• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.311-312
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• 2007

In this study, composite $BaSrTiO_3$ has been studied for high frequency device applications. Composite $Ba_{0.5}Sr_{0.5}TiO_3$ has high dielectric permittivity and low loss tangent at the relative frequency range from MHz to GHz. 10,30 and 50 wt% of epoxy doped $Ba_{0.5}Sr_{0.5}TiO_3$ powders were prepared with bisphenol A and F polymer employing ball milling process. Epoxy/($BaSrTiO_3$) composites thick films were screen printed on the Cu plated PCB substrates through screen printing methods. The specimens were designed for the embedded capacitor applications. Temperature dependent dielectric permittivity of Epoxy doped $BaSrTiO_3$ ceramics was measured.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.85-87
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• 2002

The $(Ba_xBi_{0.6-x}Sr_{0.4})TiO_3$[x=0.1, 0.2, 0.3] ceramics were prepared by conventional mixed oxide method The structural properties of the $(Ba_xBi_{0.6-x}Sr_{0.4})TiO_3$[x=0.1, 0.2, 0.3] ceramics with the sintering temperature($1200^{\circ}C,\;1250^{\circ}C,\;1300^{\circ}C$) were investigated by XRD, SEM, EDS. Increasing the sintering temperature, the intensity of the $Ba_{0.5}Sr_{0.5}TiO_3$ (100), (110), (111), (200), (310) peaks and $SrBi_4Ti_4O_{15}$ (319), (040) peaks were increased. The gram of the $(Bi_{0.2}Ba_{0.4}Sr_{0.4})TiO_3$ ceramics sintered at $1250^{\circ}C$ were fine and uniform. Increasing the sintering temperature. the average gram size of the $(Bi_{0.2}Ba_{0.4}Sr_{0.4})TiO_3$ ceramics were decreased. The density of $(Bi_{0.1}Ba_{0.5}Sr_{0.4})TiO_3$ ceramics sintered at $1250^{\circ}C$ was 5.4524 [$g/cm^2$].

• 한국세라믹학회지
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• 제30권6호
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• pp.441-448
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• 1993

The Ba1-xSrxTiO3 thin films deposited on ITO-coated glass substrate at 55$0^{\circ}C$ by rf magnetron sputtering method have individual preferential orientations as a function of composition (X=0, 0.25, 0.5, 0.75, 1) due to the stress relief interactions among the intrinsic compressive stress, thermal tensile stress adn extrinsic compressive stress (compressive stress in case of BaTiO3(Tc=12$0^{\circ}C$) and Ba0.75Sr0.25TiO3(Tc=57$^{\circ}C$)). This behavior also appears on the (BaSr)TiO3 thin films (X=0.5) deposited on ITO-coated glass substrate at deposition temperature between 35$0^{\circ}C$ and 55$0^{\circ}C$. The composition of Ba1-xSrxTiO3 thin films deposited on ITO-coated glass substrate at 55$0^{\circ}C$ is close to stoichiometry (1.009~1.089 in A/B ratio), but the compositional deviation from a stoichiometry is larger as SrTiO3 is added. The morphology of Ba1-xSrxTiO3 thin films is very similar for over all substrate temperatures, and the roughness due to the differences of cluster size is the smallest at X=0.25.

• 멤브레인
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• 제22권1호
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• pp.8-15
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• 2012

다공성 $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$로 코팅된 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막은 압출성형 및 dip coating 방법으로 제조 되었다. 코팅된 관형 분리막의 특성은 X-선 회절분석기(XRD)와 전자 주사 현미경(SEM)을 이용하여 분석하였으며, 분석결과 $2{\mu}m$의 다공성 코팅 층을 갖는 페롭스카이트 구조임을 알 수 있었다. 산소투과량 분석은 $750{\sim}950^{\circ}C$ 범위에서 공급측과 투과 측을 대기 중 공기와 진공으로 하여 수행되었다. 다공성의 $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$로 코팅된 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 산소투과량은 $950^{\circ}C$에서 $3.2mL/min{\cdot}cm^2$로 코팅되지 않은 분리막보다 높게 나타났으며, 11일 동안의 장기 안정성 실험결과 코팅 층에 의해 안정성이 증가됨을 알 수 있었다.

• Transactions on Electrical and Electronic Materials
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• 제6권5호
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• pp.210-213
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• 2005

The $BaTiO_3/SrTiO_3$ heterolayered thick films were fabricated by the screen printing method on alumina substrates. The effect of the sintering temperature on the microstructure and dielectric properties of the $BaTiO_3/SrTiO_3$ thick films has been investigated. The relative dielectric constant and dielectric loss at 1 MHz of the $BaTiO_3/SrTiO_3$ heterolayered thick films with sintering temperature of $1350^{\circ}C$ were about 751 and 1.74, respectively. The remanent polarization $(P_r)$ of the pure $(Ba_{0.5}Sr_{0.5})TiO_3$ and $BaTiO_3/SrTiO_3$ heterolayered films are approximately $5.1\;{\mu}C/cm^2$ and $10\;{\mu}C/cm^2$. This study suggests that the design of the $BaTiO_3/SrTiO_3$ heterolayered thick films capacitor with different phase should be an effective method to enhance the dielectric and ferroelectric performance in devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1432-1433
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• 2006

