• Title, Summary, Keyword: Ferroelectric property

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Effect of Sintering Temperature on the Dielectric Property of Lead Magnesium Niobate-Lead Titanate Ceramics

  • Hwang, Hak-In;Jung, Jong-Man;Park, Joon-Shik
    • The Korean Journal of Ceramics
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    • v.4 no.4
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    • pp.286-291
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    • 1998
  • Dielectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_{3}-PbTiO_{3}$, ceramics prepared by the columbite precursor method have been investigated as a function of the sintering temperature in the range of 1000∼$1250^{\circ}C$. The $Pb(Mg_{1/3}Nb_{2/3})O_{3}-PbTiO_{3}$ ceramics show typical relaxor ferroelectric behavior. As the sintering temperature increased, the dielectric constant increased and the phase transition temperature shifted to lower temperature. The TCK(temperature coefficient of dielectric constant) and VRK (variation rate of dielectric constant) increased with increasing sintering temperature. The $Pb(Mg_{1/3}Nb_{2/3})O_{3}-PbTiO_{3}$ compositions sintered at $1250^{\circ}C$ appear to be suitable for ferroelectric bolometer.

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A Study on Electric Property of BLT thin films as a function of the Post Annealing Time (열처리 시간에 따른 BLT 박막의 전기적 특성에 관한 연구)

  • Kim, Eung-Kwon;Kim, Hyun-Duk;Choi, Jang-Hyun;Kim, Hong-Joo;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.574-577
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    • 2002
  • In recent year, BLT$(Bi_{3.25}La_{0.75}Ti_3O_{12})$ has been one of promising substitute materials at the ferroelectric random access memory applications. We manufactured $(Bi_{3.25}La_{0.75}Ti_3O_{12})$ Target with a ceramic process. The BLT target was sintered at $1100^{\circ}C$ for 4 hours. Using RF magnetron sputtering, a deposited BLT thin films were estimated about ferroelectric property as a functions of post annealing time. The BLT thin films showed a promoted ferroelectric characteristics at the post annealied sample for 30 minutes. This sample exhibited the (117) preferred crystal orientation, current density of $2{\times}10^{-8}A/cm^2$, a remanent polarization of $10{\mu}C/cm^2$ and a coercive field of 62.1 KV/cm respectively.

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Enhanced Photocatalytic Activity by the Combined Influence of Ferroelectric Domain and Au Nanoparticles for BaTiO3 Fibers

  • Zhang, Xiaoshan;Huan, Yu;Zhu, Yuanna;Tian, Hui;Li, Kai;Hao, Yanan;Wei, Tao
    • Nano
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    • v.13 no.12
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    • pp.1850149.1-1850149.10
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    • 2018
  • Ferroelectric particles have been applied in the photocatalytic field because the spontaneous polarization results in the internal electric field, which can accelerate the separation and migration of photogenerated carriers. In this study, the $BaTiO_3$ (BT) fibers are synthesized by electrospinning. The BT fibers calcined above $800^{\circ}C$ exhibit a strong ferroelectric property, which is verified by a typical butterfly-shaped displacement-voltage loop. It is found that the BT fibers with the single-domain structure exhibit better photocatalytic performance than that with the multi-domain configuration. When the single-domain transforms into multi-domain, the integrated internal electric field correspondingly breaks up, inducing that the internal electric field might cancel each other out and diminish the separation of photogenerated carriers. Also, the Au nanoparticles can improve the photocatalytic activity further on account of the surface plasmon resonance. Therefore, it is suggested that Au nanoparticles decorated on ferroelectric BT nanomaterials are promising photocatalysts.

A Hystesis Loop Modeling of Ferroelectric Thin Film Using Numerical Integration Method (수치적분을 이용한 강유전체의 이력곡선 모델링)

  • 강성준;정양희;유일현
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.696-699
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    • 2003
  • In this study, we suggested the model to precisely evaluate the ferroelectric hysteresis loop, using the modified Sawyer-Tower circuit and the ferroelectric capacitor with a MDFM(Metal-Dielectric-ferroelectric-Metal) structure. The mathematical expression of dipole polarization is applied to the numerical integration algorithm, and the fatigue property can be considered including the dielectric layer between ferroelectrics and bottom electrode. The validity of our model is proved comparing the estimated value of our model and the measured results of PLT(10) thin film.

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Fabrication of the Outer type-Dynamic Microlens Array using Surface-Stabilized Ferroelectric Liquid Crystal

  • Kim, Young-Wook;Gwag, Jin-Seog;Kim, Kyung-Bae;Kang, Tae-Ho;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.344-347
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    • 2008
  • We fabricated the outer type-dynamic microlens array using a surface-stabilized ferroelectric liquid crystal, UV curable polymer and the stacked liquid crystalline polymer. The outer type-microlens array has a lower driving voltage and fast switching property. It is applicable to a variety of optical systems.

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Fatigue characteristics of $Pb(Zr,Ti)O_3$ capacitors on donor doping

  • Yang, Bee Lyong
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.3
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    • pp.113-117
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    • 2002
  • Fatigue characteristics of ferroelectric $Pb(Zr,Ti)O_3$ (PZT) based capacitors through donor doping is reported in this paper. La substitution up to 10% were carried out to study systematically the fatigue behaviors of epitaxial ferroelectric capacitors grown on Si using $(Ti_{0.9}Al_{0.1})N/Pt$ conducting barrier composite. Ferroelectric capacitors substituted with 10% La show sufficient low voltage switched polarization and fatigue free performance. Systematic decrease in the tetragonality of the ferroelectric phase (i.e., c/a ratio) results in the corresponding reduction in coercive voltage, sufficient remnant polarization at 1.5-3V, and good fatigue property.

