Field dependence of glassy freezing in a relaxor ferroelectric

Abstract

Multifrequency susceptibility measurements on the perovskite relaxor ferroelectric ͑PbMg 1/3 Nb 2/3 O 3 ͒ 0.88 ͑PbTiO 3 ͒ 0.12 were performed at various strengths of dc electric field applied along the ͓111͔ direction. The temperature-frequency dependences fit the Vogel-Fulcher form, allowing the extraction of a frequency-independent glassy freezing temperature. These Vogel-Fulcher temperatures showed significant reductions in applied fields, following an empirical Gabay-Toulouse form, similar to vector spin glasses. The magnitude of the sensitivity indicates that the glassy state is formed by interactions among the same entities which account for the susceptibility, i.e., the polar nanoregions. That interpretation is supported by other data showing a loss of Vogel-Fulcher behavior in a powder sample of PbMg 1/3 Nb 2/3 O 3 , with grains too small to support large-scale internanoregion cooperativity.

On the phase identity and its thermal evolution of lead free (Bi1/2Na1/2)TiO3-6 mol% BaTiO3

“…59,60 The normal ferroelectricity of PMN was claimed based on their observation of well-defined P(E) hysteresis loops induced at temperatures sufficiently lower than T 0 m . Note that until early 1990 s when two discrete relaxor states, i.e., ergodic and nonergodic, were identified, 43,[61][62][63][64][65][66] PMN had been consistently considered to be a normal ferroelectric with a diffuse phase transition.…”

Relaxor behavior in multiferroic BiMn2O5 ceramics

“…Several models have been used to explain the relaxor behavior, most of them inspired in those used to explain the behavior of spin glass systems. 18,19 The relaxor behavior is attributed to existence of polar nanoregions (PNR), with the mechanisms of their formation not completely understood yet. 20,21 One approach is that the relaxor crystal tends to be ferro-or antiferroelectric at low temperatures, but the quenched disorder prevents the transition and the PNR appear.…”

Description of Relaxor State in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 System of Solid Solutions

“…It is well established that τ max (T) does not follow Arrhenius law. Instead freezing of relaxation at certain temperature T f is extrapolated from Vogel-Fulcher law [5][6][7][8].…”