• Title/Summary/Keyword: coercive field

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Degradation Evaluation of Turbine Rotor Using Magnetic Method (자기적 방법에 의한 터빈 로터강의 열화도 평가)

  • Ryu, K.S.;Park, J.S.;Nahm, S.H.;Kim, Y.I.;Yu, K.M.;Ryu, J.C.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1593-1595
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    • 2000
  • We present a new procedure to evaluate the degradation in a lCr-lMo-0.25V steel. The method is based on the existence of the peak of reversible permeability in the differential magnetization around the coercive field strength. The apparatus is based on the detection of the voltage induced in a surface type coil using a lock-in amplifier tuned to a frequency to the exciting one. Results obtained the reversible permeability and Vickers hardness on the annealed samples show the peak interval of reversible permeability and Vickers hardness decreased as ageing time increased. The correlation between Vickers hardness and the peak interval of reversible permeability could well be evaluated non destructively.

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The study on Dielectric and Strain Properties of ((1-y-x)Pb(Mg$_{1}$3 Nb$_{2}$3/)O$_3$-yPbTiO$_3$-xSrTiO$_3$Ceramics ((1-y-x)Pb(Mg$_{1}$3 Nb$_{2}$3/)O$_3$-yPbTiO$_3$-xSrTiO$_3$세라믹의 유전 및 변위 특성에 관한 연구)

  • 이해영;이덕출;이능헌;김용혁
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1994.05a
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    • pp.5-8
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    • 1994
  • In this paper, Dielectric and strain properties of (1-x-y)PMN-yPT-xST Ceramics hale been investigated as a function of the amount of SrTiO$_3$(ST). The SrTiO$_3$ content is ranged from 0.01-0.05(wt%). As the amount of ST is increased, dielectric constant has a maximun value at 0.05 mol% composition. The Curie temperature is decreased linearly with increasing ST composition and Polarization properties have been investigated. Coercive field and remnant polarization has a maximum value at 0.01mo1% composiion.

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Fabrication and characteristics of PZT ferroelectric thin films by Sol-Gel processing and rapid thermal annealing (Sol-gel법과 급속 열처리에 의한 PZT 강유전 박막의 제작과 그 특성)

  • 백동수;최형욱;김준한;신현용;김규수;박창엽
    • Electrical & Electronic Materials
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    • v.7 no.5
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    • pp.369-375
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    • 1994
  • In this study, ferroelectric thin films of PZT with different Zr/Ti ratio were prepared by sol-get processing and annealed by rapid thermal annealing at >$500^{\circ}C$>$-700^{\circ}C$ for 10 sec. -1 min. Structures of the annealed films were examined by X-ray diffraction and SEM. Thin films of PZT with perovskite structure have been obtained by annealing at >$600^{\circ}C$ or above and for 20 seconds or longer. Maximum remnant polarization of 10.24.mu.C/cm$^{2}$ and minimum coercive field of 20.06 kV/cm were obtained from the 56/44 and 65/35 Zr/Ti composition films, respectively. Dielectric constant, .epsilon.$_{r}$ of 500-1300 and dielectric loss, tan .delta., of 0.01-0.035 were obtained from the films.s.

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Ferroelectirc Properties of Eu-doped PZT Thin Films (Eu 첨가에 따른 PZT 박막의 강유전 특성)

  • 김창일;손영훈;김경태;김동표;이병기
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.7
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    • pp.611-615
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    • 2003
  • Eu-doped lead zirconate titanate(Pb$\sub$1.1/(Zr$\sub$0.6/Ti$\sub$0.4/)O$_3$; PZT) thin films on the Pt/Ti/SiO$_2$/Si substrates prepared by a sol-gel method. The effect on structural and electrical properties of PZT thin films measured according to the Eu content. Eu-doping altered significantly dielectric and ferroelectric properties. The remanent polarization and the coercive field decreased with the increasing Eu content. The dielectric constant and the dielectric loss of PZT thin films decreased with the increasing Eu content. The 0.5 mol% of Eu-doped PZT thin film showed improved fatigue characteristic comparing to the undoped PZT thin film.

Electronic properties of PZT(20/80) thick film and PZT(80/20) thin film multilayer with variation of sintering temperature (다층 PZT(20/80)후막과 PZT(80/20)박막의 소결온도에 따른 전기적 특성)

  • Noh, Hyun-Ji;Lee, Sung-Gap;Park, Sang-Man;Bae, Seon-Gi
    • Proceedings of the KIEE Conference
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    • 2006.07c
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    • pp.1703-1704
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    • 2006
  • In this paper, PZT(20/80) thick films were fabricated by the screen-printing method. And the PZT(80/20) coating solution was synthesized by the sol-gel method. PZT(20/80) thick films were screen-printed on the alumina substrates. PZT(80/20) thin film was spin-coated on the PZT(20/80) thick films to obtain densification. And the structural and electrical properties of PZT thick films were investigated with variation of sintering temperature. The PZT specimen sintered at $650^{\circ}C$ showed good relative dielectric constant of 219 and dielectric loss of 2.45%. Also the remanent polarization and the coercive field were $16.48{\mu}C/cm^2$ and 35.48kV/cm, respectively.

