• Title/Summary/Keyword: Antiferroelectrics

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The Effect of Pb Mol Ratio in PbZrO3 Thin Films made by Sol-Gel Method (Sol-Gel법에서 Pb의 농도가 PbZrO3 박막 결정에 미치는 영향)

  • Bae, Se-Hwan;Jin, Byung-Moon;Kim, Sung-Dae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.6
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    • pp.552-555
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    • 2008
  • The purpose of this study was to find a best condition of fabricating lead zirconate thin film by sol-gel method, especially to find mol ratio and post annealing temperature. Lead zirconate thin film was made by spin coating method. The ratios of Pb and Zr of precursors were 1:0.8, 1:1.0, and 1:1.2. Annealing temperature of films were $600^{\circ}C$, $700^{\circ}C$, and $800^{\circ}C$ for 1 minute. Crystal structure was observed from XRD and antiferroelectricity was observed from hysteresis curves. The optimum mol ratio of Pb:Zr is 1:0.8 and annealing temperature is $800^{\circ}C$.

Simulataneous X-ray Diffraction Measurements of the Antiferroelectric-ferroelectric Phase Transition of PLZT under Electric Field (전장하에서 PLZTd의 반강유전-강유전 상전이의 동시적 X-선 회절 측정)

  • 고태경;조동수;강현구
    • Journal of the Korean Ceramic Society
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    • v.33 no.11
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    • pp.1292-1300
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    • 1996
  • In-site X-ray diffraction measurements under electric field up to 20kV/ cm were carried out on PLZT (x/70/30) with x=7.5, 8.0, 8.5, and 10.5 All of PLZT belonged to cubic phases. At x=7.5, 8.0 and 8.5 PLZT behaved as an antiferroelectric under low electric fields up to 4-8 kV/cm. PLZT became ferroelectric at the higher electric fields. The high-temperature measurements on the dielectric constants of PLZT with x=7.5, 8.0 and 8.5 showed that they were similar to relaxor ferroelectrics and underwent a diffuse phase transition from antiferroelectrics to paraelectrics at 50-7$0^{\circ}C$. Their P-E hysteresis curves confirmed that they were antifer-roelectrics. The broad distribution of Curie points suggests that there is a significant disorder of cations and vacances in the crystal structure of those PLZT due to La-substitution. The variation of the lattice strain of PLZT(10.5/70/30) with electic field was very small and did not show any hysteresis confirming that it was paraelectric. The degree of the electric-induced strain variation decreased as La doping increased. In PLZT(7.5/70/30) the intensity of 110 reflection changes sensitively by applying electric field. Some domains with polarization parallel to [110] appeared to be developed in the field-induced ferroelectric phase of the PLZT.

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