Electron diffraction characterization of nanocrystalline materials using a Rietveld-based approach. Part I. Methodology
Open Access
- 1 August 2022
- journal article
- research article
- Published by International Union of Crystallography (IUCr) in Journal of Applied Crystallography
- Vol. 55 (4), 953-965
- https://doi.org/10.1107/s1600576722006367
Abstract
Transmission electron microscopy is a powerful experimental tool, very effective for the complete characterization of nanocrystalline materials by employing a combination of imaging, spectroscopy and diffraction techniques. Electron powder diffraction (EPD) pattern fingerprinting in association with chemical information from spectroscopy can be used to deduce the identity of the crystalline phases. Furthermore, EPD has similar potential to X-ray powder diffraction (XRPD) for extracting additional information regarding material specimens, such as microstructural features and defect structures. The aim of this paper is to extend a full-pattern fitting procedure, broadly used for analysing XRPD patterns, to EPD. The interest of this approach is twofold: in the first place, the relatively short times involved with data acquisition allow one to speed up the characterization procedures. This is a particularly interesting aspect in the case of metastable structures or kinetics studies. Moreover, the reduced sampling volumes involved with electron diffraction analyses can better reveal surface alteration layers in the analysed specimen which might be completely overlooked by conventional bulk techniques. The first step forward to have an effective application of the proposed methodology concerns establishing a reliable calibration protocol to take into correct account the instrumental effects and thus separate them from those determined by the structure, microstructure and texture of the analysed samples. In this paper, the methodology for determining the instrumental broadening of the diffraction lines is demonstrated through a full quantitative analysis based on the Rietveld refinement of the EPD. In this regard, a CeO2 nanopowder reference specimen has been used. The results provide indications also on the specific features that a good calibration standard should have.Keywords
Funding Information
- Ministero dell'Istruzione, dell'Università e della Ricerca
This publication has 50 references indexed in Scilit:
- Application of theta-scan precession electron diffraction to structure analysis of hydroxyapatite nanopowderMicroscopy, 2011
- Pitfalls in the characterization of nanoporous and nanosized materialsNanoscale, 2011
- Ultrastructural Analysis of Vascular Calcifications in UremiaJournal of the American Society of Nephrology, 2010
- Comparison methods of variance and line profile analysis for the evaluation of microstructures of materialsPowder Diffraction, 2008
- The Study of Nanovolumes of Amorphous Materials Using Electron ScatteringAnnual Review of Materials Research, 2007
- Lattice parameter measurement using Le Bail versus structural (Rietveld) refinement: A caution for complex, low symmetry systemsPowder Diffraction, 2005
- Electron diffraction using transmission electron microscopyJournal of Research of the National Institute of Standards and Technology, 2001
- A transmission electron microscope (TEM) calibration standard sample for all magnification, camera constant, and image/diffraction pattern rotation calibrationsMicroscopy Research and Technique, 1995
- Choice of collimators for a crystal spectrometer for neutron diffractionNuclear Instruments, 1958
- On the intensities of electron diffraction ringsProceedings of the Royal Society of London. Series A - Mathematical and Physical Sciences, 1939