Low frequency dielectric relaxations of gold nanoparticles/ferroelectric liquid crystal composites

Abstract

We present the characterisation and dielectric relaxation spectroscopy of a ferroelectric liquid crystal (FLC), namely KCFLC 7S. It was observed that the studied FLC material possesses the tendency of homeotropic alignment on glass substrates coated with indium tin oxide. A low frequency dielectric mode, along with the Goldstone mode, was observed in the SmC* phase of the FLC material. The low frequency mode became more dominant on doping gold nanoparticles into the FLC material. The occurrence of the low frequency mode was attributed to the ionisation–recombination-assisted diffusion of slow ions present in the FLC material. The behaviour of the relaxation frequency of the low frequency mode with applied dc bias and temperature was also demonstrated.

Keywords:

• ferroelectric liquid crystal
• low frequency relaxation
• gold nanoparticles

Acknowledgements

The authors sincerely thank Professor R.C. Budhani, Director of the National Physical Laboratory, for continuous encouragement and interest in this work. We also sincerely thank Dr P. Goel, Dr I. Coondoo, Mr A. Choudhary and Ms A. Malik for fruitful discussions. The authors (T.J. and A.K.) and J.P. wish to thank the University Grant Commission (UGC) and the Council of Scientific and Industrial Research (CSIR) for providing financial assistance.