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The features of nanodomain growth during local switching in X-cut lithium niobate on insulator (LNOI) were comprehensively studied using the biased tip of a scanning probe microscope. The obtained results were discussed in terms of the kinetic approach. The revealed differences in domain growth in bulk LN and LNOI were attributed to the higher bulk conductivity of LNOI. The obtained influence of humidity on the shape and growth of isolated domains was attributed to the water meniscus. Analysis of the transition between the "forward growth" and "sideways growth" stages was performed by switching to the stripe electrode. A sand-glass-shaped domain was formed due to growth in the opposite direction after the domain touched the electrode. Stable periodical domain structures down to 300 nm were created and characterized in LNOI. Highly ordered comb-like domains of various alternating lengths, including four- and eight-fold increase periods, were produced by performing biased tip scanning along the Y axis. The obtained knowledge is important for the future development of nanodomain engineering methods in monocrystalline ferroelectric thin films on insulators. [ABSTRACT FROM AUTHOR]

The increase of the domain shape dimensionality from one-dimensional (1D) to two-dimensional (2D) representing creation of the magnetic bubbles by application of the uniform magnetic field to the stripe domain structure is a well-known effect used for the magnetic memory. The analogy between ferromagnetic and ferroelectric domains stimulates a search of a similar effect in ferroelectrics. Here, we present the discovered 1D to 2D transformation of the domain shape under the action of pyroelectric field appeared in lithium niobate crystal as a result of irradiation by IR laser pulses. The imaging at the surface reveals the transformation of the stripe domains appeared after the first pulse into the regular arrays of isolated circular domains after the second pulse, whereas the imaging in the bulk reveals the transformation of the comb-like domain to array of isolated conical domains. The process was considered in terms of the kinetic approach. The mechanism of the comb-like domain formation by continuous tooth generation during domain elongation is proposed. The 1D to 2D transformation is attributed to the domain splitting due to the backward motion of the charged domain wall. The proposed mechanisms are confirmed by computer simulation of the temporal dependence of the pyroelectric field excess over the threshold value. [Display omitted] [ABSTRACT FROM AUTHOR]