• Title/Summary/Keyword: Mg-doped

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Influence of the Heat-treatment Temperature on the Critical Properties of $C_4H_6O_5$-doped $MgB_2/Fe$ Wire ($C_4H_6O_5$ 도핑된 $MgB_2/Fe$ 선재의 임계특성에 대한 열처리 온도의 영향)

  • Jun, Byung-Hyuk;Kim, Jung-Ho;Dou, Shi Xue;Kim, Chan-Joong
    • Progress in Superconductivity
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    • v.9 no.1
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    • pp.62-67
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    • 2007

  • The effects of the heat-treatment temperature on the carbon (C) substitution amount, full width at half maximum (FWHM) value, critical temperature ($T_c$), critical current density ($J_c$) have been investigated for 10 wt % malic acid ($C_4H_6O_5$)-doped $MgB_2/Fe$ wires. All the samples were fabricated by the in-situ powder-in-tube (PIT) method and heat-treated within a temperature range of $650^{\circ}C$ to $1000^{\circ}C$. As the heat-treatment temperature increased, it seemed that the lattice distortion was increased by a more active C substitution into the boron sites from the malic acid addition. These increased electron scattering defects seemed to enhance the $J_c-H$ properties in spite of an improvement in the crystallinity, such as a decrease of the FWHM value and an increase of the $T_c$. Compared to the un-doped wire heat-treated at $650^{\circ}C$ for 30 min, the $J_c$ was enhanced by the C doping in a high-field regime. The wire heat-treated at $900^{\circ}C$ resulted in a higher magnetic $J_c$ of approximately $10^4\;A/cm^2$ at 5 K and 8 T.

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Optical characterization on undoped and Mg-doped GaN implanted with Eu (Eu이 이온주입된 undoped와 Mg-doped GaN의 분광 특성 연구)

  • Lee, So-Won;Moon, Joo-Young;Rhee, Seuk-Joo
    • Journal of the Korean Vacuum Society
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    • v.17 no.4
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    • pp.346-352
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    • 2008

  • Eu sites and the effect of Mg codoping were investigated in Eu-implanted GaN films. Photoluminescence (PL) and PL excitation spectroscopies were performed on 620nm $^5D_0\;{\rightarrow}\;^7F_2$ Eu ionic level transition and revealed the existence of 4 different Eu sites including the known 2 sites. PL intensity from one of the sites increased by a factor of 1.6 by the Mg-codoping. The enhancement of PL by Mg-codoping was less pronounced than Er- and Nd-implanted GaN, in which the trap-mediated energy transfer dominates. In GaN:Eu the above-gap excitation transfers the energy directly to the Mg related Eu site.

  • https://doi.org/10.5757/JKVS.2008.17.4.346 인용 PDF KSCI

Crystal structure, microstructure, and low-loss dielectric property of MgO-added (Ca,Sr)(Zr,Ti)O3 (MgO가 첨가된 (Ca,Sr)(Zr,Ti)O3의 결정구조, 미세구조 및 저손실 유전특성)

  • Do-Hyeok Lee;Kyoung-Seok Moon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.6
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    • pp.261-267
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    • 2023

  • Crystal structure, microstructure, and dielectric properties of the (Ca, Sr)(Zr, Ti)O3 (CSZT) system has been studied as a function of sintering temperature and MgO addition for microwave applications. A single-phase CSZT powder with the orthorhombic crystal structure was obtained by the solid-state reaction method. The powder compacts were sintered at 1200℃, 1300℃, and 1400℃ respectively. All the sintered samples had a single-phase orthorhombic crystal structure and grain size increased with sintering temperature. In the case of 1 mol% MgO addition, the orthorhombic crystal structure was the main phase; however, a secondary phase appeared during sintering at 1400℃, as determined by EDS analysis. At 1400℃, the undoped and MgO-doped CSZT had almost similar grain size distribution and densification but the grain size distribution became slightly narrow. The MgO-doped CSZT showed excellent low-loss dielectric properties: εr = 34.14, tanδ = 0.00047, τε = -3.58 ppm/℃ at 1 MHz.

  • https://doi.org/10.6111/JKCGCT.2023.33.6.261 인용 PDF

Crystalline and electrical properties of ${Li_2}{CO_3}$ and MgO doped ${Ba_{0.5}}{Sr_{0.5}}{TiO_3}$ composites (${Li_2}{CO_3}$와 MgO가 첨가된 ${Ba_{0.5}}{Sr_{0.5}}{TiO_3}$의 결정학적 전기적 특성)

  • You, Hee-Wook;Park, Yong-Jun;Nam, Song-Min;Koo, Sang-Mo;Park, Jae-Yeong;Lee, Young-Hie;Koh, Jung-Hyuk
    • Proceedings of the KIEE Conference
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    • 2006.10a
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    • pp.3-4
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    • 2006

  • ${Li_2}{CO_3}$ and MgO doped paraelectric ${Ba_{0.5}}{Sr_{0.5}}{TiO_3}$, materials were prepared and compared for LTCC applications. In these days LTCC (Low Temperature Co-fired Ceramics) technology has been widely employed for electronic modules for the communication systems such as front-end modules, antenna modules, and switching modules. In this paper, 1 ${\sim}$ 5 wt % of ${Li_2}{CO_3}$, and 30 wt % of MgO were added to ${Ba_{0.5}}{Sr_{0.5}}{TiO_3}$, respectively. The crystalline properties and electrical properties will be compared and discussed.

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