XRD analysis of the initial La/Ce-free and La/Ce-rich components. Rietveld refinement of step-scanned XRD patterns for (a) La/Ce-free powder I and (c) La/Ce-rich powder II (La–Ce/TRE = 30 wt.%) at room temperature. Experimental pattern, calculated pattern, and their differences are shown in black, red, and blue colors, respectively. The difference pattern in each curve indicates a good matching between the calculated and experimental values. The enlarged XRD patterns of 2θ between 32° and 38° are shown in (b) and (d), respectively. Bottom ticks in (e) mark the characteristic Bragg positions of the RE₂Fe₁₄B/RE-rich phase, and serve as a guide to the eye.^[22]