Anisotropic microstrain broadening of minium, Pb₃O₄, in a high-pressure cell: interpretation of line-width parameters in terms of stress variations

The diffraction-line broadening exhibited by three different Pb₃O₄ phases was studied at ambient and elevated pressures. The broadening indicates strongly anisotropic microstrain, which was interpreted in terms of (local) stress variations in association with strongly anisotropic elastic properties.

Parametric Rietveld refinement for the evaluation of powder diffraction patterns collected as a function of pressure

Parametric Rietveld refinement is extended to variable-pressure powder diffraction data. Different approaches to parameterization are described and compared.