Powder diffraction is a technique used to study the crystallographic structure of materials.
The Powder Diffraction beamline is located on a bending magnet source and has been designed to operate over the energy range 8-21 keV. The beamline consists of two experimental hutches and a user cabin. Experimental hutch one is designed for sample capillary analysis, and experimental hutch two is for specialised user setups, and those requiring a 2D detector.
The range of studies that may be carried out at the Powder Diffraction beamline includes:
- Ab initio structure solution
- In situ examination of chemical and mineralogical processes
- Structure/property studies
- Parametric studies, including variable temperature
- Phase identification and quantification
- Pair distribution function analysis
- Line profile analysis
- Examination of stress and strain
Synchrotron Powder Diffraction
Laboratory-based powder diffraction techniques are inherently resolution-limited in the range of observations (d-space range), the signal-to-noise ratio, and the shape and width of observed reflections. Synchrotron-based instruments are the only way to overcome these limitations and give the resolution required to determine and refine accurate structures of even moderately complex materials from powder samples. In addition, synchrotron measurements can be made on a 'real' time scale allowing observation of chemical processes.
Advantages of Synchrotron Radiation:
- Improved signal to noise ratio
- Very fast data acquisition
High angular and energy resolution
- Large, accessible dynamic d-space range
- Narrower peak width and simpler shape
Tunable, monochromatic X-rays
- Flexibility in experimental set-up
- Ability to avoid or exploit absorption edges
- Hard x-rays penetrate bulky sample cells
The powder diffraction beamline carries out studies in a broad range of fields including:
To develop new materials and develop existing technologies for energy applications, it is essential to understand the structural properties that govern a materials performance. Batteries are one solution to existing non-renewable energy sources. The most common type is lithium ion (LIB) battery, which rely on lithium moving from the anode through an electrolyte to the cathode during discharge, and from the cathode to anode during charging. Operando studies, where data is obtained while the battery is charged and discharged, offer the best opportunity to establish structure-property relationships. The resolution and rapid data collection offered by a synchrotron source is the only way the small structural changes that occur over very short time scales can be observed.
High voltage structural evolution and enhanced Na-ion diffusion in P2-Na2/3Ni1/3xMgxMn2/3O2 (0 ≤ x ≤ 0.2) cathodes from diffraction, electrochemical and ab initio studies. N. Tapia-Ruiz, W. M. Dose, N. Sharma, H. Chen, J. Heath, J. W. Somerville, U. Maitra, M. S. Islam and P. G. Bruce (2018). Energy & Environmental Science 11: 1470-1479.
Achieving high-performance room-temperature sodium-sulfur batteries with S@interconnected mesoporous carbon hollow nanospheres. Y. X. Wang, J. Yang, W. Lai, S. L. Chou, Q. F. Gu, H. K. Liu, D. Zhao, S. X. Dou (2016). Journal of the American Chemical Society 138, 16576-16579.
Condensed matter science
The majority of advanced materials used in magnetic, conductivity, superconductivity and ferroelectric applications are solid metal oxides. Metal oxide chemistry is dominated by classes of materials having crystal structures derived from simpler parent structures such as perovskite or rutile. Small lattice distortions, which are critical to the key electronic and physical properties of these oxides, usually lead to lower symmetries and superstructures. These distortions are characterised by subtle peak splittings and the appearance of weak superlattice reflections in diffraction data. The detection and understanding of such distortions requires the high resolution afforded by synchrotron radiation.
Subpicometer-scale atomic displacements and magnetic properties in the oxygen-isotope substituted multiferroic DyMnO3. N. Narayanan, P. J. Graham, N. Reynolds, F. Li, P. Rovillain, J. Hester, J. Kimpton, M. Yethiraj, G. J. McIntyre, W. D. Hutchison and C. Ulrich (2017). Physical Review B 95(7): 075154.
Structure and magnetism in Sr1−xAxTcO3 perovskites: Importance of the A-site cation. E. Reynolds, M. Avdeev, G. J. Thorogood, F. Poineau, K. R. Czerwinski, J. A. Kimpton, M. Yu, P. Kayser and B. J. Kennedy (2017). Physical Review B 95(5): 054430.
Earth and environment
Powder diffraction has been applied widely for analysis in the mineral processing industries and earth sciences. Due to the high mineralogical complexity of these materials, high peak resolution and peak-to-background ratios are required for full and accurate characterisation. The synchrotron-based powder diffraction technique provides the inherent high resolution, high sensitivity and high speed capability that is critical in such studies. This high speed capability can also be used in studies where the sample environment emulates the processing conditions found in industry. The availability of a range of sample environments, including high temperatures and pressures, are a key feature of this beamline.
In situ synchrotron powder diffraction studies of reduction–oxidation (redox) behavior of iron ores and ilmenite. A. Y. Ilyushechkin, M. Kochanek, L. Tang and S. Lim (2017). Metallurgical and Materials Transactions B 48(2): 1400-1408.
Ancient micrometeorites suggestive of an oxygen-rich Archaean upper atmosphere. A. G. Tomkins, L. Bowlt, M. Genge, S. A. Wilson, H. E. A. Brand and J. L. Wykes (2016). Nature 533: 235-238.
Powder diffraction has important applications in mechanical engineering, particularly in detecting phases that degrade the material properties and determining microstrain and grain size. These materials include protective coatings (e.g. thermal barrier coatings), layered ceramics and surface engineering treatments. Determining the origin of mechanical component degradation is essential to evaluate performance and can be achieved through experiments employing flat-plate asymmetric geometries. As the materials properties may also be altered by temperature, in situ experiments can be used to evaluate performance as a function of temperature. Success here requires rapid data collection, which is only possible on a synchrotron radiation source.
Failure mechanisms of calcium magnesium aluminum silicate affected thermal barrier coatings. Thornton, J., C. Wood, J. A. Kimpton, M. Sesso, M. Zonneveldt and N. Armstrong (2017). Journal of the American Ceramic Society 100(6): 2679-2689.
Experimental and predicted mechanical properties of Cr1−xAIxN thin films, at high temperatures, incorporating in situ synchrotron radiation X-ray diffraction and computational modelling. Mohammadpour, E., Z.-T. Jiang, M. Altarawneh, N. Mondinos, M. M. Rahman, H. N. Lim, N. M. Huang, Z. Xie, Z.-f. Zhou and B. Z. Dlugogorski (2017). RSC Advances 7(36): 22094-22104.
Microporous and framework materials
Detailed knowledge of the crystal structure of microporous materials including zeolite, metal organic frameworks (MOFs) and coordination framework solids is required in order to understand their properties and improve their use of catalysts, sorbants and micro-reactors. These materials typically have large unit cells and it is common to observe complex patterns because of low symmetry or subtle distortions. In many cases a very high X-ray flux, as delivered by a synchrotron source and the ability to access low d-spacings, is the only way these problems can be studied.
Temperature-regulated guest admission and release in microporous materials. G. Li, J. Shang, Q. Gu, R. V. Awati, N. Jensen, A. Grant, X. Zhang, D. S. Sholl, J. Z. Liu, P. A. Webley and E. F. May (2017). Nature Communications 8: 15777.
Highly active catalyst for CO2 methanation derived from a metal organic framework template. R. Lippi, S. C. Howard, H. Barron, C. D. Easton, I. C. Madsen, L. J. Waddington, C. Vogt, M. R. Hill, C. J. Sumby, C. J. Doonan and D. F. Kennedy (2017). Journal of Materials Chemistry A 5: 12990-12997.