Zn-Pr-Co-Cr-Dy 산화물계 바리스터의 전기적, 유전적 특성

남춘우,박종아,김명준,류정선 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.10

Dy$_2$ $O_3$의 첨가량이 0.0∼2.0 ㏖% 범위인 Zn-Pr-Co-Cr-Dy 산화물계 바리스터의 미세구조 및 전기적 특성을 조사하였다. Dy$_2$ $O_3$의 첨가량을 증가시킴에 따라 평균 결정립 크기는 18.2∼4.6 $\mu\textrm{m}$ 범위로 감소하였으며, 세라믹스 밀도는 5.49∼4.64 g/㎤ 범위로 감소하였다 Dy$_2$ $O_3$가 첨가된 바리스터는 Dy$_2$ $O_3$가 첨가되지 않은 바리스터에 비해 비직선 지수가 9배이상 증가하는 현저한 비직선성의 증가를 나타내었다. 0.5∼l.0 ㏖% 범위의 Dy$_2$ $O_3$가 첨가된 바리스터는 비직선 지수가 55 이상이고 누설전류가 1.0 $\mu\textrm{A}$ 이하의 높은 비직선성을 나타내었다. C-V특성에 있어서, 도너농도 및 계면상태밀도는 Dy$_2$ $O_3$의 첨가량 증가에 따라 각각 (4.66∼0.25)${\times}$$10^{18}$/㎤, (5.70∼1.39)${\times}$$10^{12}$/$\textrm{cm}^2$ 범위에서 감소하는 경향을 나타내었다. 유전손실계수는 Dy$_2$ $O_3$의 첨가량 증가에 따라 0.5 ㏖% 첨가시 최소치 0.0023을 정점으로 하여 다시 증가하는 경향을 나타내었다. The microstructure and electrical characteristics of Zn-Pr-Co-Cr-Dy oxides-based varistors were investigated with Dy$_2$ $O_3$ content in the range of 0.0∼2.0 ㏖%. As Dy$_2$ $O_3$ content is increased, the average grain size was decreased in the range of 18.2∼4.6 $\mu\textrm{m}$ and the ceramic density was decreased in the range of 5.49∼4.64 g/㎤. The incorporation of Dy$_2$ $O_3$ markedly enhanced the nonlinear properties of varistors more than 9 times in nonlinear exponent, compared with the varistor without Dy$_2$ $O_3$ The varistor with 0.5∼1.0 ㏖% Dy$_2$ $O_3$ exhibited the high nonlinearity, in which the nonlinear exponent is above 55 and the leakage current is below 1.0 ${\mu}\textrm{A}$. The donor concentration and the density of interface states were decreased in the range of (4.66∼0.25)${\times}$10$\^$18//㎤ and (5.70∼1.39)${\times}$10$\^$12//$\textrm{cm}^2$, respectively, with increasing Dy$_2$ $O_3$ content. The minimum dielectric dissipation factor of 0.0023 was obtained for 0.5 ㏖% Dy$_2$ $O_3$, but further addition of Dy$_2$ $O_3$ increased it.

