Kinetics effects in lithium-potassium tantalate crystals

Abstract

The study of the dielectric and acoustic constants, performed in a K0.99Li0.01TaO3 crystal between 4 and 30 K, puts in evidence a strong analogy between the kinetics of these two susceptibilities. In particular, the two characteristic times measured for each of them have near values and they are roughly constant in all the temperature range. An explanation in terms of tetragonal domains, with quadrupolar order and dipolar disorder, is suggested.( * ) Associated with the Centre National de la Recherche Scientifique.

New results about aging in an orientational glass

“…This means that the way the ergodicity is broken is determined by the freezing of the lithium ions. Subsidiarily, we mention that a nonmonotonic variation as the one we see here was already observed on the dielectric constant of a K 2 ZnCl 4 crystal near its incommensurate-ferroelectric transition [12], [13] and on the elastic constant of a KLT crystal [8]. In both cases, the effect was attributed to the competition of two processes.…”

Dynamic behavior of correlated nanodomains in K 1 − x Li x TaO 3 , x =0.011

“…It should be noticed that ageing of the domains in weakly doped KTL occurs after zeroexternal-field-cooling on time scales beyond those considered in this paper [14]. It was suggested that the temporal evolution of both dielectric permittivity and sound velocity refers to the inherent relaxation of tetragonal domains with quadrupolar order and dipolar disorder in close analogy with the kinetics observed on KTa 0.983 Nb 0.017 O 3 [15].…”

Aging and memory effects in a disordered crystal

“…-Materials, such as spin-glasses (SG) and orientational glasses (OG), which contain entities with random interactions, share peculiar properties in their low-temperature frozen phase [1][2][3][4][5]. Aging is one of these properties extensively studied [6][7][8][9][10][11][12][13]. A system ages if its evolution is non-stationary and depends on the manner it was prepared.…”

“…In the present paper we report on dielectric constant measurements performed on a potassium niobo-tantalate (KTN) in its ferroelectric phase. This material belongs to the perovskite family, just as the potassium-lithium tantalate (KLT) [11][12][13]. Aging is known to occur in KTN [16,17].…”