Coexistence of proton-glass and ferroelectric order inRb1−x(NH

Abstract

The mixed crystal Rb~-"(NH4)"HzAs04 (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 range 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 etal. in Feo»Mg0. 45C12 and by Yoshizawa etal. in Fe Mn]-Ti03.

Thermodynamics, dielectric permittivity and phase diagrams of the Rb_{1-x}(NH_{4})_{x}H_{2}PO_{4} type proton glasses

“…At the same time ε 11 (T, ν) has two maxima at T c (x) and T g (x). The same behavior was experimentally detected also for ε 11 (T, ν) and [16,18,51,52], and…”

“…Thus, T c of Rb 1−x (NH 4 ) x H 2 AsO 4 determined from the maximum of ε 33 (T, ν) in [17] are about 10 K larger than T c determined from the maximum of ε 11 (T, ν) in [16]. This means that the value of x is either overestimated in [17] or underestimated in [16].…”

“…Experimental measurements of the dielectric permittivity of Rb 1−x (NH 4 ) x H 2 PO 4 [1][2][3][4][5][6][7][8], Rb 1−x (ND 4 ) x D 2 PO 4 [7,[9][10][11][12][13][14], Rb 1−x (NH 4 ) x H 2 AsO 4 [15][16][17][18], and K 1−x (NH 4 ) x H 2 PO 4 [19][20][21][22][23] in the glass phase composition region have shown that the temperature curves of the longitudinal ε 33 (T, ν) and transverse ε 11 (T, ν) permittivities are qualitatively similar. At high temperatures the real parts of the permittivities are roughly described by the Curie-Weiss law.…”

Thermodynamics and complex dielectric permittivity of mixed crystals of the Rb_{1-x}(NH_{4})_{x}H_{2}PO_{4} type

“…The most complete experimental data for Rb 1−x (NH 4 ) x H 2 AsO 4 for the dielectric measurements in a wide frequency range at low temperatures can be found in [23][24][25][26][27][28][29].…”

Broadband dielectric spectroscopy of CuInP2Se6 crystals

“…Note that all parameters of different compounds in Table V are close to each other. Such a behaviour is very similar to behaviour of betaine phosphite with a small amount of betaine phosphate [27] and in RADA [28] crystals, where a proposition that a coexis- tence of the ferroelectric order and dipolar glass disorder appears at low temperatures was proposed. Therefore we can conclude that mixed CuInP 2 (S x Se 1−x ) 6 crystals with x≥0.95 also exhibit at low temperatures a coexistence of ferroelectric and dipolar glass disorder.…”