CHANGE OF THE NATURE OF THE MULTICRITICAL POINT IN MAGNETICALLY INDUCED SPLAY-TWIST FREEDERICKSZ TRANSITIONS

The phase diagram in the vicinity of the Freedericksz transition from the uniform to the deformed homogeneous or periodic stales of a nemati c slab under a magnetic field with rigid boundary conditions was quali tatively calculated in the mean-field approximation for intermediate g eometries between the splay and twist Freedericksz transition geometri es. II was found that the multicritical point where the uniform state, the homogeneous deformed, and the periodic deformed slates meet is of the Lifshitz type only for a limited range of the Frank elastic const ants ratio K-2/K-1.