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• 2001

Crystal structure of PbBi$_2$Nb$_2$$O_{9}$ and $Sr_{1.2}$$Bi_{1.8}$Ta$_2$$O_{9}$ were determined by Rietveld method using neutron diffraction data in the temperature range of 300 K~1273K. Phase transition temperature were measured from the dielectric permittivitytemperature curve. The PbBi$_2$Nb$_2$$O_{9}$ showed a phase transition at about 810 K. In the Sr-excess compound $Sr_{1.2}$$Bi_{1.8}$Ta$_2$$O_{9}$ the phase transition was suppressed down to room temperature. Several structural models were tested by the Rietiveld refinement. Based on the \`R\` values and the structural parameters, the B2cb model is judged to be the most feasible one for the high temperature phase at above 810 K of the PbBi$_2$Nb$_2$$O_{9}$. The $Sr_{1.2}$$Bi_{1.8}$Ta$_2$$O_{9}$ sample was refined to show the most reliable results by the Am2m model.sults by the Am2m model.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.276-279
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• 2000

Ferroelectric properties of $SrBi_2TaNbO_9$ (SBTN) thin films were changed by the amount of Bi content in SBTN. We suggested that the addition of excess Bi into the films could be accomplished by heat-treating $SBTN/Bi_2O_3/SBTN$ heterostructure fabricated by r.f. magnetron sputtering method. Excess Bi composition was controlled by the thickness of the sandwiched $Bi_2O_3$ from 0 to $400\;\AA$. When the SBTN thin films were inserted by $400\;{\AA}\;Bi_2O_3$ layer, $Bi_2Pt$ phase was formed as a second phase in SBTN films, resulting in poor ferroelectric properties. The onset temperature for hysteresis loop can be reduced by heat treating $SBTN/Bi_2O_3/SBTN$ heterostructure. The films with $SBTN/Bi_2O_3(100\;{\AA})/SBTN$ hetero-structure followed by annealing at $650^{\circ}C$ for 30 min show 2Pr and Ec of $5.66\;{\mu}C/\textrm{cm}^2$ and 54 kV/cm, respectively.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2005년도 춘계학술발표대회 및 제8회 신소재 심포지엄 논문개요집
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• pp.250-250
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• 2005

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.186.1-186
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• 2003