Abstract
The magnetic-field-induced biaxiality of the originally uniaxial antiferroelectric chiral smectic (Sm-) phase of 4-(1-methyl-heptyloxycarbonylphenyl) 4’-octylbiphenyl-4-carboxylate (MHPOBC) has been studied in a magnetic field applied perpendicular to the helical axis. The observed distortions of the central part of the conoscopic figures are explained on the basis of a perturbative approach to light propagation in spatially modulated birefringent phases. The critical magnetic field for the unwinding of the helical structure of the Sm- phase of MHPOBC is 13 T at 89 °C and is strongly temperature dependent.
- Received 23 September 1992
DOI:https://doi.org/10.1103/PhysRevE.47.1094
©1993 American Physical Society