Structural, optical and dielectric properties of relaxor-ferroelectric Pb0.78Ba0.22Sc0.5Ta0.5O3

Marinova, Vera; Mihailova, Boriana; Malcherek, Thomas; Paulmann, Carsten; Lengyel, K.; Kovács, László; Veleva, M.; Gospodinov, M.; Güttler, Bernd; Stosch, Rainer; Bismayer, U.

doi:10.1088/0953-8984/18/31/l01

Cited by 19 publications

(24 citation statements)

References 22 publications

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“…The observed Raman peaks were previously attributed to definite atomic vibrations on the basis of polarized spectra of lead scandium niobates and tantalates measured at ambient pressure and different temperatures. 3,4,29,30 Hence, the number of replicas used to fit the spectrum at ambient pressure is consistent with the number of expected peaks; the HP spectra were fit with the same number of Lorentzians. In an ABO 3 structure of Fm3m symmetry there are four Raman-active phonon modes: A 1g + E g +2F 2g .…”

Section: Resultsmentioning

confidence: 83%

“…Recently, a new canonical relaxor Pb 0.78 Ba 0.22 Sc 0.5 Ta 0.5 O 3 ͑PST-Ba͒ was synthesized. 3 As-made single crystals of this compound exhibit considerably larger B-site ordered domains than those in the corresponding Ba-free counterpart PbSc 0.5 Ta 0.5 O 3 ͑PST͒, although the latter undergoes a phase transition to a normal ferroelectric state. 4 This indicates that the dilution of the Pb 2+ system with cations showing no affinity to form lone-pair electrons plays a more important role for the relaxor behavior than the size of chemically B-site ordered regions.…”

Section: Introductionmentioning

confidence: 87%

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Effect of Ba incorporation on pressure-induced structural changes in the relaxor ferroelectricPbSc0.5Ta0.5O3

et al. 2009

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Pressure-induced structural changes in the canonical relaxor Pb 0.78 Ba 0.22 Sc 0.5 Ta 0.5 O 3 were studied with both in-house and synchrotron single-crystal x-ray diffraction as well as Raman spectroscopy at pressures up to 9.8 GPa. The results reveal that the substitution of Ba for Pb in ABO 3 perovskite-type structures, i.e., the substitution of a two-valent element with an isotropic electron shell for an isovalent element with a stereochemically active lone pair, leads to a "diffuse pressure-induced phase transition," a structural transformation over a broad pressure range, without a well-defined critical pressure point. The smeared phase transition of the average structure results from the existence of local structural deformations in the vicinity of A-positioned Ba cations.

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Section: Resultsmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 87%

Effect of Ba incorporation on pressure-induced structural changes in the relaxor ferroelectricPbSc0.5Ta0.5O3

et al. 2009

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“…Due to the larger radius of Ba 2þ compared to that of Pb 2þ , in the vicinity of Ba cations the BO 6 octahedra are deformed along h111i direction and the Pb-O bond lengths shorten within the {111} planes, so local elastic fields (EFs) arise, leading to the suppression of the longrange FE order at low temperatures and significant broadening of the maximum of the dielectric permittivity. 25,26 These EFs were also revealed by applying an external pressure to PBST relaxor. In contrast to PST, demonstrating a sharp pressure-induced phase transition near 1.9 GPa, 27 the pressure-induced phase transition in PBST is diffuse, possessing a plateaulike shape in the range 2-4 GPa, i.e., it is not well defined, but smeared out over a pressure range and slightly shifted to higher pressures.…”

Section: Introductionmentioning

confidence: 90%

Effect of A-site La and Ba doping on threshold field and characteristic temperatures of PbSc0.5Ta0.5O3 relaxor studied by acoustic emission

