Abstract
The dielectric and polarization study of K1−x(NH4)xH2PO4 mixed crystals has been made. In the crystals with 0.22 ≤ × ≤ 0.72 a transition to low temperature proton glass state is realized. It was found that the dielectric dispersion of proton glass compounds is well described by the Vogel-Fulcher law. The nature of a large thermal hysteresis of polarization in the mixed crystals (x ≤ 0.22) is discussed.