An anisotropic line broadening study of CuO is reported. X-ray powder diffraction line width modifications observed are modeled when comparing data coming from (1) commercial analytical grade CuO, (2) energetic ball milling sample for 1 h, and (3) samples prepared by thermally annealing the ball milled sample at various temperatures. X-ray powder diffraction data from commercial and produced samples were analyzed by the Rietveld method using a pseudo-Voigt function. Different assumptions including size and strain anisotropy were tried to improve pattern fitting. An anisotropic strain broadening, modeled using Stephens’ approximation, yielded the best fit, thus indicating that strain anisotropy is the main source of the departure from a smooth function of line broadening as a function of 2θ observed in all samples.
