Figure 2

(a–d) Synchrotron X-ray diffraction images and the corresponding Rietveld structure refinement plots for the melt quench Gd2Zr2O7 at different temperatures. The inner pyrochlore ring (111) fades during heating at 673–1873K, completely disappears at 2573 K (a–c), then reappears during cooling (d), confirming reversible order–disorder phase transformation.