Eur. Phys. J. B (2015) 88: 175
https://doi.org/10.1140/epjb/e2015-60202-7

Regular Article

High-resolution birefringence study at the nematic-smectic A phase transition of ZnS nano particle dispersed octyloxycyanobiphenyl

¹ Department of Physics, North Bengal University, 734 013 Siliguri, West Bengal, India
² Department of Physics, Raiganj University College, 733 134 Raiganj, West Bengal, India

^a e-mail: mkdnbu@yahoo.com

Received: 13 March 2015
Received in final form: 22 May 2015
Published online: 8 July 2015

Abstract

We have studied the effect of ZnS nano particles with different concentrations on the nematic to smectic A (N-SmA) phase transition of a thermotropic liquid crystal octyloxycyanobiphenyl (8OCB). These effects are probed using a high resolution optical birefringence measurement. A decreasing trend of the nematic range of 8OCB has been observed up to a certain limit with increasing concentrations of the guest nano particles. A simple power law analysis has been carried out to extract the critical exponent (α) at the N-SmA phase transition, which allows one to investigate the critical behaviour near the phase transition as well as the universality class. The critical exponent (α) at the N-SmA phase transition strongly indicates the change in the coupling strength between the nematic and smectic A order parameters.