Dielectric Dispersion around the Ferroelectric Phase Transition in Partially Deuterated Glycine Phosphite

Abstract

Deuteration effects on the critical relaxation in hydrogen-bonded ferroelectric glycine phosphite have been examined by the measurements of the complex dielectric constants along the ferroelectric b-axis of a series of partially deuterated crystals. The dielectric dispersion for crystals of low deuteration molar fraction was found to be composed of two Cole-Cole types with clearly different relaxation times. The shorter relaxation time shows a nearly classical mean-field exponent and the relaxation time at the temperatures with the same distance from T C increases monotonically with the fraction similarly to the deuteration in CsH 2 PO 4 . The longer relaxation time decreases with the fraction.

Dynamical Property of Domain Walls of Deuterated Glycine Phosphite in The Vicinity of Phase Transition

“…The GPI undergoes a continuous phase transition at 225 K from the monoclinic system with space group P2 1 /a → P2 1 in the ferroelectric phase [8]. Deuterium -hydrogen isotopic effect observed in this crystal gives a large T C shift from 225 K for hydrogenated to 322 K for fully deuterated systems [1][2][3][4]. We have shown that deuteration deteriorates GPI crystals homogeneity as evidenced by spatially inhomogeneous nucleation process with different activation energies [9].…”

“…Ferroelectrics of similar composition often show wide variations in their characteristic properties [1][2][3][4]. Such variations in ferroelectric properties can be largely attributed to differences in the structural arrangements of domains and distribution of defects within a multidomain crystal sample.…”