Al3O4 tailored La0.8Sr0.2FeO3 crystallization in heavy metal oxide glass: synthesis, structure, and enhanced linear & nonlinear properties

Glass containing magnetic nanocrystals are attractive to provide high optical linear and nonlinearity properties. In this study, we reported the synthesis of perovskite La0.8Sr0.2FeO3 nanocrystals in heavy metal oxide glass under the AlO3 tailoring. The influence of AlO3 amount to the formation of La0.8Sr0.2FeO3 nanocrystals and the influence of nanocrystals to glass structure, optical linear& nonlinear properties were thoroughly investigated. The 10 nm-nanocrystals of orthogonal La0.8Sr0.2FeO3 were synthesized by melting quenching followed with subsequent crystallization process at 400 degrees for 30 min under the tuning of AlO3. The formed La0.8Sr0.2FeO3 were well distributed in matrix without aggregation. Structure and chemical valence study revealed the aluminum abnormality effect and the Sr2+ induced multi-valence states of Fe ions and oxygen vacancies in La0.8Sr0.2FeO3 lattice. Such modification clearly influenced the optical ab-sorption, refractive index, polarizability, energy band gap shrinkage and nonlinearity. Physical parameters such as oxygen packing density, free volume etc. were calculated to confirm the influence of AlO3 tailored La0.8Sr0.2FeO3 crystallization to glass. The glass with 10%AlO3 amount exhibited a large thermal stability (132 degrees), low thermal expansion coefficient (10.2 x10(-6)/K) and high BO4/AlO4 units, providing suitable environment for La0.8Sr0.2FeO3 crystallization. About 20 nm nanocrystals were formed and well distributed in glass which contributed to large nonlinearity absorption coefficient (5.19 x10(-10) m/W) and FOM (13.6 x10(3) esu cm) which much superior than from relative literatures. The obtained glass with extremely good optical linear and nonlinearity performances can be promising candidate for photonics device applications. (C) 2022 Elsevier B.V. All rights reserved.