Extended Data Fig. 7: 90°-reconfiguration of SrFeO2.5 [100] ahead of advancing phase boundary.
![Extended Data Fig. 7: 90°-reconfiguration of SrFeO2.5 [100] ahead of advancing phase boundary.](http://media.springernature.com/full/springer-static/esm/art%3A10.1038%2Fs41557-024-01617-7/MediaObjects/41557_2024_1617_Fig11_ESM.jpg)
a, Time sequence HRTEM images showing the phase transformation of SrFeO2.5 [100] to SrFeO2 [110]. White dashed line in each image indicates the phase boundary. b, Magnified images of the phase boundary outlined yellow in a. The structural features inherent to the SrFeO2.5 [010] appeared as a consequence of 90°-reconfiguration, that is, the AFD rotation (β ~±7°) of FeO6 in the octahedral layers and the VO channels (δFe-Fe = 3.9 Å) in the tetrahedral layers. c, Interlayer d-spacing map of the strontium layers, dSr-Sr, for phase identification. Alternating red (tetrahedral layers) and blue (octahedral layers) stripes correspond to SrFeO2.5 while uniform blue region corresponds to SrFeO2 phase. d, Intralayer Fe-Fe distance δFe-Fe map visualizing the normally aligned VO channels. The chequerboard pattern appearing in the SrFeO2.5 [100] ahead of moving phase boundary indicates 90°-reconfiguration which brings the laterally aligned VO channels to the normally aligned one. Uniform green color far below the phase boundary indicates the pristine SrFeO2.5 [100] without reorientation.