Figure 2: Rietveld refinement of the XRD patterns of as-mixed CuO : Fe2O3 (2%) (a) and that sintered at 900°C/12h in air (b). The open circles indicate the observed pattern, and the overlying continuous line represents the calculated pattern. The vertical lines indicate the peak position of the respective phases. The bottom continuous line of each pattern represents the difference between the observed and calculated (Obs-Cal) patterns.