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 investigated. First, by using both optical and electrical measurements, an increase of the threshold field for magnetic Freedericksz transition was noticed. Second, we examined both theoretically and experimentally the relaxation phenomena occurring in these ferronematics when the magnetic field was suddenly varied. We found that for ferronematics the relaxation processes are delayed when compared to those occurring in pure nematics. The threshold fields for magnetic Freedericksz transition were determined by means of the relaxation time and the results are in good agreement with the ones obtained when using the optical and electrical methods reported before.