Soft Mode Behavior in Cubic and Tetragonal BaTiO<sub>3</sub>Crystals and Ceramics: Review on the Results of Dielectric Spectroscopy

Petzelt, J.

doi:10.1080/00150190802438009

Cited by 28 publications

(19 citation statements)

References 58 publications

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“…The absence of narrow CP also seems to be consistent with previous dielectric studies that did not reveal any significant dispersion in the microwave range, as reviewed by Petzelt. 31 The narrow CP which Sokoloff et al observed is probably part of the low-frequency doublets which we observed from the present study.…”

Section: The Existence Of Narrow Central Peakmentioning

confidence: 50%

Precursor dynamics in the ferroelectric phase transition of barium titanate single crystals studied by Brillouin light scattering

et al. 2011

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The acoustic anomalies and precursor dynamics of high-quality barium titanate single crystals were investigated by Brillouin light scattering and the birefringence measurements in the paraelectric phase above the cubic-totetragonal ferroelectric phase transition temperature (T c ). Two elastic stiffness coefficients C 11 and C 44 , the related sound velocities, and their absorption coefficients were determined from T c to 400 • C for the first time. The longitudinal acoustic (LA) mode showed a substantial softening over a wide temperature range above T c which was accompanied by a remarkable increase in the acoustic damping as well as growth of central peaks. The broad central peak (CP) exhibited a two-mode and one-mode behavior in the paraelectric and ferroelectric phase, respectively, which was consistent with recent far-infrared reflectivity measurements and first-principle-based calculations [Ponomareva et al., Phys. Rev. B 77, 012102 (2008)]. The acoustic anomalies and CP behavior were correlated with the anomalous birefringence, piezoelectric effect, and the deviation of the Curie-Weiss law observed from the same crystal. This strongly indicates similarity between the dynamics of polar clusters in typical ferroelectrics and the dynamics of polar nanoregions in relaxors, consistent with recent acoustic emission measurements [Dul'kin et al., Appl. Phys. Lett. 97, 032903 (2010)]. The relaxation times estimated from the central peak and the LA mode anomalies exhibited similar temperature dependences with comparable orders of magnitude, indicating that the polarization fluctuations due to the precursor polar clusters couples to the LA mode through density fluctuations. All these anomalies share common microscopic origin, correlated Ti off-centered motions forming polar clusters having local symmetry breaking in the paraelectric phase. The existence of the polar clusters were directly evidenced by the temperature evolution of the precise birefringence map. The narrow central peak within ±5 GHz proposed before was not confirmed to exist in the present study.

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Section: The Existence Of Narrow Central Peakmentioning

confidence: 50%

Precursor dynamics in the ferroelectric phase transition of barium titanate single crystals studied by Brillouin light scattering

et al. 2011

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“…The ionic polarization is related to lattice vibrations (phonons). [25][26][27][28][29] On the other hand, the dipole polarization is governed by the ferroelectric domain-wall contributions in multi domain crystals and ceramics. 11,12,[30][31][32] Additionally, the dielectric relaxation related to order-disorder phenomenon has been reported in single-domain crystals.…”

Section: Introductionmentioning

confidence: 99%

“…11,12,[23][24][25][26][27][28][29]32) However, the Kramers-Kronig transformation requires accurate knowledge of the reflectance over a wide frequency range and extrapolation beyond it; thus, it is not suitable for the estimation of the dielectric permittivity of BaTiO 3 , which has a multi-polarization mechanism. Moreover, the uncertainty of the analysis using a harmonic oscillator model interferes with the accurate estimation of the dielectric function of BaTiO 3 .…”

Section: Introductionmentioning

confidence: 99%

Terahertz dielectric response of single-domain BaTiO₃measured by far-infrared spectroscopic ellipsometry

Hoshina¹,

Kanehara²,

Takeda³

et al. 2014

Jpn. J. Appl. Phys.

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The complex dielectric permittivity of single-domain BaTiO 3 in the region of 30-700 cm %1 (0.90-21 THz) was directly measured using a far-infrared spectroscopic ellipsometer. The dielectric responses of the Slater, Last, Axe, and O 4 torsional modes, which are all infrared-active phonon modes in BaTiO 3 were clearly observed. The resonance frequencies of the phonon modes estimated in this study were in agreement with the previous data estimated by analysis of reflection spectra using a harmonic oscillator model. These results indicate that the far-infrared ellipsometric technique is effective for analyzing the phonon modes of BaTiO 3 single crystals. Additionally, we examine the dielectric response and the damping of the soft mode with respect to the order-disorder model.

