• Title, Summary, Keyword: ferroelectric properties

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Dielectric, Ferroelectric, Energy Storage, and Pyroelectric Properties of Mn-Doped (Pb0.93La0.07)(Zr0.82Ti0.18)O3 Anti-Ferroelectric Ceramics

  • Kumar, Ajeet;Yoon, Jang Yuel;Thakre, Atul;Peddigari, Mahesh;Jeong, Dae-Yong;Kong, Young-Min;Ryu, Jungho
    • Journal of the Korean Ceramic Society
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    • v.56 no.4
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    • pp.412-420
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    • 2019
  • In this study, the dielectric and polarization properties of manganese (Mn% = 0.0, 0.1, 0.2, 0.5) doped (Pb0.93La0.07)(Zr0.82Ti0.18)O3 (PLZT 7/82/18) anti-ferroelectric ceramics were studied for energy storage capacitor and pyroelectric applications. A systematic investigation demonstrated that the electric properties of PLZT 7/82/18 ceramics are affected significantly by the Mn-doping content. A maximum dielectric constant of ~ 2,128 at 1 kHz was found for 0.1% Mn-doped PLZT ceramics with a low dielectric loss of 0.018. The bipolar polarization versus electric field (P-E) hysteresis loops were traced for all compositions showing a typical anti-ferroelectric nature. The breakdown field was found to decrease with Mn-doping. The energy storage density and efficiency were found to be 460 J/㎤ and ~ 63%, respectively, for 0.2% Mn-doped PLZT ceramics. The pyroelectric coefficient of PLZT ceramics shows an increase based on the amount of Mn-doping.

Ferroelectric Properties and Microstructure of Pr-Substituted Bismuth Titanate Prepared by Chemical Solution Deposition (화학 용액 증착법으로 얻어진 $Bi_{4-x}Pr_{0.7}Ti_3O_{12}$ 박막의 강유전성과 미세구조에 관한 연구)

  • Kang, Dong-Kyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.290-291
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    • 2006
  • The effect of praseodymium substitution on the ferroelectric properties of $Bi_4Ti_3O_{12}$ thin films have been investigated. Ferroelectric Pr-substituted $Bi_4Ti_3O_{12}$ thin films were fabricated by chemical solution deposition onto Pt/Ti/$SiO_2$/Si substrates. The structure and morphology of the films were analyzed using Xray diffraction, and scanning electron microscopy, respectively. About 200-nm-thick BPT films grown at $720^{\circ}C$ exhibited a polycrystalline structure and showed excellent ferroelectric properties with a remanent polarization ($2P_r$) of $28.21\;{\mu}C/cm^2$ at an applied voltage of 5 V. The films a1so demonstrate fatigue-free behavior up to $10^{11}$ read/write switching cycles with 1 MHz bipolar pulses at an electric field of ${\pm}5\;V$.

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Pyroelectricity of Ni-doped PMNT Ferroelectric for Pyroelectric Detector

  • Kim, Yeon Jung
    • Applied Science and Convergence Technology
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    • v.24 no.6
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    • pp.215-218
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    • 2015
  • A pyroelctric properties of Ni(x)-doped PMNT systems were analyzed. Modified PMNT samples were prepared using the columbite structure method. Pyroelectric current, polarization, dielectric constant and dissipation factor of Ni-doped PMNT samples were measured as a function of temperature. By adding a small amount of NiO, pyroelectricity of PMNT is increased. Unlike the normal $ABO_3$ ferroelectric, Ni-doped PMNT showed properties for relaxor ferroelectric of causing the successive phase transition over a wide temperature. The optimum conditions for obtaining compositions with improvement ferroelectric properties are a nominal addition of 0.02 mole% Ni. Also, Ni-doped PMNT ferroelectric showed excellent pyroelectric figures of merit in the vicinity of room temperature. The pyroelectric coefficient ($0.00524C/m^2K$ at $25^{\circ}C$) and figures of merit ($F_v{\sim}0.039m^2/C$ and $F_d{\sim}0.664{\times}10^{-4}Pa^{-1/2}$) of composition PMNT with 0.02 mole% Ni are comparable to the earlier reports on lead-type pyroelectrics.

