Resonance Raman scattering of relaxors PbSc0.5Ta0.5O3 and PbSc0.5Nb0.5O3

Mihailova, Boriana; Bastjan, M.; Schulz, Benjamin; Rübhausen, Michael; Gospodinov, M.; Stosch, Rainer; Güttler, Bernd; Malcherek, Thomas; Bismayer, U.

doi:10.1063/1.2433763

Cited by 8 publications

(4 citation statements)

References 15 publications

(11 reference statements)

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“…The Burns temperature T d was recorded in the range of 600−700 K [8] for the known ferroelectric relaxors based on lead. Upon cooling at T < T d , nanopolar zones begin to interact with each other, and at some so-called intermediate temperature T * they merge into larger ones (corresponding to a nanoscale phase transition associated with random fields) [9,10] and long-lived polar zones [11,12]. Further cooling can lead to freezing of these dipole zones in a non-ergodic state (at a temperature T f ), i.e.…”

Section: Introductionmentioning

confidence: 99%

Thermophysical properties and phase transitions of ferroelectric PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=- at high temperatures

Kallaev

Bakmaev

Omarov

2023

Physics of the Solid State

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The thermophysical properties of the ferroelectric PbFe0.5Nb0.5O3 in the temperature range 300-800 K are studied. Anomalies in the heat capacity and thermal diffusion are found in the region of the diffuse ferroelectric transition Tc~380 K, the Burns temperature Td~670 K, and the intermediate temperature T^*~470 K. The dominant phonon heat transfer mechanisms in a ferroelectric with a nanopolar structure. Keywords: heat capacity, thermal diffusion, thermal conductivity, ferroelectric, phase transitions, relaxor.

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Section: Introductionmentioning

confidence: 99%

Thermophysical properties and phase transitions of ferroelectric PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=- at high temperatures

Kallaev

Bakmaev

Omarov

2023

Physics of the Solid State

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“…In a previous study we have applied resonance Raman spectroscopy complemented by group-theory analysis to stoichiometric PbSc 0.5 Ta 0.5 O 3 and PbSc 0.5 Nb 0.5 O 3 , using a laser wavelength λ = 325 nm (3.8 eV) [26]. The excitation photon energy was chosen to be slightly above the energy gap E 3.2 eV gap ∼ but in the vicinity of the broad maximum of the optical dielectric permittivity [28]. It was shown that under such resonance conditions the simultaneous enhancement of first-and second-order RRS generated by the antisymmetric BO 6 bending and stretching modes results exclusively from coupled polar distortions, which considerably facilitates the analysis of the structural polarity.…”

Section: Introductionmentioning

confidence: 99%

The effect of chemical variations on the structural polarity of relaxor ferroelectrics studied by resonance Raman spectroscopy

Rohrbeck

Flor

Aroyo

et al. 2016

J. Phys.: Condens. Matter

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Resonance Raman spectroscopy was applied to doped PbSc0.5Ta0.5O3 and PbSc0.5Nb0.5O3 relaxor ferroelectrics, to better understand the effect of composition disorder on the mesoscopic-scale polar order in complex perovskite-type (ABO3) ferroelectrics. The excitation photon energy used was 3.8 eV, which is slightly above the energy gap and corresponds to the maximum of the optical dielectric permittivity. Group-theory analysis reveals that the resonance Raman scattering (RRS) observed under these conditions is allowed only in polar crystal classes. Therefore, RRS is dominated by the atomic dynamics of nanoregions with coherent polar distortions, which considerably facilitates the comparison of polar order in various compounds. The results show that A-site doping (Ba(2+), Sr(2+), La(3+), Bi(3+)) has significantly stronger effect on the structural polarity than the introduction of a third element at the B site (Nb(5+) or Sn(4+) doped in PbSc0.5Ta0.5O3). The A-site substitution by cations that in contrast to Pb(2+) have isotropic outermost electron shells disturbs the system of lone-pair electrons, thus reducing the correlation length of coupled polar distortions and the strength of the electric field associated with the mean polarization of polar nanoregions. A-site doping with larger cations (Ba(2+)) augments the polar deformation of the individual BO6 octahedra due to local elastic fields. As a result, such A-site doping intensifies the initial structural polarity at high temperatures and prevails the enlargement of the polar fraction at low temperatures. A-site doping with smaller cations (Sr(2+), La(3+)), regardless if they are isovalent or aliovalent to Pb(2+), increases the correlation length of antiferrodistortive order (BO6 tilts), which in turn assists the development of double-perovskite structure with coherent local polar distortions. A-site doping with aliovalent cations (Bi(3+)) having the same outermost electron shell and ionic radius as the host A-site Pb(2+) cations leads to stronger coupling along the -B-O-B- bond linkages due to enhanced random local electric fields.

