Sm A - ferroelectric-Sm C transition in the mixture of C7+10.O.4 and in the ferroelectric C7

Tilt angle and the dielectric constant (susceptibility ) as functions of the field strength and temperature, respectively are calculated from the Landau phenomenological model and they are fitted to the observed data from the literature for the Sm A - Sm C* transition in the mixture of C7 + 10.O.4. Values of the critical exponents for the order parameters (tilt angle and polarization P) and tilt angle susceptibility of C7 and of the (dielectric constant) of the mixture C7 + 10.O.4 close to are extracted from the power-law formula. Our results indicate a second-order and a weakly first-order Sm A - Sm C* transitions for C7 + 10.O.4 and C7, respectively as also observed experimentally.