Low-frequency dielectric response of PbMg_1/3Nb_2/3O₃

Abstract

An investigation was carried out on both the linear and nonlinear parts of the complex dielectric susceptibility in the frequency and temperature ranges 10-3-103 Hz and 100-450 K, respectively. The analysis of the imaginary part of the dielectric susceptibility has revealed the existence of a broad spectrum of relaxation times in the above temperature range. The temperature dependence of the most probable frequency of the spectrum was obtained. For temperatures T

Diffuse neutron scattering in relaxor ferroelectric PbMg1/3Nb2/3O3

“…In the case of diffuse or quasi-elastic scattering, when the energy profile of the signal at any momentum transfer Q is expected to be a Lorentzian with FWHM = Γ , the measured polarization contrast, defined as the sinusoid amplitude divided by its average, should ideally decrease as P ~ exp(-Γτ F /2). A pyramid-shaped lightly brown-colored transparent single crystal PMN of about 8 cm 3 in volume has been used in the reported measurements. It had some optically inhomogeneous regions at the bottom of the pyramid.…”

“…Lead magnoniobate PbMg 1/3 Nb 2/3 O 3 (PMN) can be considered as a generic relaxor and is the most studied one. At the freezing temperature T g of about 230 K it exhibits a phase transition into a dipole-glass phase as evidenced by divergence of nonlinear susceptibility [3] and appearance of history dependent effects [4]. There are several theoretical approaches used to describe the properties of relaxors and PMN in particular.…”

Soft and central mode behaviour in PbMg1/3Nb2/3O3relaxor ferroelectric

“…The dielectric anomaly is not accompanied by any phase transition to polar state, and the structure remains cubic down to liquid He temperatures. 4 Nowadays it is generally accepted that the strong dielectric dispersion, which occurs in RFE in the broad spectral range from GHz to milliherz range 5,6 at temperatures around and below that of ε ′ (T) maximum T max , is a consequence of the dynamics of polar nano-clusters, which appear several hundred degrees above T max , at so called Burns temperature T d . 7 Although many papers have been devoted to RFE (see e.g.…”

Ultralow frequency dielectric dispersion in PZT + PFS ferroelectric ceramic

“…The dielectric relaxation at low and ultralow frequencies has been widely investigated in many materials, 1,2 including ferroelectric perovskite crystals 3,4 and ceramic structures. 5,6 Usually, the measurements are carried out down to 10 À3 -10 À5 Hz and various experimental equipments have been developed for this purpose.…”

“…5,6 Usually, the measurements are carried out down to 10 À3 -10 À5 Hz and various experimental equipments have been developed for this purpose. 2,[7][8][9] Investigation of the lowfrequency dielectric relaxation in the oxide octahedron-type ferroelectric with perovskite PMN, 3,10 PMNT, 11 tungsten bronze-type PBN 12 and NaBiTiO 3 13 structures are of considerable interest because of possibility of their technical application as actuators, pyroelectric detectors and transducers.…”