Investigation of dielectric anomalies at cryogenic temperatures in (1−x)[Pb(Mg1∕3Nb2∕3)O3]–xPbTiO3 system

Abstract

(ReceivedComplex electrical permittivity measurements in (1-x)[Pb(Mg 1/3 Nb 2/3 )O 3 ]-xPbTiO 3 ceramics for 0.10 ≤ x ≤ 0.40 were performed in the frequency and temperature range from 1 kHz to 100 kHz and from 15 to 600 K, respectively. Unexpected dielectric anomalies, which were frequency dependent, were found at cryogenic temperatures. It was verified that this dielectric behavior is always observed, independently of whether the composition presents a "normal" ferroelectric or a relaxor characteristic. The results were analyzed within the framework of two current models found in the literature. It was concluded that none of the proposed mechanisms uniquely satisfies the experimental results in the composition range investigated here.

Dielectric loss anomalies of 0.68PMN–0.32PT single crystal and ceramics at cryogenic temperature

“…Dielectric spectra at lower temperature, especially below liquid nitrogen temperature, are rarely reported. Recently, the dielectric anomalies at low temperature in PZN-PT and PMN-PT system were reported [5][6][7][8]. In this work, the dielectric spectra at cryogenic temperature were investigated for 0.68PMN-0.32PT single crystal and ceramics.…”

Damped soft phonons and diffuse scattering in40%Pb(Mg1∕3Nb2∕3)O3Stock1, Ellis2, Swainson3 et al. 2006Phys. Rev. B713551View full textAdd to dashboardCite

“…For large PT dopings in the tetragonal region, the dielectric response is largely frequency independent with the response characterized by a sharp peak around the critical temperature. [16][17][18] Therefore, the relaxor nature, as characterized by the frequency dependence of the dielectric susceptibility, is suppressed for large PT dopings when the unit cell is tetragonal and when the structural properties begin to strongly resemble those of pure PbTiO 3 . 19 Despite many studies, no unified model of the relaxor transition has been presented.…”

Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction

“…However, the anomalous behavior of the permittivity seem to vanish when the material is donor doped [4][5][6]. A similar anomalous temperature-dependent permittivity has been reported in NaNbO3 [10], (K,Na)NbO3 [11], (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 [12], and (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 [13], which are not related to any change in crystallographic symmetry. More recently, low temperature dielectric relaxations have been reported in BaTiO3-BiScO3 [15] and PbTiO3-BiScO3 [16] systems, which were parameterized by using the Vogel-Fulcher-Tammann formalism.…”

“…The final publication is available at IOPSience via http://dx.doi.org/10.1088IOPSience via http://dx.doi.org/10. /1361 3 associated the anomaly with a low temperature phase transition that is governed by an order parameter coupled to polarization in Bi-containing perovskites.Although the low temperature dielectric relaxation displayed in ordinary ferroelectrics has been reported for a wide number of systems [4][5][6][7][8][9][10][11][12][13][14][15][16], the involved mechanisms are not well understood. The universality of this phenomenon seems to be indisputable, but numerous explanations, often meaningful only for the study system, have been given about the origin of this anomalous behavior.…”

“…For instance, phase transitions appear as a maximum in the real and/or imaginary permittivity versus temperature curve. In particular, the paraelectric to ferroelectric phase transition manifests as a sharp peak at a frequency-independent temperature in ordinary ferroelectrics while a wide peak at a temperature that is frequency-dependent is observed in the so-called relaxor ferroelectrics [3].A widely studied dielectric anomaly appears at low temperatures in ordinary perovskite ferroelectrics [4][5][6][7][8][9][10][11][12][13][14][15][16]. In the PbZr1-xTixO3 (PZT) system, for instance, it appears independently of the crystallographic phase as a flat region in the real part of the permittivity (ε'), and as a dispersion of the maximum in the imaginary part of the permittivity (ε'') [5].…”