$Li_{2}CO_3$ doped $Ba_{0.5}Sr_{0.5}TiO_3$ ceramics were fabrication by sol-gel method. Sintering temperature must be suited to the LTCC technology. Structure and dielectric properties were investigated for effect of $Li_{2}CO_3$ dopants at BST. Structure of $Li_{2}CO_3$ doped $Ba_{0.5}Sr_{0.5}TiO_3$ ceramics were dense and homogeneous with almost no pore. Relative permittivity was decreased and dielectric loss was increased with increasing $Li_{2}CO_3$ doping rations. In the case of the 3wt% $Li_{2}CO_3$ doped $Ba_{0.5}Sr_{0.5}TiO_3$ ceramics sintered at $900^{\circ}C$, relative permittivity and dielectric loss were 907 and 0.003 at 100 kHz.

• 한국전기전자재료학회논문지
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• 제23권6호
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• pp.454-457
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• 2010

The influence of CuO addition on what of the $(Ba,Sr)TiO_3$ ceramics was studied. The sintering temperature of $(Ba,Sr)TiO_3$ ceramics was lowered by the addition of CuO additives. The 1 - 5 wt% CuO were selected and employed as the sintering aids. Low-Temperature Co-fired Ceramic technologies are popular technologies used in the manufacture of microwave devices. In this study, crystalline and electrical properties of CuO doped $(Ba,Sr)TiO_3$ ceramics were investigated to determine the low temperature sintering properties. The addition of CuO to $(Ba,Sr)TiO_3$ lowered the sintering temperature from $1350^{\circ}C$ to $1150^{\circ}C$. The dependence of the sintering temperature shrinkage rate and mechanism of CuO doped $(Ba,Sr)TiO_3$ ceramics are investigated and discussed. Also, the crystalline structure of CuO - doped $(Ba,Sr)TiO_3$ ceramics is discussed by the X-ray diffraction (XRD) method.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권6호
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• pp.410-415
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• 1999

$Ba_{1-x}Sr_xTiO_3$ thin films with various ratio of Sr (X = 0.4, 0.5, 0.6) were grown $Pt/TiN/SiO_2/Si$ subastrate by RF magnetron sputtering deposition. As, Ag, and Cu films were deposited on $Ba_{1-x}Sr_xTiO_3$ thin films as top electrodes by using a thermal evaporator. The electrical properties of $Ba_{1-x}Sr_xTiO_3$ thin films for various compositions were characterized and the physical properties at interface between $Ba_{1-x}Sr_xTiO_3$ thin films and top electrodes were evaluated in terms of the work function difference. At x =0.5, the degradation of capacitance is lower to the other compositions. As negative biasapplied, the specimen with Cu top electrode has board saturation region and low leakage current since work function of Cu is bigger than other electrodes.$ Ba_{0.5}Sr_{0.5}TiO_3$ thin films with Cu top electrode, the dielectric constant was measured to the value of 354 at 1 kHz and the leakage current was obtained to the value of $5.26\times10^{-6}A/cm2$ at the forward bias of 2 V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.693-696
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• 2001

The (Ba$_{0.3}$Bi$_{0.3}$Sr$_{0.4}$)TiO$_3$[BBST] ceramics were prepared by conventional mixed oxide method. The structural properties of the BBST ceramics with sintering temperature were investigated by XRD, SEM, EDS. In the case of BBST ceramics sintered at 1150~135$0^{\circ}C$, the $Ba_{0.5}$Sr$_{0.5}$TiO$_3$and SrBi$_4$Ti$_4$O$_{15}$ phase were coexisted. The 2$\theta$ value of the BST (110) peaks were shifted to the lower degree at the sintering temperature of 130$0^{\circ}C$ and 135$0^{\circ}C$. The grains of the BBST ceramics sintered at 130$0^{\circ}C$ and 135$0^{\circ}C$ were not appeared. Increasing the sintering temperature, the densities of the BBST ceramics were increased. In the BBST ceramics sintered at 130$0^{\circ}C$ and 135$0^{\circ}C$, the mole ratio of Bi was decreased.d.ed.d.d.d.

• 센서학회지
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• 제19권2호
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• pp.155-159
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• 2010

0.96$(Na_{0.5}K_{0.5})NbO_3$-0.04$(Ba_{(1-x)}Sr_x)TiO_3$ lead free piezoelectric ceramics were synthesized to enhance the piezoelectric properties of (Na,K)$NbO_3$. The systhesis and sintering method were the conventional solid state reaction method and general sintering method in air atmosphere. The polymorphic phase transition(PPT) was observed at all composition(0 $\leq$ x $\leq$ 0.05) when $(Ba_{(1-x)}Sr_x)TiO_3$ were added in the $(Na_{0.5}K_{0.5})NbO_3$. As Sr concentration was increased, grain size, dielectric loss(tan$\delta$) and mechanical quality factor($Q_m$) were decreased and piezoelectric constant($d_{33}$) and electromechanical coupling factor($k_p$) were increased within a limited value. The optimized piezoelectric and properties, $d_{33}$, $k_p$, $Q_m$, and tand, of 0.96$(Na_{0.5}K_{0.5})NbO_3$-0.04$(Ba_{(1-x)}Sr_x)TiO_3$ were 139 pC/N, 0.31 %, 95, 0.04 at the composition of x=0.04.