BiFeO₃박막의 Dy-, Mn-치환 효과에 대한 물리적 특성

배유라,김진원,도달현,김상수 한국물리학회 2011 새물리 Vol.61 No.4

We prepared pure BiFeO₃and Dy and Mn-doped BiFeO₃ (Bi_(0.9)Dy_(0.1)FeO₃,Bi(Fe_(0.975)Mn_(0.025)O_(3-δ)and (Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)thin films on Pt(111)/Ti/SiO₂ /Si(100) substrates by using a chemical solution deposition method. The coated thin films were annealed at 550℃ for 30 min by using a conventional annealing process under a nitrogen atmosphere, and the changes in the microstructure and the electrical properties with doping were investigated. The remnant polarization (2P_r) and the coercive field (2E_c) of the Dy- and Mn-codoped BiFeO₃,Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ), thin film were 47 μC/cm² and 741 kV/cm respectively at an applied electric field of 1060 kV/cm. The leakage current density of the BiFeO₃and the Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ) thin films were 2.58 ×10^(−3) A/cm² and 1.41×10^(−5) A/cm²,respectively at 100 kV/cm, and their dielectric constants and dielectric losses of the thin films were 140 and 0.049, and 152 and 0.037 at 1 kHz, respectively. The good ferroelectric properties observed in the Dy- and Mn-codoped BiFeO₃ thin film may be related to a reduction in the numbers of bismuth vacancies and oxygen vacancies. 화학 용액 증착법으로 Pt(111)/Ti/SiO₂/Si(100) 기판 위에 순수한BiFeO₃박막과 BiFeO₃의 Bi^(3+), Fe^(3+) 이온 일부를Dy^(3+), Mn^(2+) 이온으로 치환한 (Bi_(0.9)Dy_(0.1)FeO₃,Bi(Fe_(0.975)Mn_(0.025)O_(3-δ),Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)박막을 성장시켰다. 성장된 박막은 550 ℃의 질소 분위기에서통상적인 방법으로 열처리 하였으며 치환에 따른 박막의 구조와 강유전및 유전, 전류 특성 등 전기적 특성의 변화를 측정, 비교 분석 하였다. Dy와 Mn으로 동시에 치환한Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)박막시료의 전기적 특성이 순수한 BiFeO₃의 특성에 비해 크게향상되었는데 외부 전기장 1060 kV/cm 일 때 잔류 분극 (2P_r) 과항전기장 (2E_c) 값이 각각 47μC/cm², 741 kV/cm이었다. 또순수한 BiFeO₃박막과Bi_(0.9)Dy_(0.1) Fe_(0.975)Mn_(0.025)O_(3-δ)박막의 누설 전류 밀도는 외부 전기장 100 kV/cm일 때 각각 2.58×10^(-3) A/cm², 1.41×10^(-5) A/cm²이었으며, 1 kHz에서 유전상수와 유전손실 값은 각각 140, 0.049 과 152,0.037이었다. 이와 같이 Dy와 Mn으로 동시에 치환한 박막이 좋은 전기적특성을 보이는 것은 치환에 의해서 비스무스 빈자리와 산소 빈자리 수가감소하였기 때문이라고 보여진다.

1550㎚ 자기광학 응용을 위한 고농도 Dy<SUP>3+</SUP> 이온이 함유된 알루미노보로실리케이트 유리의 제조 및 자기광학 특성 분석

카다탈라 린가나(Kadathala Linganna),류용탁(Yong-Tak Ryu),박영욱(Young-Ouk Park),유봉안(Bong-Ahn Yu),김복현(Bok Hyeon Kim) 한국광학회 2024 한국광학회지 Vol.35 No.3

Zn-Pr-Co-Cr-Dy 산화물계 바리스터 세라믹스의 전기적 안정성

남춘우,박종아,김명준,류정선 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.11

Zn-Pr-Co-Cr-Dy 산화물계로 구성된 바리스터 세라믹스의 전기적 안정성을 몇 가지 DC 가속열화 스트레스 조건하에서 0.0∼2.0 mol% Dy$_2$O$_3$ 첨가량의 변화에 따라 조사하였다. 바리스터 세라믹스의 밀도는 Dy$_2$O$_3$ 첨가량이 0.5 mol%까지 증가하였으며, 보다 많이 첨가하면 감소하는 것으로 나타났다. 밀도는 전도경로와 밀접한 관계로 인해서 안정성에 큰 영향을 미치는 것으로 나타났다. Dy$_2$O$_3$ 첨가는 바리스터 세라믹스의 비직선 지수를 45 이상, 누설전류를 대략 1.0 $\mu$A 이하로 비직선성을 크게 개선시켰다. DC 스트레스 조건 0.95 V$_{1mA}$/15$0^{\circ}C$/24 h에서 안정성을 조사한 결과, 0.5 mol% 첨가시 상대적으로 가장 높은 안정성을 나타내었다. 전압-전류특성에 있어서 바리스터 전압, 비직선 지수, 누설전류의 변화율은 각각 -0.9%, -14.4%, +483.3%이었으며, 유전특성에 있어서 비유전율 및 손실계수의 변화는 각각 +7.1%, +315.4%이었다. 그 외의 바리스터 세라믹스는 낮은 밀도 때문에 열폭주 현상을 나타내는 매우 불안정한 특성을 나타내었다.다. The electrical stability of the varistor ceramics composed of Zn-Pr-Co-Cr-Dy oxides-based varistors was investigated at 0.0∼2.0 mol% Dy$_2$O$_3$ content under DC accelerated aging stress. The ceramic density was increased up to 0.5 mol% Dy$_2$O$_3$ whereas further addition of Dy$_2$O$_3$ decreased sintered ceramic density. The density sailently affected the stability due to the variation of conduction path. The nonlinearity of varistor ceramics was greatly improved above 45 in the nonlinear exponent and below nearly 1.0 ${\mu}$A by incorporating Dy$_2$O$_3$. Under 0.95 V$\_$1mA/150$^{\circ}C$/24 h stress state, the varistor ceramics doped with 0.5 mol% Dy$_2$O$_3$ exhibited the highest electrical stability, in which the variation rates of varistor voltage, nonlinear exponent, and leakage current were -0.9%, -14.4%, and +483.3%, respectively. The variation rates of relative permittivity and dissipation factor were +7.1% and +315.4%, respectively. The varistors with further addition of Dy$_2$O$_3$ exhibited very unstable state resulting in the thermal runaway due to low density.

