COEXISTENCE OF PROTON-GLASS AND FERROELECTRIC ORDER IN RB1-X(NH4)XH2ASO4

[摘要] The mixed crystal Rb1-x(NH-4)(x)H-2AsO4 (RADA) has been investigated for several values of x (x = 0, 0.12, 0.15, and 0.20) by measuring the complex dielectric permittivity along the a tetragonal axis in the temperature range from 3 to 300 K and frequency from 1 Hz to 30 kHz. We find coexistence of ferroelectric and proton-glass order in RADA for x = 0.12 and probably at x = 0.15. The long-range ferroelectric order is not destroyed by the onset of proton-glass ordering. This behavior is similar to that of other proton-glass systems and of the magnetic Ising glass systems reported by Wong et al. in Fe0.55Mg0.45Cl2 and by Yoshizawa et al. in Fe(x)Mn1-xTiO3. The partial phase diagram for Rb1-x(NH-4)(x)H2AsO4 including the coexisting proton-glass and ferroelectric phases is presented.

[关键词] SPIN-GLASS;ISING-MODEL;PHASE;STATE;TRANSITION;CRYSTALS