Phases in the (1 −x)Na0.5Bi0.5TiO3–(x)CaTiO3system

Ranjan, Rajeev; Garg, Rajni; Kothai, V.; Agrawal, Arpit; Senyshyn, Anatoliy; Boysen, H.

doi:10.1088/0953-8984/22/7/075901

Cited by 22 publications

(14 citation statements)

References 29 publications

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“…Only under tensile conditions the R3c structure can be stabilized. The results are in very good agreement with the experimental findings by Ranjan et al [37], who found for 0.05 < x < 0.15 coexistence of R3c and P bnm phases.…”

Section: A Alkaline Earth Metal Substituted Solid Solutionssupporting

confidence: 92%

“…The crystal structures within the solid solution system (NBT) (1−x) -(CaTiO 3 ) x were investigated by Ranjan et al The authors reported on phase coexistence for 0.05 < x < 0.15 of rhombohedral R3c and orthorhombic P bnm structures [36,37], the latter is identical with the crystal structure of pure CaTiO 3 [38] and the high-pressure phase of pure NBT [27]. Watanabe et al analyzed the electrical properties and the phase transition temperatures of these materials for x 0.08 [39].…”

Section: Introductionmentioning

confidence: 99%

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Theoretical prediction of morphotropic compositions inNa1/2Bi1/2T

Gröting

Albe

2014

Phys. Rev. B

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In this article we present a method based on ab initio calculations to predict compositions at morphotropic phase boundaries in lead-free perovskite solid solutions. This method utilizes the concept of flat free energy surfaces and involves the monitoring of pressure-induced phase transitions as a function of composition. As model systems, solid solutions of Na 1/2 Bi 1/2 TiO 3 with the alkali substituted and the alkaline earth substituted CaTiO 3 and BaTiO 3 are chosen. The morphotropic compositions are identified by determining the composition at which the phase transition pressure equals zero. In addition, we discuss the different effects of hydrostatic pressure (compression and tension) and chemical substitution on the antiphase tilts about the [111] axis (a − a − a − ) present in pure Na 1/2 Bi 1/2 TiO 3 and how they develop in the two solid solutions . Finally, we discuss the advantages and shortcomings of this simple computational approach.

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Section: A Alkaline Earth Metal Substituted Solid Solutionssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Theoretical prediction of morphotropic compositions inNa1/2Bi1/2T

Gröting

Albe

2014

Phys. Rev. B

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“…A coexistence of the ferroelectric (rhombohedral or tetragonal) and orthogonal phases has been reported in the A‐site disordered solid solution systems of BNT‐CT and BT‐CT . In the case of the BKT‐CT system, our study suggests that a pesudocubic phase is stable when the CT content reaches a certain amount.…”

Section: Resultssupporting

confidence: 59%

Bi_0.5K_0.5TiO₃–CaTiO₃ ceramics: Appearance of the pseudocubic structure and ferroelectric‐relaxor transition characters

et al. 2018

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In this study, solid solution ceramics of (1−x)Bi0.5K0.5TiO3–xCaTiO3 (BKT‐CT, x = 0, 0.12, 0.15, 0.18, 0.21, and 0.25) were prepared. A phase transition from the tetragonal symmetry to the pseudocubic symmetry is discovered near x = 0.25. The reasons for the appearance of the pseudocubic phase were discussed. The compositions of x ≤ 0.21 show the ferroelectric ordering at room temperature. The remnant polarization (Pr) is 22.4 μC/cm2 for the x = 0.15 composition. The temperature dependence of the relative permittivity suggests two dielectric anomalies for x ≤ 0.18. The dielectric anomaly in the low‐temperature range is related to a spontaneous transition between the ferroelectric and relaxor states. The temperature (TF‐R) for the transition decreases with the CT addition, falling from 211°C for x = 0.12‐134°C for x = 0.18. Only one relaxor‐like dielectric anomaly was observed for x ≥ 0.21. The thin double ferroelectric hysteresis loops have been observed during the ferroelectric‐relaxor transition process for x ≥ 0.21. The maximum electrostrain (Sm) reaches 0.155% at 100°C for x = 0.21. The low‐temperature Raman measurement suggests the intrinsic tetragonal distortions for x = 0.25.

