DIELECTRIC-RELAXATION IN RS-ARS

Dielectric relaxation in mixed crystals of Rochelle salt and ammonium Rochelle salt (Na[K-1-x(NH4)(x)]C(4)H(4)O6 . 4H(2)O) with various comp ositions (x=0, 0.04, 0.09, 0.28, 0.40, 0.80) has been measured in the freqency region from 100Hz to 10GHz at temperatures from 4.2K to 290K. It is indicated that the dielectric relaxation observed in the freque ncy range between 100Hz and 1KHz for the quenched sample (x=0.80) at t emperatures around 30K is connected with the well known relaxation obs erved at microwave frequencies. On the other hand, the sample of x=0 d oesn't have such low frequency relaxation. A discussion is made to exp lain the fact. Finally, the distribution of relaxation time observed i n the low frequency region is discussed together with on that observed for the relaxation in the microwave frequency region.