Automatic collection of powder data from photographs

Sonneveld, E. J.; Visser, J. W. M.

doi:10.1107/s0021889875009417

Cited by 239 publications

(143 citation statements)

References 5 publications

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“…On the assumption that it is appropriate to use the K = 0.9394, b of Fig. 3(b)] refined by smoothing, 30) sonnerveld method (background removal) 31) and Rachinger method (CuK ¡2 peaks removal), 32) and of 0.15406 nm (CuK ¡1 ), Fig. 6 indicates the detailed relationship among heat treatment temperature, D, grain size estimated from SEM images (Figs.…”

Section: Resultsmentioning

confidence: 99%

Polarization and leakage current properties of self-supported bismuth sodium titanate ceramic films deposited by aerosol deposition method

Suzuki

Akedo

2013

J. Ceram. Soc. Japan

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Self-supported (Bi 0.5 Na 0.5 )TiO 3 (BNT) dense ceramic films with a thickness of approximately 20¯m have been fabricated by use of an aerosol deposition method with heat treatment and sapphire single crystal substrates. Investigations of their constitution phase and crystal structure, observation of their microstructure, and measurement of polarization properties and leakage current density (J ) were performed. Wlile the films heat-treated at 800 and 900°C in air indicated the low J µ 10 ¹7 A/cm 2 at 150 kV/cm, the sintered bulks and the films annealed at 900°C in the BNT starting raw powder showed the relatively high J of approximately 10 ¹6 A/cm 2 at 150 kV/cm. These films heat-treated at 800 and 1000°C in air and sintered bulks showed the almost the same coercive field (E c ) of approximately 57 kV/cm (in the 56 to 58 kV/cm range), and the films heat-treated at 1000°C in air exhibited good polarization properties and remanent polarization (P r ) of 25¯C/cm 2 . The AD method is proposed to be effective for obtaining self-supported BNT thick films with good saturated hysteresis loops and low J.

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Section: Resultsmentioning

confidence: 99%

Polarization and leakage current properties of self-supported bismuth sodium titanate ceramic films deposited by aerosol deposition method

Suzuki

Akedo

2013

J. Ceram. Soc. Japan

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“…15 At 300 °C and above, ½{310} superstructure reflections associated with in-phase tilting are observed at 36.5 °2θ, consistent with the tilted tetragonal structure with polar space group P4bm. 8 The intensities of the weak antiphase and in-phase superstructure reflections were carefully measured using an iterative method after Sonneveld & Visser 16 in PANalytical HighScore Plus 17 and normalised against the most intense reflection. Plotted as a function of temperature (Figure 2a), these show the same trends as the peak widths.…”

Section: Textmentioning

confidence: 99%

Inference of oxygen vacancies in hydrothermal Na0.5Bi0.5TiO3

O'Brien

Woodward

Sardar

et al. 2012

Applied Physics Letters

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A high-resolution x-ray powder diffraction study has been made of pseudo-rhombohedral and tetragonal phases in Na 0.5 Bi 0.5 TiO 3 (NBT), produced via hydrothermal and conventional solid-state methods. Hydrothermal NBT exhibits significantly greater structural distortion at room temperature than solid-state NBT. Peak widths and superstructure peak intensities show a phase transition at ~ 305 °C, with trends suggesting that the structure tends towards cubic symmetry at this temperature. Structural refinements indicate that the transition occurs via a phase coexistence region with no clear intermediate phase. Piezoelectric data show evidence of polarisation pinning in hydrothermal NBT, interpreted as a high proportion of oxygen vacancies. TextSodium bismuth titanate, Na 0.5 Bi 0.5 TiO 3 (NBT) is a widely-studied relaxor perovskite of potential use as a lead-free piezoelectric, particularly as the end-member of a range of solid solutions including NBT-BaTiO 3 and NBT-K 0.5 Bi 0.5 TiO 3 . 1 At room temperature, the structure has long been designated as rhombohedral R3c, 2 although recent studies have suggested monoclinic Cc symmetry for both single crystals 3 and sintered ceramics. 4 However, the deviation from rhombohedral symmetry is very small and the room-temperature structure may be considered pseudo-rhombohedral. On heating, a phase transition to tetragonal symmetry is known to exist, but has been reported to take place over a range of temperatures: 278-291 °C, 5 240-270 °C 6 and 300-320 °C. 7 At the boundary between pseudorhombohedral and tetragonal structures, some studies 8 have shown the existence of a two-phase region, while others 9 have proposed the presence of an intermediate phase. The phase transition to the cubic structure takes place at 500-550 °C 8,10 although some studies 11,12 refer to the pseudorhombohedral -tetragonal transition as the ferroelectric Curie temperature.In this study, the structures, phase transitions and piezoelectric properties of polycrystalline NBT produced by a low-temperature hydrothermal method are investigated and compared with those of a sample made by conventional solid-state synthesis. This study is motivated by the observation over many years that the structures and physical properties of NBT can vary significantly depending on the synthetic method adopted and the thermal history of the material. 4 Limited previous studies of hydrothermal NBT have been undertaken 12,13 but the structural phase transitions and piezoelectric properties of hydrothermal NBT have not been investigated before.NBT was synthesised in an autoclave with a polytetrafluoroethane liner using a 1:4 molar ratio of Bi 2 O 3 :TiO 2 (99.9%, Janssen Chimica, -Bi 2 O 3 , and >98%, BDH, anatase polymorph, respectively). Typically ~4 g Bi 2 O 3 and the corresponding amount of TiO 2 were reacted in a 125 ml autoclave. 60 ml of 10 M NaOH solution was added and the suspension stirred for 2 hours. The autoclave was placed in an oven at 240 °C and left at autogenous pressure for 5 days before cooling. ...

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“…In the Rietveld method (Rietveld, 1969), the diffraction profile is calculated using the unit-cell dimensions to determine the peak positions, and the atomic positional and thermal displacement parameters as a model for the peak intensities. On the other hand, in the 'pattern-decomposition' technique, the step-scan data are decomposed into their component Bragg reflections without reference to the crystal structure (other than the unit-cell dimensions); that is, the calculated peak intensities are themselves variables in the fitting procedure (Sonneveld & Visser, 1975).…”

Section: Introductionmentioning

confidence: 99%

Quantitative phase analysis from neutron powder diffraction data using the Rietveld method

Hill¹,

Howard²

1987

J Appl Crystallogr

1,167

606

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The weight of a phase in a mixture is proportional to the product of the scale factor, as derived in a multicomponent Rietveld analysis of the powder diffraction pattern, with the mass and volume of the unit cell. If all phases are identified and crystalline, the weight fraction W of phase p is given by Wp = Sp( Z M IO p/~ S,( Z M IO,, iwhere S, Z, M and V are, respectively, the Rietveld scale factor, the number of formula units per unit cell, the mass of the formula unit and the unit-cell volume. This is the basis of a method providing accurate phase analyses without the need for standards or for laborious experimental calibration procedures. The method is demonstrated by measurements on binary mixtures of rutile, corundum, silicon and quartz.

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Automatic collection of powder data from photographs

Cited by 239 publications

References 5 publications

Polarization and leakage current properties of self-supported bismuth sodium titanate ceramic films deposited by aerosol deposition method

Polarization and leakage current properties of self-supported bismuth sodium titanate ceramic films deposited by aerosol deposition method

Inference of oxygen vacancies in hydrothermal Na0.5Bi0.5TiO3

Quantitative phase analysis from neutron powder diffraction data using the Rietveld method

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