Electrocaloric Effect in Pb0.865La0.09(Zr0.65Ti0.35)O3 Thin Film

  • Roh, Im-Jun;Kwon, Beomjin;Moon, Hi Gyu;Kim, Jin-Sang;Kang, Chong-Yun
    • Journal of Sensor Science and Technology
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    • v.23 no.4
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    • pp.224-228
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    • 2014
  • The electrocaloric effect of 9/65/35 PLZT thin film fabricated by the sol-gel method, which has not been studied yet, was investigated for its structural, electrical properties as well as temperature change property. The relaxor ferroelectric property of 9/65/35 PLZT thin film was confirmed by examining its dielectric and electrical properties. The relaxor property can cause a more pronounced electrocaloric effect (ECE) in a wider temperature range than normal ferroelectric film. To avoid errors caused by using an indirect measurement method, the leakage current generated by increasing temperatures was minimized by using the optimal maximum electric field ($350kVcm^{-1}$) in the thin film. The largest temperature change ${\delta}T$ (0.23 K) and the electrocaloric strength ${\xi}$ (0.68 mkcm/kV), calculated by equations were obtained. The maximum field change ${\delta}E$ ($191kVcm^{-1}$) was in the vicinity of the curie temperature ($200^{\circ}C$).

Fabrication of Ferroelectric BaTiO3Thin Film on Ti Substrate and Formation of Calcium Phosphate in Eagle’s MEM Solution (티타늄 기판 위에 강유전성 BaTiO3박막 형성과 분극처리에 의한 Eagle’s MEM 용액에서의 Calcium Phosphate 생성)

  • Lee, Yong-Ryeol;Jeong, Young-Hwa;Hwang, Kyu-Seog;Song, Ho-Jun;Park, Yeong-Joon
    • Korean Journal of Materials Research
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    • v.12 no.7
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    • pp.560-567
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    • 2002
  • Titanium (Ti) is a bioinert material and has lower elastic coefficient and better strength/volume property than other metals. Ferroelectric materials show alignment of positive and negative charges by poling treatment. This study was purposed to develop a new implant system by combining the advantages of Ti and ferroelectric property of $BaTiO_3$ (BTO). It was performed with the assumption that the $Ca^{2+ }$ ions would be easily attracted on negatively charged surface and the attracted cation might behave as nuclei for bone-like crystal growth in biological solutions. A ferroelectric BTO thin film on Ti was fabricated and the effect of poling treatment on the improvement of calcium phosphate (Ca-P) formation in biological solutions was evaluated. After immersion in Eagle’s minimum essential media (MEM) solution, NaCl was formed on Ti, and Ca-P layer containing NaCl was formed on Ti-O. Weak and sparse Ca-P layers were formed on BTO, while thick, homogeneous, and dense Ca-P layer was formed on negatively polarized BTO (N-BTO), which was confirmed by FE-SEM and EDX. In summary, these results demonstrate that poling the ferroelectric BTO surface negatively is effective for the formation of Ca-P layer in MEM solution, and that N-BTO coating on Ti could be used as a possible alternative method for enhancing the osseointegration of the implants.

A Study on BLT Target Preparation and Ferroelectric Property (BLT 타겟제조 및 강유전 박막 특성에 관한 연구)

  • Kim, Eung-Kwon;Park, Gi-Yub;Lee, Kyu-Il;Kang, Hyun-Il;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.87-90
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    • 2002
  • In recent year, BLT($Bi_{3.25}La_{0.75}Ti_{3}O_{12}$) has been one of promising substitute materials at the ferroelectric random access memory applications. We manufactured $Bi_{3.25}La_{0.75}Ti_3O_{12}$ Target with a ceramic process. The BLT target was sintered at ${1100^{\circ}C}$ for 4 hours. Using RF magnetron sputtering, a deposited BLT thin films were estimated about ferroelectric properly as a functions of post annealing temperatures. The BLT thin films showed a promoted ferroelectric characteristics at the post annealied sample of ${700^{\circ}C}$. This sample exhibited the (117) preferred crystal orientation, current density of $3{\times}10^{-8}A/cm^2$, a remanent polarization of $8{\mu}C/cm^2$ and a coercive field of 42.1 KV/cm respectively.

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Analysis of a Crack in Ferroelectric Ceramics Subjected to Electric Fields (전기장을 받는 강유전체 세라믹내의 균열 해석)

  • 범현규;김인옥
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.6
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    • pp.138-144
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    • 2003
  • A crack in a ferroelectric ceramic subjected to an electric field is analyzed. The boundary of the electrical saturation zone is estimated based on the finite-width saturation zone model, which is analogous to a finite-width Dugdale zone model for mode III. It is shown that the shape and size of the switching zone depends strongly on the boundary of the electrical saturation zone and the ratio of the coercive electric field to the yield electric field. The crack tip stress intensity factor under small scale conditions is evaluated by employing the model of electric nonlinear domain switching. It is found that fracture toughness of the ferroelectric material may be increased or decreased depending on the material property of electrical nonlinearity.