Dielectric, elastic, and piezoelectric properties of NaH3(SeO3)2 crystals near the α–β transition

Abstract

The dielectric permittivities E~, gY, the elastic compliances sl,, s , , , and the piezoelectric d,, coefficient were measured in the temperature range near the a-p transition of NaH,(SeO,), a t To = -78.6 "C. High values of the dielectric permittivities and losses were observed within the ferroelectric @-phase. If domain effects are suppressed by a biasing electric field, E~ and ey jump to lower values. A small but definite thermal hysteresis was observed. The elastic compliances s , , and szz exhibit anomalies near the transition point. The same is true for the piezoelectric d,, coefficient. The pecularities of the anomalies a t the phase transition point are discussed. I n der Nahe der a-P-Umwandlung bei To = -78,6 "C wurden die Dielektrizitatskonstanten sx und E~, die Elastizitlitekoeffizienten S , , und s22 und die piezoelektrische Konstante d,, von NaH,(SeO,), geniessen. I n der ferroelektrischen @-Phase wurden sehr grole Werte fur die Dielektrizitatskonstanten und dielektrisclie Verlnste beobachtet. Wenn durch Gleichfelder die Domanenprozesse untcrdruckt werden, erleiden die Dielektrizitatskonstanten E= und E~ einen Sprung zu niederen Werten. Eine geringe, aber definierte thermische Hystcrese wurde beobachtet. Die Elastizitatskoeffizienten s, , und sp2 und die piezoelektrische Honstante d,, zeigen in der Nahe des Umwandlungspunktes Anomalien. Dicse Besonderheiten am Phasenumwandlungspunkt werden diskutiert.Here we report studies on the influence of an electric dc bias field on cX and ty at the transition point as well as investigations on the elastic compliance coefficients .yI1 and sZ2 and the piezoelectric coefficient d,, within a temperature range in the vicinity of the transition temperature TO = -78.6 "C. 13, 61.

Investigation of a phase transition in NaH3(SeO3)2 by measurement of the pyroelectric current

“…The p 4 y transition resembles a typical first-order phase transition. 6. The increase in the spontaneous polarization a t the phase transition resembles neither a first-order nor a second-order phase transition.…”

“…and the normalized polarizations, at which the pyroelectric coefficient tends to infinity, are given by (6) Without an external field the phase transition temperature is equal to the Curie temperature t, and is defined by ggo = 0. From (2) and (4) we get t, = 0.75.…”

Study of the ferroelectric–paraelectric phase transition of NaH3(SeO3)2 single crystals by 1H and 23Na NMR

“…According to Blinc et al [6,7], the change in the second moment with temperature obtained with proton nuclear magnetic resonance (NMR) is not connected to the increased mobility of the hydrogen atoms, but to changes in their position in the structure, Blinc et al also determined the quadrupole coupling constants of the ferroelectric and paraelectric phases of NaH 3 (SeO 3 ) 2 and NaD 3 (SeO 3 ) 2 crystals. The quadrupole coupling constant, the asymmetry parameter, and the direction of the principal axes of the electric field gradient (EFG) tensors of 2 D and 23 Na in NaD 3 (SeO 3 ) 2 were obtained by Soda and Chiba [8].…”

“…Crystals of alkali trihydrogen selenites are an important group of hydrogen-bonded ferroelectrics that have very interesting properties. One such alkali trihydrogen selenite is NaH 3 (SeO 3 ) 2 , which undergoes two phase transitions [1][2][3]: from a paraelectric phase, phase I, to a ferroelectric phase, phase II, at 194 K, and subsequently from phase II to a ferroelectric phase, phase III, at about 100 K. In the phase between the two transition points, NaH 3 (SeO 3 ) 2 is both ferroelectric and ferroelastic [4,5]. The phases are denoted as phase I, II, and III in the order of descending temperature.…”

Dynamics of α-β transition in NaH3(SeO3)2: Brillouin scattering study

“…Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions [2], Pb [4], the number in [ ] means the translational index of the subgroup of P2,lb). We shall adopt the following notation for the axes: the twofold axes or the crystallographic b axis is along z, the crystallographic c axis is along y and x is perpendicular t o y and z .…”