Microstrain-like diffraction-line broadening as exhibited by incommensurate phases in powder diffraction patterns

Variations of lattice and modulation parameters of an incommensurately modulated phase as well as the resulting line broadening arising in powder diffraction patterns were theoretically analysed. The resulting line broadening is in principle microstrain-like. For the case that only the modulation parameters vary, only the satellite reflections are broadened, and for constant-order satellite reflections, the line broadening can then be regarded as size-like.