Single crystal growth of 67%BiFeO3-33%BaTiO3 solution by the floating zone method

Rong, Yangchun; Zheng, Hong; Krogstad, Matthew; Mitchell, J. F.; Phelan, Daniel

doi:10.1016/j.jcrysgro.2017.08.032

Cited by 6 publications

(3 citation statements)

References 26 publications

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“…When the inverted umbrella falls below the melt, it creates a non-single crystalline clump, which is visible in Figure a where the diameter of the seed-side below the melt is larger than that of the feed rod. This premelting led to frequent loss of the molten-zone and has similarly been observed and reported in floating zone growth of La 2– x Sr x CuO 4 (LSCO) and 67%BiFeO 3 -33%BaTiO 3 single crystals . The premelt zone arises either due to incongruent melting or due to capillary action resulting from porosity of the feed rod .…”

Section: Results and Discussionmentioning

confidence: 86%

“…This premelting led to frequent loss of the molten-zone and has similarly been observed and reported in floating zone growth of La 2−x Sr x CuO 4 (LSCO) 43 and 67%BiFeO 3 -33%BaTiO 3 single crystals. 44 The premelt zone arises either due to incongruent melting or due to capillary action resulting from porosity of the feed rod. 41 Therefore, the sintered rod was densified by rapidly passing a melt zone through the feed rod (40 mm/h for both the seed and feed rods) in air.…”

Section: Resultsmentioning

confidence: 99%

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Single Crystal Growth of Relaxor Ferroelectric Ba₂PrFeNb₄O₁₅ by the Optical Floating Zone Method

Wang

Zheng

Ren

et al. 2019

Crystal Growth & Design

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Uniaxial tungsten bronzes have received increasing interest because of their potential application as lead-free ferroelectrics as well as their flexibility via chemical substitution. Here we demonstrate growth of single crystals of one such material, Ba2PrFeNb4O15, which possesses the tetragonal tungsten bronze structure, by the optical floating zone method. The challenge of this growth is to control the stability of the molten zone which allows the growth to persist for a long enough time to achieve large volume single crystals. Our work reveals that the use of a slight overpressure of air allows the molten zone to be maintained up to 7 h at a traveling speed of 4 mm/h. The obtained crystals were studied using high-resolution single crystal scattering, powder X-ray diffraction, and dielectric measurements. We find that Ba2PrFeNb4O15 possesses a rather complex average structure with a monoclinic symmetry in a P112/m space group and unit cell parameters of a = 12.49188(8) Å, b = 12.49232(8) Å, c = 3.92863(1) Å, and γ = 90.056°, with an additional incommensurate superstructural modulation superimposed. The temperature dependence of dielectric properties has been investigated by comparing as-grown, O2-annealed, and Ar-annealed samples. A broad relaxation dielectric peak is observed around 150 K for the O2-annealed sample, indicating a typical relaxor behavior below 150 K. A larger dielectric permittivity (ε′ ≈ 1300) than those of corresponding ceramics (up to ε′ ≈ 200) is found in the oxygen annealed crystals. We suggest that as-grown single crystals are oxygen deficient and that the oxygen vacancies can be eliminated by an oxygen annealing treatment.

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Section: Results and Discussionmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Single Crystal Growth of Relaxor Ferroelectric Ba₂PrFeNb₄O₁₅ by the Optical Floating Zone Method

Wang

Zheng

Ren

et al. 2019

Crystal Growth & Design

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show abstract

“…Because of the possibility of oxygen deficiencies of asgrown crystals after crystal growth, which can affect the dielectric properties [41,44], a crystal obtained from the Ba 2 NdFeNb 4 O 15 crystal boule was treated by oxygen annealing before carrying out the high resolution x-ray powder diffraction. As shown in figure 2, significant differences in color were observed in the powder ground from the as-grown and oxygen annealed crystals.…”

Section: Synthesis and Characterization Of Ba 2 Ndfenb 4 O 15mentioning

confidence: 99%

Active and passive defects in tetragonal tungsten bronze relaxor ferroelectrics

Wang¹,

Krogstad²,

Zheng³

et al. 2022

J. Phys.: Condens. Matter

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Tetragonal tungsten bronze (TTB) based oxides constitute a large family of dielectric materials which are known to exhibit complex distortions producing incommensurately modulated superstructures as well as significant local deviations from their average symmetry. The local deviations produce diffuse scattering in diffraction experiments. The structure as well as the charge dynamics of these materials are anticipated to be sensitive to defects, such as cation or oxygen vacancies. In this work, in an effort to understand how the structural and charge dynamical properties respond to these two types of vacancy defects, we have performed measurements of dielectric susceptibilities and single crystal diffraction experiments of two types of TTB materials with both ‘filled’ (Ba2NdFeNb4O15 and Ba2PrFeNb4O15) and ‘unfilled’ (Sr0.5Ba0.5Nb2O6) cation sublattices. We also perform these measurements before and after oxygen annealing, which alters the oxygen vacancy concentrations. Surprisingly, we find that many of the diffuse scattering features that are present in the unfilled structure are also present in the filled structure, suggesting that the random fields and disorder that are characteristic of the unfilled structure are not responsible for many of the local structural features that are reflected in the diffuse scattering. Oxygen annealing clearly affected both color and dielectric properties, consistent with a diminishment of the oxygen vacancy concentration, but had little effect on observed diffuse patterns.

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Free-standing, non-toxic and reusable 0.67BiFeO3–0.33BaTiO3 based polymeric piezo-catalyst for organic dye wastewater treatment

Muduli

Veeralingam²,

Badhulika³

2022

Journal of Water Process Engineering

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Single crystal growth of 67%BiFeO3-33%BaTiO3 solution by the floating zone method

Cited by 6 publications

References 26 publications

Single Crystal Growth of Relaxor Ferroelectric Ba₂PrFeNb₄O₁₅ by the Optical Floating Zone Method

Single Crystal Growth of Relaxor Ferroelectric Ba₂PrFeNb₄O₁₅ by the Optical Floating Zone Method

Active and passive defects in tetragonal tungsten bronze relaxor ferroelectrics

Free-standing, non-toxic and reusable 0.67BiFeO3–0.33BaTiO3 based polymeric piezo-catalyst for organic dye wastewater treatment

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Single crystal growth of 67%BiFeO3-33%BaTiO3 solution by the floating zone method

Cited by 6 publications

References 26 publications

Single Crystal Growth of Relaxor Ferroelectric Ba2PrFeNb4O15 by the Optical Floating Zone Method

Single Crystal Growth of Relaxor Ferroelectric Ba2PrFeNb4O15 by the Optical Floating Zone Method

Active and passive defects in tetragonal tungsten bronze relaxor ferroelectrics

Free-standing, non-toxic and reusable 0.67BiFeO3–0.33BaTiO3 based polymeric piezo-catalyst for organic dye wastewater treatment

Contact Info

Product

Resources

About

Single Crystal Growth of Relaxor Ferroelectric Ba₂PrFeNb₄O₁₅ by the Optical Floating Zone Method

Single Crystal Growth of Relaxor Ferroelectric Ba₂PrFeNb₄O₁₅ by the Optical Floating Zone Method