Al2O3 tailored La0.8Sr0.2FeO3 crystallization in heavy metal oxide glass: Synthesis, structure, and enhanced linear & nonlinear properties

Abstract

Glass containing magnetic nanocrystals are attractive to provide high optical linear and nonlinearity properties. In this study, we reported the synthesis of perovskite La 0.8 Sr 0.2 FeO 3 nanocrystals in heavy metal oxide glass under the Al 2 O 3 tailoring. The influence of Al 2 O 3 amount to the formation of La 0.8 Sr 0.2 FeO 3 nanocrystals and the influence of nanocrystals to glass structure, optical linear& nonlinear properties were thoroughly investigated. The 10 nm-nanocrystals of orthogonal La 0.8 Sr 0.2 FeO 3 were synthesized by melting quenching followed with subsequent crystallization process at 400 °C for 30 min under the tuning of Al 2 O 3 . The formed La 0.8 Sr 0.2 FeO 3 were well distributed in matrix without aggregation. Structure and chemical valence study revealed the aluminum abnormality effect and the Sr 2+ induced multi-valence states of Fe ions and oxygen vacancies in La 0.8 Sr 0.2 FeO 3 lattice. Such modification clearly influenced the optical absorption, 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 Al 2 O 3 tailored La 0.8 Sr 0.2 FeO 3 crystallization to glass. The glass with 10%Al 2 O 3 amount exhibited a large thermal stability (132 °C), low thermal expansion coefficient (10.2 ×10 -6 /K) and high BO 4 /AlO 4 units, providing suitable environment for La 0.8 Sr 0.2 FeO 3 crystallization. About 20 nm nanocrystals were formed and well distributed in glass which contributed to large nonlinearity absorption coefficient (5.19 ×10 −10 m/W) and FOM (13.6 ×10 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. • Synthesis and characterization of La 0.8 Sr 0.2 FeO 3 nanocrystals in PbO-Bi 2 O 3 -B 2 O 3 glass under Al 2 O 3 tailoring. • 10 nm-nanocrystals of orthogonal La 0.8 Sr 0.2 FeO 3 were synthesized at 400 °C for 30 min at 10% Al 2 O 3 . • Sr 2+ induced oxygen vacancy and multi-valence states of Fe ions in lattice increased polarizability. • La 0.8 Sr 0.2 FeO 3 crystallization red shifted optical absorption edge and decreased E g of glass. • Glass with large α 3 (5.19 ×10 −10 m/W) and FOM (13.6 ×10 3 esu) is promising for nonlinear devices.