Journal of Magnetics

The Korean Magnetics Society (한국자기학회)
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1H Nuclear Magnetic Resonance of a Ferroelectric Liquid Crystalline System

  • Cha, J.K. (Department of Physics and Institute for Nano Science, Korea University) ;
  • Lee, K.W. (Department of Physics and Institute for Nano Science, Korea University) ;
  • Oh, I.H. (Department of Physics and Institute for Nano Science, Korea University) ;
  • Han, J.H. (Department of Physics and Institute for Nano Science, Korea University) ;
  • Lee, Cheol-Eui (Department of Physics and Institute for Nano Science, Korea University) ;
  • Jin, J.I. (Department of Chemistry, Korea University) ;
  • Choi, J.Y. (Department of Computer Science, Korea University)
  • Received : 2010.05.24
  • Accepted : 2010.06.17
  • Published : 20100600
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Abstract

We used $^1H$ nuclear magnetic resonance (NMR) to study the phase transitions and molecular dynamics in a characteristic ferroelectric liquid crystal with a carbon number n = 7, S-2-methylbutyl 4-n-heptyloxybiphenyl-4'-carboxylate (C7). The results were compared with those of our recent work on S-2-methylbutyl 4-n-octanoyloxybiphenyl-4'-carboxylate (C8), with a carbon number n = 8. While the recrystallization and isotropic phase transitions exhibited a first-order nature in the $^1H$ NMR spin-lattice and spin-spin relaxation measurements, a second-order nature was shown at the Sm-A - Sm-$C^*$ liquid crystalline phase transition. A soft-mode anomaly arising from the tilt angle amplitude fluctuation of the director, of which only a hint had been noticed in the C8 system, was manifested in the C7 system at this transition.

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References

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