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“…On the other hand, the dipolar polarization is related to the rotation of the permanent dipoles under an external AC field and takes place below ≈1 GHz. [24] Similarly, the interfacial polarization involves the movement of limited free charge carriers at interfaces or grain boundaries, which respond to low frequency fields (≈10s of kHz). [22] Therefore, only the electronic and atomic polarization processes contribute to the dielectric response during THz spectroscopy, making it possible to investigate structural changes at the lattice scale.…”

mentioning

confidence: 99%

Terahertz Probing Irreversible Phase Transitions Related to Polar Clusters in Bi_0.5Na_0.5TiO₃‐Based Ferroelectric

Meng

Zhang

et al. 2020

Adv Elect Materials

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ferroelectric materials, which are comprised of non-centrosymmetric unit cells, each possessing a switchable polarization of their electric dipole moment. Of the class of ferroelectric materials, perovskitestructured Bi 0.5 Na 0.5 TiO 3 (BNT)-based compounds have attracted worldwide research interest in recent years with the development of lead-free forms, [4] which have been deployed in a range of technological applications, including piezoelectric actuators, sensors, and dielectric capacitors. Each of these areas of utility is respectively attributed to their large electric field-induced strain, [5] high piezoelectric constant, and high specific energy. While earlier studies of the crystal structure and phase transitions of BNT have answered many questions, there still remain some key points that are controversial due to the complexity of NaO and BiO bonds, and the octahedral tilt in the unit cell. [6] Due to these unique structural properties, phase transitions in BNT, and its derivatives, can be induced by applied electric fields of 10s of kV cm −1 [7,8] which, in most cases, are indirectly represented by the electrical field-dependent bipolar current, polarization, or strain loops Electric-field-induced phase transitions in Bi 0.5 Na 0.5 TiO 3 -based relaxor ferroelectrics are essential to the control of their electrical properties and consequently in revolutionizing their dielectric and piezoelectric applications. However, fundamental understanding of these transitions is a long-standing challenge due to their complex crystal structures. Given the structural inhomogeneity at the nanoscale or sub-nanoscale in these materials, dielectric response characterization based on terahertz (THz) electromagnetic-probe beam fields is intrinsically coordinated to lattice dynamics during DC-biased poling cycles. The complex permittivity reveals the field-induced phase transitions to be irreversible. This profoundly counters the claim of reversibility, the conventional support for which is based upon the peak that is manifest in each of four quadrants of the current-field curves. The mechanism of this irreversibility is solely attributed to polar clusters in the transformed lattices. These represent an extrinsic factor, which is quiescent in the THz spectral domain.

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Soft Mode Behavior in Cubic and Tetragonal BaTiO₃Crystals and Ceramics: Review on the Results of Dielectric Spectroscopy

Cited by 28 publications

References 58 publications

Precursor dynamics in the ferroelectric phase transition of barium titanate single crystals studied by Brillouin light scattering

Precursor dynamics in the ferroelectric phase transition of barium titanate single crystals studied by Brillouin light scattering

Terahertz dielectric response of single-domain BaTiO₃measured by far-infrared spectroscopic ellipsometry

Terahertz Probing Irreversible Phase Transitions Related to Polar Clusters in Bi_0.5Na_0.5TiO₃‐Based Ferroelectric

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Soft Mode Behavior in Cubic and Tetragonal BaTiO3Crystals and Ceramics: Review on the Results of Dielectric Spectroscopy

Cited by 28 publications

References 58 publications

Precursor dynamics in the ferroelectric phase transition of barium titanate single crystals studied by Brillouin light scattering

Precursor dynamics in the ferroelectric phase transition of barium titanate single crystals studied by Brillouin light scattering

Terahertz dielectric response of single-domain BaTiO3measured by far-infrared spectroscopic ellipsometry

Terahertz Probing Irreversible Phase Transitions Related to Polar Clusters in Bi0.5Na0.5TiO3‐Based Ferroelectric

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Soft Mode Behavior in Cubic and Tetragonal BaTiO₃Crystals and Ceramics: Review on the Results of Dielectric Spectroscopy

Terahertz dielectric response of single-domain BaTiO₃measured by far-infrared spectroscopic ellipsometry

Terahertz Probing Irreversible Phase Transitions Related to Polar Clusters in Bi_0.5Na_0.5TiO₃‐Based Ferroelectric