Fluctuation X-ray microscopy: a novel approach for the structural study of disordered materials

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Disordered materials present challenges in structural analysis, particularly for medium-range order.
• Quantifying medium-range correlations is crucial for understanding material properties.

Purpose of the Study:

• To develop and demonstrate a novel technique for measuring medium-range order in disordered materials.
• To establish fluctuation X-ray microscopy as a viable method for structural correlation length determination.

Main Methods:

• Utilized fluctuation X-ray microscopy with a spatially coherent X-ray beam.
• Measured speckle patterns at multiple sample locations with varying illumination sizes.
• Analyzed speckle variance as a function of illumination spot size to extract correlation length.

Main Results:

• Successfully measured the structural correlation length in polystyrene latex spheres, a model for dense random-packed glass.
• Demonstrated the quantitative capability of fluctuation X-ray microscopy for disordered systems.
• Addressed data analysis challenges, including corrections for shot and detector noise.

Conclusions:

• Fluctuation X-ray microscopy provides quantitative insight into medium-range correlations at nanometre scales and larger.
• This technique holds potential for studying diverse disordered materials, including soft matter and nanomaterials.
• Enables exploration of subtle spatial structural changes in materials.