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Ferroelectric Properties of SBT Capacitors with Annealing Conditions (SBT 커패시터의 열처리 조건에 따른 강유전 특성)

  • Lee, Sung-Ill
    • Journal of the Korean Society of Safety
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    • v.19 no.1
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    • pp.72-76
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    • 2004
  • The $Sr_{0.7}Bi_{2.6}Ta_2O_9$(SBT)thin films are deposited on pt-coated electrode(Pt/$TiO_2/SiO_2/Si$) using a RF magnetron sputtering method. The electrical properties of SBT capacitors with annealing conditions were studied. In the XRD pattern, the SBT thin films in all annealing temperatures had (105) orientation. In the SEM images, Bi-layered perovskite phase was crystallized at $750^{\circ}C$,/TEX> and grains largely grew in oxygen annealing atmosphere. The maximum renanent polarization and the coercive electric field with annealing conditions are 12.40C/$cm^2$ and 30kV/cm, respectively. The dielectric constant and leakage current density with Pt electrode is 340 and 2.13${\times}10^{-10}A/cm^2$, respectively.

Aging Properties of SBT Thin Films Prepared by RF Magnetron Sputtering Method

  • Cho, C.N.;Kim, J.S.;Oh, Y.C.;Shin, C.G.;Choi, W.S.;Kim, C.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.474-475
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    • 2007
  • The $Sr_{0.8}Bi_{2.2}Ta_2O_9$(SBT) thin films are deposited on Pt-coated electrode(Pt/$TiO_2/SiO_2$/Si) using RF magnetron sputtering method. The aging properties of SBT capacitor with top electrodes represents a favorable properties in Pt electrode. The dielectric constant and leakage current density with Pt electrode is 340 and $6.81{\times}10^{-10}\;A/cm^2$ respectively. The maximum remanent polarization and the coercive electric field with Pt electrode are $12.40{\mu}C/cm^2$ and 30kV/cm respectively.

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Fabrication of PZT ferroelectric thin films by rapid thermal annealing (급속 열처리에 의한 PZT 강유전 박막의 제작)

  • Paik, Dong-Soo;Kim, Hyun-Gwon;Choi, Hyung-Wook;Kim, Jun-Han;Park, Chang-Yub;Shin, Hyun-Yong
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.1106-1109
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    • 1993
  • Ferroelectric thin films of PZT with differnt Zr/Ti ratio were prepared by sol-gel processing and annealed by rapid-thermal-annealing at $500^{\circ}C-700^{\circ}C$ for 10sec-1min. The structure of the annealed films were examined by X-ray diffraction and SEM. Maximum remnant polarization of 10.24 ${\mu}m/cm^2$ and coercive field of 70 KV/cm were obtained from hysteresis curve or the film.

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The Study on The Magnetic Properties of Amorphous Fe-B-Si-Ge Ribbons (Fe-B-Si-Ge 비정질 리본의 자기적 특성 연구)

  • 민복기
    • Electrical & Electronic Materials
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    • v.10 no.2
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    • pp.113-118
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    • 1997
  • For the amorphous F $e_{78}$ $B_{13}$S $i_{9-x}$G $e_{x}$ alloy, thermal analysis and measurements of the magnetic properties were carried out. As the content of Ge increased, the crystallization temperature was decreased and the Curie temperature was increased, and the tendencies were almost linear. The core loss of the amorphous alloy for x=1.7, field annealed at optimized condition, was 0.057 W/kg(l.0T, 60Hz), which was about 30% lower than that of no Ge added amorphous alloy (basic composition). Such a low core loss characteristics was thought to be caused by the lower coercive force and good squareness of B-H loop of the alloy.y.y.

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Preparation of ferroelectric SrBi2Ta2O9 thin films deposited by multi-target sputtering

  • Hoon, Yang-Cheol;Gil, Yoon-Soon
    • Journal of Korean Vacuum Science & Technology
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    • v.2 no.2
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    • pp.92-96
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    • 1998
  • Ferroelectric Bi-layered oxides SrBi2Ta2O9 (SBT) thin films have been deposited on Pt/Ti/SiO2/Si substrates using multi-target sputtering. Structure, composition, and electrical properties have been investigated on films. The SBT films were deposited with the various bismuth sputtering powers. The SBT films deposited with the bismuth sputtering power of 20 W have the most dense microstructure and the remanent polarization (Pr) of 9.2 ${\mu}$C/cm and the coercive field (Ec) of 43.8 kV/cm at an applied voltage of 5V. The SBT films deposited with the bismuth sputtering power of 20W showed a fatigue-free characteristics up to 1.0${\times}$1010 cycles under 5V bipolar pulse and a leakage current density of 2.0${\times}$10-8 A/$\textrm{cm}^2$ at 200 kV/cm.

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