• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.2
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• pp.65-68
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• 2010

$Sr_{0.6}Ba_{0.4}Nb_2O_6$ (60SBN) and $Sr_{0.75}Ba_{0.35}Nb_2O_6$ (75SBN) single crystals were grown by Czochralski method. Growing direction was <001>, and as-grown crystals has well-developed (001) plane. Temperature- and frequency dependence of dielectric constant represent relaxor ferroelectrics. 60SBN has wider optical transmittance than 75SBN.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.711-716
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• 2012

Tungsten bronze structure $Sr_{1-x}Ba_xNb_2O_6$ (SBN) single crystals were grown primarily using the Czochralski method, in which several difficulties were encountered: striation formation and diameter control. Striation formation occurred mainly because of crystal rotation in an asymmetric thermal field and unsteady melt convection driven by thermal buoyancy forces. To optimize the growth conditions, bulk SBN crystals were grown in a furnace with resistance heating elements. The zone of $O_2$ atmosphere for crystal growth is 9.0 cm and the difference of temperature between the melt and the top is $70^{\circ}C$. According to the growth conditions of the rotation rate, grown SBN became either polycrystalline or composed of single crystals. In the case of as-grown $Sr_{1-x}Ba_xNb_2O_6$ (x = 0.4; 60SBN) single crystals, the color of the crystals was transparent yellowish and the growth axis was the c-axis. The facets of the crystals were of various shapes. The length and diameter of the single crystals was 50~70 mm and 5~10 mm, respectively. Tungsten bronze SBN growth is affected by the temperature profile and the atmosphere of the growing zone. The thermal expansion coefficients on heating and on cooling of the grown SBN single crystals were not matched. These coefficients were thought to influence the phase transition phenomena of SBN.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1167-1173
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• 2001

The tetragonal tungsten bronze type of Sr$_{x}Ba_{1-x}Nb_{2}O_{6}$(SBN) (0.3$\le$x$\ge$0.7) ceramics was synthesized by the solid state reaction method, and the dielectric properties of SBN ceramics as a function of Sr/Ba ratio were examined. With increasing Sr/Ba ratio in SBN ceramics, the Curie temperature decreased and the maximum dielectric constant at the Curie temperature increased. The relaxor behavior of the SBN ceramics as a function of Sr/Ba ratio was quantitatively evaluated. More relaxor behavior of dielectric characteristics was observed as the ratio of Sr/Ba increased. The experimental results are explained with a viewpoint of crystallography of tungsten bronze structured SBN ceramics.

• Journal of the Korean Ceramic Society
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• v.43 no.3 s.286
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• pp.173-176
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• 2006

${Sr_{1-x}Ba_xNb_2O_6$(SBN) have been obtained in Pt crucible by melting and cooling in air atmosphere. Some SBNs being at the bottom of the crucible are black and transparent, and the other SBNs colorless. The black SBN became to be colorless by oxidation heat treatment $1,300^{\circ}C$ for 4 h, Curie temperature is changed by colorless change of black SBN. The reason seems to be $Nb^{5+}$ oxidation of some $Nb^{4+}$ ions in SBN or effect of unknown impurities. Diffused Phase Transition (DPT) was appeared during heating and cooling process. Various sintered SBN ceramics specimen showed relaxor characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.248-249
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• 2005

The tungsten bronze type of strontium barium niobate(SBN) thin film was synthesized by metal organic decomposion method for SBN stock solution and the SBN thin film process were deposited by spin-coating process on Pt-deposited si-wafer(100) by magnetron sputtering system. The thickness of SBN thin film was 150$\sim$200 nm and were optimized for rpm of spin-coater system. The structural variation of SBN thin film was studied by TG-DTA and XRD. The deposited SBN stock solution on annealing at $400\sim800^{\circ}C$ a pure tungsten bronze SBN phase and the corresponding average grain size about 500$\sim$1000 nm influenced by annealing temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1144-1147
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• 2002

Ferroelectric $Sr_xBa_{1-x}Nb_2O_6(0.25{\leq}x{\leq}0.75)$ thin films were prepared by the Ion Beam Sputtering method. Deposit onto Pt/Ti/$SiO_2$/Si(100) substrates. The deposited thin films were heat-treated for crystallization. Microstructure and crystallization behavior were examined using FE-SEM, XRD. Ferroelectric hysteresis were measured. The measured remanent polarization and coercive field values were $38{\mu}C/cm^2$ and 120kV/cm, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.869-873
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• 2004

