A profile-fitting procedure for analysis of broadened X-ray diffraction peaks. II. Application and discussion of the methodology

Benedetti, Alvise; Fagherazzi, G.; Enzo, Stefano; Battagliarin, M.

doi:10.1107/s0021889888006624

Cited by 96 publications

(45 citation statements)

References 5 publications

(7 reference statements)

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“…X-ray powder diffraction ͑XRPD͒ analyses were performed using a Philips 1710 diffractometer equipped with a copper anode operated at 40 kV and 35 mA, graphite curved monochromator on the diffracted beam, and a proportional counter. The crystallite sizes were determined through analyses of XRD line broadening, using a published program 20,21 with sintered silicon used as a standard.…”

Section: B Microstructural Characterizationmentioning

confidence: 99%

Characterization of densified fully stabilized nanometric zirconia by positron annihilation spectroscopy

Garay

Glade

Asoka‐Kumar

et al. 2006

Journal of Applied Physics

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Fully stabilized nanometric zirconia samples with varying degrees of porosity and grain sizes were analyzed using the coincidence Doppler broadening mode of the positron annihilation spectroscopy (PAS). A decrease in the low-momentum fraction was observed and coincided with a decrease in porosity. In addition to pores, it is proposed that defects in the negatively charged grain-boundary space region act as positron trapping centers; their effectiveness decreases with an increase in grain size. It is shown that PAS is sensitive to small grain-size differences within the nanometric regime in these oxide materials.

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Section: B Microstructural Characterizationmentioning

confidence: 99%

Characterization of densified fully stabilized nanometric zirconia by positron annihilation spectroscopy

Garay

Glade

Asoka‐Kumar

et al. 2006

Journal of Applied Physics

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“…In accordance with Wagner, 15,16 the cell edge value was extrapolated by applying a weighted least-square linear fit to the cell edge values calculated from the position of each single reflection as a function of cos cotg. The peak position was obtained using a previously reported best-fitting procedure, 17,18 where each peak is described by a couple of constrained pseudo-Voigt functions (K ␣ 1 and K ␣ 2 profiles͒ and the background by a polynomial function.…”

mentioning

confidence: 99%

Structural Investigation and Anti-Stokes Emission of Scandium Oxide Nanocrystals Activated with Trivalent Erbium

Boyer

Capobianco

Speghini

et al. 2005

J. Electrochem. Soc.

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The structural and emission ͑Stokes and anti-Stokes͒ properties of Sc 2 O 3 :Er 3ϩ nanocrystals doped with 0.1, 1, and 10 mol % Er 3ϩ were investigated. The nanocrystalline powders were characterized using X-ray scattering as well as transmission and scanning electron microscopy. The samples showed a very porous, open microstructure with the particles having a narrow distribution of sizes ͑10-60 nm͒. Furthermore, the mechanisms responsible for the anti-Stokes emission ( exc ϭ 980 nm) were elucidated. We observed that the processes responsible for populating the green ( 2 H 11/2 , 4 S 3/2 ) and red ( 4 F 9/2 ) emitting states were dependent upon the concentration of the dopant ion. In 0.1 mol % nanocrystalline Sc 2 O 3 :Er 3ϩ , upconversion was determined to occur via excited state absorption while in the 10 mol % sample, energy transfer upconversion was the dominant mechanism. The advances in nanoscale preparation techniques present an opportunity for the materials researcher to elucidate the properties of known materials synthesized directly in the nano domain without having to undergo the mechanical grinding techniques associated with conventional syntheses. A multitude of synthesis methods exist to prepare luminescent nanocrystals ranging from the very exotic ͑and expensive͒ to the very simple, involving only a heat source to initiate a combustion reaction.In this paper we study the luminescence ͑anti-Stokes emission, specifically͒ of scandium oxide (Sc 2 O 3 ) nanocrystals prepared by such a simple preparation technique, solution combustion synthesis ͑otherwise known as propellant synthesis͒. The propellant synthesis involves mixing the metal nitrate starting materials with an organic fuel to propagate the combustion reaction.1,2 Large quantities of gases are liberated as by-products of the synthesis reaction, which play a pivotal role by preventing the particle growth. One of the most attractive features of the combustion synthesis is that nanocrystals are produced at relatively low temperatures with reduced processing time. Thus, a high-temperature furnace is not required as the reaction is initiated at temperatures of 500°C or less.3 In a typical reaction the precursor mixture of distilled water, oxidizer, and fuel decomposes, dehydrates, and ruptures into a flame after approximately 5 min creating a voluminous foamy powder. The combustion reaction is influenced by a number of parameters such as type of fuel, fuel-to-oxidizer ratio, use of excess oxidizer, ignition temperature, and water content of the precursor mixture. 4,5The luminescence of nanoparticles has attracted a great deal of interest. In semiconductor nanocrystals for example, quantum size effects result when the size of the particle approaches the Bohr excitonic radius. [6][7][8] This quantum confinement results in an increase in the bandgap that in turn leads to a blue shift in the optical spectrum. 9 In insulating materials such as Y 2 O 3 :Ln 3ϩ , the bandgaps are very large with the electronic energy levels of the dopant ion residing with...

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“…From peakintegrated intensities, H2a was estimated at 32.0(1)% by volume of the total sample and H2b for the remaining. For a similar procedure, see Benedetti et al (1988). (Figures 1 and 2).…”

Section: Experimental Profilesmentioning

confidence: 99%

Determination of Mean Crystallite Dimensions from X-Ray Diffraction Peak Profiles: A Comparative Analysis of Synthetic Hematites

Crosa

1999

Clays and clay miner.

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Abstract--X-ray diffraction (XRD) profile analysis of eight synthetic hematite samples was performed to identify the best parameters for determining the apparent mean crystallite dimension (D) and, consequently, surface area. The samples are comparable to soil hematite with respect to crystallinity. The procedure included: a) deconvolution of the XRD peaks to Gauss and Cauchy components and subtraction of the instrumental profile, b) determination of D from full-width at half-maximum, integral breadth, and integral breadth measurements of the Cauchy component, and c) comparison of deduced surface areas with those obtained by the N2-BET adsorption method. As expected, D values are strongly influenced by the broadening parameters. An appropriate selection of peaks is required to obtain size values along the crystallographic axes a (hkl: 110, 300) and c (hkl: 104, 116) and to calculate reliable surface areas. Using the Cauchy component of the above peaks, the calculated surface areas compared well with those measured by the N2-BET adsorption method.

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A profile-fitting procedure for analysis of broadened X-ray diffraction peaks. II. Application and discussion of the methodology

Cited by 96 publications

References 5 publications

Characterization of densified fully stabilized nanometric zirconia by positron annihilation spectroscopy

Characterization of densified fully stabilized nanometric zirconia by positron annihilation spectroscopy

Structural Investigation and Anti-Stokes Emission of Scandium Oxide Nanocrystals Activated with Trivalent Erbium

Determination of Mean Crystallite Dimensions from X-Ray Diffraction Peak Profiles: A Comparative Analysis of Synthetic Hematites

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