Liquid crystal ferroelectric colloids; non-synthetic method of adjusting properties

  • Reznikov, Yuriy;Buchnev, Olexander;Li, Fenghua;West, John
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.163-166
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    • 2006
  • We found dramatic changes of the properties of LCs by dispersing ferroelectric nanoparticles. Specifically, ferroparticles greatly increase the nematic-isotropic transition temperature, birefringence and dielectric anisotropy of the LC. Ferroelectric nanoparticles/LCs colloids offer a simple and effective means to precisely control the physical properties of LC materials and optimize them for display applications.

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B-site Substitution Effects on the Piezoelectric Properties of Bi-based Lead-free Ceramics

  • Han, Hyeong-Su;Gang, Jin-Gyu;Yun, Chang-Ho;Lee, Han-Bok;Kim, Gyeong-Jong;Lee, Jae-Sin
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.29.2-29.2
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    • 2011
  • B-site substitution with isovalent and donor impurities was compared in terms of the piezoelectric properties of Bi-based ABO3 perovskite ceramics. X-ray diffraction study revealed that both impurities bring about degradation in their ferroelectric properties as well as piezoelectric characteristics. However, there existed a difference between the isovalent and heterovalent impurities that influence a phase transformation of ferroelectric anisotropic-to-electrostrictive pseudocubic symmetry. Based upon analyses including the crystal, microstructure, dielectric, ferroelectric properties, we believed that A-site vacancies in the ABO3 ceramic significantly contribute to a ferroelectric-nonpolar phase transition, which give rise to lead to a giant strains. The present paper will discuss the origin of giant strains in Bi-based perovskite ceramics.

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Effect of B$_2$O$_3$ Addition on the Sintering Behavior Dielectric and Ferroelectric Properties of $Ba_{0.7}$Sr$_{0.3}$TiO$_3$Ceramics (저온 액상 소결제 B$_2$O$_3$ 첨가에 의한 $Ba_{0.7}$Sr$_{0.3}$TiO$_3$ 세라믹스의 소결거동 및 유전 강유전 특성변화)

  • 임성민;홍석민;박홍진;김옥경
    • Journal of the Korean Ceramic Society
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    • v.36 no.7
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    • pp.767-772
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    • 1999
  • The effect of B2O3 addition on the sintering behavior dielectric and ferroelectric properties of Ba0.7Sr0.3TiO3 ceramics were investigated. The sample with 0.5wt% B2O3 was sintered under 115$0^{\circ}C$. The dielectric and ferroelectric properties of BST with 0.5wt% B2O3 was as good as BST without B2O3 sintered at 135$0^{\circ}C$ and its dielectric loss was even better When B2O3 was added over 1.0wt% the overdoped B2O3 remained in the specimens and formed a second phase which degraded the sintering behaivor dielectric properties of BST.

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Retention and Fatigue Properties of MFS Devices using Ferroelectric $LiMbO_3$ Thin Films ($LiMbO_3$ 강유전체 박막을 이용한 MFS 디바이스의 Retention 및 Fatigue 특성)

  • 정순원;김채규;김용성;김진규;이남열;김광호;유병곤;이원재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.17-20
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    • 1999
  • The retention and fatigue properties of ferroelectric LiNbO$_3$ thin films were studied. Metal-ferroelectric-semiconductor(MFS) devices by using rapid thermal annealed LiNbO$_3$/Si structures were successfully fabricated and demonstrated nonvolatile memory operations of the MFS devices. The I$_{D}$-V$_{G}$ characteristics of MFSFET\`s showed a hysteresis loop due to the ferroelectric nature of the LiNbO$_3$ thin film. The ferroelectric capacitors showed practically no polarization degradation up to about 10$^{10}$ switching cycles when subjected to symmetric bipolar voltage pulse (peak-to-peak 6V, 50% duty cycle) in the 500kHz. The retention properties of the LiNbO$_3$ thin films were quite good up to about 10$^{3}$ s . s .

