• Title/Summary/Keyword: Reorientation of dichroism

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Time-Resolved Infrared Spectroscopy of Molecular Reorientation During FLC Electro-Optic Switching

  • Jang, Won-Gun;Clark, Noel A.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1112-1117
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    • 2003
  • Polarized Fourier transform infrared (IR) absorption is used to probe molecular conformation in a ferroelectric liquid crystal (FLC) during the reorientation induced by the external field. Spectra of planar aligned cells of FLC W314 are measured as functions of IR polarizer orientation and electric field applied to the FLC. The time evolution of the dichroism of the absorbance due to biphenyl core and alkyl tail molecular vibration modes, is observed. Static IR dichroism experiments show a W314 dichroism structure in which the principal axis of dielectric tensor from molecular core vibration are tilted further from the smectic layer normal than those of the tail. This structure indicates the effective binding site in which the molecules are confined in the Sm-C phase has, on average, "zig-zag" shape and this zig-zag binding site structure is rigidly maintained while the molecular axis rotates about the layer normal during field-induced switching.

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Photoinduced anisotropy in the Ag and Cu photodoped chalcogenide As-Ge-Se-S thin films (칼코게나이드 As-Ge-Se-S 박막에서 Ag와 Cu 광도핑에 의한 광유기 이방성)

  • 박종화;장선주;박정일;이영종;정홍배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.535-538
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    • 2000
  • We have investigated the photoinduced anisotropy in chalcogenide $As_{40}Ge_{10}Se_{15}S_{35}$ thin films, non-doped and photodoped by Ag and Cu. The films were exposed by the linearly polarized He-Ne laser light( $\lambda$=632.8nm). The Ag and Cu photodoping resulted in reducing the time of saturation photoinduced linearly dichroism. Also photoinduced linearly dichroism was increased up to maximum 184% by Ag photodoping and 138% by Cu photodoping, respectively. As the result of this study, the linearly dichroism can be interesting for different applications of photoinduced anisotropy. In addition, it will offer lots of information for the photodoping mechanism and analysis of chalcogenide thin film.

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Characteristics of the photoinduced anisotropy(PA) in Ag/AsGeSeS multilayer thin films (Ag/AsGeSeS 다층박막의 광유기 이방성(PA) 특성)

  • Park, Jong-Hwa;Na, Sun-Woong;Yeo, Cheol-Ho;Park, Jeong-Il;Lee, Young-Jong;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.362-365
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    • 2001
  • The chalcogenide glasses of thin films have the superior property of photoinduced anisotrophy(PA). In this study, we observed the linear dichroism(D) using the irradiation with polarized He-Ne laser light, in the $Ag/As_{40}Ge_{10}Se_{15}S_{35}$ multi-layer. Mutilayer structures formed by alternating metal(Ag) a chalcogenide$(As_{40}Ge_{10}Se_{15}S_{35})$. Such multilayer structures have a greater sensitivity to illumination am larger dichroism in comparison the conventional double layer structure. Also new phenomena are discovered. These results will be show a capability of new method that suggested more improvement of photoinduced anisotropy property.

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Characteristics of the photoinduced anisotropy(PA) in Ag/AsGeSeS multilayer thin films (Ag/AsGeSeS 다층박막의 광유기 이방성(PA) 특성)

  • 박종화;나선웅;여철호;박정일;이영종;정홍배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.362-365
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    • 2001
  • The chalcogenide glasses of thin films have the superior property of photoinduced anisotrophy(PA). In this study, we observed the linear dichroism(D) using the irradiation with polarized He-Ne laser light, in the Ag/As$\sub$40/Ge$\sub$10/Se$\sub$15/S$\sub$35/ multi-layer. Mutilayer structures farmed by alternating metal(Ag) a chalcogenide(As$\sub$40/Ge$\sub$10/Se$\sub$15/S$\sub$35/). Such multilayer structures have a greater sensitivity to illumination and larger dichroism in comparison the conventional double layer structure. Also new phenomena are discovered. These results will be show a capability of new method that suggested more improvement of photoinduced anisotropy property.

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Magnetic Properties of Fe/Ni Thin Films: First Principles Study

  • Kim, Dong-Yoo;Hong, Ji-Sang
    • Journal of Magnetics
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    • v.13 no.2
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    • pp.76-80
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    • 2008
  • This study examined the magnetic properties of ultrathin Fe/Ni films on a Cu(001) surface using the full potential linearized augmented plane wave (FLAPW) method. The magnetic moment of Fe/Ni films was found to be insensitive to strain. Nevertheless, strain had a significant influence on the magnetization direction. For example, Fe/Ni films showed a thickness-dependent spin reorientation transition in the presence of strain, while the Fe/Ni films grown pseudomorphically on Cu(001) always showed perpendicular magnetization. In addition, the theoretically calculated X-ray magnetic circular dichroism (XMCD) was examined.