Bias-field effect on the temperature anomalies of dielectric permittivity inPbMg1∕3Nb2∕3

Abstract

In contrast to ordinary ferroelectrics where the temperature T m of the permittivity maximum monotonically increases with bias field E in ͑1−x͒PbMg 1/3 Nb 2/3 O 3 -͑x͒PbTiO 3 ͑0 ഛ x ഛ 0.35͒ single crystals, T m was found to remain constant or to decrease with E up to a certain threshold field E t , above which T m starts increasing. The threshold field E t decreases with increasing x, tending toward zero at approximately x = 0.4. We explain this dependence in the framework of models which take into account quenched random fields and random bonds. For crystals with 0.06ഛ x ഛ 0.13, the E-T phase diagrams are constructed. In contrast to PMN, they exhibit an additional, nearly field-independent boundary, in the vicinity of the Vogel-Fulcher temperature. We believe this boundary to correspond to an additional phase transition and the appearing order parameter is likely to be nonpolar.

Dielectric dynamics of epitaxial BiFeO3 thin films

“…16 Many other literatures have connected the anomaly in capacitance with certain phase transitions. 25,[27][28][29][30][31][32][33][34][35][36][37][38][39] In the field of multiferroics, for example, the anomalies were often accompanied by antiferromagnetic transition, 27, 37, 40-42 domain formation, 43 phase transition near the morphotropic phase boundary (MPB) 44,45 and many other magnetic phase transitions. 30,34,35,41,46 In order to recognize these anomalies, electrical circuits based curve fittings are carried out at every measured temperatures.…”

Temperature characteristics and development of field-induced phase transition in relaxor ferroelectric Pb(Mg1/3Nb2/3)0.87Ti0.13O3 ceramics

“…Just below T dp , the required electric field shows an exponential dependence on temperature, as found in a single crystal of the same composition by means of a field-cooling run. 16 However, E th = 1.55 kV/ cm at T = −5°C was discovered to be the minimum point, since the decline turned into an increase at lower temperatures. Similar U-shaped behavior has been observed previously for PLZT 12 and PMN.…”

“…This phenomenon can be attributed to a field-induced transition from relaxor to ferroelectric phase or a mixed state phase. 16 During the zero-field heating, the lowered permittivity increases to the value of the unpoled sample at T = 18°C, where a spontaneous phase transition to a high-temperature cubic structure occurs. This temperature equals the depolarization temperature T dp derived from remanent polarization measurements 17 and it is located close to the freezing temperature as expected.…”

“…12-14 Mostly heating and cooling with a constant electric field have been used to determine E-T relations of both PMN 14,15 and PMN-PT. 10,16 Nevertheless, another approach with constant temperature and a variable electric field requires a different kind of study in which field-inducing behavior can be viewed separately at individual temperatures.In this letter we study a field-induced ferroelectric transition in PMN-13PT ceramics. In particular, we examine the temperature dependence of the threshold field by measuring the dielectric response to a prepoling electric field at constant temperatures.…”

“…[12][13][14] Mostly heating and cooling with a constant electric field have been used to determine E-T relations of both PMN 14,15 and PMN-PT. 10,16 Nevertheless, another approach with constant temperature and a variable electric field requires a different kind of study in which field-inducing behavior can be viewed separately at individual temperatures.…”