XRD – X-Ray Diffraction

X-ray diffraction (XRD) is a nondestructive technique for characterization of the crystalline structure, composition and physical properties of materials. XRD gives information on crystal structure, phase, texture, average grain size, crystallinity, strain, and crystal defects.

How XRD works – a monochromatic X-ray beam illuminates the sample and X-rays are diffracted at specific angles from each set of lattice planes in the sample. The intensities of the peaks are given by the distribution of atoms within the lattice.  The X-ray diffraction pattern is the fingerprint of the periodic arrangements of the atoms atomic in a given material.

Instrumentation Available

Panalytical Empryean X-Ray Diffractometer

Panalytical X’Pert Pro X-Ray Diffractometer

Key Attributes

  • Signal Detected: Diffracted X-rays
  • Elements Detected: All if they are present in a crystalline matrix
  • Detection Limits: ~1%
  • External standard quantitative analysis: ~0.1%
  • Minimum film thickness for phase identification: ~20Å
  • Sampling depth between ~20Å to ~30µm, depends on material properties and X-ray incidence angle
  • Probe Size: Point focus: 0.1mm to 0.5mm; Line focus 2mm to 12 mm; Microdiffraction to ~20µm

Strengths

  • Nondestructive
  • Performs quantitative measurement of phase and texture
  • Minimal/no sample preparation
  • No vacuum required
  • Can analyze powers, bulk samples or thin films

Limitations

  • Does not work on amorphous materials
  • No in-depth information
  • Poor lateral resolution due to large spot size of ~20µm

Applications

  • Phase identification on bulk and thin-film samples
  • Detection of  minor crystalline phases
  • Determination of grain size for polycrystalline films and materials
  • Determination of percentage crystalline form versus amorphous in materials
  • Measurement of powder samples for phase identification
  • Analysis of films as thin as 50Å for texture and phase
  • Determination of strain and composition in epitaxial thin films
  • Determination of surface off-cut in single crystal materials
  • Measurement of residual stress in bulk metals and ceramics

Additional Reading

XRD-Technique XRD - X-Ray Diffraction