Electric field-induced phase transitions in (111)-, (110)-, and (100)-orientedPb(Mg1∕3Nb2∕3)O3

Abstract

Electric field-induced phase transitions were investigated in (111), (110), and (100) thin platelets of relaxor ferroelectric Pb(Mg 1∕3 Nb 2∕3 )O 3 single crystals with electric fields applied along the ⟨111⟩, ⟨110⟩, and ⟨100⟩ directions, respectively. Temperature dependences of complex dielectric permittivity, pyroelectric current and dielectric hysteresis loops were investigated. Electric field-temperature (E-T) phase diagrams were proposed for the different directions of the field. Alongside with the high-temperature ergodic relaxor phase and the low-temperature glassy nonergodic relaxor phase existing at E=0, the ferroelectric phase may appear in the diagram at the fields higher than the threshold field (E th ). The temperature of the first-order transition between ergodic relaxor and ferroelectric phases (T C ) was located in field cooling and field heating after fieldcooling regimes. For the ⟨111⟩ field direction, T C is higher and E th is lower than for the other directions. For the ⟨100⟩ direction, T C is the lowest and E th is the highest. The critical point bounding the T C (E) line when the field is applied in ⟨111⟩ direction [ Z. Kutnjak, J. Petzelt and R. Blinc Nature 441 956 (2006)] is not observed in the ⟨110⟩ and ⟨100⟩ directions up to the highest applied field of 7.5 kV∕cm. Extrapolation of experimental data suggests that the critical point for the ⟨110⟩ and ⟨100⟩ directions (if any) can be expected only at much higher fields. In the hysteresis loops experiments performed after zero-field cooling, the lower temperature limit is determined above which a ferroelectric phase can be induced from the frozen glassy state at a given field strength or the polarization of the induced ferroelectric phase can be reversed. This limit is located at much lower temperatures in the (100) platelet than in the (110) or (111) platelets. An additional ferroelectric rhombohedral to ferroelectric orthorhombic phase transition occurs in the (110) platelet at high electric fields (∼20 kV∕cm). The mechanisms of the field-induced transformation from the glassy nonergodic relaxor phase or the ergodic relaxor phase to the ferroelectric phase are discussed.Electric field-induced phase transitions were investigated in ͑111͒, ͑110͒, and ͑100͒ thin platelets of relaxor ferroelectric Pb͑Mg 1/3 Nb 2/3 ͒O 3 single crystals with electric fields applied along the ͗111͘, ͗110͘, and ͗100͘ directions, respectively. Temperature dependences of complex dielectric permittivity, pyroelectric current and dielectric hysteresis loops were investigated. Electric field-temperature ͑E-T͒ phase diagrams were proposed for the different directions of the field. Alongside with the high-temperature ergodic relaxor phase and the low-temperature glassy nonergodic relaxor phase existing at E = 0, the ferroelectric phase may appear in the diagram at the fields higher than the threshold field ͑E th ͒. The temperature of the first-order transition between ergodic relaxor and ferroelectric phases ͑T C ͒ was located in field cooling and field heating after fi...

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

“…Similar U-shaped behavior has been observed previously for PLZT 12 and PMN. 13,14 Especially the results for pure PMN seem to coincide with an E-T phase diagram constructed on the basis of constant-field heating-cooling experiments. 20 The temperature of the minimum threshold field E th,min in the aforementioned articles is located near the freezing and depolarization temperatures, contrary to findings in the present work.…”

“…[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.…”

Electrocaloric properties in relaxor ferroelectric (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 system

“…36 The critical point in polycrystalline PMN-xPT system is also likely to be diffuse in nature due to the observed orientational heterogeneity or even absence of critical point depending on the electric field direction. 35,[37][38][39][40] The temperature of the maximum ECE responsivity was observed to lie just above T d (¼ T C ) (extrapolated from Figure 4) which is reflected in their similar concentration dependence ( Figure 5). When the ferroelectric nature of PMN-PT is strengthened with increasing x, it is expected that T C is approaching T m (T C ¼ T m for ordinary ferroelectrics), 30,41 as shown in Figure 5.…”

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)Stock1, Xu2, Gehring3 et al. 2007Phys. Rev. BSelf Cite603462View full textAdd to dashboardCite

“…The absence of any history dependence suggests that the ground state of PMN under field cooling is not a glassy state nor in a well defined ferroelectric ground state. 35 Here longrange and short-range polar order coexist and compete with each other. Similar measurements on single crystals of PZN and PZN-8% PT do not show a suppression of diffuse scattering intensities, but only a redistribution with field history dependence.…”