A Re-Entrant Glasslike Phase in Rb1-x(NH4)xH2PO4

Abstract
The mixed crystal Rb 1- x (NH 4 ) x H 2 PO 4 shows ferroelectricity for small x and antiferroelectricity for large x . The frequency dispersion of the dielectric constant was studied in the concentration range 0.5≤ x . The low-frequency dispersion was found for 0.5≤ x ≤0.8 below 40 K. From the results, the phase diagram was obtained. Around x =0.75, a re-entrant glasslike phase with the dispersion of the dielectric constant was found.