Determination of the degree of preferred orientation within the March-Dollase approach

An analytic expression has been derived connecting the degree of preferred orientation in a polycrystalline material to the March parameter. The latter defines the spread of angular distribution of crystallite inclinations in the March-Dollase approach [March (1932). Z. Kristallogr. 81, 285-297; Dollase (1986). J. Appl. Cryst. 19, 267-272]. In turn, the March parameter can be extracted from experimental data using either the Rietveld refinement of the entire diffraction pattern or the measurement of two diffraction intensities originating in the selected crystallographic planes. Working examples taken with two different types of samples are presented.