FERROELECTRIC LIQUID-CRYSTALS IN A STATIC MAGNETIC-FIELD

The experimentally determined H-T phase diagrams as well as the magnetic field and temperature dependences of the pitch of the Sm C* helix of DOBAMBC and the mixture of racemic and chiral DOBAMBC are shown to be compatible with the predictions of the extended Landau model where in addition to polar also quadrupolar ordering around the long molecular axes is taken into account. The magnetic field dependence of the in-plane component of the dielectric constant at the C*-C unwinding transition is also shown to be compatible with the theoretical predictions if the critical increase in the relaxation time of the Goldstone mode is taken into account.