Color-tunable luminescence in Y_{7(1-<i>m</i>-<i>n</i>-<i>z</i>)}Bi_7<i>m</i>Dy_7<i>n</i>Eu_7<i>z</i>O₆F₉ (<i>m</i> = 0.001–0.05, <i>n</i> = 0–0.1, <i>z</i> = 0.005, 0.01) phosp

Yang, Sungjun,Kim, Huntae,Park, Sangmoon Elsevier 2018 Optical materials Vol.77 No.-

<P><B>Abstract</B></P> <P>Luminescent materials composed of Y<SUB>7(1-<I>m</I>-<I>n</I>-<I>z</I>)</SUB>Bi<SUB>7<I>m</I> </SUB>Dy<SUB>7<I>n</I> </SUB>Eu<SUB>7<I>z</I> </SUB>O<SUB>6</SUB>F<SUB>9</SUB> (<I>m</I> = 0.001–0.05, <I>n</I> = 0–0.1, <I>z</I> = 0.005, 0.01) were prepared using a flux-assisted solid-state reaction method. The X-ray diffraction patterns of the resultant phosphors were examined to index the peak positions. The excitation and emission spectra of Y<SUB>7(1-<I>m</I>-<I>n</I>)</SUB>Bi<SUB>7<I>m</I> </SUB>Dy<SUB>7<I>n</I> </SUB>O<SUB>6</SUB>F<SUB>9</SUB> (<I>m</I> = 0.01, <I>n</I> = 0; <I>m</I> = 0, <I>n</I> = 0.01; <I>m</I> = 0.01, <I>n</I> = 0.01) were investigated using photoluminescence (PL) spectroscopy. Critical emission quenching, as a function of Bi<SUP>3+</SUP> or Dy<SUP>3+</SUP> contents in Y<SUB>7</SUB>O<SUB>6</SUB>F<SUB>9</SUB>, was similarly observed at relatively low concentrations of both the activators. The dependence of the luminescent intensity of the Dy<SUP>3+</SUP> co-doped (<I>n</I> = 0–0.1) host lattices on the Bi<SUP>3+</SUP> content (<I>m</I> = 0.01) was also studied. Co-doping Dy<SUP>3+</SUP> into the Bi<SUP>3+</SUP>-doped host structure enabled high energy transfer from Bi<SUP>3+</SUP> to Dy<SUP>3+</SUP>; this energy transfer mechanism is discussed. Furthermore, the Y<SUP>3+</SUP> ions in the lattice were replaced by Eu<SUP>3+</SUP> ions in Y<SUB>7(1-<I>m</I>-<I>n</I>)</SUB>Bi<SUB>7<I>m</I> </SUB>Dy<SUB>7<I>n</I> </SUB>O<SUB>6</SUB>F<SUB>9</SUB> (<I>m</I> = 0.01, <I>n</I> = 0.01), and the diverse emission spectra by the energy-transfer and cooperation of Bi<SUP>3+</SUP>, Dy<SUP>3+</SUP>, and Eu<SUP>3+</SUP> transitions and color Commission Internationale de l’Eclairage (CIE) coordinates were obtained. With these phosphors, the desired CIE values including emissions throughout blue, green, white, and red color regions of the spectra were achieved.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bi<SUP>3+</SUP>, Dy<SUP>3+</SUP>, Eu<SUP>3+</SUP> co-doped Y<SUB>7</SUB>O<SUB>6</SUB>F<SUB>9</SUB> phosphors were prepared. </LI> <LI> Efficient energy-transfer occurred from Bi<SUP>3+</SUP> to Dy<SUP>3+</SUP>. </LI> <LI> Cooperation mechanism of Bi<SUP>3+</SUP>, Dy<SUP>3+</SUP>, and Eu<SUP>3+</SUP> transitions was discussed. </LI> <LI> Color-tunable luminescence was achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Neutron transmission and capture measurements and analysis of Dy from 0.01 to 550 eV

