• Title, Summary, Keyword: substitution of Ba

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Effects of Ba substitution on the electric, dielectric properties of PMN-PZT Ceramics (Ba치환이 PMN-PZT세라믹의 전기적, 유전적 특성에 미치는 영향)

  • 김만성;류주현;이수호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.158-162
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    • 1997
  • In this paper, the electrical and dielectrical properties were investigated in Pb(Zr,Ti)O$_3$-Pb(Mn,Nb)O$_3$ ceramics which are manufactured with the substitution of Ba in site Pb. In older to increase the del and Kp , Ba was substitued to site Pb from 0 to 0.1 by 0.02 mol%. As the Ba substitution is increased, dielectric constant is increased and electricmachanical coupling factor showed the maximum value at Ba 0.06mol% and the mechanical qualify factor is decreased and the tetragonality and the grain size are decreased as the Ba substitution.

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Piezoelectric and Electric Field Induced Strain Properties of PMW-PNN-PZT Ceramics with the Substitution of Ba (Ba 치환에 따른 PMW-PNN-PZT 세라믹스의 압전 및 전계유기왜형 특성)

  • 윤광희;김규수;최병수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.1
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    • pp.20-25
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    • 2001
  • To develop the piezoelectric actuator, the structural, dielectric and piezoelectric properties and electric fieldinduced strain of the ceramics(Pb$\_$1-2/Ba$\_$x/)[Mg$\_$1/2/W$\_$1/2/)$\_$0.03/-Ni$\_$1/3/Nb$\_$2/3/)$\_$0.12/-(Zr$\_$0.5/Ti$\_$0.5/)$\_$0.85/]O$_3$(x=0, 0.01, 0.03, 0.05, 0.07, 0.1) were investigated with the substitution of Ba. The tetragonality of crystal structure and grain size decreased by the substitution of Ba. Curie temperature decreased due to the decrease of the tetragonality, and dielectric constants increased with the substitution of Ba. The coercive field, remnant polarization and electromechanical coupling factor also decreased, whereas the piezoelectric constatns d$\_$33/ and d$\_$31/ were showed the highest value of 430 and 209(x10$\^$-12/C/N), respectively, because of the increase of dielectric constant. The strain induced by 60Hz AC electric field had the maximum value of 204x10$\^$-6/Δℓ/ℓ at the substitution of Ba 3mol%. As the applied electric field approaches to the coercive field, the piezoelectric element is depolarized and the electric field induced strain revealed non-linearity.

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Effect of A-Site Substitution on the Dielectric Properties of PZN Ceramics (A-자리 치환에 따른 PZN 세라믹스의 유전특성)

  • 조상희;백종갑;손정호;김정주;김남경
    • Journal of the Korean Ceramic Society
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    • v.32 no.5
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    • pp.635-641
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    • 1995
  • The effects of A-site substitution with alkaline-earth ions (Ca, Sr and Ba) on the perovskite-phase formation and dielectric properties for Pb1-xMx(Zn1/3Nb2/3)O3 (0.0 x 0.5)-based relaxors were studied. Considerable improvements in the sinterability and the extent fo perovskite formation were observed with increasing the A-site substitution (x) and sintering temperature. The maximum dielectric permittivity appeared at x=0.1 for Sr and Ba substitutiion, while the relative dielectric permittivity was almost invariant in the case of Ca ion substitution. Curie temperature decreased with increasing relative amount of Sr and Ba ions but was almost invariant in case of Ca ion substitution. With increasing the amount of x, the diffuseness parameter ($\delta$) increased but the maximum dielectric constant decreased, demonstrating an enhanced diffuse phase transition (DPT) in the presence of alkaline-earth cations.

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Piezoelectric and Dielectric Properties of (Na,Li)$NbO_3$ Ceramics According to the $BaTiO_3$ substitution ($BaTiO_3$ 치환에 따른 (Na,Li)$NbO_3$ 세라믹스의 압전 및 유전특성)

  • Lee, Sang-Ho;Lee, Kab-Soo;Ryu, Ju-Hyun;Ryu, Sung-Lim;Song, Hyun-Seon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.272-273
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    • 2007
  • In this study, in order to develop the composition ceramics of lead-free ultrasonic motor, (Na,Li)$NbO_3-BaTiO_3$ ceramics were fabricated using a conventional mixed oxide process and their piezoelectric and dielectric characteristics were investigated according to the $BaTiO_3$, substitution. $BaTiO_3$ substitution enhanced density, dielectric constants$({\varepsilon}_r)$ and electromechanical coupling factor$(k_p)$. However, mechanical quality factor was deteriorated. At the $BaTiO_3$ substitution of 4mol%, density, electromechanical coupling factor$(k_p)$, dielectric constants$({\varepsilon}_r)$ and piezoelectric constant$(d_{33})$ of specimen showed the optimum value of $4.493g/cm^3$, 0.236, 175, 70pC/N, respectively.

