Rocking Curves & High Resolution Diffraction

Rocking Curves are a useful way to study perfection in thin films and bulk single crystals. By fixing the detector at the center of the expected Bragg reflection and following the diffracted intensity as the sample is independently rotated (or “rocked”), one can gain valuable information. The full width at half maximum intensity (FWHM) is related to the dislocation density in the film and to the curvature of the sample. High Resolution variations of the method also allow us to determine misfit strain, the periodicity in artificial superlattices, the quality of the interfacial region, layer thickness, composition, and degree of mosaicity.

In a similar way, Rocking Curves can also be used to study polycrystalline materials. Key characteristic information that can be obtained are the size of the coherently diffracting domain (sometimes called the “particle” or “grain” size) and the degree of deformation in ductile materials.

Among the many uses are:

  • Film composition and strain
  • Layer thickness
  • Crystalline perfection
  • Dislocation density
  • Misfit strain
  • Superlattice period