Block, R.C.,Bishop, M.C.,Barry, D.P.,Leinweber, G.,Ballad, R.V.,Burke, J.A.,Rapp, M.J.,Danon, Y.,Youmans, A.,Drindak, N.J.,Kim, G.N.,Kang, Y.-R.,Lee, M.W.,Landsberger, S. Elsevier 2017 Progress in nuclear energy Vol.94 No.-

<P><B>Abstract</B></P> <P>Neutron capture and transmission measurements were carried out from 0.01 to over 600 eV on both natural Dy and samples highly enriched in <SUP>164</SUP>Dy. These data were analyzed for resonance parameters utilizing the SAMMY Bayesian analysis code to simultaneously fit both the capture and transmission data. Parameters were obtained for 17 resonances in Dy isotopes up to 18 eV and for the <SUP>164</SUP>Dy resonances near 147, 450 and 540 eV. The thermal capture cross section (at 0.0253 eV) and capture resonance integral were determined for <SUP>164</SUP>Dy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Transmission and capture measurements from thermal to 550 eV on Dy and <SUP>164</SUP>Dy samples. </LI> <LI> Bayesian analysis provided resonance parameters from the combined measurements. </LI> <LI> Liquid samples were used to obtain uniformly thin <SUP>164</SUP>Dy samples. </LI> <LI> The <SUP>164</SUP>Dy thermal cross section and resonance integral were obtained from these measurements. </LI> <LI> Improvements were made for the 5.45 eV <SUP>162</SUP>Dy resonance parameters. </LI> </UL> </P>

Pr₆O₁₁계 ZnO 바리스터 세라믹스의 미세구조 및 전기적 특성에 미치는 Dy₂O₃첨가의 영향

남춘우,박종아,Nahm, Choon-Woo,Park, Jong-Ah 한국재료학회 2003 한국재료학회지 Vol.13 No.10

The microstructure and electrical characteristics of $Pr_{6}$ $O_{11}$ -based ZnO varistor ceramics composed of $ZnO-Pr_{6}$ $O_{ 11}$/$-CoO-Cr_2$$O_3$-$Dy_2$$O_3$-based ceramics were investigated with $Dy_2$$O_3$content in the range of 0.0∼2.0 mol%. As $Dy_2$$O_3$content was increased, the average grain size was decreased in the range of 18.6∼4.7 $\mu\textrm{m}$ and the density of the ceramic was decreased in the range of 5.53∼4.34 g/㎤. While, the varistor voltage was increased in the range of 39.4∼436.6 V/mm and the nonlinear exponent was in the range of 4.5∼66.6 with increasing $Dy_2$$O_3$content. The addition of $Dy_2$$O_3$highly enhanced the nonlinear properties of varistors, compared with the varistor without $Dy_2$$O_3$. In particular, the varistor with $Dy_2$$O_3$ content of 0.5 mol% exhibited the highest nonlinearity, in which the nonlinear exponent is 66.6 and the leakage current is 1.2 $\mu\textrm{A}$. The donor concentration and the density of interface states were decreased in the range of $(4.19∼0.33) ${\times}$10^{18}$ //㎤ and $(5.38∼1.74) ${\times}$10^{12}$ $\textrm{cm}^2$, respectively, with increasing $Dy_2$$O_3$content. The minimum dissipation factor of 0.0302 was obtained from 0.5mol% $Dy_2$$O_3$.

고상반응법과 착체중합법으로 합성된 SrAl₂O₄: Eu²⁺, Dy³⁺ 축광성 형광체의 특성 및 열적 안정성 평가

김태호,황해진,김진호,황광택,한규성,Kim, Tae-Ho,Hwang, Hae-Jin,Kim, Jin-Ho,Hwang, Kwang-Taek,Han, Kyu-Sung 한국결정성장학회 2016 韓國結晶成長學會誌 Vol.26 No.5

