DIELECTRIC-DISPERSION IN THE INCOMMENSURATE PHASES OF [N(CH3)4]2COCL4 AND [N(CH3)4]2ZNCL4

The complex dielectric permittivity of left bracket N(CH//3)//4 right bracket //2CoCl//4 and left bracket N(CH//3)//4 right bracket //2ZnCl//4 along the a-axis was measured between 0. 35 MHz and 100 MHz. It has been found that for both substances the relaxation frequencies are about 5 MHz at T//c. The dielectric relaxation of both substances could be described by a polydispersive process beta equals 0. 74 in the vicinity of T//c. However, for the temperature region of (T minus T//c) greater than 0. 6 for left bracket N(CH//3)//4 right bracket //2CoCl//4 the dielectric absorption seems to be rather monodispersive.