• Title/Summary/Keyword: NbS

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Properties of MFSEET′s with various gate electrodes using $LiNbO_3$ ferroelectric thin film ($LiNbO_3$강유전체 박막을 이용한 MFSFET's의 게이트 전극 변화에 따른 특성)

  • 정순원;김광호
    • Journal of the Korean Vacuum Society
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    • v.11 no.2
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    • pp.103-107
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    • 2002
  • Metal/ferroelectric/semiconductor field effect transistors(MFSFET′s) with various gate electrodes, that are aluminum, platinum and poly-Si, using rapid thermal annealed $LiNbO_3$/Si(100) structures were fabricated and the properties of the FET′s have been discussed. The drain current of the "on" state of FET with Pt electrode was more than 3 orders of magnitude larger than the "off" state current at the same "read" gate voltage of 1.5 V, which means the memory operation of the MFSFET. A write voltage as low as about $\pm$4 V, which is applicable to low power integrated circuits, was used for polarization reversal. The retention properties of the FET using Al electrode were quite good up to about $10^3$ s and using Pt electrode remained almost the same value of its initial value over 2 days at room temperature.

Electrically Conductive Silicon Carbide without Oxide Sintering Additives

  • Frajkorova, Frantiska;Lences, Zoltan;Sajgalik, Pavol
    • Journal of the Korean Ceramic Society
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    • v.49 no.4
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    • pp.342-346
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    • 2012
  • This work deals with the preparation of dense SiC based ceramics with high electrical conductivity without oxide sintering additives. SiC samples with different content of conductive Ti-NbC phase were hot pressed at $1850^{\circ}C$ for 1 h in Ar atmosphere under mechanical pressure of 30 MPa. The conductive phase is a mixture of Ti-NbC in weight ratio of Ti/NbC 1:4. Composite with 50% of conductive Ti-NbC phase showed the highest electrical conductivity of $30.6{\times}10^3\;S{\cdot}m^{-1}$, while the good mechanical properties of SiC matrix were preserved (fracture toughness 4.5 $MPa{\cdot}m^{1/2}$ and Vickers hardness 18.7 GPa). The obtained results show that use of NbC and Ti as sintering and also electrically conductive additives is appropriate for the preparation of SiC-based composite with sufficient electrical conductivity for electric discharge machining.

Dielectric and Piezoelectric Properties on the Piezoceramics PZT by Molten Salt Synthesis (Flux법에 의해 제조된 압전 세라믹(PZT)의 유전 및 압전특성)

  • Lee, S.H.;Park, J.B.;SaGong, G.
    • Proceedings of the KIEE Conference
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    • 1992.07b
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    • pp.721-723
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    • 1992
  • The electrical resistivity and piezoelectric properties have been studied for Lead Zirconate-Titanate(PZT) with $Nb_2O_5$ dopant, fabricated from conventional mixed-oxide powders and molten salt synthesis. The resistivity and electromechanical coupling factor(Kp) were increased with increasing Nb contents. The reason for increasing of the electrical resistivity below the Curie Temperature(Tc), It is believed that the p-type electrical conduction in PZT is caused by the lead vacancies. The electromechanical coupling factor(Kr) and piezoelectric constant $d_{33}$ were improved by Nb additives. This behavior can be explained as a compensation effect and $Nb^{5+}$ can serve as a donar and contribute electrons to the conduction process. As a result, the optimized $Nb_2O_5$ dopants on the PZT specimens were 0.75 wt%.

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RRR Behavior due to Fatigue Damage in a NbTi Superconductor Cable (NbTi 초전도 케이블의 피로손상에 따른 RRR의 거동)

  • 신형섭;배영준;하동우;오상수
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 1999.02a
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    • pp.30-33
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    • 1999
  • In this study, the fatigue test at room temperature and residual resistivity measurement test at 12K were carried out, respectively, using a 9 strand Cu-Ni/NbTi/Cu composite cable, in order to investigate how the fatigue damage effects on critical properties. Through the fatigue test of a 9 strand Cu-Ni/NbTi/Cu composite cable, a conventional S-N curve was obtained even though there existed a possibility of fretting among strands. From the resistivity measurement of a NbTi strand after fatigue tests, it was found that with increase of the repeated number the RRR increased slightly, and the trend became significant with increase in maximum value of the applied stress amplitude.

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