Figure 5: The domain switching kinetics under e− beam-induced poling.
From: Domain topology and domain switching kinetics in a hybrid improper ferroelectric
In-plane DF-TEM images and schematics of domain structures in a CSTO crystal under different directions of induced electric field indicated by red arrows. Coloured arrows and domains represent polarization directions and FE domain states, respectively. Scale bar, 200 nm. (a–e) Image sequences showing a Z3 vortex-antivortex (V-AV) pair evolution during in-situ poling within a single ferroelastic domain. (a,b) The initial state. (c,d) The states during the charge dissipation process after defocusing electron beam. (e) The final state. With a focused electron beam at the sample edge, a direct 180° polarization reversal is observed (4−→4+) via V-AV pair creation (a–c), and the created domain disappears slowly with charge dissipation, which accompanies V-AV pair annihilation (c–e). Cyan and blue circles denote Z3 vortices and antivortices, respectively. A black arrowhead is the location marker. (f) Schematic showing the 180° ferroelectric polarization switching via splitting or coalescence of a APB into two ferroelectric walls: APB (green line)→FEt (red-solid)+FEr (red-dotted) DWs. (g,h) Image sequences and schematics showing 90° ferroelectric domain switching near a APB (green line). (g) The initial state. (h) The immediate image after electron beam focused at the sample edge away from the FA boundary (solid blue line). Only 90° poled domains (dark contrast) are observed (2−→3− and 4+→1+). The 90° poled domains are assigned with the rotation order parameter same with those of the initial domains, which is consistent with the low-energy nature of FAt DW. The induced 3− (pink) and 1+ (red) domains return slowly to the initial 2− (light yellow) and 4+ (yellow) states with charge dissipation. (i) Schematic showing a 90° ferroelectric polarization switching within a FA domain via splitting or coalescence of a APB into two ferroelastic walls: APB → FAtr (blue-solid)+FAt (blue-dotted) DWs. Emphasize that there is no hint of the presence of any intermediate states corresponding to 90°polarization reversal during this process.