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“…Both temperatures are located in the PE phase. The sequence of characteristic temperatures T d → T * → T m [8,9] has been confirmed for a number of relaxor compounds by x-ray diffraction [7,10,11], vibrational spectroscopy [10][11][12] and acoustic emission (AE) [13,14].…”

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“…PbSc 0.5 Ta 0.5 O 3 (PST) is known to belong to such a type of RFEs [3]. Previously in disordered PST with s ≈ 8% (PST-8), belonging to RFEs, T d ≈ 700 K and T * ≈ 450 K are detected using the polarized Raman spectroscopy [10], and then the T * ≈ 450 K is confirmed by AE data [20]. On the other hand, in highly ordered PST with s ≈ 65% (PST-65), belonging to FEs, no PNRs but the polar TP are observed using RUS, and a some characteristic temperature of 425 K is observed by deviation of the lattice parameter a from a straight line [21].…”

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confidence: 99%

Evidence of presence of tweed in PbSc _0.5 Ta _0.5 O ₃ crystals based on acoustic emission frequency spectrum analysis

Dul’kin¹,

Salje²,

Roth³

2015

EPL

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Ferroelectric PbSc0.5Ta0.5O3 crystals with high degree of chemical B-site order and relaxor PbSc0.5Ta0.5O3 crystals with low degree of chemical B-site order were studied by acoustic emission near their intermediate characteristic temperature T * . The acoustic emission data were subjected to fast Fourier transform procedure. It was established that, while the acoustic emission spectrum amplitude of ordered PbSc0.5Ta0.5O3 exhibits a gradual monotonic decrease as frequency decreases, the one of disordered PbSc0.5Ta0.5O3 exhibits the additional features. The differences between the acoustic emission spectra are discussed in view of corresponding differences between polar nanoregions, characteristic for relaxors, and polar tweed pattern, characteristic for ferroelectrics.

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Resonance Raman scattering of relaxors PbSc0.5Ta0.5O3 and PbSc0.5Nb0.5O3

Cited by 8 publications

References 15 publications

Thermophysical properties and phase transitions of ferroelectric PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=- at high temperatures

Thermophysical properties and phase transitions of ferroelectric PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=- at high temperatures

The effect of chemical variations on the structural polarity of relaxor ferroelectrics studied by resonance Raman spectroscopy

Evidence of presence of tweed in PbSc _0.5 Ta _0.5 O ₃ crystals based on acoustic emission frequency spectrum analysis

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Resonance Raman scattering of relaxors PbSc0.5Ta0.5O3 and PbSc0.5Nb0.5O3

Cited by 8 publications

References 15 publications

Thermophysical properties and phase transitions of ferroelectric PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=- at high temperatures

Thermophysical properties and phase transitions of ferroelectric PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=- at high temperatures

The effect of chemical variations on the structural polarity of relaxor ferroelectrics studied by resonance Raman spectroscopy

Evidence of presence of tweed in PbSc 0.5 Ta 0.5 O 3 crystals based on acoustic emission frequency spectrum analysis

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Evidence of presence of tweed in PbSc _0.5 Ta _0.5 O ₃ crystals based on acoustic emission frequency spectrum analysis