The influence of suspended nanoparticles on the Frederiks threshold of the nematic host

Susanne Klein, Robert M Richardson, Rob J Greasty, Rhys Jenkins, Joseph Stone, Michael R Thomas, Andrei Sarua

Research output: Contribution to journalArticle (Academic Journal)peer-review

13 Citations (Scopus)

Abstract

In recent years, several papers reported an enhanced dielectric anisotropy when ferroelectric particles were suspended in a liquid crystal. These results seem to be sensitive to the liquid crystal used and the preparation method of the ferroelectric particles. In this paper, we compare different preparation methods of suspended barium titanate in two different liquid crystal hosts. As a control experiment, we followed similar preparation steps with non-ferroelectric silica particles. In all cases, we found a broadening of the optical Frederiks transition but no change in the dielectric anisotropy. Raman spectroscopy has been used to investigate the loss of tetragonal structure in the barium titanate as a function of milling time and particle size. As reported in the earlier literature, barium titanate does not exhibit a well-defined tetragonal crystal structure below a certain particle size and loses its ferroelectric features. This provides a simple rationalization for the absence of any dielectric enhancement.
Original languageEnglish
Article number20120253
Number of pages14
JournalPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume371
Issue number1988
Early online date4 Mar 2013
DOIs
Publication statusPublished - 13 Apr 2013

Keywords

  • Materials Science
  • Nanotechnology
  • Optics
  • Physical Chemistry
  • liquid crystal
  • Raman
  • Phase transition

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