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Ferroelectric BiFeO3/TiO2 nanotube heterostructures for enhanced photoelectrochemical performance

  • Lee, Heejin;Joo, Ho-yong;Yoon, Chulmin;Lee, Joonbong;Lee, Hojin;Choi, Jinsik;Park, Baeho;Choi, Taekjib
    • Current Applied Physics
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    • v.17 no.5
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    • pp.679-683
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    • 2017
  • Ferroelectric based heterostructures have shown great promises in solar water splitting due to unique photoelectrochemical (PEC) properties including polarization-induced charge separation and tunable electrochemical surface reaction. A highly ordered ferroelectric $BiFeO_3/TiO_2$ nanotube (TNT) hetero-structures were fabricated by anodic oxidation and pulsed laser deposition. The microscopic morphology, optical, and PEC properties of nanostructures were characterized. The $BiFeO_3/TNT$ photoelectrode is photoactive under visible light illumination, which exhibits higher photocurrent from greater water oxidation, compared with the pure TNT photoelectrode. The coating thickness of $BiFeO_3$ strongly affected the photoelectrochemical properties. The enhanced PEC performance could be attributed to the effective charge separation and the favorable band bending for water oxidation, originating from ferroelectric polarization-related internal field.

Switching Dynamics Analysis by Various Models of Hf0.5Zr0.5O2 Ferroelectric Thin Films (Hf0.5Zr0.5O2 강유전체 박막의 다양한 분극 스위칭 모델에 의한 동역학 분석)

  • Ahn, Seung-Eon
    • Korean Journal of Materials Research
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    • v.30 no.2
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    • pp.99-104
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    • 2020
  • Recent discoveries of ferroelectric properties in ultrathin doped hafnium oxide (HfO2) have led to the expectation that HfO2 could overcome the shortcomings of perovskite materials and be applied to electron devices such as Fe-Random access memory (RAM), ferroelectric tunnel junction (FTJ) and negative capacitance field effect transistor (NC-FET) device. As research on hafnium oxide ferroelectrics accelerates, several models to analyze the polarization switching characteristics of hafnium oxide ferroelectrics have been proposed from the domain or energy point of view. However, there is still a lack of in-depth consideration of models that can fully express the polarization switching properties of ferroelectrics. In this paper, a Zr-doped HfO2 thin film based metal-ferroelectric-metal (MFM) capacitor was implemented and the polarization switching dynamics, along with the ferroelectric characteristics, of the device were analyzed. In addition, a study was conducted to propose an applicable model of HfO2-based MFM capacitors by applying various ferroelectric switching characteristics models.

Characteristics of Surface Morphology and Defects by Polishing Pressure in CMP of BLT Films (BLT 박막의 CMP 공정시 압력에 따른 Surface Morphology 및 Defects 특성)

  • Jung, Pan-Gum;Lee, Woo-Sun
    • Proceedings of the KIEE Conference
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    • pp.101-102
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    • 2006
  • PZT thin films, which are the representative ferroelectric materials in ferroelectric random access memory (FRAM), have some serious problem such as the imprint, retention and fatigue which ferroelectric properties are degraded by repetitive polarization. BL T thin film capacitors were fabricated by plasma etching, however, the plasma etching of BLT thin film was known to be very difficult. In our previous study, the ferroelectric materials such as PZT and BLT were patterned by chemical mechanical polishing (CMP) using damascene process to top electrode/ferroelectric material/bottom electrode. It is also possible to pattern the BLT thin film capacitors by CMP, however, the CMP damage was not considered in the experiments. The properties of BLT thin films were changed by the change of polishing pressure although the removal rate was directly proportional to the polishing pressure in CMP process.

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