Yurtseven, HamitKilit, Emel2025-05-102025-05-1020120031-91041029-045110.1080/00319104.2011.6512092-s2.0-84861429377https://doi.org/10.1080/00319104.2011.651209https://hdl.handle.net/20.500.14720/1123Yurtseven, Hasan Hamit/0000-0002-7745-6490The temperature dependencies of the dielectric constant and the tilt angle (order parameter) are calculated under the electric field for the smectic A-smectic C* (AC*) transition in 4-(3-methyl-2-chlorobutanoyloxy)-4'-heptyloxybiphenyl (A7). The dielectric constant is fitted to the experimental data by using our mean field model with the biquadratic coupling between the spontaneous polarisation P and the tilt angle theta. Our results show that the mean field model with the P-2 theta(2) coupling describes satisfactorily the observed behaviour of the AC* transition in A7. It is indicated here that a first-order AC* transition occurring at low electric fields changes its character towards a second order as the electric field increases in A7.eninfo:eu-repo/semantics/closedAccessDielectric ConstantOrder ParameterAc* TransitionA7Article503Q4Q3367377WOS:000304271500008