Highly anisotropic domain growth in polydomain triglycine sulfate under biased SPM tip
2Department of Applied Physics, Tver State University, Tver, Russia
In this work we have studied the current limited wall motion regime driven by anisotropic bulk screening processes during local switching in polydomain triglycine sulfate (TGS) single crystals.
The initial TGS domain structure appeared after thermal depolarization consisted of 5-μm-wide stripe domains and short narrow domains of submicron width. The field application using a conductive tip of a scanning probe microscope (SPM) in a dry atmosphere resulted in formation of partially switched area, strongly elongated in c crystallographic direction.1 At the same time, switching at high humidity led to a circular shape of the area.1 The calculation of external field spatial distribution demonstrated the possibility of domain wall shift at the distances up to hundreds of microns from the SPM tip. However, after external field switch-off the depolarization field in non-screened areas led to reverse domain wall motion. Thus, the domain wall stabilization is possible only in the regions with sufficient screening of the depolarization field. We have shown that the growth of the area size with time obeys the same current limited wall motion expressions that were derived previously for domain growth during local switching by a highly-resistive electrode.2 The change in the area shape with humidity was attributed to the change in the governing screening mechanism from anisotropic bulk conductivity to isotropic surface conductivity through an adsorbed water layer. The obtained results demonstrate the essential role of screening processes during periodical poling and pave the way for further improvement of the domain engineering methods.
The research was made possible by the Russian Science Foundation (Project No. 21-72-10160). The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University (Reg.№ 2968) was used.
1 A.P. Turygin, et al, ACS Appl. Electron. Mater., in press (doi: 10.1021/acsaelm.2c00891).
2 L.J. McGilly, et al, Nat. Nanotechnol 10, 145 (2015).
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