Effect of alkaline earth metal ions R ²⁺ (R = Mg, Ca, Sr, and Ba) on the properties of LiNbO ₃ glass ceramics

Abstract As a functional crystal, LiNbO 3 plays a significant role in nonlinear optics, optical storage, illumination, and three‐dimensional display. Recent investigations have suggested that the precipitation of LiNbO 3 in a nonequilibrium system shows unique crystallite geometry and orientation, leading to fascinating nonlinear optical properties. This work focuses on the effect of alkaline earth metal ions on the properties of Li 2 O–Nb 2 O 5 –SiO 2 glass ceramics. The results demonstrate that within the Li 2 O–Nb 2 O 5 –SiO 2 glass matrix, irregularly shaped crystals of approximately 5 µm in size precipitate through volume crystallization. Upon incorporation of Mg 2+ , the glass ceramic remains in volume crystallization while LiNbO 3 crystals grow to 10 µm and become spherical. In contrast, the compositions containing Ca 2+ , Sr 2+ , and Ba 2+ change to surface crystallization, producing submicron or even nano‐sized crystals. Besides, the nonlinear optical response can be improved after the hybridization of alkaline earth metal oxides. This research offers insights into the crystallization behavior of LiNbO 3 crystals from the nonequilibrium environment.