Modeling the Dielectric Response and Relaxation Spectra of Relaxor Ferroelectrics

Abstract

A multi-Debye relaxation model that is based upon the Boltzmann superposition principle has been used to determine the frequency-dispersion behavior of Pb(Mg 1/3 -Nb 2/3 )O 3 (PMN) and Pb 0.88 La 0.08 (Zr 0.65 Ti 0.35 )O 3 (PLZT 8/65/35) relaxor ferroelectrics. For PMN, relaxation times on the order of seconds contribute to the dispersive character of the dielectric properties. A defect-relaxation mechanism that involves Mg cation hopping in a structure that is composed of interpenetrating 〈111〉 chains of ordered Pb(Mg 1/2 Nb 1/2 )O 3 is proposed for PMN. Motion of the Mg cations results in destruction and reconstruction of these ordered chains, which contributes to the dispersive character of PMN.

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

“…Although the 0 provides no further information of their origin, it can be said that at least the lowertemperature frequency dispersive part is due to the relaxor contribution, which is apparent also from 00 . With increasing temperature, another dielectric anomaly with a frequency dispersion in 00 develops after As demonstrated by a series of earlier works, 44,[48][49][50] logarithmic relaxation time cannot be explained by a single Debye-type relaxation but by a collective contribution of multiple Debye-type relaxations that can be described by a statistical distribution of relaxation time at a given temperature. It is known that this behavior can be simulated properly either by Gaussian 48,49 or by Lorentzian 50 distribution function.…”

“…With increasing temperature, another dielectric anomaly with a frequency dispersion in 00 develops after As demonstrated by a series of earlier works, 44,[48][49][50] logarithmic relaxation time cannot be explained by a single Debye-type relaxation but by a collective contribution of multiple Debye-type relaxations that can be described by a statistical distribution of relaxation time at a given temperature. It is known that this behavior can be simulated properly either by Gaussian 48,49 or by Lorentzian 50 distribution function. Since the integrated form of Gaussian and Lorentzian functions can be simulated by sigmoidal functions, the following simple sigmoidal function was used instead to reach convergence in a reasonable time scale:…”

Loss of relaxor properties due to dipolar interactions in ferroelectrics: A 2D Monte Carlo study

“…The frequency dependence in relaxor can be explained due to the existence of a distribution of the response times of the PNRs 4, 28, 29. It can be seen in Fig.…”

Combining effects of TiO6 octahedron rotations and random electric fields on structural and properties in Na0.5Bi0.5TiO3

“…The frequency dispersion on dielectric properties in relaxor ferroelectrics can be simulated by using the multi-Debye relaxation model with Lorentzian or Gaussian distribution functions. 61,62 This model had been used to simulate the dispersive dielectric constant below the temperature of T hump in NBT-6%BT ceramics. 40 Following these works, the dielectric constant ε r for NBT ceramics was deconvolved with Lorentzian function using the software of OriginPro (Originlab, Inc).…”