Characteristics of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors synthesized by solid state reaction and polymerized complex method were comparatively analyzed. In order to evaluate thermal stability of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors at high temperature, phosphorescent properties of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ were investigated with thermal treatment at $1250^{\circ}C$ under reducing atmosphere, which was the general heat treatment conditions for ceramic manufacturing process. The phosphorescent properties of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphors synthesized by solid state reaction and polymerized complex method were investigated. The crystal structure and crystallite size were observed through XRD analysis. Microstructure and particle size of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphors were analyzed by SEM and PSA. Photoluminescence and afterglow characteristics of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors were measured by spectrofluorometer. 고상반응법과 착체중합법 두 합성법에 의해 합성된 $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ 축광성 형광체 분말의 특성을 비교 분석하였다. 열적 안정성을 평가하기 위해 산업 도자 제조공정에서 사용되는 열처리 조건($1250^{\circ}C$, 1시간 유지, LPG 환원분위기)을 적용하여 고상반응법과 착체중합법으로 합성된 $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ 축광성 형광체 분말의 열처리 전후의 축광 특성변화를 관찰하였다. 두 합성법으로 합성된 분말과 고온 열처리 전후의 분말은 XRD 분석을 통해 결정구조 및 결정자 크기변화를 확인하였고, SEM과 PSA 분석을 이용하여 미세구조 및 입자 크기 변화를 관찰하였다. Spectrofluorometer 분석을 통해 $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ 축광성 형광체의 여기 및 발광 특성, 장잔광 특성 변화를 확인하였다.

Energy Transfer and Luminescence Properties of Dy3+ Ions Doped in La2W3O12 Lattices

Cheol Woo Park,Peiqing Cai,Cuili Chen,Qin Lin,Cheng Han,Jing Wang,Thi Hang Dang,Thi Quynh Vu,Sun Il Kim,Hyo-Jin Seo 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.10

La2W3O12:Dy3+ phosphors were synthesized by using a high-temperature solid-state reaction. The Dy3+ concentration in the La2W3O12 lattice was varied from 0.01 to 100 %. The crystalline phases of the samples were confirmed by using an X-ray diffraction analyses. Emission and excitation spectra and decay curves of Dy3+ ions in the La2W3O12 lattices were measured at room temperature. The two charge-transfer (CT) bands that overlapped in the wavelength region 210 - 320 nm were identified as being due to the CT transitions of O2−-Dy3+ and WO2− 4 . The decay times of the 4F9/2 emission were shortened with increasing Dy3+ concentration, and the decay curves were slightly nonexponential even at low Dy3+ concentration. The decay curves were well fitted by the Inokuti- Harayama model based on the energy-transfer process between two Dy3+ ions at concentrations lower than 10 mol%. On the other hand, the energy diffusion among Dy3+ ions dominate the energy-transfer process at higher Dy3+ concentrations up to 100 mol%.

Bridgman growth, luminescence and energy transfer studies of Tm3+ or/and Dy3+ co-doped Bi4Si3O12 crystal phosphor

Bobo Yang,Jiayue Xu,Jun Zou,Yan Zhang,Tian Tian,Yaoqing Chu,Meiling Wang 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.6

Tm3+, Dy3+ and Tm3+/Dy3+ co-doped bismuth silicate (Bi4Si3O12, BSO) crystals were successfully grown by the modified verticalBridgeman method. The crystals have about 80% transmittance in the range from 320 nm to 650 nm except several obviouscharacteristic absorption peaks corresponding to transitions of 4f electrons of Tm3+ and Dy3+. The luminescence properties forwhite light emitting diode (w-LED) were investigated. Energy transfer from the Bi3+ ions to the Tm3+ and Dy3+ ions in Tm3+or/and Dy3+ co-doped Bi4Si3O12 crystal has been established by photoluminescence investigation upon UV excitation. Whenexcited by a proper UV-light, Tm3+ doped BSO crystal shows blue emission band centered at 460 nm ascribed to Tm3+ (1D2→ 3F4), Dy3+ doped BSO crystal shows blue band at 480 nm (4F9/2→ 6H15/2), yellow band at 574 nm (4F9/2→ 6H13/2) and red bandat 662 nm (4F9/2→ 6H11/2) of Dy3+ ions. A white light with chromaticity coordinate of x = 0.3298, y = 0.2905 by excitation of357 nm is achieved from Tm3+/Dy3+ co-doped Bi4Si3O12 crystal. These results indicate that Tm3+/Dy3+ co-doped Bi4Si3O12 as awhite emitting crystal has a potential application in white-LED.