A Re-Entrant Glasslike Phase in Rb_1−x(NH₄)_xH₂PO₄

Abstract

The mixed crystal Rb_1−x(NH₄)_xH₂PO₄ 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.