Dul’kin

Mihailova

Gospodinov

et al. 2012

Journal of Applied Physics

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Giant electrocaloric effect in ferroelectric poly(vinylidenefluoride-trifluoroethylene) copolymers near a first-order ferroelectric transition Appl. Phys. Lett. 101, 132903 (2012) Equalizing disordered ferroelectrics for diffraction cancellation Appl. Phys. Lett. 101, 111104 (2012) Characteristics of electric-field-induced polarization rotation in 001-poled Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals close to the morphotropic phase boundary J. Appl. Phys. 112, 034117 (2012) Orientation and phase transition dependence of the electrocaloric effect in 0.71PbMg1/3Nb2/3O3-0.29PbTiO3 single crystal Appl. Phys. Lett. 101, 062907 (2012) Pressure effect on the ferroelectric phase transition in nanosized NH4HSO4The structural transitions in Pb 1Àx La x Sc (1þx)/2 Ta (1Àx)/2 O 3 , x ¼ 0.08 (PLST) relaxor crystals were studied by means of acoustic emission (AE) under an external electric field (E) and compared with those observed in pure PbSc 0.5 Ta 0.5 O 3 (PST) and Pb 0.78 Ba 0.22 Sc 0.5 Ta 0.5 O 3 (PBST) [E. Dul'kin et al., EPL 94, 57002 (2011)]. Similar to both the PST and PBST compounds, in zero field PLST exhibits AE corresponding to a para-to-antiferroelectric incommensurate phase transition at T n ¼ 276 K, lying in the vicinity of dielectric temperature maximum (T m ). This AE signal exhibits a nontrivial behavior when applying E resembling the electric-field-dependence of T n previously observed for both the PST and PBST, namely, T n initially decreases with the increase of E, attains a minimum at a threshold field E th ¼ 0.5 kV/cm, accompanied by a pronounced maximum of the AE count rate _ N ¼ 12 s À1 , and then starts increasing as E enhances. The similarities and difference between PST, PLST, and PBST with respect to T n , E th , and _ N are discussed from the viewpoint of three mechanisms: (i) chemically induced random local electric field due to the extra charge on the A-site ion, (ii) disturbance of the system of stereochemically active lone-pair electrons of Pb 2þ by the isotropic outermost electron shell of substituting ion, and (iii) change in the tolerance factor and elastic field to the larger ionic radius of the substituting A-site ion due to the different radius of the substituting ion. The first two mechanisms influence the actual values of T n and E th , whereas the latter is shown to affect the normalized _ N, indicating the fractions undergoing a field-induced crossover from a modulated antiferroelectric to a ferroelectric state. Creation of secondary random electric field, caused by doping-induced A-site-O ionic chemical bonding, is discussed.

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“…This indicates that the coupled polar shifts of B-site cations for PSTBa are along the [110] direction, implying that atomic arrangements in PNRs resemble an orthorhombic or monoclinic structure. The lowering of the symmetry of PNRs in PST-Ba should result from the A-site isovalent substitution of Ba 2þ for Pb 2þ , which generates local elastic stresses along the three-fold axes of the adjacent BO 6 octahedra, 23,24 which oppose and thus destabilize the intrinsic (zero-field) polar coupling along the cubic [111] direction. These doping-induced local elastic stresses have been recently observed by accoustic emission in PST-Ba and PST-La.…”

Section: Bltzmentioning

confidence: 99%

Influence of electric field on local phase transformations in relaxor ferroelectrics PbSc0.5Ta0.5O3 and Pb0.78Ba0.22Sc0.5Ta0.5O3

Maier

Steilmann

Gospodinov

et al. 2012

Journal of Applied Physics

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In situ temperature-dependent Raman-scattering experiments under an external dc electric field E have been performed on PbSc 0:5 Ta [110]. This indicates that the actual polar B-cation shifts are along the cubic body diagonals, implying a rhombohedral structure of the polar nanoregions. The T ? ðEÞ-dependence reveals that the local structural distortions associated with locally coupled polar displacements of B-site cations reach saturation near 0.5 kV/cm. When Pb 2þ is partially replaced by Ba 2þ , the strong increase of T ? with E occurs if the electric field is applied along the [110] direction. This indicates that the substitution disorder on the A-site lowers the symmetry of the polar nanoregions to orthorhombic or monoclinic. The T ? ðEÞ dependence determined from the B-cation localized mode shows saturation near 2.0 kV/cm, indicating that the zero-field structural state of PST-Ba exhibits less coupled polar shifts of B-site cations as compared to that of PST. According to the E-dependence of the Raman scattering near 55 cm À1 , for both compounds the overall response of the Pb system to the external electric field in the vicinity of T ? ðEÞ resembles antiferroelectric behavior, which along with the fact that the coupling between the B-site cations is ferroelectric, suggests that the polar nanoregions in Pb-based relaxors are ferrielectric in nature.

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Structural, optical and dielectric properties of relaxor-ferroelectric Pb_0.78Ba_0.22Sc_0.5Ta_0.5O₃

Abstract: We report on the synthesis of a new relaxor compound with chemical formula Pb 0.78 Ba 0.22 Sc 0.5 Ta

Cited by 19 publications

References 22 publications

Effect of Ba incorporation on pressure-induced structural changes in the relaxor ferroelectricPbSc0.5Ta0.5O3

Effect of Ba incorporation on pressure-induced structural changes in the relaxor ferroelectricPbSc0.5Ta0.5O3

Effect of A-site La and Ba doping on threshold field and characteristic temperatures of PbSc0.5Ta0.5O3 relaxor studied by acoustic emission

Influence of electric field on local phase transformations in relaxor ferroelectrics PbSc0.5Ta0.5O3 and Pb0.78Ba0.22Sc0.5Ta0.5O3

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