Title:	Polar switching in the smectic-AdPA phase composed of asymmetric bent-core molecules
Authors:	Guo, Lingfeng Dhara, Surajit Sadashiva, B.K. Radhika, S. Pratibha, R. Shimbo, Yoshio Araoka, Fumito Ishikawa, Ken Takezoe, Hideo
Issue Date:	20-Jan-2010
Publisher:	American Physical Society
Citation:	Physical Review E, 2010, Vol.81, p011703
Abstract:	We have studied mesogenic properties in the smectic-AdPA phase of an asymmetric bent-core liquid crystal by means of polarizing optical microscopy, second-harmonic generation (SHG), electro-optical (EO), and dielectric measurements. In homeotropically aligned cells, EO switching is clearly observed from a schlieren texture with both four- and two-brush defects to a uniform bright domain under the application of very low in-plane electric field below 1 V/μm. The phase is SHG active under an electric field, i.e., SHG gradually increases without a threshold and saturates with the increasing field. In homogeneous cells, by applying triangular wave field at saturated voltage, the splitting of the polarization switching current peak is observed, indicating that the mesophase is antiferroelectric. The dielectric studies indicate a Debye-type relaxation of the transverse dipoles associated with the rotation of the molecules about their long axis. The dc bias-dependent dielectric relaxation time and the dielectric strength suggest that a field-induced antiferroelectric-ferroelectric phase transition occurs continuously beyond 1.2 V/μm and is reversible. The field-dependent texture observation is consistent with the dielectric measurements. Two possible models are proposed to interpret the continuous phase transition.
Description:	Open Access
URI:	http://hdl.handle.net/2289/3920
ISSN:	1550-2376 (Online) 1539-3755
Alternative Location:	http://dx.doi.org/10.1103/PhysRevE.81.011703
Copyright:	2010 American Physical Society
Appears in Collections:	Research Papers (SCM)

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