STATIC AND DYNAMIC BEHAVIOR OF FERRONEMATICS UNDER MAGNETIC-FIELDS

The static and dynamic behavior under magnetic fields of ferronematics obtained by adding an organomagnetic material to the nematic E3 is in vestigated. First, by using both optical and electrical measurements, an increase of the threshold field for magnetic Freedericksz transitio n was noticed. Second, we examined both theoretically and experimental ly the relaxation phenomena occurring in these ferronematics when the magnetic field was suddenly varied. We found that for ferronematics th e relaxation processes are delayed when compared to those occurring in pure nematics. The threshold fields for magnetic Freedericksz transit ion were determined by means of the relaxation time and the results ar e in good agreement with the ones obtained when using the optical and electrical methods reported before.