Module 2 : Structure analysis tools

Lecture 3 : Powder diffraction


XRD patterns can be used to determine

• Phase Composition of a sample:
– Quantitative Phase Analysis can determine the relative amounts of phases in a mixture by referencing the relative peak intensities

• Unit cell lattice parameters and Bravais lattice symmetry
– Index peak positions
– Lattice parameters can vary and thereby giving the information about, alloying, doping, solid solutions, strains, etc.

• Residual Strain (macrostrain)

• Crystal Structure – By Rietveld refinement of the entire diffraction pattern

• Epitaxy/Texture/Orientation

• Crystallite Size and Microstrain
– Indicated by peak broadening
– Other defects (stacking faults, etc.) can be measured by analysis of peak shapes and peak width

• The above factors can be also determined as a function of time, temperature, and gas environment in some of the advanced XRD having in-situ heating and controlled atmosphere facilities.