[ $Sr_xBa_{1-x}Nb_2O_6$ ] (SBN, $0.25{\leq}x{\leq}0.75$) ceramic is a ferroelectric material with tetragonal tungsten bronze (TTB) type structure, which has a high pyroelectric coefficient, piezoelectric, and a photo refractive properties. In this study, SBN60(x=0.6) thin film was manufactured by ion beam sputtering technique. Using the prepared SBN60 target in $Ar/O_2$ atmosphere as-deposited SBN60 thin film on Pt(100)/$TiO_2/SiO_2/Si$ substrate crystallization and orientation behavior as well as electric properties of SBN60 thin film were examined. SBN60 deposition up to $3000{\AA}$ in thickness, SBN60 thin film was heat-treated at $650^{\circ}C{\sim}800^{\circ}C$. The orientation was shown primarily along (001) plane from XRD pattern where working pressure was $4.3{\times}10^{-4}$ torr. The deposited layer was uniform, preferred orientatin and crystallization behavior resulted in the change of $O_2$ ratio was observed. In electric propertie of Pt/SBN60/Pt thin film capacitor remnant polarization (2Pr) value was $10{\mu}C/cm^2$, the coercive filed (Ec) 50 kV/cm, and the dielectric constant 615, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.85-88
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• 2003

$Sr_xBa_{1-x}Nb_2O_6$(SBN, $025{\leq}x{\leq}0.75$) ceramic is a ferroelectric material with tetragonal tungsten bronze (TTB) type structure, which has a high pyroelectric coefficient and a nonlinear electro-optic coefficient value. In spite of its advantages, SBN has not been investigated well compared to other ferroelectric materials with perovskite structure. In this study, SBN thin film was manufactured by ion beam sputtering technique using the prepared SBN target in Ar/$O_2$ atmosphere. SBN30 thin film of 500 ${\AA}$ was pre-deposited as a seed layer on Pt(l00)/$TiO_2$/$SiO_2$/Si substrate followed by SBN60 deposition up to 4500 ${\AA}$ in thickness. SBN60/SBN30 layer was deposited at different Oxygen amount of 0, 8.1, 17, and 31.8 sccm, respectively. The crystallinity and orientation behavior as well as electric properties of SBN60/SBN30 multi-layer were examined. The deposited layer was uniform and the orientation was shown primarily along (001) plane from XRD pattern. The crystal structure and the electric properties depended on the Oxygen amount, heating temperature and was the best at O2 = 8.1 seem, $750^{\circ}C$. In electric properties of Pt/SBN60/SBN30/Pt thin film capacitor prepared, the remnant polarization (2Pr) value was 13 ${\mu}C/cm^2$, the coercive field (Ec) 75 kV/cm, and the dielectric constant 1492, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.366-367
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• 2006

Different orientated SBN thin films were deposited by Ion Beam Sputtering, and electric properties were measured on each orientation. Ferroelectric $Sr_xBa_{1-x}Nb_2O_6$(SBN) has excellent electro-optic, photo-refractive, piezoelectric, pyroelectric properties. SBN thin film has been deposited by various method, of sol-gel, PLD, CVD, sputtering, etc.. To avoid lead pollution of Pb-system perovskite ferroelectric materials. SBN thin films were fabricated for pyroelectric IR sensor. Using the ceramic target of the same composition and Pt(100)/$TiO_2/SiO-2$/Si(100) substrate, crystallization and orientation behavior as well as electric properties of the films were examined. Seed layer and thin films thickness was controlled to observe the effect on preferred orientation. We measured I-V, C-V, P-E hysteresis to characterize electric-properties on each orientations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.723-727
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• 2003

[ $Sr_xBa_{1-x}Nb_2O_6$ ] (SBN, $0.25{\leq}x{\leq}0.75$) ceramic is a ferroelectric material with tetragonal tungsten bronze (TTB) type structure, which has a high pyroelectric coefficient and a nonlinear electro-optic coefficient value. In spite of its advantages, SBN has not been investigated well compared to other ferroelectric materials with perovskite structure. In this study, SBN thin film was manufactured by ion beam sputtering technique using the prepared SBN target in $Ar/O_2$ atmosphere. SBN30 thin film of $1000{\AA}$ was pre-deposited as a seed layer on $Pt(100)/TiO_2/SiO_2/Si$ substrate followed by SBN60 deposition up to $3000{\AA}$ in thickness. As-deposited SBN60/SBN30 layer was heat-treated at different temperatures of 650, 700, 750, and $800^{\circ}C$ in air, respectively The crystallinity and orientation behavior as well as electric properties of SBN60/SBN30 multi-layer were examined. The deposited layer was uniform and the orientation was shown primarily along (001) plane from XRD pattern. There was no difference in the crystal structure with heat-treatment temperature, but the electric properties depended on the heating temperature and was the best at $750^{\circ}C$. In electric properties of Pt/SBN60/SBN30/Pt thin film capacitor prepared, the remnant polarization (2Pr) value was $15{\mu}C/cm^2$, the coercive field (Ec) 75 kV/cm, and the dielectric constant 1075, respectively.