• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.39-40
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• 2005

Ferroelectric Eu-substituted $Bi_4Ti_3O_{12}$ (BET) thin films with a thickness of 200 nm were deposited on Pt(111)/Ti/SiO$_2$/Si(100) substrate by means of the liquid delivery MOCVD system and annealed at several temperatures in an oxygen atmosphere. At annealing temperature above $600^{\circ}C$, the microstructure of layered perovskite phase was observed. The remanent polarization of these films increased with increase in annealing temperature. The remanent polarization values ($2P_r$) of the BET thin films annealed at $720^{\circ}C$ were $37.71{\mu}C/cm^2$ at an applied voltage of 5 V.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.184-186
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• 2009

Composites of LSCF($La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ and CGO(gadolinium doped ceria) is an efficient candidate cathode material with CGO electrolytes. In this study, LSCF with exact perovskite structure was synthesized by using solid state reaction(SSR) method. The optimized temperature to synthesize $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ with rhombohedral structure. was $1100^{\circ}C$. The polarization resistance of the LSCF/CGO(50:50 wt.%) was smaller than those of other composite cathodes. The analysis of the EIS data of LSCF/CGO suggests that the diffusion and adsorption-desorption of oxygen can be the key process in the cathodic reaction of SOFC using LSCF/CGO as cathode material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.114-117
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• 2001

$(Ba_{0.6-x}Sr_{0.4}Ca_x)TiO_3$(x=0.10, 0.15, 0.20) ceramics were fabricated by the mixed-oxide method and their structural and dielectric properties were investigated with variation of composition ratio and sintering temperature. As a result of the differential thermal analysis(DTA), exothermic peak was observed at around $1020^{\circ}C$ due to the formation of the polycrystalline perovskite phase. BSCT(50/40/10) specimen sintered at $1500^{\circ}C$ showed the highest average grain size(18.25$[{\mu}m]$). Curie temperature and dielectric constant at room temperature decreased with increasing amount of Ca. BSCT(50/40/10) specimen sintered at $1450^{\circ}C$ showed a good dielectric constant, K, (=4324) and dielectric loss, $tan{\delta}$, (=0.972%) properties at 1[KHz].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.83-86
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• 1998

Ferroelectric PZT(40/67)/PZT(60/40)heterolayered thin films were Prepared by the alkoxide-based Sol-Gel method. PZT(40/60) and PZT(60/40) stock solutions were made and spin-coated on the P7Ti/Si02/Si substrate alternately. These PZT(40/60) and PZT(60/40) films were dried at 300$^{\circ}C$ for 30min to remove organic materials and were sintered at 650$^{\circ}C$ for 1 hour to crystalize into a perovskite structure. The coating and heating procedure were repeated 6 times to form heterolayered films. Increasing the number of coating, coercive field was decreased. The relative dielectric constant, loss, remanent polarization and coercive field of the 4-coated PZT heterolayered were 1200, 4.1[%], 30.794[${\mu}$C/㎡] and 147.22[kV/cm], respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.109-112
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• 1999

The PZT(10/90)/(90/17) heterolayered thin films were fabricated by the spin-coaling on the Pt/Ti/SiO$_2$/Si substrate using the PZT(10/90) and PZT(70/10) metal alkoxide solutions. The effect of heterolayered thin films on the ferroelectrics and electrical properties have been investigated. The lower PZT layers provided the nucleation site for the formation of a perovskite phase of the upper PZT films. Dielectric constant increased with increasing the number of coatings, and it was about 569.9 at PZT-6 heterolayered films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.649-652
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• 1999

The (Ba, Sr)TiO$_3$(BST) thin films were fabricated on Pt/Ti/SiO$_2$/Si substrate by RF sputtering technique. The structural properties of the BST thin films were investigated with substrate temperature by XRD, SEM, EDS and AES depth profils. Increasing the substrate temperature, barium multi titanate phases were decreased. The BST thin film had a structure of perovskite type, and had peaks of (100), (200) at the substrate temperature of 50$0^{\circ}C$. When the BST thin films were deposited at the substrate temperature of 50$0^{\circ}C$, the composition ratio of Ba/sr was 52/48.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.304-307
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• 1999

The Mg($_{1-x}$ )S $r_{x}$Ti $O_3$(x=0.1,0.2,0.3) ceramics were prepared by the conventional mixed oxide method. The structural properties were investigated with calcining temperature and composition ratio by XRD and DT-TGA. Increasing the calcining temperature from 80$0^{\circ}C$ to 100$0^{\circ}C$, second phase was decreased and average particle size was increased. The SrTi $O_3$ ceramics of calcined at 100$0^{\circ}C$ had a structure of polycrystalline perovskite without the secondary phases. The average particle size of the $Mg_{0.9}$S $r_{0.1}$Ti $O_3$ ceramics calcined at 100$0^{\circ}C$ were 0.67${\mu}{\textrm}{m}$..>......

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.897-900
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• 2000

Annealing dependencies of the fatigue properties of SrBi$_2$Ta$_2$$O_{9}$ thin films were observed as function of substrate temperature(400-50$0^{\circ}C$) by the rf magnetron sputtering method. With increasing annealing temperature from $600^{\circ}C$ to 85$0^{\circ}C$, flourite phase was crystalized to $650^{\circ}C$ and Bi-layered perovskite phase was crystalized above $700^{\circ}C$. The fatigue characteristics of SBT thin films deposited on Pt/TiO$_2$/SiO$_2$/Si substrate did not change up to 101o switching cycles.s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.565-568
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• 2001

We have fabricated $Bi_{3.25}$$La_{0.75}$ti$_3$O$_{12}$ (BLT) thin(200nm) films on the Pt/Ti/SiO$_2$/Si substrates using a MOD(Metalorganic decomposition) method with annealing temperature from 55$0^{\circ}C$ to 75$0^{\circ}C$. The structural properties of the films examined by x-ray diffraction. The layered-perovskite phase obtained above $600^{\circ}C$. Scanning electron micrographs showed uniform surface composed of rodlike grains. The grain size increased with increasing annealing temperature. The BLT thin films showed little polarization fatigue test up to 3.5x10$^{9}$ bipolar cycling at a 5V and 100kHz.kHz.