Development of ferroelectric order in relaxor(1−x)Pb(Mg1/3

Z.-G. Ye

¹

,

Yonghong Bing

²

,

Junjie Gao

³

et al.

Abstract

The microstructure and phase transition in relaxor ferroelectric Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) and its solid solution with PbTiO 3 (PT), PMN-xPT, remain to be one of the most puzzling issues of solid state science. In the present work we have investigated the evolution of the phase symmetry in PMN-xPT ceramics as a function of temperature (20 K < T < 500 K) and composition (0 ≤ x ≤ 0.15) by means of high-resolution synchrotron x-ray diffraction. Structural analysis based on the experimental data reveals that the substitution of Ti 4+ for the complex B-site (Mg 1/3 Nb 2/3 ) 4+ ions results in the development of a clean rhombohedral phase at a PT-concentration as low as 5%. The results provide some new insight into the development of the ferroelectric order in PMN-PT, which has been discussed in light of the kinetics of polar nanoregions and the physical models of the relaxor ferroelectrics to illustrate the structural evolution from a relaxor to a ferroelectric state.

Investigation of the electrocaloric effect in a PbMg2/3Nb1/3O3-PbTiO3 relaxor thin film

“…The existence of a structural phase transition in relaxor PMN-PT is debatable. By means of high-resolution x-ray diffraction ͑XRD͒, Ye et al 6 observed that for x Ͼ 0.05 an orthorhombic phase occurs below T m . However, there is no evidence of any structural phase transition in zero-field cooling ͑ZFC͒ and zero-field heating ͑ZFH͒ dielectric measurements.…”

“…4 PbMg 2/3 Nb 1/3 O 3 ͑PMN͒ is a well-known relaxor that develops long-range dipolar order by adding a certain amount of the ferroelectric perovskite PbTiO 3 ͑PT͒. [6][7][8] The phase diagram of the mixed solid solution ͑1−x͒PMN-xPT has generated some controversy, particularly in x Ͻ 0.3 where relaxor compositions form. The existence of a structural phase transition in relaxor PMN-PT is debatable.…”

“…This suggests that no structural phase transition takes place on cooling, which in turn suggests no structural transition on heating, despite observations to the contrary. 6 We suggest that during cooling, PNRs freeze at T f , and depolarize on heating through the depolarizing temperature T d = 18°C. The dipole glass model proposed by Viehland et al 24 describes relaxors by analogy with dipole glasses, in which dipole-dipole interactions ͑or PNR interactions͒ become stronger at low temperatures.…”

Hysteresis in acoustic properties of ferroelectric relaxor Pb[(Zn1∕3Nb2∕3)0.955Ti0.045]O3 single crystals studied by Brillouin and dielectric spectroscopies

“…25,26 According to this model, the diffuse phase transition is influenced by the number of PNRs at the phase transition temperature. The growth of a ferroelectric nucleus is restricted by the existing neighboring PNRs that cannot be collapsed with the growing nucleus for some reasons, for example, due to the local random fields.…”

Mapping bias-induced phase stability and random fields in relaxor ferroelectrics

“…18 The ͑1−x͒Pb͑Mg 1/3 Nb 2/3 ͒O 3 -x PbTiO 3 crystal with x = 0.1 ͑PMN-10%PT͒ is grown from high temperature solution and has a dielectric maximum at T max = 310 K ͑at 1 kHz͒. 19 The crystal undergoes a phase transition to a rhombohedral ferroelectric state on cooling at T c Х 280 K, 20 thus the measurements are performed in the macroscopically cubic "ergodic" relaxor state ͑note that a surface phase can exist in the frozen state due to, e.g., strain effects͒. 21 The PFM and SS-PFM measurements are performed on the mirror-polished ͑001͒ crystal surface using a commercial atomic force microscope system ͑Veeco MultiMode NS-IIIA͒, which was modified as described elsewhere.…”