Figure 7.

Rietveld refinements with X-ray diffraction patterns of STN, measured with (a) the high-resolution MAD and (b) the 2D Perkin Elmer detector in high-resolution mode at a sample detector distance of 2513 mm. The diffraction data reveal two impurity phases: SrNb_0.8Ti_0.2O₃ [1.02 (8)%] and Sr₅Nb₄TiO₁₇ [1.45 (19)%]. The insets show magnifications of a range of individual reflections. The 004 reflection in inset (I) of the high-resolution MAD data reveals an asymmetry, which may result from stacking faults along 00l, which can only be detected with the highest angular resolution and not with the 2D detector as shown in inset (II). Red dots indicate measured intensities, black lines indicate the calculated diffraction pattern from the structure model, blue lines indicate the difference between measured and calculated intensities, and green tick marks indicate reflection positions of the respective phases. λ = 0.2074426 (4) Å.