Dielectric Relaxation in the Radio Frequency Range for the Nematic Phase of M.B.B.A.

The dipolar relaxation for the component ∊‖ of dielectric tensor has been studied in nematic phase of p-methoxy benzylidene p-n butyl-aniline oriented by a magnetic field. A low frequency relaxation process corresponding to the rotational diffusion of the molecules around one of their short axes is observed. Our results are consistent with the existence of a single relaxation frequency, in the range 100 kHz - 10 MHz. The temperature dependence of this frequency can be described by an activation energy W = 0.65 ± 0.05 eV. These results contradict previous data, which have to be corrected (F. Rondelez et al, MOL. CRYST. and LIQ. CRYST. 15, 183 (1971)).