MICROWAVE DIELECTRIC-DISPERSION IN RBHSEO4

The paper presents the results of the investigation of the dielectric dispersion in RbHSeO4 crystal in the frequency range 100 Hz to 100 GHz . It is shown that the dielectric dispersion of the Debye type along t he b-axis in the frequency range 1 GHz to 100 GHz is caused by a singl e relaxational mode which frequency in the paraelectric phase is v = 1 2 GHz and does not depend on temperature. The phase transition at T-c2 = 371 K is rather improper ferroelctric transition of the order-disor der type.