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Piezoelectric and Dielectric Properties of NaNbO3-LiNbO3 Ceramics according to the BaTiO3 Substitution (BaTiO3 치환에 따른 NaNbO3-LiNbO3 세라믹스의 압전 및 유전특성)

  • Lee, Sang-Ho;Yoo, Ju-Hyun;Mah, Suk-Burm;Kim, Seang-Goo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.3
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    • pp.205-209
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    • 2009
  • In this study, in order to develop the composition ceramics for lead-free ultrasonic motor, (1-x-0.09)$NaNbO_{3-x}BaTiO_3-0,09LiNbO_3$ ceramics were fabricated using a conventional mixed oxide process and their piezoelectric and dielectric characteristics were investigated according to the $BaTiO_3$ substitution. All the specimens showed orthorhombic phase structure without secondary phase, $BaTiO_3$ substitution enhanced density, dielectric constant(${\epsilon}_r$) and electromechanical coupling factor($k_p$), However, mechanical quality factor was deteriorated. Curie temperature of specimens was observed as about $380^{\circ}C$. At the $BaTiO_3$ substitution of 4 mol%, density, electromechanical coupling factor($k_p$), dielectric constant(${\epsilon}_r$) and piezoelectric constant($d_{33}$) of specimen showed the optimum value of $4.493g/cm^3$, 0.236, 175, 70 pC/N, respectively.

Magnetic and Microwave Absorbing Properties of Ti-and Co-Substituted Barium Ferrite (BaFe12-2X TiXCoXO19)

  • Han-Shin Cho;Yong-Jin Kim;Sung-Soo Kim
    • Journal of Magnetics
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    • v.4 no.2
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    • pp.65-68
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    • 1999
  • The M-type barium ferrite ($BaFe_{12}O_{19}$) is well known magnetic material to be used as a permanent magnet due to its strong uniaxial anisotropy. The substitution of nonmagnetic $Ti^{+4}$ and magnetically weak $Co+^2ion for Fe^{+3}$ to its strong uniaxial anisotropy. The substitution of nonmagnetic $Ti^{+4}$ and magnetically weak $Co+^2ion for Fe^{+3}$ sublattices reduces the uniaxial anisotropy and those compounds open a new application field of noise suppressor at high frequencies. In this study, the magnetic and microwave absorbing properties are investigated in Ti-and Co-substituted barium ferrites ($BaFe_{12-2X} Ti_XCo_XO_{19}$). The saturated magnetization decreases linearly with the substitution of Ti and Co. The rapid drop in coercive force is observed with Ti and Co substitution upto x=1.2. The magnetic permeability spectrum shows the natural magnetic resonance in the specimens with small coercive force and large attenuation of microwave is predicted in those specimens at high frequencies (above 4 GHz).

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Cathodoluminescence and Longevity Properties of Potential Sr1-xMxGa2S4:Eu (M = Ba or Ca) Green Phosphors for Field Emission Displays

  • Ko, Ki-Young;Huh, Young-Duk;Do, Young-Rag
    • Bulletin of the Korean Chemical Society
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    • v.29 no.4
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    • pp.822-826
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    • 2008
  • We report the cathodoluminescence and aging properties of a series of green phosphors of formula $Sr_{1-x}M_xGa_2S_4$:Eu (x = 0.0-1.0, M = Ba or Ca) that have potential applications in field emission displays (FEDs). The series of phosphors was synthesized via NaBr-aided solid-state reactions in a flowing $H_2S$ stream. A low level ($\sim$20%) of Ba or Ca substitution for Sr in $SrGa_2S_4$:Eu maintains the orthorhombic phase of pure $SrGa_2S_4$:Eu phosphors. Further, a low level ($\sim$20%) of Ba or Ca substitution for Sr in $SrGa_2S_4$:Eu provides various green colors and sufficient brightness for FED applications. Substitution of Ba or Ca for Sr in $SrGa_2S_4$:Eu also improved the stability of the phosphor when it was operated under electron-beam irradiation of 5 kV.

Rietveld Refinement and Crystal Structure of K-Ba Substituted Synthetic Hollandite, ($K_{2x}Ba_{1-x}Cr_2Ti_6O_{16}$) (리트벨트법을 이용한 K-Ba 치환 합성 홀란다이트($K_{2x}Ba_{1-x}Cr_2Ti_6O_{16}$)의 결정구조 연구)

