Magneto-optical behaviour of ferronematics

The behaviour under magnetic fields of new types of ferronematics is examined. First, by using both optical and electrical method, an increase in the critical field for Freedericbsz transition was noticed in cells containing ferronematics. Second we give an explanation of the relaxation processes occurring in ferronematics when the magnetic field was suddenly varied. When ferronematics are involved, the relaxation phenomena are described by lower time constants when compared to those of pure nematics.