Fractal Structures in Single Crystals of Ferroelectric Lithium Niobate Grown Under Strongly Unstable Conditions

Abstract

Atomic force microscopy studies of lithium niobate single crystals containing heterogeneously distributed lanthanide (Gd) admixture and a regular domain structure of 100 nm to 1 µm steps obtained under conditions of severe thermal instability have revealed fractal structures of the size of 10 to 100 nm within regions of the regular domain structures. A super-structure of clustered defects with 1-2 nm steps explaining results of Raman spectra analysis is supposed to exist in the cation sub-lattice and formation of periodic fractal structures of the size of ∼1 nm-100 µm is suggested to take place in lithium niobate single crystals containing lanthanide admixture.