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“…The majority of works mainly focused on the structural phase transition under different experimental conditions. Ranjan et al [48] showed by neutron diffraction and calculation of phase tilt angle that the (1-x)NBT-xCT system exhibits an orthorhombic phase (Pbnm) for x ≥ 0.15 and rhombohedral phase (R3c) for x ≤ 0.05 with a mixture of two phases (R3c+Pbnm) for x = 0.10. Moreover, Du et al [49] demonstrated that this system is susceptible to orthorhombic distortion for x ≥ 0.14 and the MPB was found to lie around 0.08 ≤ x < 0.14.…”

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confidence: 99%

Relaxor behaviour and phase transition of perovskite ferroelectrics-type complex oxides (1–x)Na0.5Bi0.5TiO3–xCaTiO3 system

2018

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Polycrystalline powders of (1-x)Na 0.5 Bi 0.5 TiO 3 -xCaTiO 3 ((1-x)NBT-xCT, 0 ≤ x ≤ 0.55) have been synthesized by solid state route. The effects of simultaneous substitution of Na + /Bi 3+ at A-site in NBT on structural and dielectric properties were investigated. X-ray diffraction analysis revealed the phase transition from rhombohedral structure (x = 0) to orthorhombic structure (x ≥ 0.15). A distinct behaviour in dielectric properties was obtained, where for x = 0, a normal ferroelectric behaviour was observed, whereas for x ≥ 0.15, a broad dielectric anomaly was revealed such that the maximum temperature (T m ) strongly depended on the frequency and shifted towards low temperature with CT. The dielectric dispersion indicated a relaxor behaviour revealed by the degree of diffuseness and modelled via Vogel-Fulcher relation. The study highlighted the relaxor behaviour as a function of frequency and proved the transformation from a relaxor high-frequency dependence to a paraelectric phase at temperature T s . The distinct variation of the Raman spectra at room temperature was correlated with X-ray diffraction results and proved the already mentioned transition. On heating (193-500 ℃), the Raman spectra confirmed the structural stability (Pnma) of the materials. The phonon behaviour for x = 0.15 was discussed in terms of the appearance of polar nanoregions (PNRs) into a non-polar orthorhombic matrix responsible of the relaxor behaviour. For x = 0.20, unchanged phonon behaviour confirmed the variation in dielectric behaviour where the solids transformed from a relaxor to a paraelectric state without structural phase transition.

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Phases in the (1 −x)Na_0.5Bi_0.5TiO₃–(x)CaTiO₃system

Cited by 22 publications

References 29 publications

Theoretical prediction of morphotropic compositions inNa1/2Bi1/2T

Theoretical prediction of morphotropic compositions inNa1/2Bi1/2T

Bi_0.5K_0.5TiO₃–CaTiO₃ ceramics: Appearance of the pseudocubic structure and ferroelectric‐relaxor transition characters

Relaxor behaviour and phase transition of perovskite ferroelectrics-type complex oxides (1–x)Na0.5Bi0.5TiO3–xCaTiO3 system

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Phases in the (1 −x)Na0.5Bi0.5TiO3–(x)CaTiO3system

Cited by 22 publications

References 29 publications

Theoretical prediction of morphotropic compositions inNa1/2Bi1/2T

Theoretical prediction of morphotropic compositions inNa1/2Bi1/2T

Bi0.5K0.5TiO3–CaTiO3 ceramics: Appearance of the pseudocubic structure and ferroelectric‐relaxor transition characters

Relaxor behaviour and phase transition of perovskite ferroelectrics-type complex oxides (1–x)Na0.5Bi0.5TiO3–xCaTiO3 system

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Product

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Phases in the (1 −x)Na_0.5Bi_0.5TiO₃–(x)CaTiO₃system

Bi_0.5K_0.5TiO₃–CaTiO₃ ceramics: Appearance of the pseudocubic structure and ferroelectric‐relaxor transition characters