  • 최진범;김태현
    • Journal of the Mineralogical Society of Korea
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    • v.14 no.2
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    • pp.128-136
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    • 2001
  • The K-Ba complete solid solution of 7 synthetic hollandite-type minerals ($K_{2x}$ $Ba_{1-x}$ $Cr_2$/$Ti_{6}$ $O_{16}$ , x=0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0, respectively) are studied by the X-ray powder diffraction and Rietveld refinement to find structural transformation during substitution of $Ba^{2+}$ by $K^{+}$ in A site of the tunnel structure of hollandite. Rietveld indices indicate that $R_{wp}$ with respect to $R^{exp}$ ($R_{wp}$ $R_{exp}$ ) are in the range of 15.66%/20.90% and 14.74%/l9.37%, $R_{B}$ and S(Goodness of Fitness) are 6.45~8.97%, 1.45~1.63, respectively. Unit cell parameters of synthetic hollandites, space group 14/m, are a=10.1194(2)~10.0599(2)$\AA$, c=2.9572(6)~2.9512(7)$\AA$, and V=302.75~298.66$\AA^{3}$. Rutile formed as an impurity in those with more than 50% K contents in hollandite series. Substitution of Ba by K ion in a tunnel structure results in constant decrease of cell parameters, but is not sufficient enough to change the hollandite structure. Our data indicate that transformation of tetragonal 14/m to lower symmetry of monoclinic 12/m in hollandite structure may at least be affected by other cation substitution in same A site and/or by cation substitution in B site.

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Effects of A-Site Sr and B-Site Substitution on the Dielectric Properties of BaTiO3 Ceramics (A-site Sr 및 B-site Ca 첨가 BaTiO$_3$ 세라믹스의 유전특성)

  • 박재관;오태성;김윤호
    • Journal of the Korean Ceramic Society
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    • v.28 no.9
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    • pp.689-695
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    • 1991
  • Dielectric properties of Ba1-$\chi$Sr$\chi$Ti1-yCayO3-y ceramics, where Sr and Ca were doped to Ba-site and Ti-site within the range of 0 x 0.24 and 0 y 0.05, respectively, were investigated. The substitution of Ca for Ti, which maintained the high resistivity of these formulations after sintering in a reducing atmosphere, was confirmed. Ca addition decreased the tetragonality c/a, increased the unit cell volume, and lowered Curie temperature, which were attributed to the occupancy of Ca2+ ions on Ti-sites. The lowering of Curie temperature by Ca addition was affected by the substitution of Sr for Ba-site; within 2 mol% of Ca, Curie temperature was lowered at a rate of 2$0^{\circ}C$ and 16$^{\circ}C$ per mol% of Ca at x=0 and x=0.08, respectively. Whereas the resistivity of the formulations without Ca was reduced to 107 {{{{ OMEGA }}cm, when sintered at low oxygen partial pressure of 10-9 MPa, the resistivity value higher than 1011 {{{{ OMEGA }}cm was maintained for the formulations containing Ca more than 0.5 mol%. Dielectric loss factor, tan$\delta$, was about 1% for most formulations.

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Structure and Superconducting Properties of Ba-substituted (Ru,Cu)(Sr,Eu)$_2$(Eu,Ce)$_2Cu_2O_z$ System (Ba 치환에 따른 (Ru,Cu)(Sr,Eu)$_2$(Eu,Ce)$_2Cu_2O_z$ 계의 초전도 특성)

  • Lee, H.K.
    • Progress in Superconductivity
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    • v.13 no.1
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    • pp.12-17
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    • 2011
  • We investigated the effects of Ba and Cu co-substitution on the structural and superconducting properties of ($Ru_{1-y}Cu_y$)($Sr_{1.67-x}Ba_xEu_{0.33}$)($Eu_{1.34}Ce_{0.66}$)$Cu_2O_z$ samples. X-ray diffraction(XRD) reveals that single-phase samples can be obtained in the range from x = 0.1 to 0.2 for ($Ru_{0.5}Cu_{0.5}$)($Sr_{1.67-x}Ba_xEu_{0.33}$)($Eu_{1.34}Ce_{0.66}$)$Cu_2O_z$ and from y = 0.25 to 0.5 for ($Ru_{1-y}Cu_y$)($Sr_{1.47}Ba_{0.2}Eu_{0.33}$)($Eu_{1.34}Ce_{0.66}$)$Cu_2O_z$, respectively. All samples with compositions of ($Ru_{0.5}Cu_{0.5}$)($Sr_{1.67-x}Ba_xEu_{0.33}$) ($Eu_{1.34}Ce_{0.66}$)$Cu_2O_z$ (x = 0 - 0.33) show superconducting transition behavior and the onset transition temperature decreases slightly with increasing x in consistent with the change of hole concentration estimated from room temperature thermoelectric power measurements. The XRD and resistivity measurements for the ($Ru_{1-y}Cu_y$)($Sr_{1.47}Ba_{0.2}Eu_{0.33}$)($Eu_{1.34}Ce_{0.66}$) $Cu_2O_z$ system indicate that the partial substitution of Cu for Ru is necessary to form phase pure samples, but result in a small change in transition temperature in the single-phase region from x = 0.25 to 0.5.