90° Rotation of orbital stripes in bilayer manganite PrCa2Mn2O7 studied by in situ transmission electron microscopy

We present an in situ transmission electron microscopy study on the half-doped bilayer manganite PrCa2Mn2O7 to reveal the rotation process of the orbital stripes. Between the reported initial and final ordering phases, we identified an intermediate state with two sets of satellite spots to bridge the 90° rotation of the orbital stripes. Furthermore, we determined that the rotation of the orbital stripes does not always occur. Some restricted conditions for the orbital rotation to occur were found and reasons are discussed.

Graphical abstractThe intermediate state of the thermally induced 90° rotation of orbital stripes between two charge/orbital ordering CO1 and CO2 phase in the bilayer manganite PrCa2Mn2O7 is revealed by in situ TEM. A new state with two sets of satellite spots in the [001] electron diffraction patterns is found to bridge this transition. The reasons to this transition are explained. Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Intermediate states to bridge the 90° rotation of the orbital stripes in bilayer manganite PrCa2Mn2O7 were identified. ► Some restricted conditions for the orbital rotation to occur were found and reasons were discussed. ► The reported CO2 phase at high temperatures in PrCa2Mn2O7 can also exist at room temperature.