Fig. 11.

Specific magnetic birefringence Δn/c ^Fe as a function of the applied magnetic field for Fe-sucrose aqueous suspension (c ^Fe = 0.04 and 20 g/L). The dashed and solid lines are the best fit by the Langevin function by Eqs. (6) and (9). Top inset particle size distribution obtained in TEM and magnetic birefringence measurements. Bottom inset magnetization versus B/kT; the dashed and solid lines are the best fit to the experimental points (data from Gutierrez et al. 2005) by the usual Langevin function and the usual Langevin function plus the linear term χH, respectively. The size of the error bar is close to the dimension of the experimental point